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NUREG 0933

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The objective of this task was to improve the reliability and capability of nuclear power plant systems for removing decay heat and achieving safe shutdown conditions following transients and under post-accident conditions. ITEM II.E.3.1: RELIABILITY OF …
The objective of this task was to provide instrumentation to monitor plant variables and systems during and following an accident. Indications of plant variables and status of systems important to safety are required by the plant operator (licensee) …
The objective of this task was to increase the reliability and diversification of the electrical power supplies for certain safety-related equipment. ITEM II.G.1: POWER SUPPLIES FOR PRESSURIZER RELIEF VALVES, BLOCK VALVES, AND LEVEL INDICATORS DESCRIPTION …
The objective of this task was to improve public radiation protection in the event of a nuclear power plant accident by improving (1) radioactive effluent monitoring, (2) the dose analysis for accidental releases of radioiodine, tritium, and carbon-14, …
DESCRIPTION At the time this issue was identified in NUREG-0371, [1] trends in the design of nuclear power plants showed an increase in the use of digital computer technology in safety-related instrumentation and control systems. The first application of …
DESCRIPTION CP applicants for which SERs were issued after July 1, 1974, were required by the NRC to qualify all safety- related equipment to IEEE 323. [1] From the time this standard was originated, the industry developed methods that were used to …
DESCRIPTION Historical Background The Class 1E power sources provide the electric power for the plant systems that are essential to reactor shutdown, containment isolation, reactor core cooling, containment heat removal or are otherwise essential in …
DESCRIPTION By letter dated June 18, 1975, licensees of operating reactor facilities were sent a preliminary copy of a staff paper, "Guidance for Proposed License Amendments Relating to Refueling," and "Refueling Information Request Form." The purpose was …
DESCRIPTION Historical Background This NUREG-0371 [1] item involves the development of consistent and formalized acceptance criteria regarding the conversion to higher density storage racks (increased storage capacity) in existing spent fuel storage …
DESCRIPTION Historical Background This issue is documented in NUREG-0371 [1] and addresses the adequacy of safety-related DC power supplies which was questioned by a nuclear consultant in a letter to the ACRS in April 1977 (NUREG-0305, [2] Attachment B). …
DESCRIPTION This NUREG-0371 [1] item was initiated in order to develop criteria and guidelines to be used by applicants, licensees, and staff reviewers to support implementation of Regulatory Guide 1.97, [2] Revision 1. Such criteria and guidelines were …
DESCRIPTION This issue was raised in NUREG-0371 [1] following a series of events at operating plants that involved the offsite power systems. These events indicated that the reliability of the preferred source of emergency power might have been less than …
DESCRIPTION The complete loss of AC electrical power to the essential and nonessential switchgear buses in a nuclear power plant is referred to as a "Station Blackout." Because many safety systems required for reactor core decay heat removal are dependent …
DESCRIPTION The design criteria and methods for the seismic qualification of mechanical and electrical equipment in nuclear power plants underwent significant changes during the course of the licensing of commercial nuclear power plants. Consequently, it …
DESCRIPTION Nuclear power plant instrumentation and control systems are composed of safety-related protection systems and non-safety-related control systems. The safety-related protection systems are designed to satisfy the General Design Criteria …
DESCRIPTION Some prototype electrical penetration failures have occurred to date. In addition, failures of low voltage penetration modules have occurred at a licensed facility. It was originally postulated that failures of the low voltage penetration …
DESCRIPTION Historical Background Individual reactor fuel rods sometimes fail during normal operations and many fuel rods are expected to fail during severe accidents. To ensure that these fuel failures do not result in unacceptable releases to the …
DESCRIPTION This NUREG-0471 [1] task covers a spectrum of technical efforts related to the staff review of LMFBR fuel designs. The efforts include: (1) evaluating licensing requirements for the behavior of stainless steel cladding and hexcans in an LMFBR …
DESCRIPTION The seismic qualification of complex electrical and mechanical components has undergone rapid changes in the past several years. Revisions in industry standards (IEEE 344) have resulted in the need to audit the qualification programs of NSSS …
DESCRIPTION NRC environmental information needs for licensing fall into the categories of: (1) detailed site-specific investigations at a preferred site, and (2) reconnaissance level information to support alternative site assessment and selection, …
DESCRIPTION The effects of entrainment on phytoplankton and zooplankton populations are often minimal and occasionally beneficial. Numerous studies of the effects of entrainment on plankton organisms, phytoplankton, and zooplankton have shown impacts to …
DESCRIPTION The fuel assembly is a highly nonlinear structure which can be subjected to substantial loadings during seismic excitations and LOCA transients. The integrity of this assembly is critical for plant safety. Extensive work has been completed by …
DESCRIPTION Historical Background This NUREG-0471 [1] item arose in the course of the NRC review of the McGuire application, where the applicant proposed relying on the generator load break switch for isolating the generator from the stepup transformer …
DESCRIPTION Historical Background This issue was documented in NUREG-0471 [1] and resulted from a review of LERs which indicated that onsite emergency diesel generators (EDGs) at operating plants were demonstrating an average starting reliability of about …
DESCRIPTION This NUREG-0471 [1] task will make a determination as to whether plants should be designed to accommodate a total loss of all AC power for a limited period of time. CONCLUSION This issue is covered in USI A-44, "Station Blackout."     [1] …

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