Pertinence of tests used for conformity assessments of fire resistance of nuclear power plant components:Opinion of several institutions in Europe

Fire resistance of structures, systems and components (SSC) is widely identified as a fundamental issue for fire risk assessment at nuclear power plants (NPP). It is currently supported by several national or international ambitious experimental programs. Fire risk assessment at NPPs is performed under a series of hypothesis, e.g. the fire load. A problem will arise if tests used for conformity assessment do not appropriately represent the hypothesis selected during the fire risk analysis. In this case, SSCs may possibly be not meeting the expectations related to their fire resistance capacity supposed by the fire risk analysis. Ways of tackling this issue involve a regulatory approach and adapted requirements for components. While the widespread regulatory approach consists in seeking enveloping scenarios and conservative assumptions, a better knowledge of SSCs behaviour under for NPPs typical situations may be also desirable. The Institute for Energy of the European Commission's Joint Research Centre (JRC) at Petten (NL) launched a questionnaire with the aim of gathering opinions of regulatory bodies and their technical support organisations and manufacturers in Europe on this topic. Major goal was to estimate the relevance of the issue according to the perception of the specialists. The present paper collects the answers given by seven entities (AREVA, GRS, iBMB, IRSN, SJUB, SUEZ-TRACTEBEL, and VTT) and makes suggestions for addressing the issues identified by the participants.