1 / 9

IP-EUROTRANS Meeting WP 1.5 Progress in safety approach development

IP-EUROTRANS Meeting WP 1.5 Progress in safety approach development. Sophie EHSTER. TEE, March 17 2006. CONTENTS. Progress in the development of a safety approach for Eurotrans concepts First assessment of MYRRHA/XT-ADS analyses results and impact on the design.

yoshi
Télécharger la présentation

IP-EUROTRANS Meeting WP 1.5 Progress in safety approach development

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. IP-EUROTRANS Meeting WP 1.5Progress in safety approach development Sophie EHSTER TEE, March 17 2006

  2. CONTENTS • Progress in the development of a safety approach for Eurotrans concepts • First assessment of MYRRHA/XT-ADS analyses results and impact on the design

  3. Progress in activities associated with task 1.5.1 • Task 1.5.1: Safety approach • Coordination: FANP (AREVA NP) • Participants: FZK, CEA, EA, SCK, KTH • Budgets (first period): to be confirmed by KTH • Total: 180 keuros • FANP (100)/FZK (10)/CEA (10)/EA (10)/SCK (20)/KTH (30) • Deliverables: • D1.20: Report on the approach and acceptance criteria for safety design of XT-ADS • To be issued by the end of March 2006 • First draft expected by the end of April 2006 • D1.21: Report on the approach and acceptance criteria for safety design of EFIT • To be issued by the end of September 2006 • Participation to the safety studies (definition, assessment of results)

  4. Development of a general safety approach for XT-ADS - 1 • D1.20: Report on the approach and acceptance criteria for safety design of XT-ADS • The safety approach is based on the one developed for PDS-XADS concepts • Application of defense in depth principle: prevention and mitigation of severe core damage • Elimination of the necessity of off site emergency response (Generation IV objective) • Probabilistic design targets: • 10-5 per reactor year for cumulative severe core damage frequency is a minimum objective (lack of experience feedback): 2 strong LOD as a minimum for each sequence with an objective of 2 strong LOD + 1 medium LOD • Severe core damage is studied as a Design Extension Condition (mitigation provisions: 1 medium LOD) • Enhancement of prevention assessed with ALARP • For severe core damage situations which cannot be mitigated, they must result from a limited number of sequences for which a higher level of prevention is required. Their exclusion is justified by at least 2 strong LOD + 1 medium LOD for each sequence

  5. Development of a general safety approach for XT-ADS - 2 • Categories of events considered for the safety demonstration: • Determination of the list of "excluded situations" (i.e. their consequences are not considered in the design) and guidance for the provisions used for an adequate justification of their exclusion • Determination of the "dealt with" initiating faults list and associated sequences: assessment of PDS-XADS results and consideration of new XT-ADS design features • Determination of practical analysis rules and adapted to the risks (e.g. corrosion consideration) • Consideration of XT-ADS specific features: increase of the core power density, consideration of core partly loaded with minor actinides, risk of water/steam ingress, risk of freezing • Radiological consequences: use of national method (i.e. Belgium) Action: SCK • Determination of barriers (e.g. fuel, cladding, structures) criteria: to be preliminary defined and confirmed by R&D about the knowledge of material behaviour for higher temperatures Action: CEA?, KTH?, FZK?

  6. Development of a general safety approach for XT-ADS - 3 • Implementation of the approach for new concepts: • Necessity of a prior assessment of the potential consequences of initiators without consideration of safeguard measures. This allows to determine: • The list of "excluded" and "dealt with" situations • What the means necessary to mitigate the consequences should be • How many and diverse are the means required in regard to the safety objectives by means of use of Line Of Defence/ PRA methods should be • What the performances expected for these safety related means (grace period, capability…) in regard to the criteria should be

  7. Development of a general safety approach for XT-ADS - 4 • Specific safety issues have to be dealt with: • Sub-critical core: • Definition of the sub-criticality level: • No criticality any DBC and DEC (except severe core damage) • Risk of criticality during severe core damage has to be assessed • Consideration of events likely to occur during shutdown conditions (modification of the core, specific accidents): control of the sub-criticality level and implementation of a dedicated shutdown system Action: SCK?, CEA? • Confinement function: • Coupling of the reactor, spallation target and the accelerator needs to be assessed • Generation of polonium 210 due to the activation of bismuth under irradiation Action: EA? • Demonstration of exclusion of core support structures (internals, reactor vessel) failure: • ISIR of in-vessel structures under a metal coolant • Consideration of oxide formation (design, monitoring, mitigation provisions) Action: FANP

  8. First assessment of MYRRHA/XT-ADS analyses results and impact on the design - 1 • A quick assessment of the available analyses results for MYRRHA indicates that a first feedback is already needed on the design: • Risk of freezing in the Emergency Heat Exchanger (e.g. case of partial PLOFC, partial PLOH, overcooling) , leading to the complete unavailability of the DHR function shall be excluded • Impact of EHX design: core by-pass, inversion of flowrate between power conditions and natural convection, impact on the procedure for reactor shutdown • Reliability (e.g. number of systems, redundancy, diversity, duty of the cavity walls cooling system) of the DHR means has to assessed • Adequate design and temperature in operating conditions of the water cooling circuit • SA blockage consequences • … • An early check and review of the available results and their impact on the design is requested in parallel to the analysis of XT-ADS transients Action: FANP, SCK, FZK (End of May)

  9. First assessment of MYRRHA/XT-ADS analyses results and impact on the design - 2 • Safety input is necessary to implement the XT-ADS reference design • Selection of Reference Design: before summer • The general architecture (MYRRHA and its variants for XT-ADS such as fuel handling from the top) needs to be assessed in regard to safety • Use of check and review of analyses based on MYRRHA Draft 2 file • Use of available results of XT-ADS transient analyses • Working group: FANP, SCK, FZK, others? • Dedicated meeting (synthesis of the assessments) early in June?

More Related