INTERNATIONAL ATOMIC ENERGY AGENCY
TECHNICAL CO-OPERATION DEPARTMENT
PROJECT RER/9/087
PROSPECTUS FOR A
SECOND REGIONAL WORKSHOP
on
Harmonization of Low Power and Shutdown Probabilistic Safety Assessment
(PSA) for WWER Nuclear Power Plants
October 29 – November 2, 2007
UJD SR, Bratislava, Slovakia
Technical Co-operation Project:
RER/9/087 - Harmonization of Probabilistic Safety Assessment Applications
TITLE:
SECOND Regional Workshop on Harmonization of Low
Power and Shutdown Probabilistic Safety Assessment
(PSA) for WWER Nuclear Power Plants
PLACE:
UJD SR, Bratislava, Slovakia
DATES:
October 29 – November 2, 2007
DEADLINE FOR
NOMINATIONS:
20 August, 2007
ORGANIZERS:
TARGET
COUNTRIES:
International Atomic Energy Agency and Nuclear
Regulatory Authority of the Slovak Republic (UJD SR),
Slovakia
This workshop is designed for the staff of Nuclear Power
Plants (NPPs), NPP design and engineering companies,
regulatory authorities and technical support organizations
from the countries operating WWER-type reactors and
participating in the IAEA Technical Co-operation Project
RER/9/087.
PARTICIPATION:
The workshop is open to 12 participants.
LANGUAGE:
The workshop will be held in English.
PURPOSE OF
THE MEETING:
The first workshop on harmonization of low power and
shutdown (LPSD) PSAs for WWER-type NPPs was held
on 26-30 March 2007. That meeting achieved its goal to
provide a wide forum for exchange of information and
discussion on the latest results and insights from LPSD
PSA studies for WWER plants in the countries in receipt of
the IAEA technical co-operation assistance. A
questionnaire that intended to collect detailed information
on modeling approaches and PSA results was distributed,
and 12 responses were received. The information presented
in the questionnaires was extensively used during the
working group activities to identify differences in the
LPSD PSA results and understand the reasons for them
(separately for WWER-440 and WWER-1000 NPPs). The
results of comparison were documented in a comprehensive
workshop report. It was observed that the risk profiles in
terms of initiating events (IEs) modelled and plant
operational states (POSs) considered differ sometimes
substantially amongst the PSAs.
The purpose of the second workshop is to collect detailed
information on selected IEs, POSs, and modeling issues
that were identified to be the major sources for the
differences in PSA results for similar plants and continue
the detailed comparison of the technical areas needing
further analysis (IE frequencies, modeling assumptions,
accident sequences, etc.). The ultimate goal is to clarify
which differences in risk profiles are caused by the
differences in plant units design and operational practices
(i.e. consistent differences) and which ones are due to
differences in the approaches and data used. For the latter,
the best practices are to be highlighted. The report on the
detailed comparison of LPSD PSAs for WWER-type NPPs
will be compiled.
PARTICIPANTS'
QUALIFICATIONS:
NATURE OF THE
MEETING:
The participants of the workshop should be professional
staff members of NPPs, NPP design and research institutes,
engineering companies, or technical staff of the regulatory
authorities and technical support organizations possessing
comprehensive knowledge of the PSA methodology and
techniques for LPSD states and preferably immediately
involved in performance or review of LPSD PSA studies
for WWER-type NPPs.
The meeting will consist of presentations by participants
and invited experts on the topics outlined in the syllabus
and technical discussions in working groups. All
participating organizations are expected to present their
specific national experiences concerning selected modeling
aspects of LPSD PSAs that were decided to be further
elaborated at the first workshop in March 2007 (see the
Syllabus attached). The participants will also work in
groups to compare specific technical issues; for this, it
would be highly desirable that participants bring their laptops with the actual LPSD PSA models and be able to use
them for sensitivity analysis during the meeting. In
addition, the participants will be requested to complete a
relevant questionnaire on LPSD PSA issues, which will be
distributed before the workshop, and contribute to the
development of a workshop report.
RELEVANT IAEA
SAFETY STANDARDS
AND PUBLICATIONS:
1.
INTERNATIONAL
ATOMIC
ENERGY
AGENCY, Fundamental Safety Principles, Safety
Standards Series No. SF-1, IAEA, Vienna (2006).
2.
INTERNATIONAL
ATOMIC
ENERGY
AGENCY, Safety of Nuclear Power Plants: Operation
Requirements, Safety Standards Series No. NS-R-2,
IAEA, Vienna (2000).
3.
INTERNATIONAL
ATOMIC
ENERGY
AGENCY, Safety Assessment and Verification for
Nuclear Power Plants, Safety Guide, Safety Standards
Series No. NS-G-1.2, IAEA, Vienna (2002).
4.
INTERNATIONAL
ATOMIC
ENERGY
AGENCY, Review of Probabilistic Safety Assessments by
Regulatory Bodies, Safety Report Series No. 25, IAEA,
Vienna (2002).
5.
INTERNATIONAL
ATOMIC
ENERGY
AGENCY, Applications of Probabilistic Safety
Assessment (PSA) for Nuclear Power Plants, IAEATECDOC-1200, Vienna (2001).
6.
INTERNATIONAL
ATOMIC
ENERGY
AGENCY, Probabilistic Safety Assessments of Nuclear
Power Plants for Low Power and Shutdown Modes,
IAEA-TECDOC-1144, Vienna (2000).
7.
INTERNATIONAL
ATOMIC
ENERGY
AGENCY, Framework for a Quality Assurance
Programme for Probabilistic Safety Assessment, IAEATECDOC-1101, Vienna (1999).
8.
INTERNATIONAL
ATOMIC
ENERGY
AGENCY, Living Probabilistic Safety Assessment
(LPSA), IAEA-TECDOC-1106, Vienna (1999).
Technical Co-operation Project:
RER/9/087 - Harmonization of Probabilistic Safety Assessment Applications
Second Regional Workshop on Harmonization of Low Power and Shutdown
Probabilistic Safety Assessment (PSA) for WWER Nuclear Power Plants
October 29 – November 2, 2007
Nuclear Regulatory Authority of the Slovak Republic (UJD SR), Slovakia
SYLLABUS
1.
INTRODUCTION
1.1
1.2
Objectives and Agenda of the Workshop
Overview of the Results of the First Workshop (Held in March 2007) on
Harmonization of Low Power and Shutdown Probabilistic Safety
Assessment (LPSD PSA) for WWER NPPs


