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NUREG 0933

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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 …
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 …
DESCRIPTION Historical Background Operation of a LWR results in slow corrosion of the interior metal surfaces of the primary coolant system. The resulting corrosion products circulate through the reactor core and are activated by neutron flux from the …
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 …
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 …
DESCRIPTION Historical Background This issue was raised [1] by DSI/NRR in August 1982 [2] following a search of LERs which suggested that additional licensing attention was needed for certain ancillary power plant equipment. The available information …
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 …
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 …
DESCRIPTION Historical Background Combustible gases such as H 2 , propane, and acetylene are used during normal operations of nuclear power plants in limited quantities and for relatively short periods of time. H 2 , the most prevalent of these gases in …
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 …
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 …
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 …
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 …
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 …
DESCRIPTION Historical Background Issue 106 was resolved with the issuance of Generic Letter 93-06, "Research Results on Generic Safety Issue 106, Piping and the Use of Highly Combustible Gases in Vital Areas," dated October 25, 1993, [1] which included …
DESCRIPTION Historical Background The issue of potential hazards from combustible gases was raised [1] after two events involving hydrogen combustion occurred within 2 months in late-2001 at two foreign BWRs. Both these events involved sudden rupture of …
DESCRIPTION Historical Background This issue was raised [1] , [2] by an NMSS staff member whose concern arose from the observation that spent fuel pool racks using Boral for neutron absorption had experienced some problems with swelling and degradation of …
DESCRIPTION Historical Background This issue was initiated [1] in response to a recommendation in the screening analysis of Generic Issue (A)             I-195, "Potential Hydrogen Combustion in BWR Piping." GI-195 investigated the potential safety …
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, …

Page Last Reviewed/Updated 3/1/2026

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