Emergency Core-Cooling Systems for Light-Water-Cooled Power Reactors.

Potential Metal--Water Reactions in Light-Water-Cooled Power Reactors.

“…In this type of accident, heat i's generated .at a very rapid rate inU0 2 others it was a mixture containing mostly Zr0 2 • The difference ~n these fuels had no bearing on the extent of the metal-water reactions when correlated against the peak adiabatic fuel temperature. 50 Later scaleup experiments with nine-pin clusters of fuel indicated about the same results for the extent of the metal-water reaction.…”

“…Such.emergency core-cooling systems spray and/or flood the reactor core with water; they are discussed in detai'l by Law.son. 2 If the pessimistic assuinption4s made that ~he emergency core·cooling systems are inoperative, it must also be ·assumed that there will '*Thio as-sumption ·has _been questioned; see letter· from W. D. Manly, Advisory Committee on Reactor Safeguards, to G. T. Seaborg, USAEC, Nov. 24,1965; included in USAEC Press. Release, H-262, Dec. 3,1965.…”

“…cies in the metal and at the metal-oxide interface. 38 -40 . Wher,t there is .-excess steam available at· the metal's· surface, the· most accepted +ela-tion describing the reaction rate between zirconium and steam is that d~rived by Baker ahd Just; 41 which is i where w is weight (mg) of zircQnium reacted per· unit (cm 2 ) of surface area, t is time (sec)., R is the gas constant (1.987 cal/mole·°K), and Tis te'\'llperature (°K). In :this f9rmiof the correlation, ·it is tacitly 9-Ssum~d .that all lthe reacted ·metal is converted into stoichiometric Zr0 2 , but this is a simplification of the situation.…”

“…48 , 137 In these tests, Zircaloy-clad U02 fuel pins were suspended over a pool of water at room or higher temperatures and then subjected to a flat-top transient to approximate crudely the loss-of-coolant accident conditions. The specific results to be obtained from these experiments were (1) extent of the metal-water reaction, (2) pressures and temperatures,· and (3) final particle size distribution of the fragmented fuel. Three experiments have been run so far, and they are surmnarized in Table 2.1.…”

Testing of Containment Systems Used With Light--Water-Cooled Power Reactors.

“…76 The provisions made fo.r testing containment engineered safety features in typical new reactor pla11ts are summari7.ed above in Table 3 air-cooling linits must.be designed tohandle-the higher density atmospheric flow thatw'ould be encountered in the event of an accident, as well as to operate in the high-pressure high-temperature high-humidity atmosphere that would exist. Particular attention must be paid to the design of the electric motors for the blower fans.…”