K. Fukuda et al., IRRADIATION BEHAVIOR OF HTGR COATED PARTICLE FUEL AT ABNORMALLY HIGH-TEMPERATURE, Nuclear Engineering and Design, 157(1-2), 1995, pp. 221-230
Irradiation behavior of high temperature gas-cooled reactor (HTGR) coa
ted particles under temperature transient conditions was investigated
in accordance with a design-base accident scenario for HTTR, a 30 MWth
HTGR under construction at JAERI. One of the scenarios predicts that
the fuel temperature of the block-type fuel element rises to abnormall
y high temperature by blocking a coolant channel with some foreign sub
stance. For simulating this scenario the fuel compacts incorporating t
he coated particles were irradiated at normal temperature in three cap
sules, followed by temperature transient up to a maximum of approximat
ely 2000 degrees C. The post-irradiation examinations, including surfa
ce inspection, metrology, ceramography and a measurement of coated par
ticle failure were applied to the fuel compacts to investigate the the
rmal-transient effect on the fuel integrity. Integrity of the fuel com
pact was also assessed by an estimation of tangential stress introduce
d into the compact by the temperature transient.