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NUREG 0933
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Displaying 51 - 75 of 82
DESCRIPTION Historical Background Reactor protection systems (RPS) or "scram" systems are tripped by many diverse signals. The purposes of these various signals can be broadly divided into three classes: protection of the reactor core (e.g., overpower …
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 Historical Background This issue was identified in a DST/NRR memorandum [1] which addressed a condition in which some protective devices intended to trip active engineered safety features (ESF) components, under indication of equipment …
1
DESCRIPTION Historical Background In February 1983, the Westinghouse Owners Group submitted WCAP-10271, "Evaluation of Surveillance Frequencies and Out of Service Times for the Reactor Protection Instrumentation System," to the NRC for review and …
1
DESCRIPTION Historical Background The ATWS rule [1] , [2] for W plants requires the implementation of a diverse ATWS mitigation system, Auxiliary [or ATWS] Mitigating Systems Actuation Circuitry (AMSAC). The functions prescribed for AMSAC are turbine trip …
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
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 This issue was identified in the U.S. Nuclear Regulatory Commission (NRC) incident investigation team (IIT) report on the loss of integrated control system (ICS) power event at Rancho Seco Nuclear Generating Station …
1
DESCRIPTION Historical Background This issue was identified in a May 1986 DSI memorandum [1] in which 21 instances of BWR vessel draining through various paths in the RHR system piping were described. Later, in August 1986, AEOD/E609 [2] was issued …
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 was raised in SECY-89-170 [1] and addressed the potential for control system vulnerabilities as a result of fire-induced alternate shutdown/control room panel interactions. Concern for these interactions arose …
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 Historical Background This issue was raised [1] by NRR following a review of events at 3 operating BWR plants that involved inadvertent ESF actuations upon loss and subsequent restoration of power to Rosemount analog transmitter trip units …
1
DESCRIPTION This issue was identified [1] by NRR to address the concerns raised during the licensing of Nine Mile Point Unit 2. On February 7, 1985, Niagara Mohawk submitted to the NRC a report on "Non-Class 1E Devices Connected to Class 1E Power …
1
DESCRIPTION As discussed in SECY-93-049, [1] the staff reviewed significant license renewal issues and found that several related to environmental qualification (EQ). A key aspect of these issues was whether the licensing bases, particularly for older …
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
DESCRIPTION Historical Background The NRC post-TMI-2 accident shift staffing policy was codified through the issuance of 10 CFR 50.54(m) which specified minimum requirements for licensed operators at nuclear power reactor sites but not for non-licensed …
1
DESCRIPTION Historical Background The Rosemount Transmitter Review Group (RTRG) was established [1] to perform an assessment of the actions taken to address Rosemount transmitter oil-loss concerns. This assessment included an evaluation of the adequacy of …
1
DESCRIPTION Historical Background This issue was identified by RES after concern was raised for the number of component failures in the solid state protection systems of nuclear power plants that were caused by the growth of tin whiskers. [1] In 1987, …
1
This task was developed to assure that the number and capabilities of the staff at nuclear power plants are adequate to provide safe operation. To meet this goal, consideration will be given to: (1) the numbers and functions of the staff needed to safely …
1
In response to Section 306 of the Nuclear Waste Policy Act of 1982, the Commission published a "Policy Statement [1] on Training and Qualification of Nuclear Power Plant Personnel, March 1985. This Policy Statement endorsed the INPO Accreditation Program …
1
Page Last Reviewed/Updated 3/1/2026
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