adding value through knowledge © nnc limited oecd_l2psa_review/mla/dmj/02040.ppt oecd/nea...

Adding value through knowledge

© NNC Limited

OECD_L2PSA_review/mla/dmj/02040.ppt

OECD/NEA International Workshop on L2 PSA and SAM, 29th-31st March 2004, Koln

A Review of OECD Report on Level 2 PSA and SAM

Ming L Ang NNCCharles Shepherd NII

© NNC Limited


Level 2 PSA methodology (Chapters 5 & 6)

No major omission of methods for direct application or support role identified

Future revision on L2 methods may consider the following: ROAAM methodology and case studies case studies for L2 methods listed should be included

(CET is exception) critique of methods, e.g. current use of CET in the

context of epistemic uncertainty Approaches to ‘subjective judgement’, i.e. making

normative expression in L2 PSAs, should be discussed

Review of CET case studies on uncertainty treatment and rationale

Discussion in most areas still biased towards NUREG-1150 study, can benefit from more recent PSAs

© NNC Limited


Results and insights from recent Level 2 PSA (Chapter 2)

Discussion based on results applicable to PWRs and BWRs. Further examples of similar reactor designs may not be beneficial

Examples from other key groups of reactor designs should be considered, e.g. VVER, RBMK and advanced reactor

© NNC Limited


Severe accident phenomena and modelling (Chapter 3)

Description of SA phenomena well supported by a number of SOAR reviews (OECD, EC). Consideration should be given to include: Phenomena relevant to shutdown, e.g. air ingression

impact on accident progression and fp behaviour Further discussion on uncertainty characterisation of

phenomena based on more recent studies (e.g. EC STU project on significance of ST uncertainty)

No major omission of SA analysis codes identified. Consideration should be given to: Update on modelling improvement,

benchmark/validation of major integrated codes Restrict Chapter 3 to current codes in use and major

code activities (e.g. ASTEC, codes used for VVER and RBMK analysis)

© NNC Limited


Severe Accident Management (Chapter 4) and RI applications (Chapter 7)

No major omission of high level candidate strategies (both preventive and mitigative) identified

Update should reflect the significant international SAMG development and implementation programme (e.g. SAMIME review, COG SAMG development)

Discussion on probabilistic measure should be updated and included in Chapter 7 on RI applications

RI applications should be updated with recent studies and some discussion on the decision making process

© NNC Limited


Conclusions

Recent L2 PSAs have largely conformed to the approaches identified in the OECD report

Report can benefit with an update in most areas to reflect recent development

Current report does not cover SAM aspects on training and optimisation as defined in the study objective

Consideration should be given to include a discussion on source terms and L2/L3 interface

Revision as an addendum to report is recommended

adding value through knowledge © nnc limited oecd_l2psa_review/mla/dmj/02040.ppt oecd/nea...

Documents