Page 433 - Fundamentals of Magnetic Thermonuclear Reactor Design

Safety of Fusion Reactors Chapter | 14 411

radionuclides and hazardous substances. These data are used in the potential
impact analysis using normal and abnormal scenarios.
l Potential alternative use of lands for economic purposes.
l Population density, distribution, and other characteristics needed to evaluate
risk to individuals and develop emergency measures.
A site is considered to be acceptable for reactor construction if it meets the
safe operation, human health and environment safety criteria.
Reactor Safety Analysis. Such analysis is performed for all phases of the
facility’s life cycle. The purpose is to identify potential hazards and the ways
of contaminant (radionuclides and hazardous substances) release beyond the
site’s outer boundaries into the environment. Different scenarios are considered
to evaluate accident probability, potential consequences, contamination scale
and effects on human health. The reactor performance during external naturally
occurring and human-induced events is analysed. Processes taking place in the
reactor systems and accident consequences should be analysed using certified
and tested software and results available from special experimental research. A
SAR, to be submitted to licensing authorities, must include the description of
the analysed facility, including important systems, the site, as well as accident
management and mitigating procedures. The SAR must confirm that
l harmful effects on the population, personnel and the environment fall within
the limits prescribed by the design and the regulatory documents;
l both the reactor and the SIS properly react on the events; and
l the defence in depth ensures the performance of the key safety function, and
there is no need for population evacuation.
The maintenance personnel (performing testing, inspection, calibration, ser-
vice, etc.) is exposed to ionising radiation from tritium, activated parts of the fa-
cility, activated dust sputtered by IVC materials and the cooling system piping.
Radiation safety is ensured through
l compliance with prescribed dose limits,
l protection from any unjustifiable exposure to radiation, and
l reducing the radiation dose to ‘as low as is reasonably achievable’, eco-
nomic and social factors having been taken into account.

The collective workers’ radiation dose is

× × p ,
D = ∑ DRt i i D=∑DR×ti×pi,
where DR is dose rate; t is the duration of the ith operation; and p is the number
i
i
of people performing that operation. The annual collective dose per reactor is
calculated taking into account the total number of operations.
Occupational gamma radiation dose rate (DRγ) is calculated based on the
intensity of the radiation and the radiation field geometry, using the results