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

Title: Non-destructive method for determining neutron exposure and constituent concentrations of a body

Abstract

A non-destructive method for determination of neutron exposure and constituent concentrations in an object, such as reactor pressure vessel, is based on the observation of characteristic gamma-rays emitted by activation products in the object by using a unique continuous gamma-ray spectrometer. The spectrometer views the object through appropriate collimators to determine the absolute emission rate of these characteristic gamma-rays, thereby ascertaining the absolute activity of given activation products in the object. These data can then be used to deduce the spatial and angular dependence of neutron exposure or the spatial constituent concentration at regions of interest within the object.

Inventors:
 [1];  [1]
  1. (Richland, WA)
Publication Date:
Research Org.:
WESTINGHOUSE HANFORD CO
OSTI Identifier:
866050
Patent Number(s):
US 4622200
Assignee:
United States of America as represented by United States (Washington, DC) OSTI
DOE Contract Number:
AC14-76FF02170
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
non-destructive; method; determining; neutron; exposure; constituent; concentrations; determination; reactor; pressure; vessel; based; observation; characteristic; gamma-rays; emitted; activation; products; unique; continuous; gamma-ray; spectrometer; views; appropriate; collimators; determine; absolute; emission; rate; ascertaining; activity; data; deduce; spatial; angular; dependence; concentration; regions; reactor pressure; pressure vessel; non-destructive method; rays emitted; neutron exposure; constituent concentrations; /376/250/

Citation Formats

Gold, Raymond, and McElroy, William N. Non-destructive method for determining neutron exposure and constituent concentrations of a body. United States: N. p., 1986. Web.
Gold, Raymond, & McElroy, William N. Non-destructive method for determining neutron exposure and constituent concentrations of a body. United States.
Gold, Raymond, and McElroy, William N. Wed . "Non-destructive method for determining neutron exposure and constituent concentrations of a body". United States. doi:. https://www.osti.gov/servlets/purl/866050.
@article{osti_866050,
title = {Non-destructive method for determining neutron exposure and constituent concentrations of a body},
author = {Gold, Raymond and McElroy, William N.},
abstractNote = {A non-destructive method for determination of neutron exposure and constituent concentrations in an object, such as reactor pressure vessel, is based on the observation of characteristic gamma-rays emitted by activation products in the object by using a unique continuous gamma-ray spectrometer. The spectrometer views the object through appropriate collimators to determine the absolute emission rate of these characteristic gamma-rays, thereby ascertaining the absolute activity of given activation products in the object. These data can then be used to deduce the spatial and angular dependence of neutron exposure or the spatial constituent concentration at regions of interest within the object.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Jan 01 00:00:00 EST 1986},
month = {Wed Jan 01 00:00:00 EST 1986}
}

Patent:

Save / Share:
  • A non-destructive method for determination of neutron exposure and constituent concentrations in an object, such as a reactor pressure vessel, is based on the observation of characteristic gamma-rays emitted by activation products in the object by using a unique continuous gamma-ray spectrometer. The spectrometer views the object through appropriate collimators to determine the absolute emission rate of these characteristic gamma-rays, thereby ascertaining the absolute activity of given activation products in the object. These data can then be used to deduce the spatial and angular dependence of neutron exposure or the spatial constituent concentrations at regions of interest within the object.
  • A portable non-destructive method is described for determination of the neutron exposure to which a selected surface area on a object has been subjected, comprising the following steps: exposing the solid state lithium drifted silicon detector of a Compton Recoil Gamma-Ray Spectrometer to a limited portion of the surface area of the object through a small diameter collimator opening directed toward the surface area; electronically measuring the continuous spectrum of detected gamma-rays at different energy levels during a first traverse of the surface area by the shielded detector; recording a first flux density peak value of the gamma-rays at amore » selected energy level characteristic of neutron exposure; identifying a first relationship between the first flux density peak value and the spatial activity density value for the measured gamma-rays; modifying the exposure of the detector to the surface area; electronically measuring the continuous spectrum of detected gamma-rays at different energy levels during a second traverse of the surface area by the detector; recording a second flux density peak value of the gamma-rays at the previously selected energy level; identifying a second relationship between the second flux density peak value and the spatial activity density value; solving the first and second relationships to identify the spatial activity density value of the gamma-rays at the characteristic energy level; and subsequently deriving information concerning spatial and angular neutron exposure of the object by known relationships to the identified spatial activity density value.« less
  • A non-destructive method for determination of neutron exposure in an object, such as a reactor pressure vessel, is based on the observation of characteristic gamma-rays emitted by activation products in the object by using a unique continuous gamma-ray spectrometer. The spectrometer views the object through appropriate collimators to determine the absolute emission rate of these characteristic gamma-rays, thereby ascertaining the absolute activity of given activation products in the object. These data can then be used to deduce the spatial and angular dependence of neutron exposure at regions of interest within the object.
  • A non-destructive method and apparatus which is based on in-situ gamma spectroscopy is used to determine the depth of radiological contamination in media such as concrete. An algorithm, Gamma Penetration Depth Unfolding Algorithm (GPDUA), uses point kernel techniques to predict the depth of contamination based on the results of uncollided peak information from the in-situ gamma spectroscopy. The invention is better, faster, safer, and/cheaper than the current practice in decontamination and decommissioning of facilities that are slow, rough and unsafe. The invention uses a priori knowledge of the contaminant source distribution. The applicable radiological contaminants of interest are any isotopesmore » that emit two or more gamma rays per disintegration or isotopes that emit a single gamma ray but have gamma-emitting progeny in secular equilibrium with its parent (e.g., .sup.60 Co, .sup.235 U, and .sup.137 Cs to name a few). The predicted depths from the GPDUA algorithm using Monte Carlo N-Particle Transport Code (MCNP) simulations and laboratory experiments using .sup.60 Co have consistently produced predicted depths within 20% of the actual or known depth.« less
  • An apparatus and a method for determining in a body organ the amount of an element with the aid of a gaseous gamma ray source, where the element and the source are paired in predetermined pairs, and with the aid of at least one detector selected from the group consisting of Ge(Li) and NaI(Tl). Gamma rays are directed towards the organ, thereby resonantly scattering the gamma rays from nuclei of the element in the organ; the intensity of the gamma rays is detected by the detector; and the amount of the element in the organ is then substantially proportional tomore » the detected intensity of the gamma rays.« less