ML20058D720
| ML20058D720 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 10/29/1990 |
| From: | Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| SN-90-596, NUDOCS 9011060244 | |
| Download: ML20058D720 (12) | |
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e i-YlHOINIA l$1.I:CTMIC. AND l'OWi!H COMi%NY HICIIM OND, VIkutNI A DilD 61 i
October 29,1990 U.S. Nuclear Regulatory Commission Serial No.
90 596 Attention: Document Control Desk NAPS /JHL:Jbl R2 Washington, D.C. 20555 Docket Nos.
50 338 1
50 339 License Nos. NPF 4 NPF 7 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNITS 1 AND 2 2
PROPOSED OPERATING LICENSE AMENDMENT (UNIT 2)
AND CHANGE TO PREVIOUS COMMITMENT (UNIT 1) i REGARDING THE INSIDE REClRCULATION SPRAY PUMP INSPECTIONS l
Pursuant to 10 CFR 50.90, Virginia Electric and Power Company requests an
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amendment to Operating License No. NPF 7 for North Anna Unit 2. This proposed change will delete License Condition 2.C.(15)(c) which requires at least once every five years that the recirculation spray pumps inside containment be removed and inspected and the bearings replaced if necessary, i
I The Operating License for North Anna Power Station Unit 2 was originally issued with this License Condition to ensure the long term mechanical reliability of the inside l
recirculation spray pumps by providing a mechanism for the detection of pump degradation. However, this objective is now fulfilled by the ASME Section XI Inservice Testing Program for North Anna. Therefore, as an alternative to removing and i
inspecting the pumps every five years, it is proposed that full-flow testing the pumps 1
each reactor refueling in accordance with ASME Section XI serve to provide verification of the long term mechanical reliability of these pumps.
Deletion of the License Condition will prevent the unnecessary replacement of the-pump bearings and the introduction of debris to the pump suction wells. Periodic disassembly of the pumps increases the chance of introducing debris in the sump area inside the pump suction protective screening. This debris, if overlooked, could be detrimental to pump operation.
Similar to the Unit 2 License Condition,.by letter dated September 14,1979, we committed to five year inspections of the inside recirculation spray pumps for the North Anna Unit 1.
In preparation of this' letter, it _was discovered that these' Unit 1 inspections had not been performed as committed. A station deviation: report on the i
missed commitment has been submitted.
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During the 1989 refueling outage for Unit 1, the 'A' inside recirculation spray pump was disassembled and inspected for reasons unrelated to our commitment. This inspection revealed no cignificant degradation of this pump's bearings. As with Unit 2, the Unit 1 pumps are required to be full flow tested each reactor refueling in accordance with ASME Section XI. Therefore,in addition to elimination of the Unit 2 License Condition, we are advising you of our intent to change our commitment J
regarding removal and inspection of the Unit 1 inside recirculation spray pumps at least once every five years. This inspection is no longer necessary.
The proposed change to the Unit 2 Operating License is provided in Attachment 1. A discussion of the change is provided in Attachment 2 and the basis for our no significant hazards consideration determination is provided in Attachment 3.
This request has been reviewed and approved by the Station Nuclear Safety and Operating Committee and the Management Safety Review Committee. It has been determined that the proposed change does not involve an unreviewed safety question as defined in 10 CFR 50.59 or a significant hazards consideration as defined in 10 CFR 50.92.
We request approval of this License Amendment request prior to the North Anna Unit 1 refueling outage scheduled to begin January 4,1991. This schedule may seem aggressive considering that the next Unit 2 pump inspection is not required until the Unit 2 refueling outage in 1992. However, because of our previous commitment to perform the same inspection on the Unit 1 pumps, we would like to resolve any NRC questions or concerns prior to the Unit 1 refueling outage.
Should you require any additionalinformation or have any questions regarding this submittal, please contact us immediately.
Very truly yours,
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W. L. Stewa Senior Vice President - Nuclear Attachments
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cc:
U.S. Nuclear Regulatory Commission Region 11 101 Marietta Street, N.W.
