Our codes

AFCEN’s design and construction codes are generally prefixed with RCC-, while the in-service code is prefixed with RSE-.

In some cases, codes can only be used on the EPR design, in which case the code is prefixed with ETC-. This prefix is likely to be superseded by RCC-.

AFCEN currently publishes seven codes, including 6 RCC- codes and one RSE- code.

Nos codes

Codes updates

There are several reasons for updating AFCEN codes: the need to incorporate feedback, R&D work, changes to legislation and standards, and extension of the subject matter covered by the codes.

Incorporation of feedback

Incorporating feedback is a major reason for updating codes. Several examples will be provided in the following sections which describe each of the codes, but one notable example is the change to the “Liner” chapter in the RCC-CW code to reflect feedback from the Flamanville 3 plant.

New developments, scientific breakthroughs and R&D work

These also represent major reasons for updating the codes.

For example, the 2016 edition of the RSE-M code has been updated to describe the loading history effect on the resistance to the cleavage brittle fracture of RPV steel by taking account of the warm pre-stressing phenomenon (WPS) as well as the associated criteria that were proposed and which are currently being defined within a probationary phase rule (RPP).

To drive the continual improvement process, AFCEN is involved in a R&D focus group on a European level for three codes (RCC-M, RCC-CW and RCC-MRx), with the aim of producing proposals for Gen II-III mechanical engineering, Gen IV mechanical engineering and civil engineering works.

Regulatory changes

Changes to regulations in the various countries in which the codes are used constitute a major reason for updating the codes.

For example, efforts are being made to ensure that the mechanical codes can be applied to guarantee compatibility with the essential safety requirements of French regulations governing nuclear pressure equipment (ESPN Regulation).

Depending on the type of change, regulatory-related modifications are either introduced into the body of the text or as an appendix specific to the country in question.

For instance, AFCEN’s work on France’s Nuclear Pressure Equipment Regulation will either lead to modifications to the body of the code (such as the toughness of low-thickness materials), or the creation of a French appendix.

Changes in standards

AFCEN codes are updated to reflect changes to the standards on which they are based. ISO international standards are the first to be called when available. Otherwise, European EN standards are used.

AFCEN regularly analyzes the standards to determine whether any revisions have been made and updates the codes accordingly (see Section 3.1).

For example, RCC-M was updated in 2014 to introduce the new ISO 9712 standard for the qualification of non-destructive testing personnel, while the 2016 edition of RCC-CW incorporates the recent changes to EN 1992-4.

Extensions of the subject matter

AFCEN codes may be revised if the subject matter is extended.

One example is the future inclusion of a new chapter in the 2017 edition of RCC-M to cover the qualification of mechanical components under accidental conditions.



RCC-M : Design and construction rules for mechanical components of PWR nuclear islands

Purpose and scope

AFCEN’s RCC-M code concerns the mechanical components designed and manufactured for pressurized water reactors (PWR).

It applies to pressure equipment in nuclear islands in safety classes 1, 2 and 3, and certain non-pressure components, such as vessel internals, supporting structures for safety class components, storage tanks and containment penetrations.

RCC-M covers the following technical subjects:

  • sizing and design rating,
  • choice of materials and procurement.
  • fabrication and control, including:
    • associated qualification requirements (procedures, welders and operators, etc.),
    • control methods to be implemented,
    • acceptance criteria for detected defects,
    • documentation associated with the different activities covered, and quality assurance.

The design, manufacture and inspection rules defined in RCC-M leverage the results of the research and development work pioneered in France, Europe and worldwide, and which have been successfully used by industry to design and build PWR nuclear islands. AFCEN’s rules incorporate the resulting feedback.

Use and background


The RCC-M code has been used or served as a baseline for the design and/or fabrication of some Class 1 components (vessels, internals, steam generators, primary motor pump units, pressurizers, primary valves and fittings, etc.), as well as Class 2 and 3 components for:

  • France’s last 16 nuclear units (P’4 and N4).
  • 4 CP1 reactors in South Africa (2) and Korea (2).
  • 44 M310 (4), CPR-1000 (28), CPR-600 (6), HPR-1000 (4) and EPR (2) reactors in service or undergoing construction in China.
  • 4 EPR reactors in Europe: Finland (1), France (1) and UK (2).


AFCEN drafted the first edition of the code in January 1980 for application to France’s second set of four-loop reactors with a power rating of 1,300 MWe (P’4).

Export requirements (Korea, China and South Africa) and the need to simplify contractual relations between operators and building contractors quickly prompted the code to be translated and used in English, followed by Chinese and Russian.

Subsequently, the code was thoroughly updated and modified to reflect the feedback from France’s nuclear industry, as well as through regular interactions with international stakeholders. Six editions ensued (1981, 1983, 1985, 1988, 1993 and 2000) with a number of addenda between each edition.

The 2007 edition took account of changes to European and French regulations (Pressure Equipment Directive 97/23/EC and France’s Nuclear Pressure Equipment Regulation), with the harmonized European standards that were subsequently released.

To date, the 2007 edition is widely used in France and China for EPR projects and replacement steam generators.

The 2012 edition, with three addenda in 2013, 2014 and 2015, incorporated initial feedback from EPR projects. The 2013 addendum also included Probationary Phase Rules (RPP) as a way of providing an alternative set of rules in cases where industry feedback has not been sufficiently consolidated for permanent inclusion in the code.

The new information incorporated into the 2016 edition includes the first series of changes resulting from the commissioned studies into the ESPN Regulation (see Section 2.2.5).

Edition available as of early 2018

The 2017 edition is the most recent version of the code. It integrates 36 modification files.

This edition features two significant changes, such as:

  • The introduction of a new "Q" subsection in the Probationary Phase Rules (RPP4) to cover the qualification of active mechanical components. Work began on developing this subsection in 2014 with the creation of a new drafting group within the RCC-M Subcommittee to address the functional qualification of active mechanical components (valves and pumps) in close liaison with the RCC-E Subcommittee. The scope of the code, which is currently restricted to the integrity of pressure-bearing structures, is being broadened to encompass the operability and functionality of so-called "active" mechanical components. The first edition of the Q subsection is restricted to pumps and valves.
  • The introduction of a new ZC appendix with details on how to perform non-linear mechanical analyses for verifying design criteria. This non-mandatory appendix provides recommendations for carrying out and exploiting non-linear finite element analyses for dealing with excessive deformation damage, plastic instability, fatigue and fast fracture. This edition does not address progressive deformation.

