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Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
Standards Program
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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Deep Space: The new frontier of radiation controls
In commercial nuclear power, there has always been a deliberate tension between the regulator and the utility owner. The regulator fundamentally exists to protect the worker, and the utility, to make a profit. It is a win-win balance.
From the U.S. nuclear industry has emerged a brilliantly successful occupational nuclear safety record—largely the result of an ALARA (as low as reasonably achievable) process that has driven exposure rates down to what only a decade ago would have been considered unthinkable. In the U.S. nuclear industry, the system has accomplished an excellent, nearly seamless process that succeeds to the benefit of both employee and utility owner.
Tunc Aldemir, Don W. Miller
Nuclear Technology | Volume 74 | Number 3 | September 1986 | Pages 267-271
Technical Paper | Fission Reactor | doi.org/10.13182/NT86-A33829
Articles are hosted by Taylor and Francis Online.
The availability of power range monitoring systems (PRMSs) is important to reliable and safe operation of nuclear plants, since the primary functions of PRMSs are to provide control signals and generate a trip signal if the neutron flux level exceeds preset values during operation. The PRMS can be inspected for degraded modes of neutron channel failure with conventional methods during the time the plant is shut down. Recently, techniques have been developed for in situ inspection of neutron flux channels. The effect of in situ surveillance of PRMS channels on the channel and system availability is investigated as a function of the probability of detecting the degraded channels and the frequency of inspection. The PRMS and its subsystems are modeled as M-out-of-N systems with identical and statistically independent three-state units. It is shown that the single channel unavailability can be appreciably decreased (4 to 10 day/yr) using in situsurveillance techniques. The improvement in PRMS availability in pressurized water reactors, however, is predicted to be small (< 1.5 h/yr) because of channel redundancy. The effect of these techniques on PRMS availability in boiling water reactors is virtually unobservable.
