ML19337A144
| ML19337A144 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 08/07/1980 |
| From: | Counsil W NORTHEAST NUCLEAR ENERGY CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| A01126, IEB-80-17, NUDOCS 8009090017 | |
| Download: ML19337A144 (4) | |
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August 7, 1980 Docket No. 50-245 A01126 Mr. Boyce H. Grier, Director Region 1 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 July 18, 1980.
Gentlemen:
Millstone Nuclear Power Station, Unit No. 1 Response to I&E Bulletin No. 80-17, Supplement 1 In Reference (1), the NRC Staff required that we take certain specific actions regarding the Scram Discharge Volume (SDV) and the Standby Liquid Control System (SLCS).
In response to this request, Northeast Nuclear Energy Company (NNECO) proyides the information below for Millstone Unit No.1.
As also requested in Reference (1), and to assist the NRC in evaluating the value/ impact of this Bulletin Supplement, we have determined that the manpower expended in conduct of the review and preparation of the report required by the Supplement is 17 professional man-days for Millstone Unit No.1.
The manpower associated with corrective actions necessary, as identified by the Supplement, is an additional three man-days.
Item Al Provide to the NRC Regional Office an analysis of the adequacy of the "as-built" SDV system and associated vent and drain systems, including any identified design deficiencies.
Include copies of verified "as-built" isometric drawings of the SDV and detailed descriptions of the remainder of the system, verified to be correct, as part of this analysis.
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Response
NNECO'has reviewed.the SDV' system and associated vents and drains to determine the ability of the SDV t'o properly. drain following a scram and remain free of water.' This review.has revealed the following:
(1) ~ ' The~ SDV has a pitch 'of 1/8" per running foot of header. This
. pitch is adequate to ensure complete drainage of the header when the vent and drain valves are open.
t (2) The drain lines from the SDV to the instrument volume have a countant downward slope to assure complete drainage of the SDV's when the vent and drain valves are open. The drain line from the instrument volure to the drain tank ranges' from horizontal to sloping downward.
All d, sin pip'ing is below the bottom of the' instrument volume and will.11ow for free drainage of the instrument tank.
(3)~ Thu drain tank cannot backup into the instrument volume because the tank is vented and has an overflow.
Even Lf the vent and overflow lines were blocked, any water which shou 10 backup would backup out of floor drains at lower elevations before reaching the instrument tank.
.(4) The north vent line is sloped so that any water in it will flow to either the open end or back into the SDV and subsequently into the drain tank.. This vent line was previously tied into the drain line downstream of the drain valve. This line was modified so that it is j
open to atmosphere over a floor drain to assure positive venting.
.t (5) The south vent line is vented to atmosphere over a floor drain and is sloped in a similar manner to the north vent except a horizontal run exists between the vent valve and the opening to atmosphere.
A large-buildup of water in this section would not occur since if a large pool of water would fore,, it.would run over the elbow into the drains. NNECO is evaluating sloping this line.
The ability of the;SDV and ascociated vents'and drains to perform their required function has been proven-by ten years of performance and by recent testing, required by I&E Bulletin No. 80-17.
This information was reviewed by us with-NRC. Staff personnel in your Region 1 office as requested on August 4, 1980. Two copies of "as-built" SDV isometric drawings werc left with your Staff at that meeting.
NNECO agreed to further clarify and resubmit the drawings to I&E by August 13, 1980.
Item A2
-Revise and implement Operating Procedures as necessary to provide clear i
guidance to the licensed operator in the control room regarding when he should initiate the.SLCS without obtaining prior supervisory approval.
Provide a descriptio'n of the implemented procedural requirements.
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, Response Emergency procedures that stipulate SLCS initiation can be implemented by any licensed operator. The procedures clearly indicate when the SLCS will be initiated.. The basic sequence of such procedures is that the operator will first verify scram has occurred.
Should there be evidence of incomplete scram, further specific actions are stipulated to effect.a scram.
Should these further actions prove insufficient to bring the reactor within given parameters, the SLCS will be initiated.
Item A3 Assure that procedures exist and are implemented for specifying remedial action to be taken if water. is found in the SDV system at times when it.
should be free of water.
Provide a description of the implemented procedural requirements.
Response
Procedures specify remedial action if water is found in the SDV when it should be free of water.
If more than 39 gallons of water is found in the instrument volume, a scram will be initiated.
If the SDV headers are found to contain more chan one inch of water, through daily, logged, U.T.
surveillance, the plant will be shutdown within eight hours; unless, the cause is sooner found and corrected.
Item A4 Revise and implement administrative procedures as necessary to ensure that the SLCS key shall be readily available to the licensed operator in the control room.
Provide a description of the inplemented procedural require-ments..
Response
The SLCS key is required to remain in the SLCS control switch and thrs, readily available as discussed in Item A2.
Item A5 Continue daily monitoring of water levels in all scram discharge volumes until continuous monitoring systen(s) (discussed in B.1 below) is (are) installed and operational (this requirement supersedes the requirements of Item 5 of I&E Bulletin No. 80-17 which required daily surveillance for only six (6) days).
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Response
We will continue to daily monitor for water in the SDV's using U.T. until a-permanent-continuous monifering system is installed and operational.
Should you have any prestions, please contact us.
Very truly yours, NORTHEAST NUCLEAR ENERGY C MPANY
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AmW W. 'G. Counsil Senior Vice President g
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