RCC-M 2017


Next editions

In accordance with the new sales model, AFCEN will now publish annual editions instead of addenda.

The 2018 edition will incorporate a significant change in the code, since it will be compatible with all the findings from the commissioned studies related to the Nuclear Pressure Equipment Regulation. Those findings will be worked into the body of the code, featured in a specific appendix for France or described in technical publications.

This edition, along with its specific appendix and technical publications, will enable French industry to address the requirements of the new Nuclear Pressure Equipment Regulation of December 30, 2015.

The new 2018 edition of the code will also incorporate the feedback on the code’s use in current projects (EPR UK, TSN, FA3, replacement steam generators) and on the results of the studies of international groups (UK, China, Europe and MDEP), which are monitored by ASN.

Publication of interpretation requests

The RCC-M Subcommittee decided to publish the interpretation requests relating to the 2007 and 2012 editions of the RCC-M code and its addenda. This publication is presented as a compilation of anonymous interpretation requests arranged by edition and topic.

RCC-M users can download this document free of charge from the AFCEN website.

The scope of this publication will be extended in 2018.

Proof of compliance with the PED Directive / France’s Nuclear Pressure Equipment Regulation

The Editorial Committee has launched 17 working groups to demonstrate how the RCC-M code can be used to meet the essential safety and radiation protection requirements stipulated in France’s Nuclear Pressure Equipment Regulation and the European PED Directive.

These groups have the following missions:

  • risk analyses,
  • inspectability and vulnerability criteria,
  • uncertainties and safety factors,)
  • the dimensions required to ensure conformity with requirements,
  • fatigue damage,
  • specific evaluations for nuclear components,
  • toughness of low-thickness materials,
  • unacceptable defects (including defects beneath the cladding and sequential penetration),
  • visual inspections during fabrication,
  • proof of compliance with essential safety and radiation protection requirements,
  • definition of a component’s admissible limits,
  • instructions manual,
  • fabrication of assemblies,
  • developments in technologies and practices,
  • safety devices and pressure accessories,
  • technical qualification,
  • code compliance for N2 and N3 equipment.

The mission facing the last group is to extend the previous topics to encompass N2 and N3 equipment, since work initially focused on N1 equipment. The group began to work late 2015 and features AFCEN members who manufacture N2 and N3 equipment in order to draw on their feedback and deliver an appropriate and graded response for this type of equipment compared to the responses provided for N1 equipment.

The groups’ findings were published in 2016 as:

  • Generic modifications introduced into the body of the code.
  • Modifications specific to French regulations and introduced in non-generic appendices ZY and ZZ exclusively for France.
  • Technical publications in the form of guides and criteria.

The aim of the working groups is to produce all the requested changes and evidence to ensure that the 2018 edition of RCC-M conforms to the requirements of France’s Nuclear Pressure Equipment Regulation (« three-year program »).

By the end of 2017, the program had progressed according to the anticipated schedule. ASN has already formally endorsed three topics for N1 equipment (risk analysis, instructions manual and sizing standard). ASN has responded positively to the prospect of granting its full endorsement: "by the end of the three-year program and provided that the program has been carried out correctly, formal endorsement for all the topics covered will be granted when ASN can no longer identify any areas within RCC-M 2018 that fail to comply with regulatory requirements" (Nuclear Valley conference in November 2017).

In addition to the three-year program, AFCEN is also looking into the prospect of:

  • creating an oversight group to update the standard following changes to the regulation over time and thereby maintain official endorsement,
  • ensuring that the standard is sufficiently stable for implementation in projects. The next step in the ESPN Regulation may involve the possibility of submitting a safety options dossier for N1 equipment to ASN for review and subsequent advisory. The same objective is being pursued for N2/N3 equipment while taking account of the specific challenges involved (especially relating to volume).

Preparation of future changes to the code

In addition to the ESPN program, several focus groups have been set up since 2015 to pave the way for the code’s significant changes:

  • Appendix ZC addressing non-linear finite element analyses was prepared by 14 experts from 7 member companies and incorporated in the 2017 edition. However, this appendix does not cover progressive deformation damage. The appendix is therefore being revised to include this type of damage.
  • A working group comprising 18 experts from nine companies is currently carrying out a complete overhaul of the design rules for flanged connections (including Appendix Z V of RCC-M). This work will range from updating sizing rules through to joint characterization testing.
  • A new appendix on the seismic design of pipelines has been prepared and is currently being analyzed by a working group of subject-matter experts.

PTAN (AFCEN Technical Publications)


In 2015, AFCEN published a radiation protection guide for the design of nuclear pressure components in PWR plants in France. In 2018, the guide will be updated to take account of the latest feedback.

Commissioned studies into the ESPN Regulation led to a series of guides, some of which were published in 2016:

  • a guide featuring a set of methods for preparing risk analyses focusing specifically on steam generators,
  • a guide for defining dimensions in accordance with ESPN requirements and measuring dimensions while quantifying uncertainties,
  • a methodological guide specifying the contents for instructions manuals in keeping with the guide defining risk analyses.
  • a guide for examining inspectability during equipment design in relation to the risk analysis performed according to the AFCEN guide and based on sheet COLEN 37 issued by the Nuclear Pressure Equipment Liaison Committee.

Commissioned studies related to the ESPN Regulation should lead to an update of certain PTANs to include feedback from users and the publication of new PTANs in 2018:

  • a guide defining visual examinations and visual inspections during fabrication in association with the risk analysis,
  • a methodological guide to accompany the risk analysis guide for identifying the admissible limits of a given item of equipment.
  • a guide defining the visual inspections to be carried out during final verification,
  • a guide covering visual examinations during fabrication in association with the risk analysis,
  • a guide for defining dimensions in accordance with ESPN requirements and measuring dimensions while quantifying uncertainties for N2 or N3 nuclear pressure equipment,
  • two methodological guides to accompany the risk analysis guide for identifying the admissible limits of a given item of equipment (the first guide covers N1 nuclear pressure equipment while the second guide concerns N2 and N3 nuclear pressure equipment),
  • a risk analysis guide for N2 nuclear pressure equipment,
  • a guide for justifying SRMCR (Safety Related Measurement Control and Regulation) for N2 and N3 equipment,
  • a guide for carrying out specific evaluations for N2 and N3 nuclear components,
  • supporting documents to address corrosion and ageing when carrying out specific evaluations for N2 and N3 nuclear pressure components.

