ML20114B488
| ML20114B488 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 08/24/1992 |
| From: | Woodard J SOUTHERN NUCLEAR OPERATING CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML19303F046 | List: |
| References | |
| NUDOCS 9208280266 | |
| Download: ML20114B488 (7) | |
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Docket No. 50-348 U. S. Nuclear Regulatory Commission Document Control Desk ATTN:
Washington, DC 20555 Joseph H. Farley Nuclear Plant - Unit 1 rh Steam Generato_t_lubjLlurnort Plaie _ Interim Pluaaina Q1Le_r
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Gentlemen:
itted a By letter dated February 2;, 1991, Alabama Power Company su iteria. On steam generator tube support plate alternate plugging crin respo the NRC Staf f, a revised submittal was made simp'iifying the alternate p November 13, 1991, On January 29, criteria and including additional pulled tube data.
1992, the NRC Staff indicated to Southern Nuclear Operating Com 4
h Unit 2 (SNC) that the amendment would not be approved prior to t e 20, 1992, SNC submitted an By letter dated FebruaryThe interim plugging criteria was Spring 1992 outage. interim plugging criteria for Unit 2.
By letter dated June 5, 1992, iteria would approved by the Staf f on April 1,1992,the NRC Staff indicate not be approved for the Unit 1 Fall 1992 outage.SNC's pr Unit 1.
NRC approval is requested by October 8,1992.
d an SNC proposes that the Unit I technical specificc.icns be modifie i
interim bar.is, to clarify that the percent tube wall degradat on i eability criteria currently employed is inappropriate to determine serv c ctions.
of tubes with flaw indications at the tube support by a t
ity. As a meth.dology that more reliably assesses structural in egr l
Nuclear Plant, result of the structural iMegrity assessment at far ey il tube indications within the tube support plate with a bobbin co i
Flaws voltage less than or equal to 1.0 volt will be left in serv ce.dispositioned with a bobbin voltage greater than 1 volt will be Furthermore, SNC will ensure that primary-to-secondary leakage as a result of e steam line break is sufficiently low to e M
inspection.
t 100 the dose at the site boundary is a small fraction of the f the discovery of primary-to-secondary operational leakage as a re limits.
f Unit 1.
In tional 29, 1991, leakage from any one steam generator was reduced from 50 that submittal of October d
d from or.e day to 140 gallons per day. operation *' leakage through all stea OI i
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U. S. Nuclear Regulatory Commission Page 2 l
l gallon per minute (1,440 gallons per day) to 420 gallons per day.
This leakage limit bounds the 150 gallon per day limit used for the Unit 2 interim plugging criteria.
Furthermore, this limit has been administrative 1y implemented since the Unit I startup.
Consequently, revised c imarf-to-secondary operational leakage technical pecification r
pages have not been included in this submittal.
The proposed interim criteria is composed of two parts.
-entains the proposed interim voltage plugging criteria including a sanpling program. Attachment 2 contains the proposed changed Technical Spe'jfication pages in support of the interim plugging criteria. provides a significant hazards evaluation for the proposed interim plugging criteria in accordance with 10 CFR 50.92.
provides the proposed eddy current guidelines for use in the Unit 1 Eleyenth Refueling Outage, assuming the interim criteria is approved for use.
The supporting environmental evaluation is provided in Attachment 5.
Based upon the evaluation provided, SNC has determined inat pursuant to 10 CFR Sl.22(c)(9), the proposed license amendment can be categorically excluded from the requirement to perform an environmental assessment or an environmental impact statement.
i Enclosed in Attachment 6 are:
1.
WCAP-13464, " Response to NRC Questions on the Farley Steam Generator Tube Alternate Plugging Criterion Presentation Materials" (Proprietary).
2.
WCAP-13465, " Response to NRC Questions on the Farley Steam Generator Tute Alternate Plugging Criterion Presentation Materials" (Non-Proprietary).
Also enclosed are a Westinghouse authorization letter, CAW-92-342, accompanying affidavit, Proprietary Information Notice, Copyright Notice, and Electric Power Research Institute (EPRI) affidavit.
As item 1 contains information proprietary to Westinghouse Electric
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Corporation and EPRI, it is supported by affidavits signed by l
Westinghouse and EPRI, the owners of the information.
The affidavits set forth the basis on which the information may be withheld _ from public disclosure by the Commission and addresses with specificity the i
considerations listed in parsgraph (b) (4) of Section 2.790 of the Commission's regulations.
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U. S. Nuclear Regulatory Conmission Page 3 Correspondence with respect to the copyright or proprietary aspects of the items listed above with paragraphs marked (a) through (f) or the supporting Westinghouse affidavit should reference CAW-92-342 and should be addressed to Nicholas J. Li3arulo, Manager of Nuclear Safety and Regulatory Activities, Westin91ouse Electric Corporation, P. O. Box 355, Pittsburgh, ret.
'vania 15230-0355.
Correspondence with respect to the proprietary aspt of items with paragraphs marked (g) or the supporting EPRI
.ridavit should be addressed to Arthur Kenny, P. O. Box 10412, Palo Alto, California 94303.
l Enclosed in Attachment 7 are:
l 3.
Electric Power Research Institute's Report EPRI TR-100407, "PWR 4
Steam Generator Tube Repair Limits: Technical Support Document for j
Outside Diameter Stress Corrosion Cracking at Tube Support Plates," (Proprietary).
4.
Electric Power Research Institute's Report EPRI TR-100407, "PWR Steam Generator Tube Repair Limits: Technical Support "
aent for Outside Diameter Stress Corrosion Cracking at Tube Sun -
Plates," (Non-Proprietary).
