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Title: Neutron experiments at Portsmouth for measuring flow and {sup 235}U content in UF{sub 6} gas

Abstract

The Portsmouth Gaseous Diffusion Plant produces enriched uranium for use in commercial power reactors. The plant also aids disposal of excess high-enrichment uranium (HEU) by blending it with lower-enrichment material. Experiments were conducted to test two neutron-based methods for monitoring the down-blending of HEU. Results of the initial experiments showed that gas (on-off) could be detected, but that additional tests and data are needed to quantify the flow velocity and {sup 235}U content. The experiments used a {sup 252}Cf neutron source to induce fission in a small fraction of the {sup 235}U contained in the UF{sub 6} gas. The first method measured the attenuation of neutrons passing through the low-pressure UF{sub 6} gas in a 7.6-cm diameter pipe. The concept was based on the fact that some of the thermal neutrons are absorbed by {sup 235}U, thus changing the observed count rate. The second method, tested on a 20-cm diameter pipe where gas pressure was higher, used a modulated neutron flux to induce fission in the {sup 235}U. Modulation was achieved by moving a neutron source. During both experiments, plant monitoring equipment showed that light gases (freon, oxygen, and nitrogen) were present in widely varying amounts, along with the UF{submore » 6} gas. These gases may have affected the experimental results, at least to the extent that they replaced UF{sub 6}. This report also contains results of computer simulations and tests performed on the electronics after the experiments were completed at Portsmouth. Recommendations are made for follow-on work to measure the flow velocity and {sup 235}U content.« less

Authors:
; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
495718
Report Number(s):
PNNL-11566
ON: DE97053055; TRN: AHC29715%%37
DOE Contract Number:  
AC06-76RL01830
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: Apr 1997
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; 21 NUCLEAR POWER REACTORS AND ASSOCIATED PLANTS; 05 NUCLEAR FUELS; RADIOMETRIC ANALYSIS; URANIUM HEXAFLUORIDE; PORTSMOUTH GASEOUS DIFFUSION PLANT; NUCLEAR MATERIALS MANAGEMENT; HIGHLY ENRICHED URANIUM; MIXING; SLIGHTLY ENRICHED URANIUM; URANIUM 235; CONCENTRATION RATIO; FLOW RATE; NEUTRON DETECTION

Citation Formats

Stromswold, D C, Reeder, P L, and Peurrung, A J. Neutron experiments at Portsmouth for measuring flow and {sup 235}U content in UF{sub 6} gas. United States: N. p., 1997. Web. doi:10.2172/495718.
Stromswold, D C, Reeder, P L, & Peurrung, A J. Neutron experiments at Portsmouth for measuring flow and {sup 235}U content in UF{sub 6} gas. United States. https://doi.org/10.2172/495718
Stromswold, D C, Reeder, P L, and Peurrung, A J. 1997. "Neutron experiments at Portsmouth for measuring flow and {sup 235}U content in UF{sub 6} gas". United States. https://doi.org/10.2172/495718. https://www.osti.gov/servlets/purl/495718.
@article{osti_495718,
title = {Neutron experiments at Portsmouth for measuring flow and {sup 235}U content in UF{sub 6} gas},
author = {Stromswold, D C and Reeder, P L and Peurrung, A J},
abstractNote = {The Portsmouth Gaseous Diffusion Plant produces enriched uranium for use in commercial power reactors. The plant also aids disposal of excess high-enrichment uranium (HEU) by blending it with lower-enrichment material. Experiments were conducted to test two neutron-based methods for monitoring the down-blending of HEU. Results of the initial experiments showed that gas (on-off) could be detected, but that additional tests and data are needed to quantify the flow velocity and {sup 235}U content. The experiments used a {sup 252}Cf neutron source to induce fission in a small fraction of the {sup 235}U contained in the UF{sub 6} gas. The first method measured the attenuation of neutrons passing through the low-pressure UF{sub 6} gas in a 7.6-cm diameter pipe. The concept was based on the fact that some of the thermal neutrons are absorbed by {sup 235}U, thus changing the observed count rate. The second method, tested on a 20-cm diameter pipe where gas pressure was higher, used a modulated neutron flux to induce fission in the {sup 235}U. Modulation was achieved by moving a neutron source. During both experiments, plant monitoring equipment showed that light gases (freon, oxygen, and nitrogen) were present in widely varying amounts, along with the UF{sub 6} gas. These gases may have affected the experimental results, at least to the extent that they replaced UF{sub 6}. This report also contains results of computer simulations and tests performed on the electronics after the experiments were completed at Portsmouth. Recommendations are made for follow-on work to measure the flow velocity and {sup 235}U content.},
doi = {10.2172/495718},
url = {https://www.osti.gov/biblio/495718}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Apr 01 00:00:00 EST 1997},
month = {Tue Apr 01 00:00:00 EST 1997}
}