Improvements in or relating to nuclear reactors

摘要

1,038,087. Controlling reactors. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. Dec. 6, 1962 [Dec. 20, 1961], No. 45610/61. Addition to 981,423. Heading G6C. In a boiling water nuclear reactor, the water acts on both coolant and moderator and a rapid fall in the water level is used to cause shutdown during fault conditions. The fall in water level is effected by reducing steam pressure to cause a more rapid boiling or " flashing." The reactivity falls in proportion to the increase in steam voids and the consequent reduction in the moderating effect as the liquid level is reduced. During " flashing " the excess steam is directed into a dump condenser through a valve automatically adjusted in accordance with the coolant level, temperature, reactor reactivity and period. The control is adjusted so as to leave the spiral water level adequate to conduct the " decay heat " from the core.