ML19330A499
| ML19330A499 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 07/25/1980 |
| From: | Sylvia B VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | Harold Denton, Youngblood B Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0694, RTR-NUREG-694 651, NUDOCS 8007280406 | |
| Download: ML19330A499 (7) | |
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VraOINIA Ex.ncruic Ann Powan CoxPArv Ricmsown.VamorazA noget July 25, 1980 Mr. Harold R. Denton, Director Serial No. 651 Office of Nuclear Reactor Regulation N0/RWC:smv Attention:
Mr. B. Joe Youngblood, Chief Docket No. 50-339 Licensing Branch No. 1 License No. NPF-7 Division of Licensing Washington, D. C.
20555
Dear Mr. Denton:
IMPLEMENTATION SCHEDULE NUREG-0694 NORTH ANNA UNIT 2 Attachment I shows the currently scheduled installation dates for the NUREG-0660 items identified in NUREG-0694.
Confirming our discussions with the staff on July 23, 1980, four of these items have installation currently scheduled beyond January 1, 1981.
For two of these items (containment hydrogen indication and effluent monitors), interim systems currently in operation will be utilized until the scheduled dates.
The reactor coolant vents and level indication are currently scheduled for the first refueling outage due to the requirement of an extended outage, removal of the reactor vessel head and the unavailability of the level indication system design until mid-1981.
We currently plan to use the snubber inspection outage presently scheduled for
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November for installation of the remaining modifications. Three of these items have potential material delivery problems for individual components which might delay complete compliance, but not operation of the systems, beyond January 1, 1981. Any of the outage work that cannot be supported by material delivery will be done during the next outage scheduled for April,1981.
In addition, the modifications will be installed to the extent possible during any unscheduled outage.
Attachment II providas a detailed discussion of any item that may potentially be delayed beyond January 1, 1981.
If you have questions, we will be glad to provide additional information.
Very trul yours, A
B. R.
Ivia Manager - Nuclear Operations and Maintenance RWC/sav:SIl Attachment ec:
Mr. James P. O'Reilly Office of Inspection and Enforcement Region II Atlanta, Georgia 30303 6 0 072 80 l.O. (,
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ATTACHMENT 1 INSTALLATION SCHEDULE TMI MODIFILATIONS NORTH ANNA UNIT 2 i
I NUREG-0660 CURRENT INSTALLATION SCHEDULE SECTION TITLE 11/80 4/81 12/81 II.B.1 RCS VENTS X
i II.B.2 PLANT SHIELDING
- remote H Iine valves X(1,2) 2 IX(I)
- S.W. rad, monitor pump motor 1,2)
- mission check valve bearings X
II.B.3 POST-ACCIDENT SAMPLING
- RCS X
- containment atmosphere X
II.E.1.2.
AUXILIARY FEED WATER FLOW Complete INITIATION AND INDICATION II.E.4.1.
CONTAINMENT DEDICATED PEF'TRATION
- redundant isolation ve <es X(1,2)
II.F.1.
ADDITIONAL ACCIDENT MONITORING INSTRUMENTATION
- containment pressure Complete
- containment water level Complete
- containment hydrogen X(1,2)
- containment radiation I
4l'
- effluent monitors process & vent No outage required - install upon receipt of equipment approximately 7/81.
II.F.2 INADEQUATE CORE COOLING
- reactor vessel level X
III.A.I.2.
UPGRADE EMERGENCY SUPPORT Schedule to be determined after FACILITIES issuance of NUREG-0696.
III.D.3.3 IN PLANT RADIATION MONITORING Complete l
ATTACHMENT 1
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NOTES:
X Current schedule for outage relate work Worst case date for outage related work required for full compliance based on potential material delivery problems.
Systems will be operational by 1-1-81 even if identified material delivery problems occur.
(1) Relicf on Technical Specifications requirements required to support complete compliance by these dates.
(2) Dual plant outage no later than first refueling if Technical Specifi-cation relief is not available.
ATTACHMENT II II.B.2.
PLANT SHIELDING a.
