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Conference Article: Analytical method and result of off-site exposure during normal operation of high-temperature engineering test reactor (HTTR)

Abstract

This paper describes analytical method and result of off-site radiation exposure during normal operation of the High Temperature Engineering Test Reactor (HTTR). Even in normal operation, some amounts of fission products are assumed to be released from the fuel particles with defect of coating layers. In the evaluation of off-site radiation exposure, 1% of coated fuel particles is conservatively assumed to be failed in the HTTR. The release paths of fission products from the core to the stack are divided into two patterns, namely continuous release and periodical release. Continuous releases of fission products are leaked from the reactor containment vessel which contains fission products leaked from the primary coolant system. On the other hand, periodical release of fission products are brought by the purge of radioactive gas from the decay tank which accumulates the gaseous wastes from the primary helium purification system and the primary coolant sampling system and by the fuel handling system. Off-gas from the sweep gas sampling system for the fuel failure test is also considered. The annual off-site radiation exposure from the HTTR is 0.77 piiSv/y in effective dose equivalent. This value is sufficiently lower than the reference dose of 50 piiSv/y in normal operation.

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Reference:

Technical committee meeting on gas-cooled reactor technology safety and siting Dimitrovgrad (Russian Federation) 21-23 Jun 1989

International Atomic Energy Agency, Vienna (Austria)

IAEA-TC--389.26, pp:105-124