Section
Resolution Product Category
Facilities Type
Related Technical Area
Image
NUREG 0933
Applied Filters
Displaying 26 - 50 of 52
DESCRIPTION An AEOD memorandum [1] to NRR on July 15, 1980, identified the concern that some operating nuclear power plants do not have technical specifications or Administrative controls governing operational restrictions for Class 1E 120 VAC vital …
1
DESCRIPTION Historical Background In January 1982, AEOD published a report (AEOD/C201 [1] ) on safety concerns associated with reactor vessel level instrumentation in BWRs. The report was forwared to NRR for further action. Safety Significance BWRs use …
1
DESCRIPTION Historical Background This issue was identified at an NRC Operating Reactor Events meeting on January 7, 1982, [1] and addressed fire protection system (FPS) actuations that resulted in adverse interactions with safety-related equipment at …
1
DESCRIPTION Historical Background Protection systems in nuclear power plants are required to meet the design criteria of IEEE-279, "Criteria for Protection Systems for Nuclear Power Generating Stations." [1] One of the criteria of IEEE-279 requires that …
1
DESCRIPTION Historical Background In an evaluation of INPO/NSAC Significant Operating Experience Report 81-17, [1] the operators at Fort Calhoun determined that the configuration of their plant made it susceptible to the possibility that all AFW supply …
1
DESCRIPTION Historical Background On two occasions (February 22 and 25, 1983), Salem Unit 1 failed to scram automatically due to failure of both reactor trip breakers to open on receipt of an actuation signal. In both cases, the unit was successfully …
1
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 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 This issue was recommended [1] for prioritization by DSI after a review of the AEOD engineering evaluation report (AEOD/E325) [2] on vapor binding of the AFW pumps at H.B.Robinson Unit 2. Further AEOD study of the event …
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 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 The loss of all feedwater event at Davis-Besse on June 9, 1985, resulted in the formation of an NRC project team to investigate the event. The team's findings were published in NUREG-1154 [1] and were subsequently reviewed by DL/NRR. As a …
1
DESCRIPTION In 1985, operating experience as well as staff and industry studies indicated that AFW systems continued to fail at a high rate. These studies also indicated that plants with similar AFW system reliabilities (as calculated in accordance with …
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 This issue was identified as an alternative approach to the Finding 15 recommendation [1] discussed in Issue 125.I.5, "Safety Systems Tested in All Conditions Required by DBA," which states that "[t]horough integrated …
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 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 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
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.