MEASUREMENT OF EIGENVALUE SEPARATION BY USING POSITION-SENSITIVE PROPORTIONAL COUNTER

Eigenvalue separation is an important index of power reactor stability in the view of neutronics. In recent years, a long, slender Position Sensitive Proportional Counter has been developed. By using this propo rtional counter, the spatial neutron flux distribution of a nuclear re actor can be measured rapidly. Using these characteristics, we intend to develop the experimental method evaluating eigenvalue separation as an index for reactor stability. A method based on spatial integrals o f neutron flux measured at a subcritical system with an external sourc e is proposed. To verify this method, experiments were carried out at Kyoto University Critical Assembly. It was confirmed that eigenvalue s eparation can be evaluated within a relative error of 10%. (C) 1998 El sevier Science Ltd.