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Title: Pulsed neutron uranium borehole logging with prompt fission neutrons

Abstract

The gross count natural gamma log normally used for uranium borehole logging is seriously affected by disequilibrium. Methods for the direct measurement of uranium, such as neutron logging, which are not affected by disequilibrium have been the object of considerable effort in recent years. This paper describes a logging system for uranium which uses a small accelerator to generate pulses of 14 MeV neutrons to detect and assay uranium by the measurement of prompt fission neutrons in the epithermal energy range. After an initial feasibility study, a prototype logging probe was built for field evaluation which began in January 1976. Physical and operational characteristics of the prototype probe, the neutron tube-transformer assembly, and the neutron tube are described. In logging operations, only the epithermal prompt fission neutrons detected between 250 microseconds to 2500 microseconds following the excitation neutron pulse are counted. Comparison of corrected neutron logs with the conventional gross count natural gamma logs and the chemical assays of cores from boreholes are shown. The results obtained with this neutron probe clearly demonstrate its advantages over the gross count natural gamma log, although at this time the accuracy of the neutron log assay is not satisfactory under some conditions. Themore » necessary correction factors for various borehole and formation parameters are being determined and, when applied, should improve the assay accuracy.« less

Authors:
; ;
Publication Date:
Research Org.:
Sandia Labs., Albuquerque, NM (USA)
OSTI Identifier:
7125703
Report Number(s):
SAND-76-9100; CONF-761059-12
TRN: 77-006075
DOE Contract Number:  
E(29-1)-789
Resource Type:
Conference
Resource Relation:
Conference: 4. annual conference on the use of small accelerators, Denton, TX, USA, 25 Oct 1976
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; 47 OTHER INSTRUMENTATION; NEUTRON-NEUTRON LOGGING; EQUIPMENT; URANIUM DEPOSITS; PERFORMANCE TESTING; PROMPT NEUTRONS; PULSED NEUTRON TECHNIQUES; BARYONS; ELEMENTARY PARTICLES; FERMIONS; FISSION NEUTRONS; GEOLOGIC DEPOSITS; HADRONS; NEUTRON LOGGING; NEUTRONS; NUCLEONS; RADIOACTIVITY LOGGING; RESOURCES; TESTING; WELL LOGGING; 050200* - Nuclear Fuels- Exploration- (-1987); 440400 - Well Logging Instrumentation

Citation Formats

Bivens, H M, Smith, G W, and Jensen, D H. Pulsed neutron uranium borehole logging with prompt fission neutrons. United States: N. p., 1976. Web.
Bivens, H M, Smith, G W, & Jensen, D H. Pulsed neutron uranium borehole logging with prompt fission neutrons. United States.
Bivens, H M, Smith, G W, and Jensen, D H. Thu . "Pulsed neutron uranium borehole logging with prompt fission neutrons". United States.
@article{osti_7125703,
title = {Pulsed neutron uranium borehole logging with prompt fission neutrons},
author = {Bivens, H M and Smith, G W and Jensen, D H},
abstractNote = {The gross count natural gamma log normally used for uranium borehole logging is seriously affected by disequilibrium. Methods for the direct measurement of uranium, such as neutron logging, which are not affected by disequilibrium have been the object of considerable effort in recent years. This paper describes a logging system for uranium which uses a small accelerator to generate pulses of 14 MeV neutrons to detect and assay uranium by the measurement of prompt fission neutrons in the epithermal energy range. After an initial feasibility study, a prototype logging probe was built for field evaluation which began in January 1976. Physical and operational characteristics of the prototype probe, the neutron tube-transformer assembly, and the neutron tube are described. In logging operations, only the epithermal prompt fission neutrons detected between 250 microseconds to 2500 microseconds following the excitation neutron pulse are counted. Comparison of corrected neutron logs with the conventional gross count natural gamma logs and the chemical assays of cores from boreholes are shown. The results obtained with this neutron probe clearly demonstrate its advantages over the gross count natural gamma log, although at this time the accuracy of the neutron log assay is not satisfactory under some conditions. The necessary correction factors for various borehole and formation parameters are being determined and, when applied, should improve the assay accuracy.},
doi = {},
url = {https://www.osti.gov/biblio/7125703}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1976},
month = {1}
}

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