Skip to main content

NUREG 0933

Displaying 1 - 25 of 96

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 …
The objective of this task was to provide instrumentation to monitor plant variables and systems during and following an accident. Indications of plant variables and status of systems important to safety are required by the plant operator (licensee) …
The objective of this task was to increase the reliability and diversification of the electrical power supplies for certain safety-related equipment. ITEM II.G.1: POWER SUPPLIES FOR PRESSURIZER RELIEF VALVES, BLOCK VALVES, AND LEVEL INDICATORS DESCRIPTION …
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 …
TASK III.D.1: RADIATION SOURCE CONTROL The objective of this task is to perform evaluations to establish additional design features that should be included in the rulemaking proceeding of Item II.B.8. The purpose of these evaluations is to identify design …
The objective of this task was to improve public radiation protection in the event of a nuclear power plant accident by improving (1) radioactive effluent monitoring, (2) the dose analysis for accidental releases of radioiodine, tritium, and carbon-14, …
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 At the time this issue was identified in NUREG-0371, [1] trends in the design of nuclear power plants showed an increase in the use of digital computer technology in safety-related instrumentation and control systems. The first application of …
DESCRIPTION CP applicants for which SERs were issued after July 1, 1974, were required by the NRC to qualify all safety- related equipment to IEEE 323. [1] From the time this standard was originated, the industry developed methods that were used to …
DESCRIPTION Historical Background This issue is documented in NUREG-0371 [1] and addresses the adequacy of safety-related DC power supplies which was questioned by a nuclear consultant in a letter to the ACRS in April 1977 (NUREG-0305, [2] Attachment B). …
DESCRIPTION This NUREG-0371 [1] item was initiated in order to develop criteria and guidelines to be used by applicants, licensees, and staff reviewers to support implementation of Regulatory Guide 1.97, [2] Revision 1. Such criteria and guidelines were …
DESCRIPTION Nuclear power plant instrumentation and control systems are composed of safety-related protection systems and non-safety-related control systems. The safety-related protection systems are designed to satisfy the General Design Criteria …
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 This NUREG-0471 [1] task involves the maintenance and improvement of calculational capabilities for assessing doses to individuals from radiation and radioactive effluents from normal operation and from radioactive releases from postulated …
DESCRIPTION Compilation of occupational radiation exposure reports from operating reactors has shown that exposures to station and contractor personnel have generally been increasing over the past 7 years for both PWRs and BWRs. The overriding problem at …
DESCRIPTION This NUREG-0471 [1] task involves evaluating information from semiannual operating reports, inplant measurements program and topical reports, and revisions to models for calculating releases of radioactive materials in effluents from PWRs and …
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 Practice in health impact assessments at the time of identification of this issue was to convert radiation exposure estimates into estimates of health effects, such as cancer deaths, illness, and life shortening. However, the models that were …
DESCRIPTION Historical Background The ACRS raised a concern that there is a need to develop criteria for vibration monitoring systems which could provide early warning of excessive vibration inside the reactor vessel. This item is documented in …
DESCRIPTION Historical Background This NUREG-0471 [1] item was developed because of concerns regarding the long-term capability of hermetically- sealed instruments and equipment which must function in postaccident environments. Certain classes of …

Page Last Reviewed/Updated 3/1/2026

Disclaimer: Some of the formatting in NUREG-0933 may not be correct. We are currently working on fixing the formatting.