RCC-M criteria:

The RCC-M criteria, prepared by Jean-Marie Grandemange and approved by the Subcommittee members, were published late 2014.

This 550-page document, produced in both English and French, takes a look back at the code’s background since the decision was taken for its creation.

The technical origins of the code and the changes made to the recommendations until publication of the 2007 edition are explained from the point of view of an engineer who was required to draft a design specification in alignment with the RCC-M code.

A PTAN was also published in 2016 to justify the absence of any requirements for measuring resilience in austenitic stainless steels and nickel-based alloys, and their welds as defined in RCC-M for products less than 5 mm thick.

International challenges

The RCC-M Subcommittee is continuing to scale up its activities on an international level by arranging events, carrying out communication initiatives and taking part in technical work sessions within the different organizations influencing the standardization process.

Events in 2017:

  • On February 27, 2017, two seminars specializing in non-destructive testing and non-linear analyses in the nuclear sector were organized in the run-up to the AFCEN Conference. The seminars were attended by experts from across Europe, the United States, Russia and Asia, who reviewed the latest technologies and state of the art in these two highly active nuclear fields. Experts fielded questions from over 70 auditors in the audience, which not only generated instructive technical discussions but also simplified networking on an international level.
  • The ensuing AFCEN Conference set aside a whole day to discuss the changes to the three mechanical codes (RCC-M, RCC-MRx and RSE-M), while offering a global insight into all active work projects (Appendix ZC for carrying out non-linear analyses and a new Probationary Phase Rule for qualifying active mechanical components).
  • Four experts from the RCC-M Subcommittee traveled to China in May and October 2017 to answer questions from the Chinese Specialized Users Groups (CSUGs). The two-day meetings each attracted over 70 Chinese members from various local companies and allowed the experts to answer several dozens of questions which, where applicable, resulted in code interpretation or modification requests.
  • AFCEN's determination to meet with representatives from the Chinese nuclear industry elicited a positive response from all parties and led to a visit to Jiuli's facilities near Suzhou in May 2017.

  • In December 2016, the RCC-M UK Users Group was invited by Doosan Babcock to attend a meeting in Glasgow, which was led by TWI. In addition to presentations by NNB and AFCEN, and a question and answer session with the 20 companies represented, work continued on preparing an RCC-M application guide, which is mainly focused on the use of RCC-M for the Hinkley Point C project.

In 2017, the RCC-M Subcommittee also took part in several international working groups and participated in the associated events, including the following :

  • RCC-M experts play an active role in the Convergence Board of Mechanical Standards Developing Organizations (SDO Convergence Board) during the ASME Code Week. Members are currently taking an in-depth look at several topics for harmonization
  • Representatives from the SDO Convergence Board met the Nuclear Safety Authorities during the fourth MDEP Conference in September and again during a joint meeting with the MDEP Codes & Standards Task Force (CSWG-MDEP) in November in Phoenix, which was also attended by the CORDEL/WNA Codes & Standards group.
  • AFCEN presented its approach for addressing the issue of Safety and Quality Management Systems in the nuclear industry during the IAEA Technical Meeting in November 2017 (GSR Part 2 "General Safety Requirements: Leadership and Management for Safety").
  • At the European level, the organizations taking part in the GEN II/III Prospective Group (PG1) of CEN Workshop WS 64 - Phase 2 issued several modification requests for the RCC-M code. With Phase 2 due to end in 2017, the Workshop decided to extend the phase by one year.

In 2018, there are plans to maintain international initiatives:

  • Focusing on international comparisons by publishing the studies launched by CORDEL and the SDO Convergence Board, in line with the expectations of the other SDOs.
  • taking part in IAEA discussions about the standards on safety and quality management systems, thereby incorporating GSR Part 2 into the code,
  • furthering the aims of OECD/NEA by continuing relevant work on equivalent codes and regulations alongside the Safety Authorities in the CSWG,
  • By leading the Chinese and UK Users Groups, and the corresponding international training courses.


RSE-M : In-Service Inspection Rules for Mechanical Components of PWR Nuclear Islands.

Purpose and scope

The RSE-M code defines in-service inspection operations. It applies to pressure equipment used in PWR plants, as well as spare parts for such equipment.

The RSE-M code does not apply to equipment made from materials other than metal. It is based on the RCC-M code for requirements relating to the design and fabrication of mechanical components.

Use and background


The inspection rules specified in the RSE-M code describe the standard requirements of best practice within the French nuclear industry, based on its own feedback from operating several nuclear units and partly supplemented with requirements stipulated by French regulations.

To date:

  • The 58 units in France’s nuclear infrastructure enforce the in-service inspection rules of the RSE-M code.
  • Operation of 30 commissioned units in China’s nuclear infrastructure, corresponding to the M310, CPR-1000 and CPR-600 reactors, is based on the RSE-M code (since 2007, use of AFCEN codes has been required by NNSA for Generation II+ reactors).


AFCEN drafted and published the first edition in July 1990.

This initial edition served as a draft for preparing the 1997 edition, which extended the code’s scope to encompass elementary systems and supporting structures for the mechanical components concerned.

This edition was updated on a number of occasions (in 2000 and 2005) before undergoing a complete overhaul in 2010.

The 2010 edition is supplemented by addenda in 2012, 2013, 2014 and 2015.

The 2016 edition is in keeping with the work that has been pursued since the 2010 edition by continuing to update the existing version and incorporating EPR aspects (FLA3). The changes made to this new edition mainly involve:

  1. Restructuring Sections A/B/C/D: Section A still contains the rules that apply to all pressure equipment, while Sections B, C and D describe the specific rules for components depending on their class.
  2. Changes to make the text easier to understand:
    • difference between "maintenance operations" and "inspection operations",
    • set of rules relating to cleanliness,
    • procedure for performing hydraulic tests,
    • surveillance of main primary system leaktightness,
    • recommendations for maintenance operations,
    • new chapters on spare parts,
    • quality system requirements,
    • requalification hydraulic test methods,
    • classification method for maintenance operations,
    • inspection of safety devices,
    • classification of maintenance operations.
  3. Enhancement of the code for simplified implementation with EPR projects (FLA3).

    AFCEN is aiming to prioritize development of the RSE-M code in the following directions:

    • incorporate developments in technology and legislation,
    • factor in the constraints facing operators-partners,
    • deliver support for all international practices.

