1. 38th Nuclear Safety Standards Committee 37th Radiation Safety Standards Committee 38th Waste Safety Standards Committee Joint Session 26 – 27 November 2014
Agenda item NRW 6.7
DS476 Draft Safety Requirements:
Safety of Research Reactors
D.F. Sears, RRSS-NSNI

2. Introduction
DS476 is a revision of the NS-R-4, which was published in 2005.
The scope of the DS476 remains essentially the same as NS-R-4. However:
Sub-critical assemblies are covered;
A Section on “Preparation for Decommissioning” replaced “Decommissioning”;
Interfaces between safety and security are covered.
Coherency and consistency of the technical contents with the other relevant IAEA Safety Standards (e.g. SF-1 and GRSs) ensured, including topics not originally covered.

3. Introduction Relevant feedback from Fukushima accident included;
Material on “regulatory supervision”, “siting”, and “management system” was revised in accordance with the Committees and Commission decisions;
Feedback from MS use of the document and from the IAEA Incident Reporting System for Research Reactors (IRSRR) incorporated;
Material more suitable to guidance removed;
References updated.

4. Contents Introduction
Applying safety objectives, concepts and principles for research reactor facilities
Regulatory supervision for research reactor facilities
Management and verification of safety for research reactor facilities
Site evaluation for research reactor facilities
Design of research reactor facilities
Operation of research reactor facilities
Preparation for decommissioning of a research reactor
Interfaces between safety and security for a research reactor
App I: Selected postulated initiating events for research reactors
App II: Operational aspects of research reactors warranting particular consideration
Annex: Selected safety functions for research reactors

5. Development Process
The DPP was approved by the Committees and the CSS (April 2014);
The first draft was developed in two CSMs during 2014,
The first draft was subjected to internal review in accordance with the internal QA process;
Cleared by the NSGC, November 2014;
Committees review before submission to MSs for comments;

6. NUSSC/WASSC/RASSC comments
647 comments received from 11 MS (Argentina, Belgium, Canada, Finland, France, Germany, Japan, Korea, South Africa, Ukraine, USA);
All comments (including those submitted after the deadline) were carefully considered, most were accepted. Resolution tables were posted on the webpage.

7. NUSSC/WASSC/RASSC comments
Incorporating the resolutions resulted in several refinements:
Enhancing the flow of information;
Enhancing consistency with other SS in some areas (mainly DEC);
Adding clarity to some areas (e.g., use of a graded approach);
Removal of text more relevant to guidance;
Editorial (rationalization of cross references, definitions, updating reference, etc.).

8. NUSSC/WASSC/RASSC comments: Examples of rejected comments
Conflicting comments: Some requested deletion, others requested elaboration – dealt with on a case-by-case basis;
Make Fukushima feedback relevant in an integrated manner (in one location): Current structure consistent with the approved DPP and with the structure of SSR-2/1 and SSR-2/2;
Request for application of Safety Guides specific to NPP to research reactors and sub-critical assemblies;
Request to delete some Req. on the basis that there are no equivalent Req. in SSR-2/1 and -2/2: The Req. in DS476 are specific to RRs;
Some proposed deletions were rejected: Text retained as link to applicable GSRs and for the benefit of users from operating organizations with only RRs/subcritical assemblies – in MSs with small nuclear programme (no NPP);
Redundancies and Inconsistencies with the IAEA safety glossary.

9. Requested Action
Request approval to submit DS476 to Member States.