Aspects of a seismic study of the MITR

Abstract

The design version of the Massachusetts Institute of Technology research reactor (MITR-II) was analyzed subject to earthquake forces. The problem was divided into three major areas. First, the reactor core tank and support structure were studied. The reactor can be adequately cooled and shutdown if the core tank remains undamaged. Using a SABOR-5 computer program, the peak accelerations required to cause yielding of the core tank were calculated to be well above potential earthquake accelerations. Second, the possibilities of potential damage to miscellaneous reactor systems were studied, The miscellaneous systems were studied to see if earthquake accelerations, resonance response, or differential motions would result in damage leading to major radioactive releases. No major potential hazards were discovered. Third, the possibility of earthquake damage to the reactor stack was studied. An approximate analysis of the stack subject to dynamic earthquake shear and a 100 mile per hour wind was made. A case of a fallen stack was modeled to determine its effect on the containment building. The conservative calculations indicate that it is unlikely that the stack will fall and even if it were to fall onto the containment shell, it would not cause damage to the reactor core tank. Within the scope of this report, it appears that the design MITR-II is adequate to provide required protection even in the event of the maximum expected earthquake motions.