Editions available as of early 2018

The 2017 edition is the most recent version of the RSE-M code.
It builds on the technological, legislative and international developments that occurred in 2016. The changes made to this new edition mainly involve:

  • further clarification regarding the limits of main secondary systems,
  • creation of a chapter on the extended shutdown of equipment in the main secondary system (especially steam generators), including the chemical specifications for extended shutdowns,
  • alignment of the paragraphs in B 4000 that describe a manual penetrant testing technique for defence-in-depth examinations (hypothetical defects) with MC 4000 in RCC-M,
  • creation of two chapters: B 4800 (inspection of piping in the main primary and secondary systems) and B 4900 (global inspection of the main primary system) to ensure consistency with current practices,
  • creation of a specific chapter on pre-service inspections, which is neither a periodic requalification nor a periodic inspection, and an update to the text,
  • clarification of the existing definition for an essential parameter: removal of the reference to the primary parameter and addition of further information to improve on-site monitoring of these parameters,
  • complete update to Chapters II and III in Appendix 4.4 relating to the eddy current examination of steam generator tubes to take account of the new transversal rotating probes and offer a clearer description of the operating modes and the examination by acoustic emission method,
  • creation of a new section to introduce Appendix 5 (Appendix 5.0) and provide a detailed explanation of how Appendices 5.1 to 5.8 link together,
  • alignment of Appendices 5.3 and 5.4 for calculating Keq according to the theta combination method, clarification when |KII| < 0.02 |KI|,
  • integration of the kth2 method in RCC-MRx 2016 (for aligning Appendix 5.4 of RSE-M with Appendix A16 of RCC-MRx),
  • update of the inspection tables (complete, partial and EPR pre-service inspection) with references to the examination methods for alignment with new sections B 4800 and B 4900.

Outlook and next edition

2018 edition

The 2018 edition has the objective to consolidate and build on the technological, legislative and international developments that occurred in 2017.

With this aim in mind, special attention will be paid to the following points:

  • update of the references specified in the list of applicable standards and codes (Appendix 1.3), especially by analyzing any impacts from the changes made to RCC-M,
  • examination of the prospect of incorporating the requirements of the French regulation on nuclear facilities into the RSE-M code,
  • introduction of an appendix with a safety rating for the modification sheets in RCC-M and an explanation about its use,
  • inclusion of changes to the conventional qualification of NDT tests,
  • incorporation of regulatory changes as applicable to repairs / modifications (§ 8000 and Appendix 1.6 concerning the associated documents),
  • development of the section covering spare parts,
  • introduction of changes resulting from work on the three-year program for the ESPN Regulation (introduction of a new volume covering installations and references to the corresponding PTANs).

Work relating to France’s Nuclear Pressure Equipment Regulation (ESPN)

As part of its involvement in France’s ESPN Regulation, the RSE-M Subcommittee has commissioned four studies on the following topics:

  • guide to classifying repairs/ modifications/ installations on nuclear pressure equipment (not including Class 1 equipment),
  • documentation associated with repaired / modified N2/N3 nuclear pressure equipment,
  • methodology for verifying the measures taken to protect against admissible limits being exceeded for circuits manufactured according to the old regulations,
  • guide to the procurement of the main pressure parts for main primary / secondary systems,
  • methodology for the periodic requalification of N2 or N3 piping,
  • guide for equipment not subject to in-service inspections,
  • installation of nuclear systems.

AFCEN criteria and technical publications for RSE-M

“WPS” criteria (relating to Probationary Phase Rule 2 of RSE-M)

The purpose of this publication is to describe the loading history effect on the resistance to the cleavage brittle fracture of RPV steel by taking account of the warm pre-stressing phenomenon as well as the associated criteria that were proposed and which are currently being defined within a probationary phase rule (RPP2) in RSE-M.

"Appendix 5.4" criteria

These criteria were published in 2017.
AFCEN's members have made major changes to the mechanical fracture methods specified in the appendix. As part of the Hinkley Point C EPR project in the United Kingdom, an Independent Expert Working Group (IEWG) carried out a thorough review and decided that the methods were suitable for use.

Criteria and PTAN scheduled for 2018

Other AFCEN criteria and technical publications (PTAN) are being prepared:

  • criteria “Appendix 5.5” for offering a clearer insight into the criteria for analysing the impac of planar defects such as described in Appendix 5.5 of the RSE-M code,
  • criteria “Appendix 1.4” for helping control the specific provisions for applying RCC-M for modifications/ repairs,
  • technical publications associated with work on the ESPN Regulation (see point above).

Discussions with NNB

With respect to the use of the RSE-M code for the Hinkley Point C project, a series of meetings was held in 2017 to produce a UK-specific appendix tailored to UK regulations and the operator's constraints.

To simplify the process of making the code accessible to a global audience, the Subcommittee analysed the sections of the code that could be modified by a foreign operator and the parts that are applicable irrespective of the country. NNB will work with this aim in mind while focusing on in-service inspections.

Contents of the 2017 edition of the RSE-M Code



RCC-E : Design and construction rules for electrical equipment of PWR nuclear islands

Purpose and scope

RCC-E describes the rules for designing, building and installing electrical and I&C systems and equipment for pressurized water reactors.

The code was drafted in partnership with industry, engineering firms, manufacturers, building control firms and operators, and represents a collection of best practices in accordance with IAEA requirements and IEC standards.

The code’s scope covers:

  • architecture and the associated systems,
  • materials engineering and the qualification procedure for normal and accidental environmental conditions,
  • facility engineering and management of common cause failures (electrical and I&C) and electromagnetic interference,
  • testing and inspecting electrical characteristics,
  • quality assurance requirements supplementing ISO 9001 and activity monitoring.

Use and background


RCC-E has been used to build the following power plants:

  • France’s last 12 nuclear units (1,300 MWe (8) and 1,450 MWe (4)),
  • 2 CP1 reactors in South Korea (2),
  • 44 M310 (4), CPR-1000 (28), CPR-600 (6), HPR-1000 (4) and EPR (2) reactors in service or undergoing construction in China,
  • 1 EPR reactor in France.

The RCC-E code is used for maintenance operations in French power plants (58 units) and Chinese M310 and CPR-1000 power plants.

RCC-E has been chosen for the construction of the two EPR units in Hinkley Point C(UK).

