Deterministic Analysis of a Beyond Design Basis Accident in a Low Power, Pin-Type Fuel Research Reactor

A Beyond Design Basis Accident has been analyzed for a pool type research reactor with pin-type, Zry4 clad fuel. This is a low power research reactor (maximum power: 100kW) with neutron beam facilities. Two scenarios are considered: a neutron beam rapture that results in a fraction of the core submerged in water and a catastrophic failure that results in a fully uncovered core. The paper discusses the different cooling mechanisms for these two BDBAs and compares results for both scenarios, with predictions of no core damage in any situation. Core damage is defined as CHFR↔1.5 and/or Tclad→T start of breakaway oxidation temperature. In addition, the paper compares calculations with a thermalhydraulic code and an analytical model. This paper allows to analyze the applicability of regular thermalhydraulic codes to BDBA accident scenarios in low power research reactors