ML20008E472
| ML20008E472 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 01/19/1981 |
| From: | Dunn C DUQUESNE LIGHT CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-80-24, NUDOCS 8103090060 | |
| Download: ML20008E472 (6) | |
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gm 4se ecco GYP January 19, 1981 United States Nuclear Regulatory Commission f
g Office of Inspection and Enforcement g-Attn:
Boyce H. Grier, Regional Director gy d[
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King of Prussia, Pennsylvania 19406 C
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Reference:
Beaver Valley Power Station, Unit No.
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Docket No. 50-334, License No. DPR-66 IE Bulletin 80-24
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Dear Mr. Grier:
The originct response to the referenced bulletin, dated January 5, 1981, was reviewed by the onsite Senior Resident Inspector with members of our organization.
It was requested by the Senior Resident Inspector that additional detailed information be provided to add further clari-ficationtoourresponsetobulletinitems2aandQc.
Attached herewith is a supplemental response which will document items'of discussion between the above mentioned parties and should be evaluated with our original response to this bulletin.
It ir estimated that 117 manhours involving 8 individuals were devoted to responding to this bulletin.
If you have any questions concerning this response, please contact my office.
Very truly yours,
YW l
C. N. Dunn Vice President, Operations Attachment cc:
Mr. D. A. Beckman, Resident Inspector U.S. Nuclear Regulatory Commission Beaver Valley Power Station Shippingport, PA 15077 U.S. Nuclear Regulatory Commission c/o Document Management Branch Washington, DC 20555 h
8103 0q0060
Supplemental Response IE Bulletin 80-24 2a.
" Verify existence or provide redundant means of detecting and promptly alerting control room operators of a significant accumulation of water in containment (including the reactor vessel pit if present)."
Response
As identified in our January 5 response, two areas exist for the accumulation of water within containment; the containment sump and the incore instrument room sump.
The containaa.t sump will collect all water accumulation due to leaks inside enntainment.
As identified in our original response, there is only one open cooling water system inside containment and under normal operating conditions it has limited use.
There are two level switches in the containment sump, each having the same setpoint.
One switch controls operation of the two pump 3 whit.e the other switch alarms in the control room as CONTAINMENT SUMP LEVEL HIGH.
Discharge from the sump pumps is recorded by the containment sump discharge flow measurement system. As previously stated, the Technical Specifications require that the plant be shutdown within 7 days should the containment sump discharge flow measurement system become inoperable. Redundant indication of abnormal water accumulation in containment exists in the form of the level switches and the flow measurement system integrator which is read on a shift basis. Additionally, there are operator actions required when the readings taken on the containment sump discharge flow measurement system exceed specified values.
If the integrator indicates greater than two gpm or there are three successive readings showing nc change, an investigation including containment entry would be necessary.
There also exists further indication of the containment sump level with instrumentation associated with the Containment Depressurization System.
Two level transmitters read out in the control room and are set to alarm when water level in containment is six feet above the floor.
These are read once per shif t and have action levels associated with them whereby any level indication of three inches or more requires a containment entry for investigation.
There is a monthly surveillance test performed whereby river water flow is established through the recirculation spray coolers which are part of the Containment Depressurization System.
Leakage from this system during the surveillance test would be identified on the daily balance of the Waste Handling Systems 7-Day Running Inventory, by the failure of the containment sump alarm to clear and by increasing level in the containment main sump.
Also, a significant increase in the containment sump discharge flow for the day the surveillance test is run would make the recirculation spray coolers suspect, requiring further investigation.
In the event the Reactor Plant River Water System is placed in service to back-up the Chilled Water System, the operators are required to go to a temporary log, recording, on an hourly basis, the main sump level as indicated by the level transmitters associated with the Containment Depressurization System.
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Supplemental Response t
IE Bulletin 80-24 Page 2 There is currently planned for the scheduled spring shutdown a l
modification of the containment sump level ueasuring system. This includes l
the addition of two narrow range level indicators installed near the sump pumps and a replacement of the two existing level transmitters previously discussed with new environmentally qualified, wide range level transmitters.
Regarding the incore instrument room sump, the potential sources for water accumulation are the Reactor Coolant System or the Component Cooling Water System serving the neutron shield tank, both of which are closed cooling water systems.
The neutron shield tank cooling is itself.a closed system requiring manual make-up should the level in the expansion tank drop to a point requiring make-up.