Users include:

  • equipment suppliers,
  • engineering firms responsible for designing, building and installing equipment and systems,
  • control and inspection organizations,
  • Nuclear Safety Authorities.


The editions published between 1981 and 2002 address Generation II reactors.

The 2005 edition incorporated the requirements stipulated in the design codes specific to the EPR project - ETC-I and ETC-E, which focus on I&C and electrical systems respectively (ETC: EPR Technical Code Instrumentation and Electrical).

The 2005, 2012 and 2016 editions concern Generation II and III reactors. As from the 2005 edition, project specifications must be written to supplement and implement the rules in RCC-E and allow the code to be used in the project.

The various editions of the code have been published in French and English.

The 2005 edition was translated into Chinese and published under CGN’s authority in 2009.

Edition available as of early 2018

The RCC-E 2016 edition is the most recent version. French and English versions of the code have been available since early 2017.

The following sources are used when revising the RCC-E codes:

  • feedback from facilities under construction and in operation,
  • the Nuclear Safety Authorities’ investigation process,
  • users inquiries,
  • changes in the standards used and IAEA’s requirements,
  • changes in industry’s maturity.

The 2016 edition:

  • represents a departure from previous editions, which have been updates instead of overhauls,
  • addresses Generation II, III and IV reactors, research reactors and naval reactors,
  • organizes requirements into four key areas for easier identification and greater clarity: monitoring, systems, equipment, and component and systems installation. Each key area covers all lifecycle activities,
  • takes account of IAEA requirements as applicable to the scope of the code,
  • clearly defines the supplements to the requirements in the chosen IEC standards for I&C systems.

Reasons for overhauling the code include:

  • changes to IAEA requirements SSR-2/1, GSR Parts 2 and 4, and recommendations for designing and building electrical and I&C systems (SSG 34 and SSG 39), which are used as inputs to the drafting process,
  • the WENRA handbook on the design of new reactors,
  • changes to IEC standards relating to the SC 45 Technical Committee and IEC industry standards.
  • feedback from current projects: EPR, ITER, RJH and ASTRID,
  • lessons learned following the British Safety Authorities’ investigation into the UK’s EPR as part of the generic design assessment into the electrical and I&C systems,
  • feedback following Fukushima.

Requirements are:

  • adapted so that they can be applied to nuclear projects other than pressurized water reactors,
  • harmonized and coordinated with the requirements of the relevant IEC international standards.



Technical publication of the RCC-E Subcommittee:

Contribution to the ESPN program

The RCC-E Subcommittee commissioned a study on the following topic:

SRMCR (Safety Related Measurement, Control and Regulation): the purpose of this study is to define the practical rules for designing an SRMCR in compliance with the applicable requirements for safety devices.

Editions gap analysis

AFCEN has produced :

  • a document that compares the 2012 and 2005 editions of the code entitled: “Nuclear Codes & Standards: RCC-E 2012 Gap analysis with the RCC-E 2005”
  • a document that compares the 2016 and 2012 editions of the code entitled "Nuclear Codes & Standards: RCC-E 2016 Gap analysis with the RCC-E 2012".


The work topics for the next editions will include:

  • feedback from the application of RCC-E 2016,
  • measurement, control and regulation systems,
  • design extension situations,
  • IT security.


RCC-CW : Design and construction rules for civil works in PWR nuclear islands

Purpose and scope

RCC-CW describes the rules for designing, building and testing civil engineering works in PWR reactors.

It explains the principles and requirements for the safety, serviceability and durability of concrete and metal frame structures, based on Eurocode design principles (European standards for the structural design of construction works) combined with specific measures for safety-class buildings.

The code is produced as part of the RCC-CW Subcommittee, which includes all the parties involved in civil engineering works in the nuclear sector: clients, contractors, general and specialized firms, consultancies and inspection offices.

The code covers the following areas relating to the design and construction of civil engineering works that play an important safety role:

  • local cases and combinations,
  • geotechnical aspects,
  • reinforced concrete structures and galleries,
  • prestressed containments with metal liner,
  • metal containment and pool liners,
  • metal frames,
  • anchors,
  • concrete cylinder pipes,
  • paints and coatings,
  • containment leak tests.

The RCC-CW code is available as an ETC-C version specific to EPR projects (European pressurized reactor).

Use and background

AFCEN published the first civil engineering code (RCC-G) in 1980. This edition included feedback from France’s 900 MWe nuclear reactors and mainly drew inspiration from the French BAEL regulation (limit state design of reinforced concrete) and BPEL regulation (limit state design of prestressed concrete). It has been used for the Ulchin project in Korea and the M310 project in China.

AFCEN updated the edition in 1985 and again in 1988 to reflect the latest developments in civil engineering technology.

In particular, the 1988 edition served for France’s 1,450 MWe PWRs. In April 2006 in response to the specific needs of its Flamanville 3 EPR project in France, EDF published a reference document called ETC-C for the design and construction of civil engineering works.

The reasons that prompted the development of the ETC-C code are as follows:

  • cover both French and German legislative requirements and practices,
  • consider new load cases to represent severe accident conditions or events of a more serious nature,
  • integrate application of Eurocodes into the design of nuclear structures,
  • take account of the latest feedback on the operation of in-service nuclear power plants and updated requirements for safety analyses,
  • incorporate the latest knowledge on the behavior of materials and structures (obtained through laboratory and model testing).

The EDF document was not published by AFCEN, but acted as a blueprint for a civil engineering code that AFCEN produced in 2009 as part of the RCC-CW Subcommittee, which led to:

  • initially, the publication of a specific code for EPR projects: ETC-C edition 2010, followed by ETC-C edition 2012,
  • subsequently, the publication of a generic civil engineering code, called RCC-CW, that is not specific to any given project. Two successive editions of RCC-CW were published in 2015 and 2016.

The ETC-C 2010 edition, which was the first version prepared and published by AFCEN, was used for the generic design assessment of the EPR project in the United Kingdom.

Edition available as of 2018

The RCC-CW 2017 edition is the most recent version

In 2015, AFCEN prepared and published the first edition of a generic civil engineering code that does not relate to any specific project.

As from the 2015 edition, this RCC-CW code no longer adheres to the EPR project and can be used for PWR reactors featuring a prestressed containment with a metal liner. This code is being usted for the new EPR project in France.

