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NUREG 0933
Displaying 1 - 25 of 25
TASK II.E.1: AUXILIARY FEEDWATER SYSTEM The objective of this task was to improve the reliability of the auxiliary feedwater (AFW) system. ITEM II.E.1.1: AUXILIARY FEEDWATER SYSTEM EVALUATION This item was clarified in NUREG-0737, [1] requirements were …
1
The objectives of this task were to perform systems reliability analyses and to effect changes in emergency operating procedures and operator training to improve the capability of plants to mitigate the consequences of the small-break LOCAs and …
1
DESCRIPTION The issue was raised after the occurrence of various incidents of water hammer that involved steam generator feedrings and piping, emergency core cooling systems, RHR systems, containment spray, service water, feedwater, and steam lines. The …
1
DESCRIPTION This issue was raised in an AEOD memorandum [1] to NRR and OIE in October 1980 and addressed the problem of flow blockage by Asiatic clams (Corbicula) in redundant safety-related cooling water systems at Arkansas Nuclear One. CONCLUSION This …
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DESCRIPTION Historical Background On June 19, 1981, AEOD issued a preliminary report [1] on the incident at Calvert Cliffs Unit 1 in which the plant lost both redundant trains of service water when the service water system became air-bound as a result of …
1
DESCRIPTION While operating at 100% power on March 10, 1980, San Onofre Unit 1 experienced a complete loss of the salt water cooling system. The event involved an unlikely triple failure and desiccant contamination of the instrument air system was found …
1
DESCRIPTION Historical Background On April 7, 1980, Arkansas Nuclear One (ANO) Units 1 and 2 experienced a significant event resulting from a loss of offsite power. Although both units were safely shut down, the analysis and evaluation of the event …
1
DESCRIPTION Historical Background This issue was raised in a DL memorandum [1] to DST in March 1982 and addressed the subject of service water system (SWS) fouling at operating plants primarily by aquatic bivalves. Prior to and following this memorandum, …
1
DESCRIPTION This issue was raised in an AEOD memorandum [1] to NRR in May 1982 and addressed the problem of flow blockage by blue mussels (Mytilus Edilus) in the reactor building closed cooling water system at Pilgrim. CONCLUSION This issue has been …
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 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 November 11, 1981, the DAILY REPORT-REGION I carried a "prompt report" from Calvert Cliffs Units 1 and 2 indicating the licensee had been notified that the water tight integrity of the service water pump rooms in both …
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 In December 1984, the staff recommended in SECY-83-357B [1] that rulemaking with regard to H 2 control for LWRs with large, dry containments could be safely deferred due to the greater inherent capability of these containments to accommodate …
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 [1] when the staff found the Byron Unit 1 vulnerable to core-melt sequences in the absence of the availability of Byron Unit 2 which was not yet operational. Because of the licensing status of …
1
DESCRIPTION Historical Background This issue was identified by NRR/EIB in February 1986 when it was suggested that Issue 106, "Piping and the Use of Highly Combustible Gases in Vital Areas," be expanded to include new safety concerns associated with the …
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 in SECY-89-170 [1] and addressed the effectiveness of manual fire-fighting in the presence of smoke. This concern arose as a result of an NRC-sponsored Fire Risk Scoping Study [2] which focused on …
1
DESCRIPTION Historical Background This issue was raised in SECY-89-170 [1] and addressed the effect of premature failure of fire barriers on CDF. Concern for fire barriers arose as a result of an NRC-sponsored Fire Risk Scoping Study [2] which focused on …
1
DESCRIPTION Historical Background The reliability of essential service water (ESW) systems and related problems have been an ongoing staff concern which has been documented in NUREG/CR-2797, [1] IE Bulletins 80-24 [2] and 81-03, [3] Generic Letter No. …
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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 In February 1993, The U.S. Nuclear Regulatory Commission (NRC) Office of Nuclear Reactor Regulation (NRR) completed a reassessment of the reactor fire protection review and inspection programs, in response to programmatic concerns raised …
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Page Last Reviewed/Updated 3/1/2026
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