Suite 2900 Atlanta, GA 30323 Mr. M. S. Lesser NRC Senior Resident inspector North Anna Power Station Commissioner Department of Health Room 400 109 Governor Street Richmond, Virginia 23219 1
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COMMONWEALTHOFVIRGINIA )
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COUNTYOFHENRICO
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The foregoing document was acknowledged before. me, in and for the County and Commonwealth afc.'esaid, today by W. L. Stewart who is Senior Vice President - Nuclear, of Virginia Electric and Power Company.
Heis duly authorized to execute and file the. foregoing document in behalf of that Company, and the statements in the document are true to.the best of his knowledge and bellef.
Acknowledged before 'me this 29 day of
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,1999.
My Commission Expires:
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i ATTACHMENT 1 i
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PROPOSED OPERATING LICENSE CHANGE NORTH ANNA UNIT 2 I'
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i (15) Prior to resuming power operation following the first refueling i
outage except as specifically noted in paragraphs (h)(2) and (h)(4) below:
(a)
VEPCO shall submit the details of the inspection program for r
control rod guide thimble tube ~ wall wear for Commission approval; (b)
VEPCO shallinstallinspection ports in the steam generators; (c)
[ Deleted]
(d)
VEPCO shall install leak test connection on the RHR isolation t
valves; (c)
VEPCO shall demonstrate by test the backup depressurization capability of the PORV's using the same shutdown procedure as.
described in VEPCO's procedure 2-OP 3.2 dated 07/23/80; (f)
VEPCO shall submit for Commission approval, the results of the tests applicable to North. Anna Power Station, Unit 2, of a study concerning mixing of added borated water and cooldown -
under natural circulation conditions; (g)
VEPCO shall retest all enginu; red safety features reset control action to verify proper reset action; and (h)
VEPCO shall implement the following design and procedural modifications with respect to diesel generator reliability:
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- 1) Complete a formal training program for all the. mechanical and electrical maintenance and quality control personnel, t-including supervisors, who are responsible for the maintenance and availability of the diesel generators, The depth and quality of this training program shall be at least equivalent to that of training programs normally conducted by major diesel engine manufacturers;
- 2) The lube oil system shall be modified to the manufacturer's recommendations for providing' continuous lubrication of the lower portions of the engine.
The modification shall i
further provide for partial filling of the upper lube oil supply header and a lube oil booster / accumulator system-which will force oil into the upper lube oil header during engine startup. The modifications shall be completed -no later than the second refueling outage.
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ATTACHMENT 2 i
DISCUSSION OF PROPOSED CHANGES FOR DELETION OF. LICENSE CONDITION 2.C.(15)(c)
FROM LICENSE NO. NPR-7 NORTH ANNA UNIT 2 i
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n DISCUSSION OF THE PROPOSED CHANGE Backaround During the review of the licensing basis for issuance of the Operating License for North Anna Unit 2, the NRC expressed their concern for the long term mechanical reliability of the recirculation spray pumps inside containment.
The NRC questioned the advisability of the monthly dry start and stop test for these pumps. This is documented in Supplements 9 and 10 of the NRC's Safety Evaluation Report (SER), NUREG-0053, dated March 1978 and April 1980, respectively. As part of their resolution of this concern, the NRC required that we revise the dry test interval from monthly to quarterly for the inside recirculation spray pumps, in addition, the NRC required that we remove and inspect the inside recirculation spray pumps during the first refueling for each unit and at least once every five years thereafter. By letter dated September 4,1979 (Serial No. 712), we agreed to the quarterly dry testing and committed to aerform the disassembly and inspection as requested for both units. Our comm tment was reiterated in Supplement 10 to the NRC's SER (NUREG 0053). On August 21,1980, i
the NRC issued the Operating License for North Anna Unit 2 with the License Condition 2.C.(15)(c) which states that, " Prior to resuming power operation following the first refueling outage, VEPCO shall remove and inspect the recirculation spray pumps inside containment and replace the bearings if necessary A similar inspection shall be performed at least once every five years thereafter "
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Both inside recirculation spray pumps were removed and inspected during the first i
refueling outage for each unit. The inspection revealed no significant degradation of the pump bearings. From the first refueling outages and until 1987, the inside recirculation spray pumps on both pumps were tested dry on a quarterly frequency.
