ML20041B359
| ML20041B359 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 02/19/1982 |
| From: | Wisenburg M TENNESSEE VALLEY AUTHORITY |
| To: | Vassallo D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8202230567 | |
| Download: ML20041B359 (3) | |
Text
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TENNESSEE VALLEY. AUTHORITY CHATTANOOGA. TENNESSEE 37401 400 Chestnut Street Tower II February 19, 1982 Director of Licensing 4
Attention:
Mr. Domenic B. Vassallo, Chief
/f Operating Reactors Branch No. 2 g
U.S. Nuclear Regulatory Commission CS/;fy 3
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Washington, DC 20555 2
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Dear Mr. Vassallo:
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tr In the Matter of the
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Docket No. 50-259 3
Tennessee Valley Authority
)
50-260
, fw,
50-296 By letter from T. A. Ippolito to H. G. Parris dated December 17, 1981, NRC provided their conclusions and Safety Evaluations regarding containment purging during normal operation at the Browns Ferry Nuclear Plant. Enclosed is our response to the requests made in that letter.
Very truly yours, TENNES EE VALLEY UTHORITY
? n Mark R.
,isenburg Nuclear Engineer
-Subscribegya sworn to be me this / 6f day of
_1982.
j.
N'otary Public My Commission Expires Enclosure cc:
U.S. Nuclear Regulatory Commission Region II ATTN: James P. O'Reilly, Regional Administrator 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303 g/
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8202230567 820219 DR ADOCK 05000259 p
PDR An Equal Opportunity Employer
i e
i ENCLOSURE 1
- RESPONSE TO NRC LETTER FROM T. A. IPPOLITO TO H. G. PARRIS DATED DECEMBER 17, 1981 BROWNS FERRY NUCLEAR PLANT (DOCKET NOS. 50-259, -260, -296)
NRC Concern Inclusion of a' requirement in technical specifications to periodically test that large butterfly valves meet 2.5-second closure time.
TVA Response Modifications to the large purge valves to decrease the valve closure time are being performed during the refueling outages. Technical specifications will be submitted as part of the normally submitted package for each cycle's operation. In the event that an opportunity occurs that these modifications can be performed during the cycle, the valve closure times will be incorporated in the surveillance test as if the condition was in the technical specifications. A formal license amendment change request would then be submitted. Note that these technical specifications have been approved for Browns Ferry unit 1 and have been submitted for unit 3 Unit 2 modifications are scheduled for the summer 1982 refueling outage.
NRC Concern Propose technical specification changes to perform leak tests of containment purge valves periodically.
TVA Response We have reviewed the NRC concerns regarding purge / vent valve leakage tests and have the following comments.
(1) The Browns Ferry purge butterfly valves use rubber seats and do not appear to be susceptible to the types of degradation described in IE Circular 77-11.
(2) The valves are located in a moderate environment and are not subject to variations in outside temperature.
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-2 Present leakage tests are performed in accordance with 10 CFR 50 Appendix J.-
As reflected in previous submittals, the purge valves are manifolded on both the inlet'and exhaust sides. Leakage tests on individual valves can only be performed by breaking the lines and installing blanks. These tests can only be conducted efficiently during refueling outages. The "as found" leakage tests have shown a general improvement over the latest operating cycles. This improvement appears to be the result of improved maintenance procedures and refinements in establishing the valve stop positions. Furthermore, we expect that the modifications to increase rate of valve closure will further improve the valve sealing by 4
increasing the dynamic closing force. We will tua evaluatir.g the effectiveness of these modifications.
Therefore, for the reasons stated above, plus the fact that physically performing the tests during the cycle is extremely difficult, we do not believe that periodic testing of the valves is warranted.
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TENNESSEE VALLEY AUTHORITY CH ATTANOOGA, TENNESSEE 37401 1100 Chestnut Street Tower II February 19, 1982 Director of Licensing Attention:
Mr. Dcmenic B. Vassallo, Chier Operating Reactors Branch No. 2 U.S. Nuclear Regulatory Commission Washington, DC 20555
Dear Mr. Vassallo:
In the Matter of the. _
-)
Docket No. 50-259 Tennessee Valley Authority
)
50-260 50-296 By letter from T. A. Ippolito to P. ". Parris dated December 17, 1981, NRC provided their conclura and Safety Evaluations regarding containment purging du. sng normal operation at the Browns Ferry Nuclear Plant. Enclosed is our response to the requests made in that letter.
Very truly yours, TENN EE VALLEY AUTHORITY Mark R. Nisenburg Nuclear Engineer Subscribed, n sworn to b e
me this /
day of
. 1982.
t%hA 61. 'lV1&"
Notary Public 7
My Commission Expires Enclosure cc:
U.S. Nuclear Regulatory Commission Region II ATTN: James P. O'Reilly, Regional Administrator 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303 An Equal Opportunity Employer
o ENCLOSURE RESPONSE TO NRC. LETTER FROM T. A. IPPOLITO TO H. G. PARRIS DATED DECEMBER 17, 1981 BROWNS FERRY NUCLEAR PLANT (DOCKET NOS. 50-259, -260, -296)
NRC Concern Inclusion of a requirement in technical specifications to periodically test that large butterfly valves meet 2.5-second closure time.
TVA Response Modifications to the large purge valves to decrease the valve closure time are being performed during the refueling outages. Technical specifications will be submitted as part of the normally submitted package for each cycle's operation.
In the event that an opportunity occurs that these modifications can be ber~ formed during the cycle, the valve closure times will be incorporated in the surveillance test as if the condition was in the technical specifications. A formal license amendment change request would then be cubmitted. Note that these technical specifications have been approved for Browns Ferry unit 1 and have been submitted for unit 3 Unit 2 modifications arc scheduled for the summer 1982 refueling outage.
NRC Concern Propose technical specification changes to perform leak tests of containment purge valves periodically.
TVA Response We have reviewed the NRC concerns regarding purge / vent valve leakage tests and have the following comments.
(1) The Browns Ferry purge butterfly valves use rubber seats and do not appear to be susceptible to the types of degradation described in IE Circular 77-11.
(2) The valves are located in a moderate environment and are not subject to variations in outside temperature.
9
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.v.-e.
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f f
.,f - Present leakage tests are performed in accordance with 10 CFR 50 Appendix J.
As reflected in previous submittals, the purge valves are manifolded on both the inlet and exhaust sides. Leakage tests on indivicial valves can only be performed by breaking the lines and installing blanks. These tests can only be conducted efficiently during refueling outages. The "as found" leakage tests have shown a general improvement over the latest operating cycles. This improvement appears to be the result of improved maintenance procedures and refinements in establishing the valve stop positions. Furthermore, we expect that the modifications to increase rate of valve closure will further improve the valve sealing by increasing the dynamic closing force. We will be evaluating the effectiveness of these modifications.
Therefore, for the reasons stated above, plus the fact that physically performing the tests during the cycle is extremely difficult, we do not believe that periodic testing of the valves is warranted.
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