GB1117315A - Nuclear reactors - Google Patents

Abstract

1,117,315. Controlling reactors. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. 26 Oct., 1965 [14 Dec., 1964], No. 50751/64. Heading G6C. In a nuclear reactor control system a control fluid is passed through a matrix of channels in the core. The fluid is separate from the coolant. Both spectral shift and flux-trap control may be effected or the fluid may be a neutron absorber such as boric acid or cadmium nitrate solution. A purging liquid, e.g. water, may be pumped round the control ducting and the system cooled by passing the control fluid through external heat exchangers. Reactor shut-down heat is extracted in this way. The reactor coolant flow is arranged so as to balance the control fluid and coolant pressures across the channel walls. In the spectral shift control method, the control fluid is a mixture of light and heavy water. Where an absorber liquid is employed, Fig. 2, the water cooled fuel channels 13 are separated by the zircalny sheets 13a, 13b between which the control liquid is urged. Cross pressures between the coolant channels are illuminated by the perforations 32. For an emergency condition, a highly concentrated neutron absorber may be introduced into the spaces between 13a and 13b.