The manual valves in the Hyn ogen Analyzer and Hydrogen Recombiner System are being replaced with remotely operated valves. These valves are cur-rently scheduled for delivery in December, 1980.
A single unit outage and relief on Techaical Specifications is required to take an analyzer or recombiner out of service during valve replacement.
Any work not sup-ported by material delivery during the Unit 2 November outage will be scheduled during the Unit I refueling outage (12/80) and the Unit 2 maintenance outage (4/80).
If relief on Technical Specifications is not possible, the valves will be replaced during the first dual plant outage and no later than the first refueling of Norti nna Unit 2.
b.
Bearings will be replaced on 26 of the 28 Mission check valves for North Anna 1 & 2 by 1-1-81.
Replacement of the remaining 2 valve bearings will l
be by 1-1-81 if relief on Technical Specifications can be obtained.
If relief on Technical Specifications is not possible, the bearings will be l
replaced during the first dual plant outage and no later than the first refueling of North Anna Unit 2.
The two valves are 1-CC-60 and 2-CC-37 in the component cooling water system which supplies the gas stripper, boron evaporators and fuel pool coolers as shown on 11715-FM-79A.
These systems are not required to mitigate an accident.
II.B.3.
POST ACCIDENT SAMPLING i
As stated in our letter of July 7,1980, the entire Reactor Coolant Sampling System will be installed and operational by January 1,1981.
However, four replacement valves (S0V's rather than A0V's) are scheduled for delivery in December, 1980.
If the valves are not available to support the scheduled outage, they will be installed during the next outage of sufficient duration and no later than the maintenance outage scheduled for April, 1981.
The containment atmosphere aample system is scheduled for completion prior to January 1, 1981.
II.E.4.1 CONTAINMENT DEDICATED PENETRATION Installation of new redundant valves to isolate the post-accident hydrogen penetration requirat either a dual plant outage or relief on Technical Speci-fications. The valves are currently scheduled for delivery in December, 1980.
If relief on Technical Specifications is possible and delivery supports the outage, they will be installed by 1-1-81.
If delivery is late the valves will be installed during the first outage of sufficient duration and no later than the maintenance outage of April, 1980.
If relief on Technical Specifications is not possible, the valves will be installed during the first dual outage and not later than the first refueling outage of North Anna Unit 2.
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ATTACHMENT II II.F.1 ADDITIONAL ACCIDENT MONITORING a.
Containment hydrogen monitoring Two new hydrogen analyzers have been purchased from Comsip to replace the existing hydrogen analyzers which were seismically designed to withstand an Operating Basis Earthquake and Design Basis Earthquake. % is replace-ment is required to upgrade qualification to IEEE-323, 1974.
The equipment is presently scheduled for delivery in March, 1981.
While no vendor has completed an environmental test program showing qualification to Regulatory Guide 1.89, Comsip plans to have such a program complete several months before other vendors.
The two cross-connected hydrogen analyzers will be located in the auxil-iary building where the existing hydrogen analyzers are now located and will provide redundancy for both units. The analyzers will take suction from the same penetrations as the containment vacuum pumps and return the sample to the containment through the dedicated hydrogen return line.
Indicators and recorders will be located in the control room.
Installation of new hydrogen analyzers requires either a dual plant outage or relief on Technical Specifications to take a hydrogen analyzer out of service.
Installation is scheduled for completion during the April, 1981 maintenance outage if Technical Specification relief is possible and no later than the first refueling outage of Unit No. 2 if a dual outage is required.
We plan to rely on the existing hydrogen analyzers that cover the range of 0 to 10%. Rese analyzers were purchased to specifications which cover the environment in which they must function; however, as is the case of the (48) items listed in the NUREG 0588 review, the analyzers are lacking in a complete set of test data for qualification purposes.
They have, however, been certified by the manufacturer to meet the design specifica-tion.
As a backup, post-accident containment atmosphere sampling by Baseline gas chromograph will also be available.
b.
Effluent monitors An effluent monitor system for the process and ventilation vent that satisfies the requirements of NUREG-0578 as modified by a draft NRC clarification letter will be delivered mid-1981.
No outage is required and the system will be installed upon equipment delivery.
