Measurements for the JASPER Program Gap Streaming Experiment

Abstract

The Gap Streaming Experiment was conducted at the Oak Ridge National Laboratory (ORNL) Tower Shielding Facility (TSF) during the three month period from February to April, 1992, as part of the continuing series of eight experiments planned for the Japanese-American Shielding Program for Experimental Research (JASPER) program that was started in 1986. This series of experiments which are intended to provide support in the development of current reactor shield designs proposed for Liquid Metal Reactor (LMR) systems both in Japan and the United States. The program is a cooperative effort between the United States Department of Energy (USDOE) and the Japanese Power Reactor and Nuclear Development Corporation (PNC). The program was designed to study neutron streaming in annular gaps typical of those anticipated in future reactor enclosure systems for advanced LMRs. The two configurations studied in this experiment were: (1) an iron-lined, concrete-filled, vessel that was designed to allow changes in annular gap widths and/or their locations; or (2) a solid piece of concrete. In two of the studies, Items IIID and IIIE, stainless steel slabs were added to simulate the effect of a cover plate above the reactor head. The configurations were preceded by either a spectrum modifier that modeled the sodium pool above the LMR core or the bare Tower Shielding Reactor H (TSR-II) beam. Bonner ball measurements were made behind each configuration and neutron spectra and Hornyak button measurements were made behind selected configurations.