ML19294B971
| ML19294B971 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 01/18/1980 |
| From: | Counsil W NORTHEAST NUCLEAR ENERGY CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-80-01, IEB-80-1, NUDOCS 8003060473 | |
| Download: ML19294B971 (3) | |
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January 18, 1980 Docket No. 50-245 Mr. Boyce H. Grier, Director Region I Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406
Reference:
(1)
B. H. Grier letter to W. G. Counsil dated January 14, 1980, transmitting ISE Bulletin No. 80-01.
Gentlemen:
Millstone Nuclear Power Station, Unit No.1 I&E Bulletin No. 80-01 ADS Valve Pneumatic Supolv Reference (1) requested Northeast Nuclear Energy Company (NNECO) to:
(1) Determine whether hard-seat check valves were installed to provide isolation of the ADS accumulator system from the pneumatic supply system.
(2) Determine if periodic leak tests have been performed on the ADS accumulator systems.
(3) Review seismic qualifications of the ADS pneumatic supply system from ADS valve operator to isolation valve outside containment.
(4) Evaluate operability of the ADS for the conditions under which it is required to be operable including a seismic event.
The followirg information is submitted in reply to the corresponding requests listed above:
(1) A review of available design documentation indicates that the ADS accumulator system check valves are hard-seated, one (1) inch, six hundred (600) pound pressure class, velan check valves.
(2) Periodic leak tests of the individual ADS accumulator systems has not, in the past, been a requirement and, therefore, were not performed.
However, these systems involving the ADS accumulator check valve are being added to the ISI requirements.
8003060h
e (3) A review of the seismic qualifications of the pneumatic supply system from the accumulator isolation check valve to the ADS valve operator and from the outside containment iso 3 4 tion valve up to the accumulator check valve has been accomp1f shed.
Documentation indicates two (2) supporting schemes were used in the installation of instrument air lines.
Original design criteria used by the architect-engineer, which required supports every four (4) feet and modifications requiring support every nine (9) feet.
Although actual geometry and calculations are unavailable, since these types of piping installations are typically field run, bounding, worst case conditions have been identified to verify structural integrity during a seismic event.
Based on available design criteria and documentation, the piping in question is seismically adequate from the outside isolation valve to the ADS valve operator.
(4) The ADS accumulator system for each valve is operable following a seismic event. The seismic qualification of the instrument air piping in the drywell ensures adequate air supply to each ADS valve independent of the leak tightness of each accumulator check valve. The instrument air supply piping has been tested, as described below.
A bottled air supply system located outside the drywell ensures the drywell instrument air piping will remain pressurized for all necessary ADS valve operations.
The bottled air supply system is available from outside containment and is currently being upgraded to meet seismic criteria.
The seismic air source consists of six compression air bottles located on the outer drywell wall.
These air bottles will be dedicated to only supply the instrument air header within the check valves outside the drywell.
It is anticipated that all analyses necessary to qualify this air source will be completed by January 19, 1980.
A test of the instrument air system has been performed. The test is conservative with respect to the individual accumulator systems in that all other uses and boundaries of this system inside containment were included.
Based upon the results of this test, it was determined that an adequate supply of air to the ADS valve operators will be available, sufficient for five actuations of all three ADS valves over a period of at least one hcur following loss of the air compressors.
Therefore, with :.he proven availability of a long-term supply of air providing pressurization for all necessary ADS operations, and the seismic adequacy of the piping valves and accumulators in question, operability of the ADS for the conditions under which it is required to be operable including a seismic event has been established. A review by both the onsite (PORC) and offsite (NRB) saf ety review committees of the test ani evaluations performed, have concluded that the ADS system will perform its intended function as designed ticluding a seismic event.
J NNECO trusts this information satisfactorily dispositions the concerns of Reference (1).
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY lWW W.'G.
Counsil Vice President