Generic letter

On August 8, 1985, the U.S. Nuclear Regulatory Commission (NRCf requested the operators of nuclear power plants in the U.S. to perform Individual Plant Examinations (IPE) on their plants. IPEs are probabilistic analyses that estimate the core damage frequency (CDF) and containment performance for accidents initiated by internal events (including internal flooding, but excluding internal fire). Generic Letter (GL) 88-20 was issued to implement the IPE request to identify any plant-specific vulnerabilities to severe accidents and report the results to the Commission. ... 

The Severe Accident Policy Statement formulates systematic safety examinations for detection of accident vulnerabilities and implementation of cost-effective changes. The NRC issued Generic Letter 88-20 to implement this plan through IPEs. While the primary goal was the identification of plant vulnerabilities, no definition of vulnerability was provided. Only 4 operators of BWRs identified vulnerabilities and only 16 operators of PWRs did so. Over 500 plant improvements were identified, but few vulnerabilities were. 

The Safety Goal Policy Statement was published to define acceptable radiological risk IVom nuclear power plant operation, and by implication provide a de minimus risk to be assured without cost considerations. Safety beyond the minimum requires cost-benefit analysis. Since being promulgated, bulletins and generic letters have been imposed to enhance safety, under the provisions of 10 CFR 50.109, the Backfit Rule. 

Generic Letter 88-20 IPE for Severe Accident Vulnerabilities at Nuclear Power Plants, NRC, December 1,... 

NRC, 1989, Installation of a Hardened Wetwell Vent, Generic Letter 89-16. 

The LER data base served as the primary source of DG failure data, while a data base for DG successes was formed from nuclear plant licensees responses to a USNRC questionnaire (Generic Letter 84-15). Estimates of DG failure on demand were calculated from the LER data, DG test data, and response data from the questionnaire. The questionnaire also provided data on DG performance during complete and partial LOSP and in response to safety injection actuation signals. Trends in DG performance are profiled. The effects of testing schedules on diesel reliability are assessed. Individual failures are identified in an appendix. 

Report recommendations include ways to improve DG reliability and maintenance programs. Other information provided includes the DG reliability at every site for the last 20 starts and last 100 starts, a listing of the number of DGs per unit, summaries of responses to generic letter 84-15 including population data, and summaries of individual utility reponses to the BNL questionnaire. 

Mass mailing of a generic letter to many potential investigative sites... 

French and international operational feedback (Generic Letter dated 17 October 1988 from the USNRC) ... 

An annex to NRC Generic Letter 89-10 (USNRC 1989) lists the most common deficiencies of motor valves. Many of them apply to air-operated valves and non-retum valves too, and are as follows ... 

AR607 USNRC (1990) Results of the public workshops , Supplement 1 to generic letter 89-10. 

AR608 USNRC (1994) Information on schedule and grouping, and staff responses to additional public questions . Supplement 6 to generic letter 89-10. 

AR609 USNRC (1996) Consideration of valve mispositioning in PWRs , Supplement 7 to generic letter 89-10. 

NRC (1992), Generic Letter (GL) 92-01 Revision 1, Reactor Vessel Structural Integrity, 10 CFR 50.54(f) , US Nuclear Regulatory Commission, Washington, DC. 

Generic Letter 88-03, "Steam Binding of Auxiliary Feedwater Pumps , U.S. Nuclear Regulatory Commission. 

Based on the above considerations and the loss-of-RHR event reported in NUREG-1269, the NRC issued Generic Letter (GL) 88-17 (Reference 4) containing recommendations for improved instrumentation, controls, operating procedures, and administrative procedures to minimize the risk of loss of RCS cooling in cold shutdown. 

The acceptance criteria for the resolution of GSI I.C.l, is that the intent of the guidance identified in NUREG-0737, as supplemented by Generic Letter 82-33, shall be met. 

The owner-operator of a nuclear power generating facility using a System 80+ Standard Design must meet the intent of NUREG-0737, Supplement 1, as supplemented by Generic Letter 82-33, by establishing emergency procedures which address the evaluation and development of procedures for transients and accidents. 

Combustion Engineering provides analyses and guidance (CEN-152) to assist the owner-operator in meeting the guidance of NUREG-0737, Supplement 1 and Generic Letter GL 82-33. Therefore, this issue is resolved for the System 80+ Standard Design. 

US NRC. 1988. Individual plant examination for severe accident vulnerabilities-10 CFR 50.54(f). Generic Letter 88-20, November 23. Available at http //www.nrc.gov/reading-rm/adams. html (accessed October 2, 2015). 

USNRC Generic Letter 87-02, Verification of seismic adequacy of mechanical and electrical equipment in operating reactors. 

As a result of the NRC staff review of licensee responses to Generic Letter (GL) 92-01, Revision 1, a comprehensive database was developed to compile and record summaries of die materials properties of the reactor vessel beltline materials for each plant. This database is known as the RVID. Version 1.1 was issued in 1996. 

ASME Code Case N-557, "In place dry annealing of a PWR nuclear reactor vessel," March, 1996. USNRC Generic Letter 92-02, Revolution of Generic Issue 79 Unanalyzed reactor vessel (PWR) thermal stress during natural convection cooling. ... 

USNRC Generic Letter 92-01 Rev 1, Reactor vessel structural integrity. 

USNRC IN-95-40, Supplemental information to Generic Letter 95-03, "Circumferential cracking of steam generator tubes."... 

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