ML19338D397
| ML19338D397 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 08/11/1980 |
| From: | Heider L VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-80-17, WVY-80-113, NUDOCS 8009230100 | |
| Download: ML19338D397 (4) | |
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ja VERMONTYAN KEE NUCLEAR POWER CORPORATION
' SEVENTY SEVEN GROVE STREET-B.4.1.1-
'.RuTLAxo, VERMONT ' 05701
'WVY 80-113' REPLY TO:
ENGINEERING OFFICE -
August 11, 1980
. TURNPIKE RO AD WESTDORO. M ASSACHUSETT3 01581 TELEPHONE 619-336-90t, United States Nuclear Regulatory Commission Office of Inspection and Enforcement
. Region 1 631 Park: Avenue King of. Prussia, Pennsylvania 19406 Attention:
Mr. Boyce H. Grier Re ferences: -(a) License No. DPR-28'(Docket No. 50-271).
(b) USNRC Letter to VYNPC dated July 18, 1980; IE Bulletin 80-17, Supplement 1 (c) USNRC Letter to VYNPC dated July 3, ~1980; IE Bulletin 80-17
Subject:
Response t'o.IE Bulletin 80-17, Supplement 1
Dear Sir:
Refereuce (b) delineates certain' actions to be taken by BWR licensees and subsequent reporting requirements. The following information is submitted on behalf of Vermont Yankee:
.-Item A 1)
- " Provide to the 'NRC Regional Office an analysis of the adequacy of the "as-built" SDV system and associated vent and drain systems,
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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."
s
- Response:
Description-
' There -are two Scram Discharge Volumes (SDVs); one for the north Hydraulic LControl Unit -(HCU) bank and one for the south HCU bank.
i Both SDV's ' drain via'2 ' inch, SCH 160 pipe to a single Instrument
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Volume?(IV).- Each SDV is. composed of three parallel sections of.
six-inch,-SCH 80 pipe,~' tie'd together at one end by.six inch, SCH 80 pipe.4 The piping is pitched as shown on the isometric
' drawings. The low point of the 'six J nch-tie header drains via the 1
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JB ~Uriited Stttes[Nu il%r ~ R:guldtjry: Commicdidn 1 Augudt[11,l1980
.Attintidnt h Mr. Boysa Hf GridrD
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2finchpipe.
The 3f high points are tied 'together by a common 1
~ inch vent line, which' goes to an air operated vent valve, and 'then to:a' check ~ valve' installed las a" vacuum breaker..whose disc'has been. removed" per I&E.Bulletin 80-17, Supplement II. - The vent.line
-then'goes to a,HVAC duct. The: instrument volume drains open-ended via a pneumatically operated valve to 'a nearbyL floor drain. - The vent and drain valves are; air. operated to open, spring to close, and controlled by the scram pilot air system via their own dual
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redundant!and-test solenoid valves.
Valves close on scram,.~open
- on ' reset.-
Analysis The vents :and drain are' dedicated systems.' 'They are not intertied
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. with any.other' system 'that could have an' adverse effect on, proper functioning.. The HVAC ducts have fixed lower openings nearby so E that11n effect, the vents are to atmosphere. Similarly,.the drain
_ pipe terminates open ended inside a floor drain pipe collar and is not -interconnected with anything else.
The instrument volume does not vent automatically, so no damage to level: instruments has been experienced nor is any expected.
IT a vent line were 'to be plugged.. the SDV might fail to drain.
'Recent testing demonstrates that the existing pipe pitch is
- adeque ee to ensure that proper draining will occur if a vent path Tis'present.
. Tests showed that the IV can drain faster than the.SDV, so that the plant could be susceptible to that rare dynamic failure where inleakage to the-SDV exceeded drain rate without raising the level in the IV.
The analysis discussed above is preliminary and is continuing. It
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will ultimately identify changes that may be necessary for improvement.
Isometric drawings were handed'.to NRC representatives on August 4 at the Region - I office. It'is assumed this meets your' requirements.
. Item A 2)1
" Revise and. implement ' Operating Procedures as necessary to provide clear guidance to. the licensed -operator in the control room
- regarding when he should ' initiate the SLCS without obtaining prior supervisory approval. -Provide a description of the implemented procedural' requirements."-
o
' Re sponse:
'See:the response tocItem A4 below.
Item A'3)
" Assure.thati procedures existiand are implemented for specifying
-remedial. action to be ~ tr'cen if water is ~ found in the SDV-system at times when it should be: free of' water.
Provide a description of
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L the ; implemented procedural _ requirements."
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NUnitedStEt' Nu 1:_r R gulatory Commic ian Augu:t 11, 1980 Att : tion; Me, Boy; H. Grier
' Pag: 3
Response
Operating Procedure 2111, Control Rod Drive System, was revised 8/1/80 to specify remedial actions to be taken should water be discovered in the Scram Discharge Volume.
These actions include immediate verification of proper operation of the SDV vent and drain valves as well as requirements for inspection for leaking scram valves or other abnormal conditions.
If the water cannot be drained within four hours, shutdown to cold shutdown is then required.
Item A 4)
" Revise and implement alministrative 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 implemented procedural requirements."
Re spons e :
Operating Procedure 2114, Standby Liquid Control System, was revised 8/1/80 to provide further guidance to the Shift Supervisor concerning initiation of SLC. With this revision, the Shift Supervisor has the authority to initiate SLC in any of the following situations:
- 1. If at any time it becomes apparent there has been a gross failure of the control rods such that they cannot be scrammed or moved under normal hydraulic pressure.
- 2. Normal rod exercise indicates rods st ick and not able to scram such that it is apparent that Shutdown Margin Requirements of Technical Specifications cannot be met.
- 3. The Reactor Engineer determines the Shutdown Margin Requirements of Technical Specifications cannot be met.
- 4. Any time reactor water level cannot be maintained or torus water temperature cannot be maintained below the torus scram 0
limit (110 F) and the control rod drive system is unable to maintain the reactor subcritical as indicated by neutron monitors.
In addition, the procedure also specifies that "the key to the SLC r. witch shall be kept in the switch itself."
Item A 5)
" continue daily monitoring of watcr levels in all scram discharge volumes until continuous monitoring system (s) (discussed in B.1 below) is(are) installed and operational (this requirement supersedes the requirements of Item 5 of IE Bulletin 80-17 which required daily surveillance for only 6 days)."
Re sponse:
Daily monitoring of water levels have been and will be continued.
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f*-AUnited.St'it h INu;1&r R;gulatdry.C:mmiccitn.
Augu;t 11, 1980-
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- A'ttantidn..Mr.lBoyc0 H. Gricr:
- Paga 4; The -following information is submitted as an estimate of.the manpower -
expended in~ the.research and response for this Bulletin:
- Manpower ~ Activicy '
Manhours Expended'
- Research and Response Preparation 340 Corrective Actions -(SDV level 2/ day monitoring)
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We' trust that the above supplied-information is satisfactory; however,
. should you desire additional infonnation, please contact. us.
.Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION L. H. Heider Vice President RJ4/ncj COMMONWEALTH OF MASSACHUSETTS)
)ss COUNTY OF WORCESTER
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.Then personally appeared before me, L. H. Heider,. who, being duly' sworn, did state that he is a Vice President of Vermont. Yankee Nuclear Power Corporation, that he is duly authorized to execute and file the foregoing
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request in the name and on the behalf of Vermont Yankee Nuclear Power Corporation, and that the statements therein are true to the best of his l
knowledge.and belief.
M Armand R. Soucy
' Notary Public'
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My Commission Expires September 7, 1984 I
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