United States Nuclear Regulatory Commission - Protecting People and the Environment

Emerging Technologies in Instrumentation and Controls: An Update (NUREG/CR-6888, ORNL/TM-2005/75)

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Publication Information

Manuscript Completed: November 2005
Date Published: January 2006

Prepared by:
K. Korsah, R. Wetherington, R. Wood
Oak Ridge National Laboratory
P.O. Box 2008, MS 6010
Oak Ridge, Tennessee 37831-6010
Managed by UT-Battelle, LLC

L.F. Miller, K. Zhao, A. Paul
University of Tennessee
315 Pasqua Engineering Building
Knoxville, Tennessee 37996-2300

Christina E. Antonescu, NRC Project Manager

Prepared for:
Division of Engineering Technology
Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001

NRC Job Code Y6962

Availability Notice

Abstract

This report is a summary of advances in eight instrumentation and control (I&C) technology focus areas that have applications in nuclear power plant digital upgrades as well as in new plants. It is the second in a series of planned update reports (the first one was NUREG/CR-6812) in an NRC-sponsored Emerging Technologies study. This study is designed to provide “heads-up” information that will make the NRC better prepared to make regulatory decisions in these areas.

This study update focuses on advances in sensors (e.g., temperature, neutron and thermal power sensors) and their potential regulatory impact. Highlights of the findings and conclusions in this report are as follows:

  1. The silicon carbide neutron detector has advanced past the developmental stage. However, important information such as long-term performance (degradation information), drift, etc., could not be adequately assessed. While the detector has a wide dynamic range (with potential for replacing present-day startup, intermediate, and power range monitors), it is important that a combined neutron monitor based on this technology not only exhibit the full dynamic range from startup to 100% power, but also be shown to maintain performance over the long term when at 100% power. Progress in the development of these detectors should continue to be monitored, because of the potential for improved operating and safety margins that such detectors will provide, should they also meet the criteria mentioned above.
  2. The Johnson noise thermometer could be commercially available for nuclear power plant applications within 5 years. A temperature sensor based on Johnson noise is immune to the drift that plagues thermocouples and resistance thermometers. The lack of drift has advantages that could have regulatory implications such as extending calibration intervals. The technology should continue to be monitored.
  3. Sensors that are less developed and therefore will require a longer time to reach commercialization are scintillation-based sensors for in-core temperature and flux measurements and vacuum nanotriodes. In the case of scintillation-based sensors, the primary deficiencies in the technology preventing its use for in-core measurements have been the lack of an effective technique for measuring light within reactor core environments and the rapid darkening of fiber-optic light pipes in high radiation fields. Additionally, scintillation materials darken too rapidly to be useful in bulk form near a nuclear reactor core. For the purposes of this update, no significant progress in overcoming these problems were identified. In the case of vacuum nanotriodes, the technology is also still in early research. However, because of the advantages that advances in both technologies could provide for nuclear power plant I&C, both scintillation-based sensors and vacuum nanotriodes should continue to be monitored.
  4. Variability in the radiation response of COTS devices is a significant radiation hardness assurance (RHA) issue. Approaches such as radiation-hard technologies and improved manufacturing processes may overcome this impediment. For example, advances in radiation-hardened electronics are giving rise to technologies such as phase transition-based random access memories (P-RAMs), which may make application of I&C in harsh environments such as containment possible. These technologies should be monitored.
  5. A set of best practices in digital communication in nuclear power plant safety I&C systems should be developed to support the review of digital I&C system upgrades in current generation plants, as well as in Generation III and Generation IV plants.
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