The reactor also has decay heat removal systems consisting of four independent circuits of 8MWt capacity each.
2.
Both the ICS and PCCS heat exchangers are submerged in a pool of water large enough to provide 72 hours of reactor decay heat removal capability.
3.
These engines are able to provide emergency electrical power for reactor decay heat removal, as well as enough electric power to supply an emergency propulsion mechanism.
4.
In contrast to current commercial fission reactors, hybrid reactors potentially demonstrate what is considered inherently safe behavior because they remain deeply subcritical under all conditions and decay heat removal is possible via passive mechanisms.
5.
These include : Core heat removal through natural circulation; direct injection of emergency core coolant system ( ECCS ) water in fuel; and the availability of a large inventory of borated water in overhead gravity-driven water pool ( GDWP ) to facilitate sustenance of core decay heat removal.
6.
EBR-II had a negative thermal coefficient of reactivity that shut down the reactor when the temperature increased due to loss of the coolant pumps; the time required to heat the large pool of sodium surrounding the reactor provided a sufficient time buffer for the passive decay heat removal system to prevent the EBR-II reactor from melting down.
7.
This coolant has several extremely beneficial properties for a reactor : it is opaque to gamma radiation, but transparent to neutron flux; it melts easily at a low temperature, but does not boil until an extremely high temperature is reached; it does not greatly expand or contract when exposed to heat or cold; it has a high heat capacity; it will naturally circulate through the reactor core without pumps being required-whether during normal operation or as a means of residual decay heat removal; and it will solidify once decay heat from a used reactor has dropped to a low level.