Table 1.2 Materials in the Nuclear Steam Supply (1000 Mwe) Component Material+ Mass Materials Issues (MT) Fuel UO2, (U,Pu)O2 100 Fission gas release (21); fission product swelling; thermal conductivity decrease with burnup (19) Cladding, Zircaloy 1.7 Sn; 0.5 25 Waterside corrosion and hydriding (Chap.22); spacer grids (Fe, Ni, Cr); 0.1 O; embrittlement (26), growth (Chap 27); bal Zr; Zr-Nb interaction (Ch.23) ; fretting Ag-Cd-In (PWR), ~1 B4C (BWR; Neutron absorbers None except in severe accident (both) Reactor Pressure Low-alloy steel ~350 Vessel 2 Cr ; 1 Mo; bal Fe Radiation embrittlement (PWR only) (Chapter 26) Steam Generator Low-alloy steel Tube plugging, cracking, denting; leakage from (PWR) Inconel: 600 Ni; 25 the primary coolant to the secondary loop water Cr; 15 Fe Stainless Steel:18 Cr; 8 Ni; bal Fe; Reactor Internals Stress-Corrosion Cracking (25), Fatigue, Inconel Ex-core - components, Stainless steel Stress-corrosion cracking ( BWR) (25) primary piping Valves, pumps Stainless steel; - Cobalt dissolution => activation in core stellite: (high cobalt) => deposition in primary circuit Special Core alloy 718 Creep, SCC Components (holdown springs) 1.8 Capacity Factor The single most important measure of the efficiency of a power plant is its annual capacity This quantity is defined as the net quantity of electricity generated in one year divided by factor. the maximum possible amount had operation been continuous at the rated power. The capacity factor is generally less than 100% because of shutdowns due to the following: for refueling and regular maintenance (typically for 20 30 days every scheduled outages – 18-24 months a capacity factor loss of ~ 5%) – due to equipment or fuel element failures Forced outages Operation at reduced power due to: -load-following (changing because of reduced or increased demand on the electrical grid) power maneuvering at a low rate (to avoid damage to fuel elements)
Table 1.2 Materials in the Nuclear Steam Supply (1000 Mwe) Component Material+ Mass (MT) Materials Issues Fuel UO2, (U,Pu)O2 100 Fission gas release (21); fission product swelling; thermal conductivity decrease with burnup (19) Cladding, spacer grids Zircaloy 1.7 Sn; 0.5 (Fe, Ni, Cr); 0.1 O; bal Zr; Zr-Nb 25 Waterside corrosion and hydriding (Chap.22); embrittlement (26), growth (Chap 27); interaction (Ch.23) ; fretting Neutron absorbers Ag-Cd-In (PWR), B4C (BWR; (both) ~1 None except in severe accident Reactor Pressure Vessel Low-alloy steel 2 Cr ; 1 Mo; bal Fe ~350 Radiation embrittlement (PWR only) (Chapter 26) Steam Generator (PWR) Low-alloy steel Inconel: 600 Ni; 25 Cr; 15 Fe Tube plugging, cracking, denting; leakage from the primary coolant to the secondary loop water Reactor Internals Stainless Steel:18 Cr; 8 Ni; bal Fe; Inconel Stress-Corrosion Cracking (25), Fatigue, Ex-core components, primary piping Stainless steel - Stress-corrosion cracking ( BWR) (25) Valves, pumps Stainless steel; stellite: (high cobalt) - Cobalt dissolution => activation in core => deposition in primary circuit Special Core Components (holdown springs) alloy 718 Creep, SCC 1.8 Capacity Factor The single most important measure of the efficiency of a power plant is its annual capacity factor. This quantity is defined as the net quantity of electricity generated in one year divided by the maximum possible amount had operation been continuous at the rated power. The capacity factor is generally less than 100% because of shutdowns due to the following: scheduled outages for refueling and regular maintenance (typically for 20 – 30 days every 18-24 months – a capacity factor loss of ~ 5%) Forced outages due to equipment or fuel element failures Operation at reduced power due to: -load-following (changing because of reduced or increased demand on the electrical grid) power maneuvering at a low rate (to avoid damage to fuel elements)
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