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NUREG 0933

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The objective of this task was to demonstrate by testing and analysis that the relief and safety valves, block valves, and associated piping in the reactor coolant system (RCS) were qualified for the full range of operating and accident conditions; …
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) …
TASK III.A.1: IMPROVE LICENSEE EMERGENCY PREPAREDNESS - SHORT-TERM The objectives of this task were to improve and upgrade licensee emergency preparedness by requiring improvements in facilities, plans, procedures, offsite support, technical assistance, …
The objective of this task was to upgrade the emergency preparedness of nuclear power plants. Specific criteria to meet this objective were delineated in NUREG-0654. [1] ITEM III.A.2.1: AMEND 10 CFR 50 AND 10 CFR 50, APPENDIX E The four parts of this item …
The objective of this task is to enable NRC, in the event of a nuclear accident at a licensed reactor facility, to: (1) monitor and evaluate the situation and potential hazards, (2) advise the licensee's operating staff as needed, and (3) in an extreme …
The objective of this task is to upgrade the state of emergency preparedness of State and local governments affected by nuclear facilities. The Federal Emergency Management Agency was given the lead on this effort by the President on December 7, 1979. …
The objectives of this task are: (1) to have information available for the news media and the public describing how nuclear plants operate, radiation and its health effects, and protective actions against radiation; and (2) to provide training for members …
DESCRIPTION Because of the remote possibility of failure of nuclear reactor pressure vessels designed to the ASME Boiler and Pressure Vessel Code, the design of nuclear facilities does not provide protection against reactor vessel failure. Prevention of …
DESCRIPTION Pipe cracking has occurred in the heat-affected zones of welds in primary system piping in BWRs since mid-1960. These cracks have occurred mainly in Type 304 stainless steel which is the type used in most operating BWRs. The major problem is …
DESCRIPTION Historical Background SRP [1] Section 3.6, issued in 1975, addressed pipe breaks outside containment by combining limited design basis breaks for mechanistic protection with unlimited breaks for non-mechanistic protection. Prior to this, …
DESCRIPTION Applicants are required to provide confirmation of the adequacy of computer programs used in the structural analysis and design of piping systems and components. At the time this issue was identified, this consisted of applicants providing, …
DESCRIPTION Surface cracks have been discovered in control rod drive internal parts at some operating BWR plants. Although only observed to be localized in nature, this cracking, if propagated, could potentially affect the capability of the control rod …
DESCRIPTION GDC-53, "Provisions for Containment Testing and Inspection," requires in part that the reactor containment be designed to permit: (1) periodic inspection of all important areas, and (2) an appropriate surveillance program. 10 CFR 50, Appendix …
DESCRIPTION Present NRC actions taken in response to a serious incident are directed from an Incident Response Center (IRC). To implement an adequate response, it is necessary that the IRC be equipped with appropriate communications services, information …
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 …
DESCRIPTION Historical Background Structural damage to the primary system, including the reactor pressure vessel and internals, associated piping and steam generator tubing in PWRs, can be caused by vibrations of sufficient magnitude. These vibrations can …
DESCRIPTION Background Flow-induced vibrations caused by vortex shedding resulting from rapid area change, buffeting due to random flow turbulence, fluid structures interaction instability, leakage excitation, steady operation of positive displacement …
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 …
DESCRIPTION Historical Background A memorandum [1] from AEOD to NRR dated May 23, 1980 drew attention to the generic issue of BWR jet pump integrity. The concern that motivated the AEOD memo was a February 1980 jet pump failure at Dresden Unit 3, together …
DESCRIPTION Historical Background This is an ACRS concern raised by the Subcommittee on TMI-2 Implications in October 1979. This issue centers around the possibility of a breach in the reactor coolant system boundary caused by the failure of nonsafety …
DESCRIPTION Historical Background Cracking has occurred in PWR piping systems as a result of stress corrosion, vibratory and thermal fatigue, and dynamic loading. However, as of February 1981, no cracking had been experienced in the primary system piping …
DESCRIPTION Historical Background This issue addressed the potential problem of radiation embrittlement of reactor vessel support structures (RVSS). It was originally identified as a Candidate USI in NUREG-0705 [1] where it was recommended for further …
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 …
DESCRIPTION Pressurized water reactors are susceptible to certain types of hypothetical accidents that, under circumstances such as operation of the reactor beyond a critical time in its life, could result in failure of the pressure vessel as a result of …
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 …

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