skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Evaluation of Neutron Absorbers in the DOE Standardized SNF Canister

Abstract

The goal of this evaluation was to evaluate different options for a neutron absorber in the U.S. Department of Energy (DOE) Standardized spent nuclear fuel (SNF) Canister. This was accomplished by taking the two most relevant criticality evaluations and replacing the advanced neutron absorber (ANA) basket material with borated stainless steel. This work was initiated, because alternative storage options for DOE SNF has become a priority for DOE. Idaho National Laboratory (INL) is initiating activities to ensure the continued operation of the Advanced Test Reactor (ATR) by providing alternative and redundant storage options for spent ATR fuel. In addition, the DOE Office of Environmental Management (EM) has recently initiated studies to understand and improve the technical basis for long-term dry storage of aluminum clad SNF (e.g., ATR, High Flux Isotope Reactor [HFIR]) (Connolly 2018). While currently in the lab-scale phase, the next step involves validation and verification (V&V) of the lab-scale results. One method to perform V&V is to load aluminum-clad spent fuel in an instrumented DOE Standardized SNF Canister as a demonstration. In order to minimize the need for repackaging before disposal and to provide a representative environment in a demonstration, the fuel is planned to be loaded withmore » an appropriate criticality control mechanism, such as neutron absorbing basket material. While ANA was originally selected as the basket material for ATR fuel in the Yucca Mountain Repository, it has never been produced on a large scale. Therefore, incorporating this material in the DOE Standardized SNF Canister as part of a near-term demonstration could be more challenging than moving forward with a commercially available material, such as borated stainless steel. Past evaluations eliminated borated stainless steel as a long-term neutron absorbing material, because it corroded too quickly and may not always remain in the waste package after degradation. This led to the invention and selection of ANA for use as the basket material in the DOE Standardized SNF Canister. After selecting ANA, new corrosion tests were performed on borated stainless steel using a different method for fabrication. This method of fabrication significantly improved the corrosion resistance properties of borated stainless steel, so much so that it out-performed ANA in corrosion testing. Researchers used the information obtained from these tests to select borated stainless steel as the neutron absorber in the Transportation, Aging, and Disposal Canister (TAD) designed for commercial SNF. This evaluation compares the criticality control of borated stainless steel to ANA. In every case and scenario, the calculated effective neutron multiplication factor (k_eff) using a borated stainless steel basket was lower than that using an ANA basket, though the borated stainless steel must be thicker due to corrosion effects over the regulatory time period. Although the borated stainless steel performed better than the ANA, it still required additional neutron-absorbing material, gadolinium shot, for the calculated k_eff to fall below the upper critical limit of 0.93 in a few cases evaluated. More research using thicker baskets or inserts could be performed in an attempt to lower the k_eff without the use of gadolinium shot. In addition, a reevaluation of the degraded ATR material used in the previous evaluations may prove that the original assumptions were over-conservative.« less

Authors:
ORCiD logo [1]
  1. Idaho National Laboratory
Publication Date:
Research Org.:
Idaho National Lab. (INL), Idaho Falls, ID (United States)
Sponsoring Org.:
USDOE Office of Nuclear Energy (NE), (NE-8)
OSTI Identifier:
1560078
Report Number(s):
INL/EXT-19-53193-Rev000
DOE Contract Number:  
DE-AC07-05ID14517
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
12 - MGMT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; DOE Standardized Canister; ANA; Borated Stainless Steel; ATR; Criticality

Citation Formats

Petersen, Gordon M. Evaluation of Neutron Absorbers in the DOE Standardized SNF Canister. United States: N. p., 2019. Web. doi:10.2172/1560078.
Petersen, Gordon M. Evaluation of Neutron Absorbers in the DOE Standardized SNF Canister. United States. doi:10.2172/1560078.
Petersen, Gordon M. Wed . "Evaluation of Neutron Absorbers in the DOE Standardized SNF Canister". United States. doi:10.2172/1560078. https://www.osti.gov/servlets/purl/1560078.
@article{osti_1560078,
title = {Evaluation of Neutron Absorbers in the DOE Standardized SNF Canister},
author = {Petersen, Gordon M},
abstractNote = {The goal of this evaluation was to evaluate different options for a neutron absorber in the U.S. Department of Energy (DOE) Standardized spent nuclear fuel (SNF) Canister. This was accomplished by taking the two most relevant criticality evaluations and replacing the advanced neutron absorber (ANA) basket material with borated stainless steel. This work was initiated, because alternative storage options for DOE SNF has become a priority for DOE. Idaho National Laboratory (INL) is initiating activities to ensure the continued operation of the Advanced Test Reactor (ATR) by providing alternative and redundant storage options for spent ATR fuel. In addition, the DOE Office of Environmental Management (EM) has recently initiated studies to understand and improve the technical basis for long-term dry storage of aluminum clad SNF (e.g., ATR, High Flux Isotope Reactor [HFIR]) (Connolly 2018). While currently in the lab-scale phase, the next step involves validation and verification (V&V) of the lab-scale results. One method to perform V&V is to load aluminum-clad spent fuel in an instrumented DOE Standardized SNF Canister as a demonstration. In order to minimize the need for repackaging before disposal and to provide a representative environment in a demonstration, the fuel is planned to be loaded with an appropriate criticality control mechanism, such as neutron absorbing basket material. While ANA was originally selected as the basket material for ATR fuel in the Yucca Mountain Repository, it has never been produced on a large scale. Therefore, incorporating this material in the DOE Standardized SNF Canister as part of a near-term demonstration could be more challenging than moving forward with a commercially available material, such as borated stainless steel. Past evaluations eliminated borated stainless steel as a long-term neutron absorbing material, because it corroded too quickly and may not always remain in the waste package after degradation. This led to the invention and selection of ANA for use as the basket material in the DOE Standardized SNF Canister. After selecting ANA, new corrosion tests were performed on borated stainless steel using a different method for fabrication. This method of fabrication significantly improved the corrosion resistance properties of borated stainless steel, so much so that it out-performed ANA in corrosion testing. Researchers used the information obtained from these tests to select borated stainless steel as the neutron absorber in the Transportation, Aging, and Disposal Canister (TAD) designed for commercial SNF. This evaluation compares the criticality control of borated stainless steel to ANA. In every case and scenario, the calculated effective neutron multiplication factor (k_eff) using a borated stainless steel basket was lower than that using an ANA basket, though the borated stainless steel must be thicker due to corrosion effects over the regulatory time period. Although the borated stainless steel performed better than the ANA, it still required additional neutron-absorbing material, gadolinium shot, for the calculated k_eff to fall below the upper critical limit of 0.93 in a few cases evaluated. More research using thicker baskets or inserts could be performed in an attempt to lower the k_eff without the use of gadolinium shot. In addition, a reevaluation of the degraded ATR material used in the previous evaluations may prove that the original assumptions were over-conservative.},
doi = {10.2172/1560078},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {9}
}

Technical Report:

Save / Share: