Bulletin 74-002A: Metropolitan Edison Company
ATOMIC ENERGY COMMISSION
DIRECTORATE OF REGULATORY OPERATIONS
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
P. O. Box 542
Reading, Pennsylvania 19603
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
RO Information Request No. 74-2
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
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,
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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