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NUREG 0933

Displaying 1 - 25 of 74

The objective of this task was to improve the quality assurance program (QA) for design, construction, and operations to provide greater assurance that plant design, construction, and operational activities were conducted in a manner commensurate with …
The objectives of this task were to: (1) decrease reliance on the emergency core cooling system (ECCS) for events other than LOCAs; (2) ensure that the ECCS design basis reliability and performance were consistent with operational experience; (3) reach a …
TASK II.J.1: VENDOR INSPECTION PROGRAM The objective of this task was to improve vendor-supplied components and services through a modified and more effective vendor inspection program. ITEM II.J.1.1: ESTABLISH A PRIORITY SYSTEM FOR CONDUCTING VENDOR …
The objective of this task was to improve the qualification of licensees for operating nuclear power plants by requiring greater oversight of design, construction, and modification activities. ITEM II.J.3.1: ORGANIZATION AND STAFFING TO OVERSEE DESIGN AND …
The objective of this task was to clarify deficiency report requirements to obtain uniform reporting and earlier identification and correction of problems. ITEM II.J.4.1: REVISE DEFICIENCY REPORTING REQUIREMENTS DESCRIPTION This TMI Action Plan [1] item …
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 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 …
DESCRIPTION Historical Background Prior to May 1978, tests conducted by GE showed that the presence of steam and/or increased pressure in and above the upper core region of BWRs could adversely affect the distribution of flow from certain types of core …
DESCRIPTION By letter dated June 18, 1975, licensees of operating reactor facilities were sent a preliminary copy of a staff paper, "Guidance for Proposed License Amendments Relating to Refueling," and "Refueling Information Request Form." The purpose was …
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 Numerical reliability goals and methods of analysis have not been established by the NRC. The current basis for plant licensing continues to be NRC regulations which require, among other things, that the consequences of a LOCA be suitably …
DESCRIPTION Historical Background This NUREG-0471 [1] item concerned staff positions [2] BTP EISCB 18 and BTP RSB 6-11 which required physical locking out of electrical sources to specific MOVs in the ECCS. The existing staff positions established the …
DESCRIPTION A number of applicants for operating licenses have been performing sump tests to demonstrate ECCS operability during the recirculation phase following a postulated loss-of-coolant accident. These tests have shown that vortex formation is not …
DESCRIPTION Most vendors, in the conduct of internal audits of emergency core cooling performance computer codes, discovered errors in coding and/or logic which had significant effects on the prediction results of approved models. This NUREG-0471 [1] task …
DESCRIPTION Historical Background Individual reactor fuel rods sometimes fail during normal operations and many fuel rods are expected to fail during severe accidents. To ensure that these fuel failures do not result in unacceptable releases to the …
DESCRIPTION This NUREG-0471 [1] task covers a spectrum of technical efforts related to the staff review of LMFBR fuel designs. The efforts include: (1) evaluating licensing requirements for the behavior of stainless steel cladding and hexcans in an LMFBR …
DESCRIPTION The fuel assembly is a highly nonlinear structure which can be subjected to substantial loadings during seismic excitations and LOCA transients. The integrity of this assembly is critical for plant safety. Extensive work has been completed by …
DESCRIPTION Historical Background This issue was identified in NUREG-0471 [1] and addressed the establishment of surveillance test intervals and allowable equipment outage periods, using analytically-based TS criteria and methods. At the time the issue …
DESCRIPTION Following a plant transient or accident, provisions are required for long-term decay heat removal. Redundancy of components is required as necessary to assure that a failure in the RHR system will not impair the ability to maintain the plant …
DESCRIPTION Historical Background As identified in NUREG-0471, [1] Appendix K of 10 CFR 50 specifies the requirements for LWR ECCS analysis. These requirements call for specific conservatisms to be applied to certain models and correlations used in the …
DESCRIPTION This issue was documented in NUREG-0471 [1] and stemmed from an ACRS recommendation that the staff explore diverse means of obtaining ECCS capability for future plants. The ACRS also recommended the staff explore the issue in the context of …
DESCRIPTION Historical Background This issue is identified in Appendix D of NUREG-0572 [1] and is one of the key observations made after the ACRS requested its members and consultants to make comprehensive reviews of all Licensee Event Reports (LERs) …
DESCRIPTION Background This issue was identified [1] after a review of LERs involving the failure or degraded performance of essential equipment that resulted from the failure of protective devices such as fuses and circuit breakers. The affected systems …
DESCRIPTION The concern of this issue involves the requirement for verification that the balance-of-plant equipment satisfies the design intent. This issue was identified in NUREG-0705. [1] CONCLUSION Task I.F in NUREG-0660, [2] the TMI Action Plan, is a …
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 …

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