RCC-CW 2015 includes all the relevant proposals based on the experience acquired during current projects:

  • technical discussions concerning the licensing process for Flamanville 3 and the generic design assessment of the EPR project in the United Kingdom,
  • the experience acquired by members through their participation in the Olkiluoto, Flamanville and Taishan projects.

It takes account of the latest changes in European standards. It includes technological openings and improvements:

  • bonded prestressing has been supplemented with unbonded prestressing,
  • the code covers the design and development of seismic isolation devices,
  • the section on external hazards has been updated to include tornadoes.
  • The design approach has been expanded to provide greater focus on design extension situations.

The 2016 edition of the RCC-CW code implements the following changes:

  • Correction of various editorial mistakes.
  • Thorough revision of the DANCH chapter on anchors and inclusion of the latest changes to EN 1992-4.

The 2017 edition of the RCC-CW code implements the following changes:

  • rules for anchor channels and active channels have been worked into the DANCH and CANCH chapters,
  • the CCONC chapter has been completely revised to ensure a better fit with EN 13670 and has been based on the latest version of EN 206,
  • a new CCOAT chapter has been created for paints and coatings,
  • the actions to be considered in design extension hazards have been amended (DGENR chapter),
  • requirements for seismic soil column calculations have been included (Appendix DA).

RCC-CW 2017 covers anchor-related topics




As already initiated by AFCEN in preparing the RCC-CW code, the development of the civil engineering code is continuing in the following directions:

  • integrate feedback from projects currently under development or construction,
  • broaden the scope of robust technologies covered by the code (anchors, metal liners, and so on),
  • encourage application of the code in the European and international arena by offering greater coverage of the latest international standards and promote the code as a civil engineering benchmark for the Prospective Groups that CEN set up to prepare the future nuclear codes,
  • according to AFCEN’s requirements and development objectives, develop appendices and addenda specifically addressing how the code can be adapted to the countries targeted by AFCEN.

The work program includes the following core topics:

  • composite steel and concrete structures,
  • pile foundations,
  • improved reinforcement rates,
  • maintenance,
  • anchor channels,
  • tolerances.

Technical publication on seismic isolation

Technical publication “PTAN – French Experience and Practice of Seismically Isolated Nuclear Facilities” was published in 2014.

It presents the best practices and experience of French industry resulting from the last 30 years in designing and installing seismic isolation systems beneath nuclear facilities.

This publication enables European industry to:

  • codify the industrial design and construction practices according to AFCEN: in this respect, RCC-CW 2015 includes a section on seismic isolation,
  • showcase its experience within international organizations and bodies (IAEA, OECD, WENRA, etc.).

At the same time, experts are working on dissipation systems to reinforce the seismic resistance of existing structures.

International activities


The Subcommittee is involved in the activities of CEN Workshop 64.

The RCC-CW code is being shared with the other European participants.

During the workshop’s activities, AFCEN will examine all requests to update the code.

Chinese Users Group (CSUG)

The ETC-C and RCC-CW codes are being shared within the Chinese Users Group, which held a meeting in 2015, 2016 and 2017 attended by 30 Chinese experts.

Any interpretation requests for AFCEN codes issued during the meetings are examined by the Subcommittee.

UK Users Group

The UK Users Group on civil engineering codes includes the main companies involved in the Hinkley Point C project. The Users Group was officially launched during the AFCEN 2017 Conference. Following the kick-off meeting in November 2016, two meetings were held in June and December 2017.



RCC-C : Design and construction rules for fuel assemblies of PWR nuclear power plants

Purpose and scope

The RCC-C code contains all the requirements for the design, fabrication and inspection of nuclear fuel assemblies and the different types of core components (rod cluster control assemblies, burnable poison rod assemblies, primary and secondary source assemblies and thimble plug assemblies).

The design, fabrication and inspection rules defined in RCC-C leverage the results of the research and development work pioneered in France, Europe and worldwide, and which have been successfully used by industry to design and build nuclear fuel assemblies and incorporate the resulting feedback.

The code’s scope covers:

  • fuel system design, especially for assemblies, the fuel rod and associated core components,
  • the characteristics to be checked for products and parts,
  • fabrication methods and associated inspection methods.

Use and background


The RCC-C code is used by the operator of the PWR nuclear power plants in France as a reference when sourcing fuel from the world’s top two suppliers in the PWR market, given that the French operator is the world’s largest buyer of PWR fuel.

Fuel for EPR projects is manufactured according to the provisions of the RCC-C code.

The code is available in French and English. The 2005 edition has been translated into Chinese.


The first edition of the AFCEN RCC-C code was published in 1981 and mainly covers fabrication requirements. The second edition of the code was released in 1986 and supplemented the first edition by including design requirements in a specific section at the end of the code. This structure remained unchanged and prioritized the fabrication aspects.

Between 2013 and 2015, the RCC-C Subcommittee was busy overhauling the code to implement a new structure for improved clarity as well as to reflect the requirements of the latest quality assurance standards and describe all technical requirements that have been missing from previous editions. 45 nuclear fuel experts were involved in these activities. The Subcommittee's work culminated in the 2015 French edition, which was translated into English the following year.

Edition available as of early 2018

The RCC-C 2018 edition is the most recent version

The new 2018 English version of the RCC-C is an update of the 2017 edition. The changes to the RCC-C code for the 2018 release have focused on the following topics:

  • Grid weld inspection,
  • Guide thimble welding,
  • Pellet inspection method,
  • Nickel base alloys,
  • Peripheral power suppression assemblies.


The main changes between the 2015 and 2017 versions are as follows:

In terms of the general requirements and description of the fuel:

A customer surveillance section has been added to Chapter 1 that specifies the customer's duty to monitor its fuel suppliers. It sets outs out the reasons and principles for implementing customer surveillance measures as well as the associated objectives. It includes the practice suggested in IAEA Guide NF-G-2.1 concerning quality aspects in nuclear power reactor fuel engineering.

In terms of design:

No changes have been made to the design chapter, insofar as ASN reviewed the fuel performance criteria in the summer of 2017.

The RCC-C 2018 edition takes account of any changes requested by ASN.

