UNITED STATES ATOMIC ENERGY COMMISSION DIRECTORATE OF REGULATORY OPERATIONS REGION I 631 PARK AVENUE KING OF PRUSSIA, PENNSYLVANIA 19405 February 22, 1974 Metropolitan Edison Company Docket Nos. 50-289 Attention: Mr. J. G. Miller 50-320 Vice President P. O. Box 542 Reading, Pennsylvania 19603 Gentlemen: The enclosed Directorate of Regulatory Operations' Information Request No. 74-2 is sent to you for response. Please submit your reply within thirty (30) days of the date of this letter to this office with a copy to the Assistant Director for Construction and Operation, Directorate of Regulatory Operations, U. S. Atomic Energy Commission, Washington, D. C. 20545. Very truly yours, James P. O'Reilly Director Enclosure: RO Information Request No. 74-2 7911110107 . ENCLOSURE Directorate of Regulatory Operations Information Request No. 74-2 PWR MAIN STEAM LINE ISOLATION VALVES In the past several months Regulatory Operations has received notification of a number of abnormal occurrences involving main steam isolation valves at various PWR facilities. Licensees' investigations following preoperational tests and spurious valve closures have indicated that these valves, particularly those of the check valve type, may be subject to generic failures. To permit evaluation of the extent of the problem, the suitability of specific valves for isolation purposes under postulated steam line rupture accident conditions, and the appropriateness of possible remedial measures, you are requested to provide the following specific information: 1. Facility name and unit number. 2. A line diagram or sketch showing the locations of the isolation valve(s) with some identification of the type of each valve (check, globe, gate, etc.). 3. Assembly or sectional drawings of each valve type with dimensions and identification of material. 4. Name of the manufacturer of each valve type. 5. Steam line pressure at full power and at hot stand-by conditions, compared with valve design pressure. 6. Functional design requirements contained in the original design specifications for each valve. 7. An assessment of the adequacy of each valve type to perform the isolation function under postulated steam line rupture accident conditions. 8. Discussion of any operational malfunctions of each valve. In your response to this request, please also include information relating to modifications or other methods of resolution which are planned or which may have been made to valves of this type installed, or scheduled to be installed, in your facility(ies).
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