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

Title: Dosimetry characterization of the Godiva Reactor under burst conditions

Abstract

A series of sixteen (16) burst irradiations were performed in May 2014, fifteen of which were part of an international collaboration to characterize the Godiva IV fast burst reactor at the National Criticality Experiments Research Center (NCERC). Godiva IV is a bare cylindrical assembly of approximately 65 kg of highly enriched uranium fuel (93.2% 235U metal alloyed with 1.5% molybdenum for strength) and is designed to perform controlled prompt critical excursions (Myers 2010, Goda 2013). Twelve of the irradiations were dedicated to neutron spectral measurements using a Bonner multiple sphere spectrometer. Three irradiations, with core temperature increases of 71.1°C, 136.9°C, and 229.9°C, were performed for generating comparative fluence data, establishing corrections for varying heights, testing linearity with burst temperature, and establishing gamma dose characteristics.

Authors:
 [1];  [1];  [1];  [1];  [2];  [3];  [3];  [4]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
  3. Atomic Weapons Establishment (AWE), Berkshire (United Kingdom)
  4. Inst. for Radiation Protection and Nuclear Safety, Fontenay-aux-Roses (France)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1378515
Report Number(s):
LLNL-TR-729408
DOE Contract Number:
AC52-07NA27344
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; 61 RADIATION PROTECTION AND DOCIMETRY; 22 GENERAL STUDIES OF NUCLEAR REACTORS

Citation Formats

Hickman, D. P., Heinrichs, D. P., Hudson, R., Wong, C., Ward, D., Wilson, C., Clark, L., and Trompier, F. Dosimetry characterization of the Godiva Reactor under burst conditions. United States: N. p., 2017. Web. doi:10.2172/1378515.
Hickman, D. P., Heinrichs, D. P., Hudson, R., Wong, C., Ward, D., Wilson, C., Clark, L., & Trompier, F. Dosimetry characterization of the Godiva Reactor under burst conditions. United States. doi:10.2172/1378515.
Hickman, D. P., Heinrichs, D. P., Hudson, R., Wong, C., Ward, D., Wilson, C., Clark, L., and Trompier, F. 2017. "Dosimetry characterization of the Godiva Reactor under burst conditions". United States. doi:10.2172/1378515. https://www.osti.gov/servlets/purl/1378515.
@article{osti_1378515,
title = {Dosimetry characterization of the Godiva Reactor under burst conditions},
author = {Hickman, D. P. and Heinrichs, D. P. and Hudson, R. and Wong, C. and Ward, D. and Wilson, C. and Clark, L. and Trompier, F.},
abstractNote = {A series of sixteen (16) burst irradiations were performed in May 2014, fifteen of which were part of an international collaboration to characterize the Godiva IV fast burst reactor at the National Criticality Experiments Research Center (NCERC). Godiva IV is a bare cylindrical assembly of approximately 65 kg of highly enriched uranium fuel (93.2% 235U metal alloyed with 1.5% molybdenum for strength) and is designed to perform controlled prompt critical excursions (Myers 2010, Goda 2013). Twelve of the irradiations were dedicated to neutron spectral measurements using a Bonner multiple sphere spectrometer. Three irradiations, with core temperature increases of 71.1°C, 136.9°C, and 229.9°C, were performed for generating comparative fluence data, establishing corrections for varying heights, testing linearity with burst temperature, and establishing gamma dose characteristics.},
doi = {10.2172/1378515},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month = 6
}

Technical Report:

Save / Share:
  • This document provides the scope and details of the “Plan for Testing the Y-12 and AWE Criticality Accident Alarm System Detectors at the Godiva IV Burst Reactor”. Due to the relative simplicity of the testing goals, scope, and methodology, the NCSP Manager approved execution of the test when ready. No preliminary CED-1 or final design CED-2 reports were required or issued. The test will subject Criticality Accident Alarm System (CAAS) detectors supplied by Y- 12 and AWE to very intense and short duration mixed neutron and gamma radiation fields. The goals of the test will be to (1) substantiate functionality,more » for both existing and newly acquired Y- 12 CAAS detectors, and (2) the ability of the AWE detectors to provide quality temporal dose information after a hypothetical criticality accident. ANSI/ANS-8.3.1997 states that the “system shall be sufficiently robust as to actuate an alarm signal when exposed to the maximum radiation expected”, which has been defined at Y-12, in Documented Safety Analyses (DSAs), to be a dose rate of 10 Rad/s. ANSI/ANS-8.3.1997 further states that “alarm actuation shall occur as a result of a minimum duration transient” which may be assumed to be 1 msec. The pulse widths and dose rates which will be achieved in this test will exceed these requirements. Pulsed radiation fields will be produced by the Godiva IV fast metal burst reactor at the National Criticality Experimental Research Center (NCERC) at the Nevada National Security Site (NNSS). The magnitude of the pulses and the relative distances to the detectors will be varied to afford a wide range of radiation fluence and pulse widths. The magnitude of the neutron and gamma fields will be determined by reactor temperature rise to fluence and dose conversions which have been previously established through extensive measurements performed under IER-147. The requirements for CAAS systems to detect and alarm under a “minimum accident of concern” as well as other functional requirements specified in ANSI/ANS-8.3.1997, are not included in the test. Routine and periodic maintenance and calibrations performed at Y-12 and AWE are intended to provide adequate confirmation for meeting these requirements.« less
  • This report documents the experimental conditions and final results for the performance testing of the Y-12 Criticality Accident Alarm System (CAAS) detectors at the Godiva IV Burst Reactor at the National Criticality Experimental Research Center (NCERC) at the Nevada National Security Site (NNSS). The testing followed a previously issued test plan and was conducted during the week of July 17, 2017, with completion on Thursday July 20. The test subjected CAAS detectors supplied by Y-12 to very intense and short duration mixed neutron and gamma radiation fields to establish compliance to maximum radiation and minimum pulse width requirements. ANSI/ANS- 8.3.1997more » states that the “system shall be sufficiently robust as to actuate an alarm signal when exposed to the maximum radiation expected”, which has been defined at Y-12, in Documented Safety Analyses (DSAs), to be a dose rate of 10 Rad/s. ANSI/ANS-8.3.1997 further states that “alarm actuation shall occur as a result of a minimum duration transient” which may be assumed to be 1 msec. The pulse widths and dose rates provided by each burst during the test exceeded those requirements. The CAAS detectors all provided an immediate alarm signal and remained operable after the bursts establishing compliance to the requirements and fitness for re-deployment at Y-12.« less
  • The dynamic computer model developed to simulate GODIVA-IV prompt bursts adequately predicts the magnitude of power bursts. Also, it demonstrates the characteristic features of prompt bursts in metal assemblies, such as the change in shape of power pulses and the ringing of fuel surfaces at the onset of inertial effects. The model will be used to test more sophisticated reactivity feedback coefficients and neutronic-hydrodynamic coupling schemes. It will also be used for a more detailed analysis of inertial effects.