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Title: Post-Irradiation Examination of 237Np Targets for 238Pu Production

Abstract

Oak Ridge National Laboratory is recovering the US 238Pu production capability and the first step in the process has been to evaluate the performance of a 237Np target cermet pellet encased in an aluminum clad. The process proceeded in 3 steps; the first step was to irradiate capsules of single pellets composed of NpO 2 and aluminum power to examine their shrinkage and gas release. These pellets were formed by compressing sintered NpO 2 and aluminum powder in a die at high pressure followed by sintering in a vacuum furnace. Three temperatures were chosen for sintering the solution precipitated NpO 2 power used for pellet fabrication. The second step was to irradiate partial targets composed of 8 pellets in a semi-prototypical arrangement at the two best performing sintering temperatures to determine which temperature gave a pellet that performed the best under the actual planned irradiation conditions. The third step was to irradiate ~50 pellets in an actual target configuration at design irradiation conditions to assess pellet shrinkage and gas release, target heat transfer, and dimensional stability. The higher sintering temperature appeared to offer the best performance after one cycle of irradiation by having the least shrinkage, thus keeping the heatmore » transfer gap between the pellets and clad small minimizing the pellet operating temperature. The final result of the testing was a target that can meet the initial production goals, satisfy the reactor safety requirements, and can be fabricated in production quantities. The current focus of the program is to verify that the target can be remotely dissembled, the pellets dissolved, and the 238Pu recovered. Tests are being conducted to examine these concerns and to compare results to code predictions. Once the performance of the full length targets has been quantified, the pellet 237Np loading will be revisited to determine if it can be increased to increase 238Pu production.« less

Authors:
 [1];  [1];  [1];  [1]
  1. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
Work for Others (WFO)
OSTI Identifier:
1185863
DOE Contract Number:  
AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Conference: Nuclear and Emerging Technologies for Space 2015, Albuquerque, NM, USA, 20150223, 20150226
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 07 ISOTOPE AND RADIATION SOURCES; NESDPS Office of Nuclear Energy Space and Defense Power Systems; Post-Irradiation Examination; Np-237 Target; Pu-238; Cermet pellet

Citation Formats

Morris, Robert Noel, Baldwin, Charles A, Hobbs, Randy W, and Schmidlin, Joshua E. Post-Irradiation Examination of 237Np Targets for 238Pu Production. United States: N. p., 2015. Web.
Morris, Robert Noel, Baldwin, Charles A, Hobbs, Randy W, & Schmidlin, Joshua E. Post-Irradiation Examination of 237Np Targets for 238Pu Production. United States.
Morris, Robert Noel, Baldwin, Charles A, Hobbs, Randy W, and Schmidlin, Joshua E. Thu . "Post-Irradiation Examination of 237Np Targets for 238Pu Production". United States. doi:. https://www.osti.gov/servlets/purl/1185863.
@article{osti_1185863,
title = {Post-Irradiation Examination of 237Np Targets for 238Pu Production},
author = {Morris, Robert Noel and Baldwin, Charles A and Hobbs, Randy W and Schmidlin, Joshua E},
abstractNote = {Oak Ridge National Laboratory is recovering the US 238Pu production capability and the first step in the process has been to evaluate the performance of a 237Np target cermet pellet encased in an aluminum clad. The process proceeded in 3 steps; the first step was to irradiate capsules of single pellets composed of NpO2 and aluminum power to examine their shrinkage and gas release. These pellets were formed by compressing sintered NpO2 and aluminum powder in a die at high pressure followed by sintering in a vacuum furnace. Three temperatures were chosen for sintering the solution precipitated NpO2 power used for pellet fabrication. The second step was to irradiate partial targets composed of 8 pellets in a semi-prototypical arrangement at the two best performing sintering temperatures to determine which temperature gave a pellet that performed the best under the actual planned irradiation conditions. The third step was to irradiate ~50 pellets in an actual target configuration at design irradiation conditions to assess pellet shrinkage and gas release, target heat transfer, and dimensional stability. The higher sintering temperature appeared to offer the best performance after one cycle of irradiation by having the least shrinkage, thus keeping the heat transfer gap between the pellets and clad small minimizing the pellet operating temperature. The final result of the testing was a target that can meet the initial production goals, satisfy the reactor safety requirements, and can be fabricated in production quantities. The current focus of the program is to verify that the target can be remotely dissembled, the pellets dissolved, and the 238Pu recovered. Tests are being conducted to examine these concerns and to compare results to code predictions. Once the performance of the full length targets has been quantified, the pellet 237Np loading will be revisited to determine if it can be increased to increase 238Pu production.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Jan 01 00:00:00 EST 2015},
month = {Thu Jan 01 00:00:00 EST 2015}
}

Conference:
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