Regional Basic Professional Training Course in Korea

❙ 935 ❙
16. In‐Plant Accident Management
During and following a severe accident, in order to follow the general conditions in the
containment and to facilitate the use of guidelines for the management of severe
accidents, essential parameters for the containment such as pressures, temperatures,
hydrogen concentrations, water levels and radiation dose rates should be monitored.
To follow the progression in the values of parameters specific to severe accidents,
consideration should be given to the installation of instrumentation to measure the
following parameters:
The status of core depressurization devices (such as relief valves) for the early
indication of possible high pressure melting of the core;
The concentration of combustible gases, in order to assess the likelihood of fast
deflagration or detonation;
Pressure and temperature signals over a wide range, in order to detect possible late
failure of the containment;
The sump water level, as an indication of the amount of water available for long
term injection into the core and for containment spraying.
In order to execute emergency procedures, the operator should have available controls
and instrumentation for the containment systems provided specifically for the prevention
and mitigation of severe accidents. These may include, for example:
A filtered venting system;
A monitoring and control system for combustible gases.
An assessment of the radiological consequences of a possible severe accident should be
conducted in a timely manner to assist in decisions on long term actions for the protection
of the population (off‐site emergency measures). Instruments for assessing radiological