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NUREG 0933

Displaying 1 - 14 of 14

DESCRIPTION BWRs are operated in such a manner as to attempt to produce an axial power distribution with as little peaking as possible. When the reactor moderator is not boiling (e.g., during startup and heatup), the axial flux distribution is much more …
DESCRIPTION Historical Background In response to a 1967 ACRS concern relative to the potential of melting and subsequent disintegration of a portion of a fuel assembly due to inlet orifice flow blockage, GE submitted NEDO-10174 [1] in May 1970. As a …
DESCRIPTION Historical Background This issue was initiated to address concerns raised by the Union of Concerned Scientists. (References [1] , [2] , and [3] .) The purposes for including this issue as a generic issue are to: (1) provide brief background …
DESCRIPTION Historical Background Experiments conducted at several test facilities prior to 1984 showed that irradiated fuel can fragment (crumble) into small pieces during a LOCA. Some evaluation of this effect was made for NRC by EG&G. [1] Although it …
DESCRIPTION Historical Background This issue was raised [1] in March 1985 to address the staff's concern that there were no requirements for dynamic qualification testing or dynamic surveillance testing of large bore hydraulic snubbers (> 50 kips load …
DESCRIPTION Historical Background This issue was identified in a RRAB memorandum [1] in March 1985 and addressed the possibility of relay contact chatter during a seismic event and its resulting effect upon safety and safety-related electrical control …
DESCRIPTION Historical Background This issue was identified [1] by NRR when concerns were expressed that the seismic loading on equipment and pipe-mounted components may have been underestimated. These concerns could be divided into two sub- issues: …
DESCRIPTION In 1977, the NRC initiated the Systematic Evaluation Program (SEP) to review the designs of 51 older, operating nuclear power plants. The SEP was divided into 2 phases. In Phase I, the staff defined 137 issues for which regulatory requirements …
DESCRIPTION Historical Background Following the TMI-2 accident, the NRC converted its fuel behavior research program into a severe accident research program and, consequently, no further confirmatory work on fuel damage criteria was pursued. However, some …
DESCRIPTION Core design is a fundamental component of plant safety because maintaining fuel integrity is the first principal safety barrier (i.e., fuel cladding, reactor coolant system boundary, or the containment) against serious radioactive releases. …
DESCRIPTION The objective of this task was to respond to the Regulatory Review Group (RRG) Item #55. The RRG recommendations were to provide quicker review of core reload codes and to revise existing TS to permit changes, in accordance with approved core …
DESCRIPTION Historical Background This issue was identified [1] following an NRR request for reconsideration of the safety priority ranking (DROP) of GSI-22, "Inadvertent Boron Dilution Events," based on new information on high burn-up fuel and new …
DESCRIPTION Historical Background Beginning in the early-1980s, the NRC sponsored the development of a Probabilistic Seismic Hazard Analysis (PSHA) methodology by LLNL. For the purpose of conducting a systematic evaluation of the licensing criteria for …
DESCRIPTION On May 26, 2005, the Office of Nuclear Reactor Regulation (NRR), Division of Engineering, recommended that issues related to closed Generic Issue (GI)-194, "Implications of Updated Probabilistic Seismic Hazard Estimates," dated September 23, …

Page Last Reviewed/Updated 3/1/2026

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