CHAPTER 4: Introduction to Accident Management

Preventive and mitigative measures

Preventine domain

Aim

The aim is prevention of severe fuel damage, through fulfilment of a set of safety functions of primary importance (often and also here called: 'critical safety functions').

Establishment of priorities

As the fulfilment of the critical safety functions needs a certain chronology (not everything can be done at the same time, e.g. to achieve subcriticality is mostly a prime action) and also places different demands on supportive functions (such as power supply, available resources) and staff, priorities must be established among the various 'critical safety functions'.

Responsibilities

For most events, the shift supervisor of the control room is the responsible authority. For more complex events and for severe accidents, authority may shift to other persons or groups of persons of the plant staff.

The usual approach is as follows: for all events where the ARPs, EOPs are the proper response, the Control Room shift supervisor is the responsible authority. The leader of the plant Emergency Response Organization (ERO) is available for advice to the control room, or decision making for complex tasks, if deemed appropriate. More information is in Module 4.

Procedures/guidelines

Use of procedures for accident management measures (i.e. EOPs) is in the control room.

Mitigation domain

Aim

The aim is the protection of remaining fission product boundaries and the limitation of releases of radioactive material to the environment through actions comprising termination of core melt progression, maintenance of containment integrity and control of releases. This includes attempts to maintain reactor vessel integrity.

Establishment of priorities

Priorities should be established between mitigatory measures, with the highest priority to mitigation of significant ongoing releases and immediate threats to fission product barriers.

Responsibility

Responsibility is with the ERO, with control room staff available for advice and execution of measures. The ERO is responsible for decision making. Further information is in Module 4.

Procedures / Guidelines

Use of guidance documents (SAMG) by the ERO or other designated staff.


Table 1-5: Summary of Features of an Accident Management Programme (SSG-54, Appendix I, Table 1)