2.
Insights from Harmonization of LPSD PSAs for WWER-440
NPPs
Insights from Harmonization of LPSD PSAs for WWER-1000
NPPs
PRESENTATION AND DISCUSSION OF DETAILED MODELING ISSUES
FOR SELECTED INITIATORS – ASSUMPTIONS, DATA, HUMAN
RELIABILITY ANALYSIS, ACCIDENT SEQUENCES, ETC.
2.1
Group of WWER-440 NPPs:








2.2
Human-induced LOCA
Loss of non-essential service water
Reactivity accidents including boron dilution
Loss of natural circulation
Heavy load drops
Loss of non safety buses (reserve)
Small LOCA 20-60 mm
Total loss of self-consumption
Group of WWER-1000 NPPs:


Loss of offsite power
Heavy load drops on primary circuit




Primary circuit leaks outside containment
Small LOCA from primary to secondary circuit
Loss of heat removal from reactor core via primary side
Pressurize Safety Valves Leaks after opening during hydrotest
3.
INSIGHTS FROM PERFORMANCE AND REVIEW OF LPSD PSAs FOR
OTHER NPPs WORLDWIDE AND LPSD PSA APPLICATIONS
4.
GROUP DISCUSSIONS AND DEVELOPMENT OF THE WORKSHOP
REPORT ON DETAILED COMPARISON OF LPSD PSAs FOR WWER NPPs
5.
DISCUSSION ON FURTHER WORK AND RECOMMENDATIONS FOR
FUTURE ACTIVITIES ON HARMONIZATION OF PSAs FOR WWER NPPs