{"id":13795,"date":"2017-02-08T20:34:29","date_gmt":"2017-02-08T20:34:29","guid":{"rendered":"http:\/\/sitepourvtc.com\/?page_id=13795"},"modified":"2022-10-21T07:39:59","modified_gmt":"2022-10-21T07:39:59","slug":"operational-factors","status":"publish","type":"page","link":"https:\/\/sitepourvtc.com\/nuclear-power\/reactor-physics\/nuclear-fission-chain-reaction\/operational-factors\/","title":{"rendered":"Operational factors that affect the multiplication in PWRs"},"content":{"rendered":"
Detailed knowledge of all possible operational factors that may affect the multiplication factor of the system is of importance in reactor control<\/strong>. It was stated the keff<\/sub> <\/strong>is during reactor operation kept as near to the value of 1.0 as possible<\/strong>. Many factors influence the criticality of the reactor<\/b>. For illustration, in an extreme case, the presence of humans (due to the water, carbon, which are good neutron moderators<\/a>) near fresh uranium fuel assembly influences the multiplication properties of the assembly.<\/p>\n If any operational factor changes one of the contributing factors to keff<\/sub><\/strong>\u00a0(keff<\/sub> = \u03b7.\u03b5.p.f.Pf<\/sub>.Pt<\/sub><\/strong>), the ratio of 1.0 is not maintained, and this change in keff<\/sub><\/strong>\u00a0makes the reactor either subcritical<\/strong> or supercritical<\/strong>. In most cases, each operational change influences all coefficients in the six-factor formula, but there is always a dominant effect that can be separated. For illustration, here are some examples of these operational changes and their impacts on keff<\/sub><\/strong>\u00a0that may take place in PWRs<\/a>.<\/p><\/div><\/div>