ML20198Q219

Forwards RAI in Response to GL 87-02 for Resolution of Unresolved Safety Issue A-46 for Plant,Units 1 & 2

ML20198Q219
Person / Time
Site:	Hatch
Issue date:	10/31/1997
From:	Le N NRC (Affiliation Not Assigned)
To:	Sumner H SOUTHERN NUCLEAR OPERATING CO.
References
REF-GTECI-A-46, REF-GTECI-SC, TASK-A-46, TASK-OR GL-87-02, GL-87-2, TAC-M69451, TAC-M69452, NUDOCS 9711120146
Download: ML20198Q219 (7)

Text

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October 31, 1997 Mr. H. L. Sumner Jr. Dis'ribution: LBerry PYChen Vice President - Nuclear SockcEilea OGC Hatch Project PUBLIC ACRS Southern Nuclear Operating Company, Inc. PD 11-2 Rdg. JJohnson, Ril Post Office Box 1295 BBoger PSkinner, Ril Birmingham, Alabama 35201-1295 HBerkow NLe

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION ON THE RESOLUTION i3 OF UNRESOLVED SAFETY lSSUE A EDWIN 1. HATCH NUCLEAR PLANT, UNITS 1 AND 2 (TAC NOS. M69451 AND M69452)

Dear Mr. Sumner:

The NRC staff has reviewed the submittal dated May 30,1995, from Georgia Por ~

Company (GPC)in response to Generic Letter 87-02 for the resolution of unresolved safety issue (USI) A-46 for the Edwin 1. Hatch Nuclear Plant, Units 1 and 2. The staff has a; o reviewed GPC's responses to the staff's requests for additional information (RAls) of June 27, 1996, and January 30,1997. As a result of those reviews, the staff has determhed that further Eq information is needed to complete its evaluation of your resolution of USI A-46. Accordingly, 5 21 we request that you respond to the enclosed RAI within 60 days from receipt of this letter. If you have any questions regarding this matter, please contact me at 301415-1458.

Sincerely, ORIGINAL SIGNED BY:

N90c B. (Tommy) Le, Project Manager Project Directorate 11-2 >

hM Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation r

J Docket Nos. 50-321 and 50-30

Enclosure:

As stated t I cc w/ encl: See next page

(( g g((q g@t;r To receive a copy of this document, indicate in the box:"C" = Copy without attachment / enclosure "E" = Coy with attachment / enclosure "N" = No copy Y%d6M OFFICE PM:PD!l-2 0 LA:PDil-2n d BC:EMEEk/ D:PQt%%l l N

NAME NLE:cn ddd LBERRY W RWESSMAN[ ' HB$RFDW DATE ip/W/97 ()'W\/97 \

/0 I?f/97 10 / N/97 / /97 , /97 DOCUMENT NAME: G:\ HATCH \ HAT-A46.RAI OFF!CIAL RECORD COPY 9711120146 971031

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pa U:o g UNITED STATES i n j NUCLEAR REGULATORY COMMISSION WASHINGTON, o.C. IDe6H001

% * . . . + ,[g October 31, 1997 Mr. H. L. Sumner, Jr.

Vice President - Nuclear Hatch Project Southem Nuclear Operating Compan,, Inc.

Post Office Box 1295 ,

Birmingham, Alabama 35201-129S

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION ON THE RESOLUTION

. OF UNRESOLVED SAFETY ISSUE A EDWIN 1. HATCH NUCLEAR PLANT, UNITS 1 AND 2 (TAC NOS. M69451 AND M69452)

Deat Mr. Sumner.

The NRC staff has reviewed the submittal dated May 30,1995, from Georgia Power Company (GPC)in response to Generic Letter 87-02 for the resolution of unresolved safety issue (USI) A-46 for the Edwin 1. Hatch Nuclear Plant, Units 1 and 2. The staff has also reviewed GPC's responses to the staff's reouests for additionalinform.aion (RAls) of June 27, 1996, and January 30,1997. As a result of these reviews, the ctzff hes determined that further information is needed to complete its evaluation of your resoluuon of USl A-46. Accordingly, we request that you respond to the enclosed RAI within 60 days from receipt of this letter, if you have any questions regarding thic matter, please contact me at 301-415-1458.

Sincerely, Ngoc B. (Tommy) Le, Project Manager Project Directorate 112 Division of Reactor Projects -I/!!

Office of Nuclear Reactor Regulation Docket Nos. 50-321 and 50-366

Enclosure:

As stated ec w/ encl: See next page

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f Edwin 1. Hatch Nuclear Plant cc:

Mr. Emest L. Blake, Jr. Charles A. Patrizia, Esquire Shaw, Pittman, Potts Paul, Hastings, Janofsky & Walker and Trowbridge 10th Floor 2300 N Street, NW. 1299 Pennsylvania Avenue Washington, DC 20037 Washington, DC 20004 9500 Mr. D. M. Crowe Chairman Manager, Licensing Appling County Commissioners Southem Nuclear Operating County Courthouse Company, Inc. Baxley, Georgia 31513 P. O. Box 1295 Birmingham, Alabama 35201-1295 Mr. J. D. Woodard -

Executive Vice President Resident inspector Southem Nuclear Operating Plant Hatch Company, Inc.

11030 Hatch Parkway N. P. O. Box 1295 Baxley, Georgia 31531 Birmingham, Alabama 35201-1295 Regional Administrator, Region ll Mr. P. W. Wells U.S. Nuclear Regulatory Commission General Manager, Edwin I. Hatch Atlanta Federal Center Nuclear Plant 61 Forsyth Street, SW, Suite 23T85 Southem Nuclear Operating Atlanta, Georgia 30303 Company, Inc.