A water level of two feet on the containment floor would be required f
before water from the containment floor would begin flooding the incore instrument room. Water accumulation of this magnitude would be detected by the containment sump measurement system and the level transmitters associated with the Containment Depressurization System.
There are two level switches in the incore instrument room sump.
The first level switch to be activated will start the sump pump which discharges to the main containment sump.
Failure of this switch or water i
accumulation greater than pump capacity,10 gpm, will result in the second
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level switch s.1 arming in the control room, indicating a high level in the sump.
If the incore sump high level alarm is inoperable, a weekly con-l tainment entry is required to perform a visual inspection of the incore
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sump. Water accumulation of greater than 2 gpm will result in the main containment sump flow measurement system indicating this flow rate which a
i would require a containntat entry to determine the source of water.
We have concluded that as a result of the following, all abnormal water accumulation inside containment would be detected, thus satisfying the intent of this bulletin:
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The limited use of the open cooling water system in containment.
2.
The limited sources of water leakage into the incore sump (both of which are undar observation by the operator).
3.
The containment sump discharge flow measurement system.
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The incore sunp level switches used in conjunction with the
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containment discharge flow measurement system.
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The main sunp level switches used in conjunction with the
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containment. discharge flow measurement system.
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Procedural requirements imposed as a result of log readings
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outside of normal operating limits.
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i Supplemental Response IE Bulletin 80-24 Page 3 e
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" Verify or establish at least monthly surveillance procedures, with I
appropriate operating limitations, to assure plant operators have at
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least two methods of determining water level in each location where i
water may accumulate.
The surveillance procedures shall assure that I
at least one method to remove water from each such location is avail-able during power operation.
In the event either the detection or a
removal systems become inoperable, it is recommended that continued
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power operation be limited to seven days and added surveillance
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measures be instituted."
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Response
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Monthly surveillance procedures do not exist for equipment associated with either the containment sump or the incore instrument room sump. As I
previously identified, the incore sump is not subject to water accumulation from the open cooling water system inside containment and any leakage into f
the sump from closed systems can be detected and identified by existing procedures.
This sump is dry under normal operating conditions and access is prohibited because it is an Exclusion Area.
The instrumentation is i
discussed in part 2a of this response as to the affects of failure of either level switch and actions taken by the plant operators to assure there is no
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undetected accumulation of water in this sump.
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The containment sump pumps are tested by starting each pump and verifying discharge pressure.
This test is part of the operating surveillance test to be performed prior to entering Mode 4.
There is also a calibration procedure I
for the sump discharge flow measurement system and it is performed every 18 i
months.
Procedures for verifying the containment sump float operation have l
not been prepared and are not considered necessary for the following
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reasons.
1.
The radiation and contamination levels within the immediate i
sump area are high.
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2.
There dc not exist any provisions for filling the containment sump
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with water which is required to observe operation of the float.
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3.
The construction of the float and the trigger mechanism for the level switches is such that a movement which would change set-points is not likcly.
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Supplemental Response IE Bulletin 80-24
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It is considered that the daily use of the containment sump pumps and discharge flow measurement system establishes operability of the equipment necessary to remove water from the containment sump. Action levels are procedurally established requiring increased surveillance in the event suspect readings are observed during completion of shif t logs.
Finally, requirements for operability of the containment sump flow dis-
- harge measurement system, as it affects power operation, are identified in the Technical Specifications.
It is concluded that existing controls will allow operators to f
I determine operability of instrumentation and equipment necessary for the detection and removal of abnormal accumulations of water within containment.
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.______,_m._
(CORPORATE SEAL)
Attest:
/ m, /LIAD Thomas W'elfer,pJr. '
Secretary COMMONWEALTH OF PENNSYLVANIA)
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COUNTY OF ALLEGIENY
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4 On this
/9' day of
'I//m'/> M 1981, before me, 150NAT.T1 W. WAmTON
, a Notary Public in and for said Commonwealth and County, personally appeared C. N. Dunn, who being duly sworn, deposed, and said that (1) he is Vice President of Duquesne Light, (2) he is duly authorized to execute and file the foregoing Submittal on behalf of said Company, and (3) the statements set forth in the Submittal are true and correct to the best of his knowledge, information and belief.
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DONALD W. SHANNON. NOTARY PUBLIC PITTSBURGH. ALLEGHENY COUNTY MY COMMISSION EXPIRES JUNE 7,1983 Member, Pennsylvania Assocaten of Notanes
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