ML19332E551
| ML19332E551 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 11/30/1989 |
| From: | Cockfield D PORTLAND GENERAL ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML19293A068 | List: |
| References | |
| NUDOCS 8912070359 | |
| Download: ML19332E551 (5) | |
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PORTLAND CENERAL ELECTRIC COMPANY EUGENE WATER & ELECTRIC BOARD
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Operating License NPF-1 Docket 50-344 License Change Application 187 b:
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ThisLicenseChangeAhplicationrequestsmodificationstoOperating H
- License NPF-1~.for the Trojan Nuclear Plant to revise the Trojan Technical
. Specifications)for; steam generators to allow tube repair by sleeving'~as l,
.'an alternative.to' plugging.
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- PORTLAND GENERAL ELECTRIC COMPANY
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.D. W. Cockfield Vice President Nuclear l.
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- Subscribed and1 sworn to before me this 30th day of November 1989.
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My Commission Expires:
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.LCA 187 Attachment A Page 1 of 4 1
Description of changes
.The proposed changes to Trojan Technical Specification (TTS) 3/4.4.5,
" Steam. Generators", and the associated Bases will allow cleeving of steam-
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generator tubes. There is also one editorial change as indicated below.
The specific changes are as follows:
1.
TTS 4.4.5.2.b.1 is changed so that whereas it was required to include all nonplugged degraded tubes in the first-sample of tubes selected for each inservice inspection, now only the nonplugged
-degraded-tubes that have not been sleeved in-the affected area will
'li tua required to be included in the sample.
2.
TTS 4.4.5.4.a.11 is changed to clarify that F* distance no longer applies if a sleeve is installed in the roll expanded portion of a tube..
a 3.
TTS 3/4.4.5'throughout is changed to require the same actions for sleeves with imperfections as is required for tubes with imperfec-tions.
4.'..TTS 4.4.5.4.a.5 is changed to refer to the repair limit rather than.
the plugging limit in the definition of " defect".
5.
TTS 4.4.5.4.a.5 is changed so that whereas a tube containing a
- defect was defined as defective, now a-tube containing a defect and not sleeved in the affected area is defined as defective.
6.
TTS 4.4.5.4.a.6 is changed so that what was called the " plugging
~1imit" is now called the " repair-limit" and the definition indicates that when a tube reaches the limit, which is an imperfection depth of_40 percent of the nominal tube wall thickness, that the tube shall be removed from service by plugging or can now be repaired by sleeving in the affected area.
7.-
TTS 4.4.5.4.a.6 is changed to remove unnecessary parentheses from around the "40" ir "(40) percent of the nominal wall thickness" -
editorial.
8.
TTS 4.4.5.4.b is changed so that whereas a steam generator was considered operable after the plugging of all tubes exceeding the plugging limit, now a steam generator shall be considered operable after either the plugging or slooving in the affected areas of all tubes exceeding the repair limit.
9.
TTS 4.4.5.5.a is changed to include in the 15-day report following each inservice inspection of steam generator tubes the number of sleeved tubes in each steam generator in addition to the number of plugged tubes in each steam generator.
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LCA 187 Attachment A t
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K 10.
TTS 4.4.5.5 b.3 is changed to include in the annual report of the L'
results of the steam generator tube inservice inspection the identi-
- f ification of tubes sleeved in addition to the' identification of tubes p.
_ plugged.
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- 11. : Table 4.4-2, " Steam Generator Tube Inspoetion", is changed in five places to indicate in applicable." Action Required" blocks that defective tubes are to be plugged or now sleeved.
12.
TTS 3/4.4.5 Bases are changed as follows:
a.
Third paragraph is changed to indicate that leaking steam gener-M>A
'ator tubes will-be plugged or now sleeved in the affected area.
b.
Fourth paragraph is changed so that whereas plugging was
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required cf all tubes. exceeding the plugging-limit, now plugging or sleeving in the affected area will be required of all tubes exceeding the repair limit.
- c. -A'new section is addedito discuss steam generator sleeving, to list the sleeve designs which are approved by the Nuclear
- Regulatory Commission (NRC) for use at Trojan, and to document
-the' requirement that future sleeve designs must be approved by the NRC-prior to their use.
