Heat transfer experiments simulating a failure of the inlet piping to a K reactor process tube
This in DECLASSIFIED i . DEI L,SSIFIEO -2-m_-68el)_ HEAT _NSFER EXP_ SIMULATING A FAILUBE OF THE _ PIPING TO A K REACTORPROCESS IRTRODUCTION°R eported herein are the results of laboratory heat transfer experiments. These experiments were conducted to investigate fuel element temperatures which could result from coolant flow loss follo_rlng a failure of the inlet piping to a process tube at a K reactor. The failure of the inlet coolant piping between the front header and the process tube on a
... rocess tube on a reactor would cut off the flow of cooling water to the fuel elements but should immediately i_itiate a reactor scram by causing a low trip on the Panellit pressure monitor. However, the reactor power reduction would not be immediate nor absolute and would be dictated by the time required to insert the emergency contrcl rods (VSR's) and by postscram delayed fission and fission product de_,ayheating. The only means of heat remo,_l from the affected tube and fuel elements during the post-scram period would be by reverse flow of hot water from the rear header. The objective of the subject experiments was to determine what rear header pressures would be required to achieve adequate cooling of a K reactor fuel assembly during such a post-scram period. Such information is of value in updating of reactor hazards evaluation reports. Experimental studies were previously reported concerning failure of a front hyd;B_ullc,fittingon a C reactor 'Operational-charge-discharge' geometry.(1,2,3 )* Preliminary experimentst_re also conducted for a standard K reactor coolant inlet geometry, _ ; but failure of the test section caused postponement of the program. The previous studies did indicate appreciable differences in the rear header pressures required for adequate post-scram cooling of the two assemblies and thus the C reactor data could not be applied to K reactor.