Msre Design and Operations Report. Part Vii. Fuel Handling and Processing Plant.

A New Look at Licensing Basis Events for the Molten Salt Reactor Experiment

“…ORIGEN calculations indicate a reduction from 1,055 PBq (28.5 million Ci) to 167 PBq (4.5 million Ci) after a decay period of 3 days [23]. • When the fuel salt in the storage tank was treated with a mixture of HF and H 2 for the removal of oxides, volatilization of corrosion or fission products was not significant [24]. However, during fluorination (for recovery of U), many elements were volatilized out of the fuel salt.…”

“…This was to prevent an excessive release of Xe when beginning to purge the gas space in the fuel processing equipment. After the decay period, the decay rate of Xe would be equal to the production rate [24], and the overall radioactivity of the fuel salt would be notably lower than it was when it was circulating in the fuel salt loop.…”

“…During fuel processing, the FVs in the transfer lines to the fuel salt drain tank were frozen, and the salt sampler contained at least two independent barriers preventing the release of radioactive material. This design is similar to that of the fuel salt samplerenricher (see footnote 13 above) [24]. As discussed in Section 3.1.3, little radioactivity was volatilized during H2-HF treatment for oxide removal: during this process, most of the radioactive material was either in the fuel storage tank or in the NaF bed.…”

“…The second barrier preventing release for the fuel processing equipment was similar to the barrier for the fuel salt. The main portion of the fuel handling and processing system was in the fuel processing cell, in which all penetrations were tightly sealed, and a negative was pressure maintained during processing [24]. The off-gas filter, hydrogen flame arrester, activated charcoal trap, and waste salt removal line were located in the spare cell adjacent to the fuel-processing cell.…”

“…Before these industry-standard system analyses are completed, a preliminary set of MSRE operational modes and plant states can be postulated using MSRE design and operations reports [9] [12], as well as the list of safety functions derived in Section 3.3, to develop a preliminary list of MSRE IE categories based on the challenges presented to the safety functions of the system. Then, the preliminary hazards report [6] and the MSRE safety analysis documentation [7] [11] [24] can be used to populate each of these categories with IEs.…”