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NUREG 0933

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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 This NUREG-0371 [1] item involves the development of consistent and formalized acceptance criteria regarding the conversion to higher density storage racks (increased storage capacity) in existing spent fuel storage …
DESCRIPTION At all nuclear plants, overhead cranes are used to lift heavy objects in the vicinity of spent fuel. If a heavy object such as a spent fuel shipping cask or shielding block were to fall onto spent fuel in the storage pool or reactor core …
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 The risks of beyond design basis accidents in the spent fuel storage pool were examined in WASH-1400 [1] (App. I, pp. I-96ff). It was concluded that these risks were orders of magnitude below those involving the reactor …
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 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 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 …
In November 1992, two engineers who had previously worked under contract for the Pennsylvania Power and Light Company (PP&L) filed a report contending that the design of the Susquehanna station failed to meet regulatory requirements with respect to …
DESCRIPTION Historical Background The Office of Nuclear Reactor Regulation (NRR) identified this issue in April 1999, [1] when the concern was raised that licensees operating within the regulatory guidelines of Generic Letter (GL) 85-11, Completion of …
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, …
DESCRIPTION Historical Background Spent fuel pools (SFPs) at PWRs are Seismic Category I structures that contain borated water, maintain spent fuel temperatures, and provide radiation shielding. The SFPs are typically lined with stainless steel plates, …
DESCRIPTION This issue was identified by an NMSS engineer in December 2006 and addressed concerns about potential safety issues with cranes that are used to lift spent fuel casks at nuclear power plants. The areas of concern involved questions about the …

Page Last Reviewed/Updated 3/1/2026

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