Penetration shielding applications of CYLSEC

With the increased industry interest in cost-effectively reducing operator exposures and with the development of the CYLSEC[1] gamma transport computer code at Bechtel, a comprehensive program was initiated to reduce penetration shielding but still provide a prudent degree of protection from radiation streaming. This program was more comprehensive than previous efforts due to the recently developed code and increased efforts to control project costs while still maintaining radiation exposures ALARA. By using the CYLSEC code's three-dimensional modeling and multi-source capabilities, the elimination of shielding was justified in many cases. Where shielding was necessary, it was optimized to reduce costs. For cases in which shielding was not practical or cost effective, the results are used to identify locations for future access controls (permanent or temporary) and to highlight areas of high radiation for use by health physicists in planning work activities