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Title: Analysis of Radiation Transport Due to Activated Coolant in the ITER Neutral Beam Injection Cell

Detailed spatial distributions of the biological dose rate due to a variety of sources are required for the design of the ITER tokamak facility to ensure that all radiological zoning limits are met. During operation, water in the Integrated loop of Blanket, Edge-localized mode and vertical stabilization coils, and Divertor (IBED) cooling system will be activated by plasma neutrons and will flow out of the bioshield through a complex system of pipes and heat exchangers. This paper discusses the methods used to characterize the biological dose rate outside the tokamak complex due to 16N gamma radiation emitted by the activated coolant in the Neutral Beam Injection (NBI) cell of the tokamak building. Activated coolant will enter the NBI cell through the IBED Primary Heat Transfer System (PHTS), and the NBI PHTS will also become activated due to radiation streaming through the NBI system. To properly characterize these gamma sources, the production of 16N, the decay of 16N, and the flow of activated water through the coolant loops were modeled. The impact of conservative approximations on the solution was also examined. Once the source due to activated coolant was calculated, the resulting biological dose rate outside the north wall of themore » NBI cell was determined through the use of sophisticated variance reduction techniques. The AutomateD VAriaNce reducTion Generator (ADVANTG) software implements methods developed specifically to provide highly effective variance reduction for complex radiation transport simulations such as those encountered with ITER. Using ADVANTG with the Monte Carlo N-particle (MCNP) radiation transport code, radiation responses were calculated on a fine spatial mesh with a high degree of statistical accuracy. In conclusion, advanced visualization tools were also developed and used to determine pipe cell connectivity, to facilitate model checking, and to post-process the transport simulation results.« less
Authors:
ORCiD logo [1] ; ORCiD logo [1] ; ORCiD logo [1] ; ORCiD logo [1] ;  [2]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. ITER Organization, St. Paul Lez Durance (France)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Fusion Science and Technology
Additional Journal Information:
Journal Volume: 72; Journal Issue: 3; Journal ID: ISSN 1536-1055
Publisher:
American Nuclear Society
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 59 BASIC BIOLOGICAL SCIENCES; ITER; variance reduction; radiation transport
OSTI Identifier:
1408606

Royston, Katherine, Wilson, Stephen C., Risner, Joel M., Ibrahim, Ahmad, and Loughlin, Michael. Analysis of Radiation Transport Due to Activated Coolant in the ITER Neutral Beam Injection Cell. United States: N. p., Web. doi:10.1080/15361055.2017.1333867.
Royston, Katherine, Wilson, Stephen C., Risner, Joel M., Ibrahim, Ahmad, & Loughlin, Michael. Analysis of Radiation Transport Due to Activated Coolant in the ITER Neutral Beam Injection Cell. United States. doi:10.1080/15361055.2017.1333867.
Royston, Katherine, Wilson, Stephen C., Risner, Joel M., Ibrahim, Ahmad, and Loughlin, Michael. 2017. "Analysis of Radiation Transport Due to Activated Coolant in the ITER Neutral Beam Injection Cell". United States. doi:10.1080/15361055.2017.1333867. https://www.osti.gov/servlets/purl/1408606.
@article{osti_1408606,
title = {Analysis of Radiation Transport Due to Activated Coolant in the ITER Neutral Beam Injection Cell},
author = {Royston, Katherine and Wilson, Stephen C. and Risner, Joel M. and Ibrahim, Ahmad and Loughlin, Michael},
abstractNote = {Detailed spatial distributions of the biological dose rate due to a variety of sources are required for the design of the ITER tokamak facility to ensure that all radiological zoning limits are met. During operation, water in the Integrated loop of Blanket, Edge-localized mode and vertical stabilization coils, and Divertor (IBED) cooling system will be activated by plasma neutrons and will flow out of the bioshield through a complex system of pipes and heat exchangers. This paper discusses the methods used to characterize the biological dose rate outside the tokamak complex due to 16N gamma radiation emitted by the activated coolant in the Neutral Beam Injection (NBI) cell of the tokamak building. Activated coolant will enter the NBI cell through the IBED Primary Heat Transfer System (PHTS), and the NBI PHTS will also become activated due to radiation streaming through the NBI system. To properly characterize these gamma sources, the production of 16N, the decay of 16N, and the flow of activated water through the coolant loops were modeled. The impact of conservative approximations on the solution was also examined. Once the source due to activated coolant was calculated, the resulting biological dose rate outside the north wall of the NBI cell was determined through the use of sophisticated variance reduction techniques. The AutomateD VAriaNce reducTion Generator (ADVANTG) software implements methods developed specifically to provide highly effective variance reduction for complex radiation transport simulations such as those encountered with ITER. Using ADVANTG with the Monte Carlo N-particle (MCNP) radiation transport code, radiation responses were calculated on a fine spatial mesh with a high degree of statistical accuracy. In conclusion, advanced visualization tools were also developed and used to determine pipe cell connectivity, to facilitate model checking, and to post-process the transport simulation results.},
doi = {10.1080/15361055.2017.1333867},
journal = {Fusion Science and Technology},
number = 3,
volume = 72,
place = {United States},
year = {2017},
month = {7}
}