Reason for= Changes
.The TTS now requires that all defective steam generator tubes be plugged. -Plugging tubes reduces reactor coolant flow and is less desi-E 1rable in'some cases than a repair technique that does not remove the i
tubes from service. The changes described above will allow sleeving of steam generator. tubes as a corrective or. preventive maintenance action.
Sleeving is a safe and effective proceduro which does not remove tubes from service.
' Portland Ceneral Electric Company (PGE) has reviewed the sleeving designs of a variety of vendors. Three vendors have been selected for use at
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iTrojan. Reports which describe their sleeving designs and provide information to support their use are as follows:
1.
BAW-2094P, " Recirculating Steam Generators Kinetic Sleeve Qualification for 7/8-inch OD Tubes", October 1989.
2.
a.
BKAT-01-P, " Topical Report:
Repair of Defective Steam Generator Tubes by Sleeving", Revision 1, April 1989.
b.
EDR-TRJ-01-P, " Design Report:
Repair of Defective Steam Generator Tubes by Sleeving for Trojan Nuclear Power Plant",
October 1989.
3.
CEN-395-P, " Trojan Steam Generator Tube Repair Using Loak Tight Sleeves", November 1989.
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>F LCA 187
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Attachment A page 3 of 4
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i Determination of Significant Hazards Considerations
..In;accordance with the requirements of Title 10 Code of Federal Regulations (CFR). part 50.92, this License Change Application is judged l
torinvolve no significant hazards based upon the following information:
j' 1.
Does"the proposed license change' involve a significant' increase in the probability or consequences of an accident previously evaluated?
~:Some steam generator tubes have been found to have a varying amount of wall degradation. When the degradation is extensive, the normal j
practice of plugging defective. tubes may reduce the effectiveness of ll Ethe steam generators and eventually. reduce the performance of the l
nuclear steam supply system. An alternative to plugging tubes is
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i installing a sleeve as~a new pressure boundary inside the' original
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' tubes to bridge the degraded area, thus permitting the tubes to.
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>-remain in service. Thel integrity of the steam generator tubes will j
l-be equivalent to.that of an original tube..In addition, the steam generator.'will-remain capable of performing its required heat trans-
-fer function.. Therefore, the proposed change does not involve an increase in the probability or consequences of an accident previ-j ously evaluated.
- 2. ;Does the: proposed 111 cense' change create the possibility of a new or idifferent kind of accident from any previously evaluated?
-As discussed above, both1the structural integrity and the heat
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transfer capability of the steam generators will not be signifi-I cantly affected by the installation of sleeves.
In addition, the tube. sleeves do not interact with any of the other plant systems, f
Thus, the proposed change does not create the possibility of a new or different kind of' accident from any previously evaluated.
- 3..Does the proposed license change involve a significant reduction in I
a margin of safety?
11e heat transfer capabilities of the steam generators will be improved by utilizing the sleeving process rather than the currently required plugging, since the reactor coolant system flow will not be reduced as much.
Furthermore, the structural integrity of the steam
. generators will not be degraded.
Therefore,-the proposed change does not involve a reduction in a margin of safety.
Safety / Environmental Evaluation Safety and environmental evaluations were performed as required by 10 CPR 50 and the TTS.
The review determined that the proposed change q
does not create an unreviewed safety question, nor does it create an unreviewed environmental question.
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r LCA 187 Attachment A Page 4 of 4 Schedule consideration f
' Primary water. stress corrosion cracking (PWSCC) resulted in the plugging
'of a;significant number of steam generator tubes during Trojan's 1989 J
Refueling Outage. A number of corrective actions are being taken to arrest-the further development of PWSCC; however, there exists a real possibility-that the number of tubes required to be plugged during the 1990. Refueling-Outage could exceed the presently analyzed limit of 111-1/2 percent uniform tube plugging. Therefore, to address this contin-
'gency, PGE desires that the'NRC review and' approve this proposnd license change by March:10, 1990 and make the effective date March 21, 1990.
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