Assessment of damage domains of the High-Temperature Engineering Test Reactor (HTTR)

• We developed an adequate model for the identification of damage domains of the HTTR.
• We analysed an anticipated operational transient, using the HTTR5+/GASTEMP code.
• We simulated several transients of the same sequence.
• We identified the corresponding damage domains using two methods.
• We calculated exceedance frequency using the two methods.

This paper presents an assessment analysis of damage domains of the 30 MWth prototype High-Temperature Engineering Test Reactor (HTTR) operated by the Japan Atomic Energy Agency (JAEA). For this purpose, an in-house deterministic risk assessment computational tool was developed based on the Theory of Stimulated Dynamics (TSD). To illustrate the methodology and applicability of the developed modelling approach, assessment results of a control rod (CR) withdrawal accident during subcritical conditions are presented and compared with those obtained by the JAEA.