Page 105 - AERB

07 SAFETY ANALYSIS AND RESEARCH

AERB recognises the importance of Safety Analysis seen that the maximum steady state temperature is well
& Research in support of its regulatory function. In-house within specified limits.
safety related R&D helps in obtaining deeper insights
into the issues concerning nuclear and radiation safety to 7.1.2 Thermal Transient Analysis of CORAL High-
arrive at scientifically sound and risk informed regulatory level Waste Raffinate
decisions. Safety analysis and research activities are
carried out by AERB as a part of its regulatory activities. To support the regulatory review related to replacement
Several important developmental studies were taken up of cooling towers of CORAL high-level waste raffinate,
by AERB and completed during this year. A brief overview an independent verification calculation for estimating the
of these activities is presented in the following sections. maximum temperature of raffinate waste solution, during
unavailability of primary cooling water, was carried out.
7.1 THERMAL HYDRAULICS SAFETY STUDY A transient heat transfer model was developed in-house
and used to estimate the raffinate level and temperature
7.1.1 Heat Transfer Studies on FBTR Fast Flux transients for two separate scenarios of raffinate loading
Experimental Facility for 5 year period;

As part of regulatory review of the proposed Fast Case-1: The entire raffinate generated by reprocessing
Breeder Test Reactor (FBTR) fast flux experimental of 72 fuel assemblies (after a two-year cooling period,
facility for irradiation of radioactive samples at 400 kW, subsequent to attaining a maximum burn-up) is assumed
an independent verification study was carried out. During to be filled in the storage tank in one single campaign.
the irradiation procedure, it is essential to ensure that the Case-2: A more realistic scenario, wherein, raffinate
temperatures do not exceed the approved safe limit during generated by reprocessing the specified quantity of fuel
its operation of six hours. A detailed 3-D transient heat assemblies each year is progressively filled and stored in
transfer analysis was carried out using COMSOL (Multi- the tank.
physics software). The temperature transient at the centre
of the Pu coated gold foil during irradiation is shown in The temperature transients for Case-1 and Case-2 are
Fig. 7.1(a). The temperature contour of the entire domain depicted in Fig. 7.2 (a) and (b) respectively. The results
after six hours of operation is given in Fig. 7.1(b). It is are in agreement with results in the submission.

(a) (b)

Fig. 7.1: (a) Foil Temperature Transient and (b) Contour Plot

AERB Annual Report 2019 77