In terms of manufacturing:

The most significant modifications examined by the working group are as follows:

  • Conditions for examining welded joints on core components: feedback from the manufacturing process has been taken into consideration for defining the most appropriate examination conditions in terms of magnification.
  • Heat treatment of alloy 718: the use of specified heat treatment methods representing an alternative to those defined in the code have been introduced if they improve resistance to stress corrosion cracking. Specific measures relating to the partially recrystallized state have also been introduced.
  • Harmonization of provisions relating to heat treatment on nozzles: stress relieving heat treatment is no longer mandatory due to the measures taken during dimensional inspections.
  • Need to qualify laser marking: laser marking must be qualified in case of cladding tubes due to the component's criticality.
  • Harmonization of the cobalt content for small components: the requirements of the RCC-M code have been included to specify the maximum cobalt content for the small stainless steel components in the assembly.
  • Ultrasonic inspection of cladding tubes: the intervals for verifying ultrasonic inspection equipment have been adjusted to allow sufficient time to perform the inspection.
  • Adaptation of the conditions for qualifying skeleton weld joints in terms of corrosion resistance: corrosion testing may be performed during qualification if the supplier continuously monitors the welding parameters during production.
  • Declaration of the heat treatment conditions for debris filter plates: the code's provisions for this component have been harmonized with ASTM A638.
  • Examination conditions for grid weld joints: if weld parameters are monitored in-line, visual inspections of the beads are no longer required. However, the examination conditions during qualification have been reinforced (high-magnification metallographic inspections).
  • Certification of NDT personnel: the US standard SNT-TC-1A used by Westinghouse and AREVA in the United States has been introduced into the code. The list of standard and non-standard processes has been updated.
  • Clarification of the conditions for the radiographic inspection of seal weld.


Next edition

The next edition (French and English) is scheduled for 2019.


The RCC-C Subcommittee's work on adapting the design requirements will focus on incorporating the conclusions of the French 2017 Groupe Permanent on fuel performance criteria.

The code will also be amended to reflect changes in products. As such, there are plans to incorporate the design and manufacturing requirements for the new hafnium stationary control assemblies that are intended to reduce vessel fluence.

Manufacturing process requirements will be modified according to the proposals and feedback from Subcommittee members. There are also plans to clarify how heat treatment requirements apply to factories.



RCC-F : Design and construction rules for PWR fire protection systems

Purpose and scope

The RCC-F code defines the rules for designing, building and installing systems used in a PWR nuclear plant for managing the risk of fire outbreak inside the facility in light of the nuclear hazards involved and thereby control the fundamental nuclear functions. The code also defines the rules for analysing and justifying the means used to create the safety demonstration.

This code’s target readership is therefore:

  • suppliers of fire protection equipment,
  • engineering firms responsible for designing, building and installing the buildings constituting a PWR,
  • engineering firms responsible for analysing fire hazards and establishing the safety demonstration from a fire hazard perspective,
  • engineering firms responsible for designing the means to prevent and protect against fires and mitigate the effects of a fire outbreak,
  • laboratories carrying out qualification testing of fire protection equipment,
  • Nuclear Safety Authorities responsible for approving the safety demonstration.

The code defines fire protection systems within a finite scope of service buildings in a light water nuclear power plant.

Design studies can be used to satisfy the code's requirements.

The code provides recommendations for guaranteeing that fire hazards are under control from a safety perspective during the design phase, while incorporating aspects relating to:

  • the industrial risk (loss of assets and/or operation),
  • personnel safety,
  • the environment.

The code is divided into five main sections:

  • generalities,
  • design safety principles,
  • fire protection design bases,
  • construction provisions,
  • rules for installing the fire protection components and equipment.

The RCC-F code is generally suited to light-water reactors, such as PWRs, as well as EPRs.

Use and background

In response to the needs of its Flamanville 3 EPR project in France, EDF published a reference document called ETC-F for the design of fire protection systems.

The EDF document was not published by AFCEN, but acted as a starting point for a fire protection code that AFCEN produced in 2009 as part of the RCC-F Subcommittee, which led to:

  • Initially, the publication of the 2010 edition of the ETC-F code similar to the EPR projects,
  • Subsequently, the drafting of the 2013 edition, which gave less focus to the specifics of EPR projects but which still addresses the safety principles in alignment with existing EPR projects; UK regulations were incorporated into this version of the code,
  • Finally, the publication of the RCC-F 2017 code, which is generally suited to light-water reactors, such as PWRs.

Edition available as of early 2018

The RCC-F 2017 edition is the most recent version

Amendments have been made based on the ETC-F 2013 edition and concern the following key topics:

  1. 1. Removal of the code's adherence to the safety principles for EPR projects
    Safety principles (aggravating events, fire combined with thermal-hydraulic transients, combined stresses, fire outbreaks following an earthquake, and so on) are generally specified for each project according to the national and international context. In a code that covers fire hazards such as RCC-F, a concerted effort must be made to define an approach for adapting fire protection measures according to these principles. However, even if the principles used for this purpose correspond to updated best practices, they are mentioned for guidance only so their implementation can be adapted to suit other options by a project using the code. The code contains practical principles with this goal in mind.
  2. 2. Improved traceability of requirements
    Various improvements have been made to this subject area to satisfy users' need to easily identify the source of the requirements that led to the rules defined within the code.
  3. 3. Improved identification of the code's scope
    The code's scope is defined in the introductory chapters with a clear distinction between the parts of the installation where the code is fully applicable and the parts where national practices and regulations may take precedence.
  4. 4. Update to the appendix on French regulations
    Appendix A incorporates the specific changes to French and English regulations. The French appendix has undergone a significant review to incorporate the latest major changes (regulation on nuclear facilities and the ASN decision on the applicable rules for nuclear facilities). One of the consequences is that the body of the text in the code now features the new presentation of defence-in-depth vs. fire hazards in accordance with WENRA safety levels.
Finally, the 2017 edition overhauls the RCC-F code to ensure suitability for a wider range of light-water reactors, such as PWRs, while building on feedback from EPR reactors.

Content of the 2013 edition of the ETC-F code

International activities

In 2017, the RCC-F Subcommittee held a meeting with the CSUG (Chinese Specialized Users Group):

  • The Chinese working group comprises 19 permanent members and was created during the first meeting in March 2015. . Every year, a meeting is organized in China to improve interaction and help address the interpretation and/or modification requests issued by the CSUG.
  • Two meetings have been scheduled for 2018: one in June to coincide with the AFCEN Day event in June and the other in October in China.
  • A publication about RCC-F was released during the SMiRT 24 conference (15th International Post-Seminar on Fire Safety in Nuclear Power Plants and Installations). A publication is planned for the 26th ICONE Conference in 2018.

