BOUNDARY ELEMENT FORMULATION OF FISSION NEUTRON SOURCE PROBLEMS USINGONLY BOUNDARY INTEGRALS

The present paper describes a general way of transforming domain integ rals into equivalent boundary ones in boundary element formulations of fission neutron source problems. The critical eigenvalue, which is de fined originally by the ratio of two different domain integrals has be en transformed into a ratio involving only boundary integrals. The dom ain integral of fission source multiplied by the fundamental solution is converted into an equivalent boundary integral by the use of a part icular solution technique, in which the source distribution is expande d into a Fourier series. The coefficients required in the expansion ar e determined using a boundary-only integral which has a recurrence for m and is updated throughout the neutron source iteration scheme.