USNRC

D. F. Haasl et al.. Fault Tree Handbook, USNRC, NUREG-0492, Washington, DC, jantiaiy 1981. 

This method, developed under USNRC sponsorship, was demonstrated in the analysis of system interactions in the Watts Bar plant (Sacks et al., 1983), Indian Point 3 (Alesso, 1984). It had... 

Fig. 8.3-3 Correction factors for stability class (USNRC Kegulai...

Reg. Guide 1.145, 1983, Atmospheric Dispersion Models for Potential Accident Consequence Assessments at Nuclear Power Plants, USNRC, February. 

SECT-93-106, 1993, Revised Guidelines for Prioritization of Generic Safety Issues, USNRC. 

SECY-89-102,1990, Implementation of the Safety Goals, USNRC, memorandum from S. J. Chalk to J. M. Taylor. 

SECY-88-147, 1987, Integration Plan for Closure of Severe Accident Issues, USNRC. 

SECY-80-283, 1980, Report of the Task Force on Interim Operation of Indian Point, USNRC. 

In April 1982, a data workshop was held to evaluate, discuss, and critique data in order to establish a consensus generic data set for the USNRC-RES National Reliability Evaluation Program (NREP). The data set contains component failure rates and probability estimates for loss of coolant accidents, transients, loss of offsite power events, and human errors that could be applied consistently across the nuclear power industry as screening values for initial identification of dominant accident sequences in PRAs. This data set was used in the development of guidance documents for the performance of PRAs. 

The LER data base served as the primary source of DG failure data, while a data base for DG successes was formed from nuclear plant licensees responses to a USNRC questionnaire (Generic Letter 84-15). Estimates of DG failure on demand were calculated from the LER data, DG test data, and response data from the questionnaire. The questionnaire also provided data on DG performance during complete and partial LOSP and in response to safety injection actuation signals. Trends in DG performance are profiled. The effects of testing schedules on diesel reliability are assessed. Individual failures are identified in an appendix. 

NUMRER AND TYPE OF RECORDS 5000 events from responses to USNRC and... 

This report provides an aging assessment of electric motors and was conducted under the auspices of the USNRC NPAR. Pertinent failure-related information was derived from LERs, IPRDS, NPRDS, and NPE including failure modes, mechanisms, and causes for motor problems. In addition, motor design and materials of construction were reviewed to identify age-sensitive components. The study included consideration of the seismic susceptibility of age-degraded motor components to externally-induced vibrational effects. 

The aforementioned reviews and assessments were assimilated to characterize the effect of dielectric, rotational, and mechanical hazards on motor performance and operational readiness. Functional indicators were identified that can be monitored to assess motor component deterioration caused by aging or other accidental stressors. The study also includes a preliminary discussion of current standards and guides, maintenance programs, and research activities pertaining to nuclear power plant safety-related electric motors. Included are motor manufacturer recommendations, responses from repair facilities to a questionnaire, in-service inspection data, expert knowledge, USNRC-IE audit reports, and standards and guides published by the Institute of Electrical and Electronics Engineers (IEEE). 

EGSG Idaho s Idaho National Engineering Laboratory reviewed Licensee Event Reports (LERs), both qualitatively and quantitatively, to extract reliability information in support of the USNRC s effort to gather and analyze component failure data for U.S. commercial nuclear power plants. LERs describing failures or command faults (failure due to lack of needed input) for selected components have been analyzed in this program. Separate reports have been issued for batteries and battery chargers, control rods and drive mechanisms, diesel generators, ISC, Inverters, primary containment penetrations, protective relays and circuit breakers, pumps, and valves. 

The sources of data for this report were associated with NUREG-0737, (c) Diesel generator data submitted to the USNRC in response to a questionnaire prepared as part of the study. 

Appendix III of this report provides a detailed description of the reliability data used in event tree and fault tree quantification. Because of its extensive operating experience and the uniqueness of the BRP design, BRP plant-specific data was used whenever possible. Plant-specific data sources included plant maintenance orders, control room log books, surveillance tests, LERs, event reports, deviation reports, plant review committee meeting minutes, and USNRC correspondence. The plant-specific data used spanned the period from 1970 to 1979. Data before 1970 did not include maintenance orders or surveillance tests and therefore were excluded. The plant-specific data collected for BRP is presented in detail in Appendix XIII. Table III-4 summarizes 30 plant-specific component failure rates and Table 11-06 contains plant-specific maintenance unavailabilities for 20 components. These tables are a summary of the BRP component failure and maintenance outages. 

The Reactor Safety Study (WASH-1400) was published by the USNRC in 1975 to set down a methodology for assessing nuclear plant reliability and risk. Of particular Interest to the data analyst are Appendix III, "Failure Data," and Appendix IV, "Common Mode Failures."... 

USNRC United States Nuclear Regulatory Commission... 

USNRC. 1999. Standards for the protection against radiation, table 1004(b). 1. 10 CFR 20.1004. U.S. Nuclear Regulatory Commission, Washington, D.C. 

The key findings of the 1980 USNRC analysis of instrument tube breaks at the reactor vessel may be adjusted for breaks at the seal table by applying a multiplier of 3.55. That is, 3.55 tubes broken at the seal table are the equivalent to 1 tube broken at the reactor vessel. 

Donaldson, M. R., and R. E. Pulfrey, 1979, Imaging Optical Probe for Pressurized Steam-Water Environments, Proc. Review Group Conf. on Advanced Instrument for Reactor Safety Research, USNRC, NUREG/CP-0007, III.17-1-27. (3)... 

Organization (WHO) recommends limits for the safe intake of chemical elements. The limit for Hg is 300 pg per week of which a maximum of 200 pg is Me-Hg [11]. In April 2004 the European Food Safety Authority (EFSA) published new limits for Me-Hg. On the one hand, a Provisional Tolerable Weekly Intake (PTWI) of 1.6 pg kg-1 body weight is given on the other hand, a significantly lower intake limit of 0.7 pg kg-1 body weight per week from a previous evaluation by the United States National Research Council (USNRC) is established [12]. 

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