Piping, Pumps and Heat Exchangers

In the initial design of the seawater intake pumps the commonly used material for impeller was zinc free bronze and Al-bronze with 5% Ni. Corrosion problems, however, occurred with these materials in the Indian plant. It is apparent that the initial selection of better material for components in critical areas would considerably reduce future operational problems and provide long life. 

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The primary loop consiata of two essentially different parts (1) The 1004 process tubes penetrating the reactor, and (2) The exterior piping, pumps and heat exchangers. These are discussed separately. 

The inventories in these reactors depend in part on the volume of the fuel in the pipes, pumps, and heat exchangers in the external portion of the fuel circuit. The inventories listed in Table 14-1 are for systems having a volume of 339 ft external to the core, which corresponds approximately to a power level of 600 Mw of heat. In these calculations it was assumed that the heat was transferred to an intermediate coolant composed of the fluorides of Li, Be, and Na before being transferred to sodium metal. In more recent designs (see Chapter 17), this intermediate salt loop has been replaced by a sodium loop, and the external volumes are somewhat less because of the improved equipment design and layout. 

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