Fuel rod element

The hot side of steam turbines and the blades of feed water pumps are made from 12% chromium steels, also wear resistant components such as bearings and pump shafts and valve spindles, which are sometimes hard chrome plated. Support grids for fuel rod elements are also made from chromium steel. The corrosion loss of these materials in demineralised water at 260 °C is 0.007 mm/a at pH 7 and 0.11 mm/a at pH 10 [72]. 

Figure A1.18 Simplified iayout of typicai BWR NPP (courtesy of US NRC) geneiai basic features (1) thermal neutron spectrum (2) UO2 fuel (3) fuel enrichment about 3% (4) direct cycie with steam separator (steam generator and pressurizer are eiiminated), ie, singie-flow circuit (singie loop) (5) RPV with verticai fuel rods (elements) assembled in bundle strings cooled with upward flow of fight water (water and water—steam mixture) (6) reactor coolant, moderator, and power cycle working fluid are the same fluid (7) reactor cooiant outlet parameters pressure about 7 MPa and samration temperature at this pressure is about 286°C and (8) power cycle subcritical-pressure regenerative Rankine steam turbine cycie with steam reheat.

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