RADIATION-INDUCED ELECTROMOTIVE-FORCE IN MINERAL INSULATED CABLE UNDER REACTOR IRRADIATION

A radiation induced electromotive force (RIEMF) was measured in minera l insulated cables (MI-cables) under fission reactor irradiation. A ne gative electromotive force of about 10 V was generated in the center l ead by the reactor irradiation. The RIEMF increased with increasing ir radiation dose with about -14 V measured under the reactor full power irradiation at 573 K with a total dose of 1.1 x 10(10) Gy ionizing irr adiation and 1.1 x 10(24) n/m(2) fast neutron irradiation. The measure d voltage of the RIEMF was found to depend linearly on the reciprocal temperature. The observed RIEMF was a so-called current driven source and the measured current was linearly dependent on the reactor power a nd was about 50 nA for the 0.7 m long MI-cables at 573 K. Under full p ower, irradiation conditions were 6 W/g of a gamma flux (6 x 10(3) Gy/ s ionizing dose rate) for iron and 5 x 10(17) n/m(2)s and 1.1 x 10(18) n/m(2)s fast and thermal neutron fluxes, respectively.