Outlook and preparation of the RCC-F 2020 edition


AFCEN is aiming to develop the code in the following directions:

  • integrate state of the art and feedback from projects currently under development or construction,
  • drive the code’s application on a European and international level by including international standards and regulations. According to requirements, this will prompt AFCEN to develop appendices and addenda specifically addressing how the code can be adapted to local regulations (refer to the exercise already carried out for the United Kingdom).

RCC-F 2020 edition

The next edition of RCC-F is scheduled for 2020. The content of the planned changes will be defined in 2018.

The general spirit behind these changes is to strengthen the sections that detail the code's application and provide the most extensive coverage possible, including methods, technical solutions and links with operations. The tasks currently on the to-do list will be prioritized, for example:

  • integration of methods based on EDF references,
  • modification requests issued by the CSUG,
  • post-Fukushima considerations,
  • comparison with international codes.

Examination of the RCC-F code in France as part of a new concept (EPR2) may give rise to new modification requests.



RCC-MRx: Design and construction rules for mechanical components in high-temperature structures, experimental reactors and fusion reactors

Purpose and scope

The RCC-MRx code was developed for sodium-cooled fast reactors (SFR), research reactors (RR) and fusion reactors (FR-ITER).

It provides the rules for designing and building mechanical components involved in areas subject to significant creep and/or significant irradiation. In particular, it incorporates an extensive range of materials (aluminum and zirconium alloys in response to the need for transparency to neutrons, Eurofer, etc), sizing rules for thin shells and box structures, and new modern welding processes: electron beam, laser beam, diffusion and brazing.

Background and use

Since 2009, the RCC-MRx code created by AFCEN’s RCC-MRx Subcommittee has been an inclusion of two documents:

  • The RCC-MR code, drafted by AFCEN’s RCC-MR Subcommittee together with the Tripartite Committee formed on March 16, 1978 by the Commissariat à l’Energie Atomique, Electricité de France and Novatome, to establish the applicable rules for designing components working at high temperatures. AFCEN published four editions of RCC-MR in 1985, 1993, 2002 and 2007.
  • The RCC-MX code, drafted by the RCC-MX Approval Committee formed on March 31, 1998 by the Commissariat à l’Energie Atomique, AREVA-TA and AREVA-NP for the specific needs of the RJH project (Jules Horowitz reactor). This code applies to the design and construction of experimental reactors, auxiliary systems and associated experimental devices. It can also be used for the design and construction of components and systems for existing facilities. CEA published two editions of RCC-MX in 2005 and 2008.

An unpublished preliminary version of RCC-MRx created in 2010 by AFCEN was chosen as the baseline for the CEN CWA European Workshop (entitled “CEN-WS-MRx, Design and Construction Code for mechanical equipment of innovative nuclear installations”), which was intended to familiarize European partners with the RCC-MRx 2010 code and propose modifications to satisfy the needs of their projects. The results of the workshop were incorporated into the 2012 edition of RCC-MRx published by AFCEN.

The RCC-MR code was used to design and build the prototype Fast Breeder Reactor (PFBR) developed by IGCAR in India and the ITER Vacuum Vessel.

The RCC-Mx code is being used in the current construction of the RJH experimental reactor (Jules Horowitz reactor).

The RCC-MRx code is serving as a reference for the design of the ASTRID project (Advanced Sodium Technological Reactor for Industrial Demonstration), for the design of the primary circuit in MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) and the design of the target station of the ESS project (European Spallation Source).

edition available as of early 2018


SECTION I General provisions

SECTION II Additional requirements and special provisions

SECTION III Rules for nuclear installation mechanical components

VOLUME I: Design and construction rules

  • Volume A (RA): General provisions and entrance keys
  • Volume B (RB): Class 1 components and supports
  • Volume C (RC): Class 2 components and supports
  • Volume D (RD): Class 3 components and supports
  • Volume K (RK): Examination, handling or drive mechanisms
  • Volume L (RL): Irradiation devices
  • Volume Z (Ai): Technical appendices

VOLUME II: Materials

VOLUME III: Examinations methods

VOLUME IV: Welding

VOLUME V: Manufacturing operations

VOLUME VI: Probationary phase rules

The 2015 edition is the most recent version

The edition of the RCC-MRx code was released in 2015.

This edition reflects feedback on the use of the 2012 edition and/or its 2013 addendum, especially in current projects and mainly the Jules Horowitz reactor and the Astrid project. Examples include the inspection and welding procedures for aluminum, as well as the code’s improvements and new structure relating to components used at high temperatures (design rules, welded assemblies and material properties).

Initial feedback on the code’s application also helped analyze and integrate additional data on the Eurofer material used by the fusion community.

Furthermore, this edition pays special attention to ensuring consistency between RCC-MRx and the other reference documents that interact with the code, including RCC-M, European and international standards.


In 2017, efforts focused centered on preparing the new edition of RCC-MRx, which is scheduled for publication in 2018. This edition will include:

  • the findings of Workshop 64 (CWA),
  • the results of the commissioned study aimed at improving the rules to take account of irradiation: the study led to two modifications relating to an adjustment of the toughness values for 316L(N) and the fields to which the code applies in respect of irradiation,
  • a new organization for the chapters addressing fast fracture,
  • a new organization for the chapters addressing progressive deformation.
  • feedback from the RJH project,

In 2016, work was finalized on the commissioned study entitled "Terms for introducing a new material into RCC-MRx". This study led to the publication of a methodological guide (AFCEN/RX.17.004 "Guide for introducing a new material in RCC-MRx"), which explains, when introducing a non-coded material into RCC-MRx, the definition of the methods for obtaining the characteristics in Appendix A3 (expected / possible tests, meaning of the data).

The RCC-MRx Subcommittee launched three commissioned studies in 2017:

  • Fast fracture analysis: this commissioned study also involves the RCC-M code. The aim is to standardize practices between the RCC-M and RCC-MRx codes and clarify the approach for identifying areas where fast fracture analyses must be performed.
  • Preparation of a document describing the sources and key reasons underlying Appendix A1 (guide for the seismic analysis of equipment): the aim of this commissioned study is to publish the criteria for Appendix A1 in a PTAN.
  • Update of RCC-MRx – Section II – Part REC 3000 (Special instructions for equipment subject to regulations): the purpose of this commissioned study is to update the sections on French regulations in line with the work carried out for RCC-M.

Use of the RCC-MRx code in high-temperature and fusion reactors