This dry test was the only testing method utilized during this penod for determining 1
pump operability During each unit's outage in 1987, the NRC required the inside recirculation spray pumps to be full flow tested. In addition, by NRC letter dated February 18,1988, the NRC added the requirement that the inside recirculation spray i
pumps were to be flow tested each reactor refueling. Here ' the inside recirculation spray pumps have been dry tested quarterly and full-flow U
. each refueling outage since 1987. For Unit 2, the inside recirculation spray pun., _ were flow tested during the 1987,1989, and 1990 refueling outages. For Unit 1, the inside recirculation spray pumps were flow tested during the 1989 refueling outage. These flow tests have verified the pumps' hydraulic performance to be fully acceptable.
During the 1987 refueling outage, in addition to the full flow testing required by the NRC, both of the Unit 2 inside recirculation spray pumps were removed and inspected in accordance with the License Condition requirement (as amended May 11, 1987).
This inspection revealed no significant degradation of the pump bearings. During the 1989 refueling outage for Unit 1, the 'A' inside recirculation. spray pump was disassembled and inspected for reasons unrelated to our commitment.
This inspection revealed no significant degradation of this pump's bearings.
In preparation of this letter, it was discovered that the five year removal and inspection commitment had been missed for Unit 1. A station deviation report on the missed l
commitment has been submitted.
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Discussion of Proocsed Chance Pursuant to 10 CFR 50.90, Virginia Electric and Power Company requests an amendment t ) Operating License No. NPF 7 for North Anna Unit O.
The proposed-j change will c 91ste License Condition 2.C.(15)(c) which requires at least once every I
five years thii the recirculation spray pumps inside containment be removed and i
inspected and the bearings replaced if necessary.
l The Opcrating License for North Anna. Power Station Unit 2 was originally issued with this License Condition to ensure the long term mechanica! reliability of the inside recirculation spray pumps by providing a mechanism for the detection of pump j
degradation. The detection of pump degradation by this inspection method was originally required because flow testing these pumps was not anticipated to occur during the operating life of the plant. However, as discussed above, the inside recirculation spray pumps are now required to be full flow tested every refueling outage in accordance with the ASME Section XI Inservice Testing (IST) Program for North Anna. Therefore, the teardown inspection is no longer required to ensure the mechanical reliability of the pumps.
The inside recirculation spray pumps are maintained dry during normal operation.
Therefore, in addition to the Section XI full flow testing each refueling outage,-the IST program also requires the pumps to be " dry bump" tested quarterly. The " dry bump" tests serm to ensure proper functioning of the-operating. circuitry and to ensure 1
operational readiness of the pumps.
The deletion of the requirement to remove and inspect the inside recirculation spray pumps every five years has additional benefits for North Anna. The pump bearings are made of a hard, bntile graphite material and are press fitted onto the pump shafts.
1 Each time the pumps are removed for inspection, the bearings require r6 placement because of damage due to handling. Deletion of the License Condition will prevent unnecessary damage and replacement of the bearings.1 In addition, deletion of the License Condition will prevent potential pump damage and reduced reliability from shaft scoring or improper pump reassembly..We assert that a centrifugal pump need not be opened for inspection unless evidence, of either direct or indirect nature, is available to indicate that an overhaul is necessary.
This' ' evidence', such as decreased pump hydraulic performance, unusual noises, excess vibration, etc., can be obtained from pump _ flow tasting, if debris is introduced into these pumps, it could'be detrimental'to pump operation.
. Current surveillance procedures require the visualinspection of the containment sump and inside recirculation spray pump suction screens _each refueling outage to look for debris blockage, corrosion buildup and barrier' integrity. Periodic disassembly.of the pumps would increase the chance of introducing debris in the sump area inside the
. pump suction protective screening.
