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NUREG 0933
Displaying 26 - 50 of 84
DESCRIPTION Historical Background This NUREG-0471 [1] item deals with two concerns regarding the ice condenser containment design. The first concern arises from an ACRS comment on the D. C. Cook Unit 1 review. The normal procedure used by the staff (CSB) …
1
DESCRIPTION Historical Background This issue was documented in NUREG-0471 [1] and resulted from a review of LERs which indicated that onsite emergency diesel generators (EDGs) at operating plants were demonstrating an average starting reliability of about …
1
DESCRIPTION This NUREG-0471 [1] task will make a determination as to whether plants should be designed to accommodate a total loss of all AC power for a limited period of time. CONCLUSION This issue is covered in USI A-44, "Station Blackout." [1] …
1
DESCRIPTION Offsite power system frequency decay, depending on the rate of decay, could provide an electrical brake on the reactor coolant pump motors that could slow the pumps faster than the assumed flywheel coastdown flow rates normally used in …
1
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 …
1
DESCRIPTION Inadvertent operation of containment sprays can result in a rapid depressurization of the containment building. Where containment external design pressure may be exceeded, many plants have been provided with vacuum breakers or control system …
1
DESCRIPTION Various kinds of insulation are used on piping and components inside the containment of a nuclear power plant. The concern of this NUREG-0471 [1] item was the behavior of insulation under pipe break accident conditions where the potential …
1
DESCRIPTION Combinations of fabrication, stress, and environmental conditions have resulted in isolated instances of stress corrosion cracking of low pressure Schedule 10 Type 304 stainless steel piping systems. Although these systems are not part of a …
1
DESCRIPTION This NUREG-0471 [1] task will respond to a concern of the ACRS about the effectiveness of various containment sprays to remove airborne radioactive materials which could be present within the containment following a LOCA. This concern has been …
1
DESCRIPTION This NUREG-0471 [1] item was an ACRS generic concern that initially addressed the common mode failure of identical components exposed to identical or nearly-identical conditions or environments. This concern was later expanded to include other …
1
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) …
1
DESCRIPTION Historical Background This issue apparently originated as a DOR proposal and was discussed in SECY-80-325. [1] The issue as previously evaluated [2] is whether periodic replacement of the squib charges and circuit checks of the traveling …
1
DESCRIPTION This issue involves a potential deficiency in the ability to control leakage past the main steam isolation valves (MSIV) in BWR plants. Requirements for MSIV leakage control systems outlined in Regulatory Guide 1.96 [1] were developed as a …
1
DESCRIPTION Historical Background In the event of a LOCA in which offsite power remains available, the reactor operator may choose to shut down the emergency diesel generators shortly after the LOCA. If, after the diesels are shut down, offsite power is …
1
DESCRIPTION On November 10, 1979, an event occurred at the Oconee Power Station, Unit 3, that resulted in loss of power to a non-Class 1E 120-volt AC single-phase power panel that supplied power to the integrated control system (ICS) and the nonnuclear …
1
DESCRIPTION Historical Background This concern was raised [1] because of the potential for a high-altitude nuclear weapon detonation causing a large electromagnetic pulse (EMP) which subsequently could induce large currents and voltages in electrical …
1
DESCRIPTION In a San Onofre Unit 1 Preliminary Notification issued in September 1980, it was reported that, during testing, the licensee had identified a problem with the design of the diesel generator sequencing circuitry. This problem occurred when a …
1
DESCRIPTION Historical Background Prior to 1981, the number of bolting-related incidents reported by licensees was on the increase. A large number of these were related to primary pressure boundary applications and major component support structures. As a …
1
DESCRIPTION Historical Background This issue was identified [1] after AEOD completed a study on internal appurtenances in LWRs. This study, AEOD/E101, [2] was initiated because of the relatively high number of LERs that described events in which internal …
1
DESCRIPTION Historical Background This issue was identified [1] when AEOD expressed concerns about the use inside containment of a particular polymer coating that could flake off and fail when subjected to DBA conditions. In addition to the concern for …
1
DESCRIPTION Historical Background This issue was initiated in response to an immediate action memorandum [1] issued by AEOD in September 1981 regarding desiccant contamination of instrument air lines. NRR responded to the AEOD memorandum by establishing a …
1
DESCRIPTION Historical Background This proposed generic issue has its origin in a January 1981 event at Millstone Unit 2. [1] An operator inadvertently opened a 125V DC main feeder breaker, causing the loss of one of the two redundant emergency systems …
1
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 …
1
DESCRIPTION An AEOD memorandum [1] to NRR on July 15, 1980, identified the concern that some operating nuclear power plants do not have technical specifications or Administrative controls governing operational restrictions for Class 1E 120 VAC vital …
1
DESCRIPTION Historical Background In an AEOD memorandum [1] to NRR, it was concluded that the design of the Point Beach Nuclear Plant, Units 1 and 2, under certain conditions, allowed manual interconnection of redundant electrical load groups, thereby …
1
Page Last Reviewed/Updated 3/1/2026
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