The interim high range effluent monitors will be utilized until mid-1981.
c.
Post-accident monitoring and control panel A Post-Accident Monitoring and Control (PAMC) panel will be supplied and mounted in the Main Control Room for North Anna Units 1 & 2.
Each panel will house the controls and indication for the Hydrogen Analyzer and the line up controls for the hydrogen recombiner.
Delivery for the PAMC is currently scheduled for December, 1980.
If equipment delivery does not support the outage, it will be installed along with the hydrogen analyers no later than the maintenance uttage scheduled for April,1981.
ATTACHMENT II II.B.1 & II.F.2 REACTOR COOLANT SYSTEM HIGH POINT VENTS AND INADEQUATE CORE COOLING It is requested that North Anna Power Station Unit 2 be allowed to operate until its first refueling outage in the fall of 1981 at which time the reactor coolant system vents and reactor vessel level monitoring system will be in-stalled and operational.
The reason for this request is based upon the availability of justifying analyses for unambiguous indication of vessel level and procedural guidelines for initiation and termination of the vent system.
Installation of reactor coolant system vents without the above items will not allow the operator to know when to vent or when to terminate venting.
Our present analyses, demonstrating that direct venting of noncondensable gases with high hydrogen concentrations will not result in violation of combustible gas concentration limits in containment as described in 10 CFR Part 50.44, Regulatory Guide 1.7 (Rev. 1) and Standard Review Plan Section 6.2.5, are near completion.
A review of the progress to date indicates that vent effluent from the reactor coolant system can be maintained within the recommended requirements.
However, the concern for the operation of the vent system is not limited to containment hydrogen concentrations only.
The reliable, accurate means for determining the existence and location of a bubble in the reactor coolant system to the degree required in section 2.1.3.b of the NRC's letter to all operating nuclear power plants dated October 30,1979 is presently in the developmental stages.
It is essential that a reactor vessel level syst en providing unambiguous indication for the full range of vessel level from the top of the vessel to the bottom of the core be available to insure the operator of when to operate the reactor coolant system vents.
Operation of the reactor vessel head vent without reliable information as to the location of a bubble in the reactor coolant system could be detrimental to maintaining adequate core cooling and cause core uncovery.
For instance, opening of the reactor vessel head vent with a bubble located elsewhere in the reactor coolant system could possibly move the bubble to the reactor vessel head region.
Decreased reactor coolant system pressure after head vent operation causing possible movement and expansion of the oubble to the vessel head region could reduce the vessel level and potentially uncover the reactor core inducing a more serious condition.
Therefore, it is intended that the reactor coolant system vents be installed in an operational mode when the reactor vessel level monitoring system with its supporting analyses and qualified procedural guidelines become available.
This topic was discussed with Mr. Dromerick, Mr. Speis and other members of your staff by telecon on July 24, 1980.
Installation of the reactor vessel vent system by January 1, 1981 would require removal of the reactor vessel head and penetration of the reactor coolant system pressure boundary without a reactor vessel level monitoring system available to provide unambiguous indication as to the location, size, or existence of a bubble in the reactor coolant system or qualified procedural guidelines to operate the vents.
This installation would require an approxi-mate one month outage which would otherwise be unnecessary.
ATTACHMENT II e
Installation of the reactor vessel level monitoring system requires removal of the reactor vessel head also.
Present schedules show that the Westinghouse reactor vessel level monitoring system along with the supporting analyses will become available in June of 1981. The balance of plant engineering and stress analysis will require approximately three months following receipt of the Westinghouse reactor vessel level monitoring system design.
His places availability of the reactor vessel level system for installation in late summer 1981.
Installation would require an approximate two month outage.
However, cycle 1 refueling for North Anna Unit 2 is scheduled for late 1981.
Therefore, we propose to install the reactor coolant system vents, and the reactor vessel level monitoring system during the late 1981 refueling outage.
His will provide a fully operational qualified reactor coolant vent system as well as a fully operational qualified reactor vessel level monitoring system that will satisfy the requirements as set forth in Enclosure 1 of the NRC 4
letter to all operating nuclear power plants dated October 30, 1979.
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