Deletion of the License Condition will prevent the unnecessary disassembly of the pumps and prevent the possibility of introduction of' debris into the pump suction wells due to maintenance on the pump.
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Any significant degradation of the pump bearings, shaft journal wear, shaft bow, or; significant impeller / bell cracking will be identified by vibration analysis. Also, the pump's_ hydraullo. test data will provide indication of a worn impeller / bell or increased pump clearances. Past functional test data and teardown inspections of the IRSPs have shown no significant problems. This should not be surprising since the pumps are only run dry for a totcl of approximately 10 minutes per year, and about 20 minutes wet each refueling outage. Therefore, no reason exists for these pumps to degrade.
Previous inspections have not shown-any signlficant degradation of the inside recirculation spray pump bearings. In addition, periodic testing quarterly dry test and reactor refueling full flow test) for determinmof the pumps (i.e.,
g operability have not Indicated any problems. The proposed change does not affect the Technical Specification operability requirements for these pumps or the inside recirculation spray subsystem.
In addition to requesting elimination of the Unit 2 License Condition, we are notifying you of our intent to change our conimitment regarding removal and inspection of the Unit 1 inside recirculation spray pumps at least once every five years.
Full-flow testing of the North Anna Units 1 and 2 inside recirculation spray pumps in accordance with Section XI on a reactor refueling frequency Is sufficient to provide quantitative verification of the pumps' ability to perform their intended function.
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ATTACHMENT 3 l
I NO SIGNIFICANT HAZARDS DETERMINATION FOR DELETION OF LICENSE CONDITION 2.C.(15)(c)
FROM - LICENSE : NO. : NPR-7.
NORTH ANNA UNIT 2 3
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BASIS FOR NO SIGNIFICANT HAZARDS CONSIDERATION The proposed change will delete License Condition 2.C.(15)(c) which requires at least once every five years that the_ recirculation spray pumps inside containment be removed and Inspected and the bearings replaced if necessary, The License Condition was intended to ensure the long term mechanical reliability of
-l the inside recirculation spray pumps by providing a mechanism for the detection of pump degradation. However, this objective is now fulfilled by the ASME Section XI Inservice Testing Program for North Anna.' Therefore, as an alternative to removing and inspecting the pumps every five years, it is proposed that full flow testing the pumps each reactor refueling In accordance with ASME Section XI serve to provide verification of the long term mechanical reliability of these pumps.
Deletion of the License Condition will prevent the unnecessary replacement'of the pump bearings and the introduction of debris to the pump suction wells. -Periodic disassembly of the pumps increases the chance of introducing debris in the sump area..
Inside the pump suction protective screening. This debris, if overlooked, could be detrimental to pump operation.
This proposed change does not involve a significant hazards consideration as defined -
in 10 CFR 50.92. Operation of North Anna Unit 2 will not be affected and will not:'
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result in a significant increase in the probability or consequence of an accident previously evaluated. Full flow testing of the Inside recirculation spray pumps each refueling outage provides a more meaningful method of detecting pump degradation than inspecting the pumps once every five years. 'Long term mechanical reliability and pump operability can continue to be ensured by the full flow testing, Any significant pump degradation can be identified by analysis of the vibration and hydraulic data obtained from the full flow test.
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create the possibility of a new or different kind of accident from any accident i
previously identified. Full flow testing of.the inside recirculation spray pumps each refueling outage provides a more, meaningful method of detecting pump degradation than inspecting the pumps once every five years._ The full flow-pump testing will continue to ensure the pumps are capable of performing their containment depressurization function. Any significant pump degradation can I
be ide.ntified by analysis of the vibration and hydraulic data obtained from the--
full flow test.
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result in a.significant reduction in a margin of safety.
Eliminati g the unnecessary replacement of the inside recirculation spray pump bearings and -
performing full-flow testing of the pumps each refueling. outage will enhance pump operability.
-Therefore, pursuant to 10 CFR 50.92, based on the above considerations, it has been-l determined that this change does not involve a significant hazards consideration..
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