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NUREG 0933
Displaying 51 - 75 of 87
DESCRIPTION Historical Background This issue was identified [1] when a number of concerns regarding DC power systems were raised during the review of the proposed resolution of Issue A-30, "Adequacy of Safety-Related DC Power Supplies." The main concerns …
1
DESCRIPTION Historical Background STS for newer OLs require licensees to keep account of the number of transient occurrences to ensure that transient limits, based on design assumptions, are not exceeded. However, a number of older plants for which …
1
DESCRIPTION Historical Background On March 18, 1983, B&W expressed [1] concern for unanalyzed reactor vessel thermal stress that could occur during natural convection cooldown of PWRs. The concern emerged from a preliminary B&W evaluation of a voiding …
1
DESCRIPTION Historical Background This issue was identified by the ACRS in 1978 during the operating license reviews of some BWRs. The ACRS posed questions concerning the likelihood and effects of a LOCA which could cause interactions with the CRD …
1
DESCRIPTION Historical Background In October 1982, the Executive Director for Operations appointed the Committee to Review Safety Requirements at Power Reactors (CRSRPR) to review U.S. Nuclear Regulatory Commission (NRC) security requirements at nuclear …
1
DESCRIPTION This issue was raised by the ACRS in a memorandum [1] to the Commission in October 1983. Following the TMI-2 accident, the purpose and use of PORVs had been the subject of considerable analyses and discussion. The original purpose for which …
1
DESCRIPTION Historical Background In BWRs, SRVs are mounted on the main steam line inside the drywell. Each SRV discharge is piped through its own discharge line (tailpipe) to a point below the minimum water level in the primary containment suppression …
1
DESCRIPTION Historical Background In March 1982, leaks were detected in the heat-affected zones of the safe-end-to-pipe welds in two of the 28 in. diameter recirculation loop safe ends at Nine Mile Point Unit 1. Subsequent UT revealed extensive cracking …
1
DESCRIPTION Historical Background Low temperature overpressurization originally identified in NUREG 0371 [1] as item A-26. This issue later became USI A-26 and was resolved in September 1978 with a revision to SRP [2] Section 5.2. The resolution of USI …
1
DESCRIPTION Historical Background This issue was identified during the staff review of the Indian Point 2 and Zion PRAs [1] ; in both of these studies, the dominant interfacing systems LOCA events were estimated to be through the RHR suction valves. The …
1
DESCRIPTION Historical Background On April 17, 1984, a DSI memorandum [1] on the subject of RHR interlocks for W plants described staff concerns that the design basis for RHR interlocks had been misunderstood and that these concerns had not been …
1
DESCRIPTION Historical Background Issue 50 addressed several areas of concern with BWR water level instrumentation and its resolution involved voluntary implementation of water level measurement improvements for all of the staff concerns, except the one …
1
DESCRIPTION Historical Background In January 1984, AEOD issued a special study report (AEOD/S401) [1] describing the number of events that resulted from human error in identification of the correct unit or train. This study focused on LERs issued during …
1
DESCRIPTION In the prioritization of Issue 22, "Inadvertent Boron Dilution," it was found that inadvertent boron dilution events during cold shutdown operation do not constitute a significant risk to the public. Further work by DSI confirmed this …
1
DESCRIPTION Historical Background Potential stress corrosion cracking (SCC) of reactor vessel (RV) closure studs was raised as a GSI in December 1984. [1] Concerns were expressed that two contributors to SCC had not been subject to careful research and …
1
DESCRIPTION Historical Background This issue was identified in a NRR/DST memorandum [1] and addressed the potential risk reduction that might result from training operators and having procedures developed to assist the operators in managing accidents …
1
DESCRIPTION In an August 1983 memorandum, [1] the EDO requested a comprehensive review of NRC requirements in the area of nuclear power plant piping. In response to this request, the NRC Piping Review Committee (PRC) was formed to review and evaluate …
1
On June 9, 1985, Davis-Besse had a partial loss of feedwater while operating at 90% power. Following a reactor trip, the loss of all feedwater occurred. The two OTSGs became dry and were ineffective as a heat sink. Consequently, the RCS pressure increased …
1
DESCRIPTION Historical Background Potential seismic interaction involving the movable in-core flux mapping systems was identified as a generic issue in August 1985. [1] This potential interaction exists because portions of the in-core flux mapping system, …
1
DESCRIPTION Historical Background In IE Circular No. 80-02, [1] the concern of overtime work for licensee staff who perform safety-related functions was discussed and limits on maximum working hours were recommended. In July 1980, a letter [2] was issued …
1
DESCRIPTION Since the TMI-2 accident in March 1979, to which human error was a major contributor, the issue of academic requirements for reactor operators has been a major concern of the NRC. In October 1985, the NRC issued a Policy Statement on …
1
DESCRIPTION Historical Background This issue arose as the result of an event at the Palo Verde Nuclear Generating Station (PVNGS) Unit 3 in which inadequate lighting conditions exacerbated an unrelated reactor trip. [1] During this event, half of the …
1
DESCRIPTION To calculate the value of RT PTS as required in 10 CFR 50.61 and 10 CFR 50, Appendix G, licensees must determine the value of the fast neutron fluence on the inside surface of their pressure vessels. Through a number of reviews, NRR found [1] …
1
DESCRIPTION The issue of fatigue of metal components was identified in SECY-93-049 [1] following the staff's senior management review of key license renewal issues. The recommendation to treat fatigue of metal components as a generic safety issue was …
1
In resolving GSIs over the years, the staff generally found it necessary to make assumptions and establish limitations on the scope of the issues. As a result of its review of the resolution of some GSIs, the ACRS expressed concerns that the assumptions …
1
Page Last Reviewed/Updated 3/1/2026
Disclaimer: Some of the formatting in NUREG-0933 may not be correct. We are currently working on fixing the formatting.