J l
Developed in parallel with WCAP-12872, the basis for the farley l
alternate plugging criteria, this EPRI document nrovides guidance to.-
i the development of a generic plugging limit for outside diameter stress j
corrosion cracking of tubes occurring at the tube support plates of a
steam generaivrs.
This documentation is provided to assist the NRC l
Staff in the review of future alternate plugging criteria for cracking j
at tube support plates, i
Also enclosed is an EPRI affidavit. As item 3 contains information I
proprietary to EPRI, it is supported by an affidavit signed by EPRI, the owner of the information.
The affidavit sets forth the basis on which the information may be withheld from public disclosure by the Commission and addresus with specificity the considerations listed in paragraph (b)(4) of Section 2.790 of the Commission's regulations.
Accordingly, it is respectfully requested that the information which is proprietary to EPRI be withheld form public disclosure in accordance l
with 10CFR Section 2.790 of the Commission's regulations.
C - respondence with respect to the proprietary aspects of the items lhted above or the supporting EPRI affidavit should be addressed to Arthur Kenny, P.O. Box 10412, Palo Alto, California 94303.
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i U. S. fluclear Regulatory Commission Page 4 If there are any questions, please advise.
Respectfully submitted, SOUTHERfQ10CLEAROPERATlflGCOMPAtlY
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' J.D.
Woodard 4
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REM: map a:\\ipc-ul.cr6 Attachments SWORil TO Afl0 SUBSCRIBE 0 BEFORE ME cc:
Mr. S. D. Ebneter
% DAY Of @ j}L A /u g u d 1992 Mr. S
- 1. Hoffman THIS Mr. G. f. Maxwell Dr. Carole Samuelson V 'fe f f ot U TTc My Commi sion Expires: g;[/-94/
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Attachment I s
Interim Plugging Criteria Description And Safety Analysis I
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Interim Plugging Criteria Description And Safety Analysis Page 1 ij j
. Southern Nuclear Operatinu Company Proposal i
1.
A bobbin inspection of 100% of the hot and cold leg steam generator tube support plate intersections will be performed.
l 2.
Flaws within the bounds of the tube support plate with bobbin voltage less than or equal to 1.0 volt will be allowed to remain in service.
l 3.
Flaws within the bounds of the tube support plate with a bobbin voltage greater than 1.0 volt will be repaired or plugged except as noted in 4.
4.
Flaw indications within the bounds of the tube support plate with a bobbin voltage greater than 1.0 volt but less than or equal to 3.6 volts may remain in service if a rotating pancake coil probe (RPC) inspection does not detect a flaw.
Flaw indications with a bobbin voltage greater than 1
3.6 volts will be pluoged or repaired.
5.
A sample RPC inspection of at least 100 tube support plate intersections j
will be performed. All intersections with a bobbin dent voltage exceeding 5 volts will be inspected. Other intersections in the sample population will be based on inspecting intersections with artifact indications and 1
intersections with unusual phase angles.
Expansion of the sample plan, if l
required, will be based on the nature and number of the flaws.
3 1
6.
RPC flaw indications not found by the bobbin due to masking effects (due i
to denting, artifact Indications, noise) will be plugged or repaired.
End-of-Cycle (E00) Voltaae Distribution 1'
Acceptable methods for determining the E0C voltage distribution are as
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follows:
1.
The methodology described in WCAP-12871, Revision 2.
(This involves sampling the cumulative probability distributions of NDE uncertainty and the voltage growth rate using Monte Carlo techniques and applying the j
results to the beginning-of-cycle (80C} voltage distribution.)
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2.
A sinplified approach may be used as an alternative (to the WCAP-12871, Revision 2 approach) provided it provides for a conservative treatment of the tails of the cumulative probability distributions of NDE uncertainty and the voltage growth rate to the 100% cumulative probability values.
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l Interim Plugging Criteria Description And Safety Analysis Page 2 l
j Steam line Break __leakaag 1
i Steam line break leakage as a function of E0C voltage (EOC-V) shall be j
determined as follows:
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j E0C Voltaae (LOC-V)
SLB lea.k.agfL E0C-V s 2.5 volts 0 liter / hour i
2.5 volts < EOC-V s 4 volts I liter / hour j
E0C-V > 4 volts 10 liters / hour Jhould the calculated steam line break leakage exceed the 1 gallon per minute 1
Farley technical specifications limit, tubes with the highest voltages would j
be plugged or repaired until the 1 gallon per minute leakage rate is satisfied.
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Safety Analysis 4
WCAP-12871, Revision 2, "J. M. Farley Units 1 and 2 SG Tube Plugging Criteria j
for 005C0 at Tube Support Plates," provides the development of a 3.6 volt
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alternate plugging criteria. Use of a 1.0 volt threshold for application of J
the current Technical Specification is more conser vative than the use of the l
3.6 volt criteria.
Burst pressure for steam generator tubes with flaws within the bounds of the tube support plate will still meet the requirements of j
The Unit 1 interim plugging criteria proposes that tubes within the bounds of the tube support plate with flaw indications with bobbin voltage less than or j
equal to 1.0 volt be allowed to remain in service. Steam line break leakage i
must take into account the expected leakage from these flaws. This will be i
accomplished by using the thresholds in the steam line break leakage as a function of E0C voltage table above. Use of these limits for leaving tubes in j
service will ensure that leakage in the event of a steam line break will i
remain less than the 1 gallon per minute limit currently in the bases of the Farley technical specifications.
i i
The steam line break leakage values of 0,1, and 10 liters / hour for the 1
voltage range shown on the steam line break leakage as a function of E0C l
voltage table are considered to be conservative based on WCAP-13464, " Response to NRC Questions on Farley SG Tube Alternate Plugging Criteria Presentation Material."
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