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

Title: Method and apparatus for measuring reactivity of fissile material

Abstract

Given are a method and apparatus for measuring nondestructively and non-invasively (i.e., using no internal probing) the burnup, reactivity, or fissile content of any material which emits neutrons and which has fissionable components. No external neutron-emitting interrogation source or fissile material is used and no scanning is required, although if a profile is desired scanning can be used. As in active assays, here both reactivity and content of fissionable material can be measured. The assay is accomplished by altering the return flux of neutrons into the fuel assembly. The return flux is altered by changing the reflecting material. The existing passive neutron emissions in the material being assayed are used as the source of interrogating neutrons. Two measurements of either emitted neutron or emitted gamma-ray count rates are made and are then correlated to either reactivity, burnup, or fissionable content of the material being assayed, thus providing a measurement of either reactivity, burnup, or fissionable content of the material being assayed. Spent fuel which has been freshly discharged from a reactor can be assayed using this method and apparatus. Precisions of 1000 MWd/tU appear to be feasible.

Inventors:
 [1];  [2]
  1. Los Alamos, NM
  2. Santa Fe, NM
Issue Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
OSTI Identifier:
865310
Patent Number(s):
4493810
Assignee:
United States of America as represented by United States (Washington, DC)
DOE Contract Number:  
W-7405-ENG-36
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
method; apparatus; measuring; reactivity; fissile; material; nondestructively; non-invasively; internal; probing; burnup; content; emits; neutrons; fissionable; components; external; neutron-emitting; interrogation; source; scanning; required; profile; desired; active; assays; measured; assay; accomplished; altering; return; flux; fuel; assembly; altered; changing; reflecting; existing; passive; neutron; emissions; assayed; interrogating; measurements; emitted; gamma-ray; count; rates; correlated; providing; measurement; spent; freshly; discharged; reactor; precisions; 1000; mwd; appear; feasible; spent fuel; fuel assembly; fissile material; fissionable material; count rate; count rates; reflecting material; passive neutron; neutron emissions; neutron emission; emitted neutron; fissile content; /376/976/

Citation Formats

Lee, David M, and Lindquist, Lloyd O. Method and apparatus for measuring reactivity of fissile material. United States: N. p., 1985. Web.
Lee, David M, & Lindquist, Lloyd O. Method and apparatus for measuring reactivity of fissile material. United States.
Lee, David M, and Lindquist, Lloyd O. Tue . "Method and apparatus for measuring reactivity of fissile material". United States. https://www.osti.gov/servlets/purl/865310.
@article{osti_865310,
title = {Method and apparatus for measuring reactivity of fissile material},
author = {Lee, David M and Lindquist, Lloyd O},
abstractNote = {Given are a method and apparatus for measuring nondestructively and non-invasively (i.e., using no internal probing) the burnup, reactivity, or fissile content of any material which emits neutrons and which has fissionable components. No external neutron-emitting interrogation source or fissile material is used and no scanning is required, although if a profile is desired scanning can be used. As in active assays, here both reactivity and content of fissionable material can be measured. The assay is accomplished by altering the return flux of neutrons into the fuel assembly. The return flux is altered by changing the reflecting material. The existing passive neutron emissions in the material being assayed are used as the source of interrogating neutrons. Two measurements of either emitted neutron or emitted gamma-ray count rates are made and are then correlated to either reactivity, burnup, or fissionable content of the material being assayed, thus providing a measurement of either reactivity, burnup, or fissionable content of the material being assayed. Spent fuel which has been freshly discharged from a reactor can be assayed using this method and apparatus. Precisions of 1000 MWd/tU appear to be feasible.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1985},
month = {1}
}

Patent:

Save / Share: