Passive cooling of the PBMR spent and used fuel tanks

Abstract

The PBMR is a new generation high temperature gas cooled reactor, making use of spherical fuel elements. The spent fuel and partially burnt fuel (called used fuel) is stored in large storage tanks. This paper presents the cooling design of the storage tanks, with special emphasis on its passive cooling ability. For corrosion protection, the tanks are cooled with a closed loop active system, however, passive cooling is seen as the ultimate cooling mode for the storage tanks. If the active cooling fails, the flow automatically bypasses the active system and passive cooling takes over. The active cooling is thus not safety-related; rather its purpose is for investment protection. It has been shown through diverse techniques that the fuel inside the tanks can be cooled passively. There are still a few aspects which need to be explored in more detail, but overall it can be said that passive cooling of the PBMR spent and used fuel in bulk storage tanks is viable.

Corrosion issues in high temperature gas-cooled reactor (HTR) systems

“…These tubes could therefore also be exposed externally to the corrosive environment. Internally, the tank will be filled with an inert gas such as He or N, hence there is no risk of internal corrosion (Fuls, 2005). looking at the potential materials for spent fuel tanks without the need for intensive maintenance (see Table 20.3), the range can be limited to allowable aSme pressure vessel materials.…”

Radionuclide Characteristics of Rde Spent Fuels

“…Radionuclide activity is important in assessing the performance of spent fuel in geological disposal [8]. Thermal power quantification of spent fuel is used as the basis for safety analysis of heat removal in the spent fuel storage tank [9,10]. Neutron production and photon release rates are also crucial for shielding analysis of spent fuel cask [11,12].…”