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Title: Induced Radioactivity in Lead Shielding at the National Synchrotron Light Source

Journal Article · · Health Physics
 [1];  [2];  [2]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States). Energy Sciences Directorate. National Synchrotron Light Source II
  2. Brookhaven National Lab. (BNL), Upton, NY (United States). Environment Safety and Health Directorate. Radiological Control Division

The National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory was shut down in September 2014. Lead bricks used as radiological shadow shielding within the accelerator were exposed to stray radiation fields during normal operations. The FLUKA code, a fully integrated Monte Carlo simulation package for the interaction and transport of particles and nuclei in matter, was used to estimate induced radioactivity in this shielding and stainless steel beam pipe from known beam losses. The FLUKA output was processed using MICROSHIELD® to estimate on-contact exposure rates with individually exposed bricks to help design and optimize the radiological survey process. This entire process can be modeled using FLUKA, but use of MICROSHIELD® as a secondary method was chosen because of the project’s resource constraints. Due to the compressed schedule and lack of shielding configuration data, simple FLUKA models were developed in this paper. FLUKA activity estimates for stainless steel were compared with sampling data to validate results, which show that simple FLUKA models and irradiation geometries can be used to predict radioactivity inventories accurately in exposed materials. During decommissioning 0.1% of the lead bricks were found to have measurable levels of induced radioactivity. Finally, post-processing with MICROSHIELD® provides an acceptable secondary method of estimating residual exposure rates.

Research Organization:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
SC0012704
OSTI ID:
1425109
Report Number(s):
BNL-200054-2018-JAAM; TRN: US1802044
Journal Information:
Health Physics, Vol. 112, Issue 6; ISSN 0017-9078
Publisher:
Health Physics SocietyCopyright Statement
Country of Publication:
United States
Language:
English