ESWBR final
Nuclear power plants provide the most economically efficient, safe, and sustainable source of power generation available to our generation; however it comes with it’s own set of issues that must be dealt with to mitigate any potential harm to the environment or population. One of the larger issues is that once the reactor has attained initial criticality, it is never truly “off”. The reactor will still produce heat due to decay of non-stable isotopes within it caused by fission.
Because decay heat will be forever present within a shutdown reactor, it is imperative that the ESWBR design incorporates a system to combat this heat in the event of a long shutdown period or following a SCRAM due to an adverse reactor condition. The Emergency Core Cooling System (ECCS) provides a means of maintaining the core cooled and covered preventing cladding failure, damage to the Reactor Pressure Vessel (RPV) or the release of radioactive isotopes outside of the RPV.
Normally used for power operations, the reactor coolant pumps can be also used for decay heat removal at slower speeds or different coolant pump combinations. In an intensive emergency situation where coolant exits the system, known as a Loss of Coolant Accident (LOCA), emergency measures must be enacted to provide a source of makeup water to the core to provide adequate cooling. This emergency cooling is provided for by the ECCS which is comprised of four subsystems; the Gravity Driven Cooling System (GDCS), Isolation Condenser System (ICS), Standby Liquid Cooling System (SLCS), and the Automatic Depressurization System (ADS). The later is technically a part of the Nuclear Boiling System (NBS). The GDCS is central to the ECCS and core protection. Its main purpose is to store and insert emergency cooling water into the RPV in the event of a reactor accident. The main components of the system consist of three water poops, automatic initiation logic circuits, all associated piping and valves, along with
Because decay heat will be forever present within a shutdown reactor, it is imperative that the ESWBR design incorporates a system to combat this heat in the event of a long shutdown period or following a SCRAM due to an adverse reactor condition. The Emergency Core Cooling System (ECCS) provides a means of maintaining the core cooled and covered preventing cladding failure, damage to the Reactor Pressure Vessel (RPV) or the release of radioactive isotopes outside of the RPV.
Normally used for power operations, the reactor coolant pumps can be also used for decay heat removal at slower speeds or different coolant pump combinations. In an intensive emergency situation where coolant exits the system, known as a Loss of Coolant Accident (LOCA), emergency measures must be enacted to provide a source of makeup water to the core to provide adequate cooling. This emergency cooling is provided for by the ECCS which is comprised of four subsystems; the Gravity Driven Cooling System (GDCS), Isolation Condenser System (ICS), Standby Liquid Cooling System (SLCS), and the Automatic Depressurization System (ADS). The later is technically a part of the Nuclear Boiling System (NBS). The GDCS is central to the ECCS and core protection. Its main purpose is to store and insert emergency cooling water into the RPV in the event of a reactor accident. The main components of the system consist of three water poops, automatic initiation logic circuits, all associated piping and valves, along with
Cited: ESBWR Chapter 7 “Design and Control Document, Tier 2” 2007 ESBWR “Plant General Description” 2011, June 1