U.S. Highway 1 North Mr. Charles H. Badger P. O. Box 2010 Office of Planning and Budget Baxley, Georgia 31515 Room 610 -

< 270 Washington Street, SW. Mr. R. D. Barker Atlanta, Georgia 30334- Prugram Manager Fossil & Nuclear Operations Harold Reheis, Director Oglethorpe Power Corporation Department of Natural Resources 2100 East Exchange Place 205 Butler Street, SE., Suite 1252 P. O. Box 1349 Atlantc, Georgia 30331 Tucker, Georgia 30085-1349 Steven M. Jackson Senior Engineer- Power Supply Municipal Electric Authority of Georgia 1470 Riveredge Parkway, NW Atlanta, Georgia 30328-4684

REQUEST FOR ADDITIONAL INFORMATION USI A-46 REVIEW AT HATCH NUCLEAR PLANT UNITS 1 AND 2

1. In the staff's request for additional information (RAI), dated June 27,1996, Georgia Power Company (GPC) was requested to provide the analytical calculations for the resolution of the outlier conduit and cable raceways. GPC did not provide the analytical calculations in response to this RAI, but requested the NRC staff to review them at the Southem Nuclear Operating Company (SN.C). Thus, the staff is requesting that you provide the analytical calculations for the raceway supports identified below. After a review of the calculations, the staff will determine the necessity for an audit in the SNC office.

_ Appendix K of Ref.1: (a) Baseplate 1D-28 (Drawing No. H-13203)

(b) Supports 1E gA (Drawing No. H 13215) and 1U 10ED (Drawing No.- H-17355) ,

(c) Expansion anchor (Drawing No. H-13217)

(d) Cable tray support 1Y-5A (Drawing No. H-17262).

2. Previously, the NRC staff had concems about the way the A-46 cable trays and conduit raceways issue was being disposed of by some USI A-46 plant licensees, and thus had issued requests for additional information (R E 1 severallicensees on this issue.

Subsequently, the Seismic Qualifications Utilites Group (SQUG) responded to these RAls, instead of the licensees, because SQUG considered the RAls b be generic in nature. The staff then issued a followup RAI to SQUG; however, the staff found that correspondence with SQUG did not achieve the intended results because they did not address the identified plant-specific technical concems. Therefore, the staff is restating its cor$cems via the following discussion.

The generic implementation procedure (GIO recommended performing what is called "a limited analytic evaluation" for selected cable and conduit raceway supports. The procedure further recommended that when a certain cable tray system can be judged to be ductile and if the verticalload capacity of the anchorage can be established by a load check using three times the dead weight, no further evaluation is needed to demonstrate lateral resistance to vibration from earthquakes. The staff has the following concems with the manner oy which these simplified GIP criteria were implemented at the Hatch plant.

The GIP eliminates horizontal force evaluations by invoking ductility._ However, some so-called nonductile cable tray support systems would ever.tually become ductile by inelastic deformation, buckling or failure of the nonductile cable tray supports and members. This procedure is a basic departure from conventional methods of engineering evaluation and the GIP does not provide an adequate basis for dealing with -

those cable trays that are initially judged to be nonductile but are eventually called ductile by postulating failure of the lateral supports.11 this procedure was followed for eliminating cable trays from further assessment at Hatch, then all the cable trays could Aceivably be screened out from the A 46 evaluation. Thus, we request that you provide the following additional information:

Enclosure

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L a.- Define ductility in engineering terms as used at Hatch for the USI A-46 evaluation.

i- Clarify how this definition is applied to actual system configurations at Hatch consistently for the purpose of analytical evaluation.

b. Provide the total number of receways that (1) were selected for worst-case analytical calculatons, (2) were classified as ductile la your A 46 evaluation at Hatch, and (3) did not have a horizontal load cvaluation performed. Indicate the approximate percentage of such raceways as compared with the population selected for your analytical review, and discuss how the ductility concept is used in your walkdown procedures.

c. Describe the typical configurations of your ductile raceways (dimension, member size, suppMs, etc.).

d. Justify the position that ductile raceways need' not be evaluated for horizontal load.

When a reference is provided, state the page number and paragraph. The reference should be self-contained, and not refer to another source of reference.

e. In your evaluation of the cable trays and raceways, if the ductility of the attachments is assumed in one horizontal direction, does it necessarily follow that the same system is ductile in the perpendicular direction? If yes, provide the basis for this conclusion. If it is not ductile in the perpendicular direction, how was the seMmic adequacy of the attachmaats evaluated ?

f. Discuss any receways and cable trays, including supports, at Hatch that are outside of the experience cata. Explain what criteria are used for establishing their safety adequacy and specify your plan for resolution of outliers that did not meet -

the acceptance criteria.' Provide examples of the configurations of such raceways and cable trays including supports. Also, indicate the percentage of cable trays and raceways that are outside the experience data in relation to the population of -

s raceways and cable trays examined during the walkdowns of the safe shutdown

- path. How are they going to be evaluated and dispositioned?

g. Submit the evaluation and analysis results for four of the representative sample

- raceways (one single nonductile, one single ductile, one multiple nonductile, and one multiple ductile raceway), including their specific configurations (dimension, member size, supports, etc.).

3. In the staffs RAI dated June 27,1996, you were requested to provide copies of the

• 15 percent broadened in-structure response spectra (IRS) curves that you had committed to for the USI A-46 resolution. However, you indicated in the response (Reference 2) that thera are no formal broadened IRS curves. Rather, the seismic demand from the three (lower bound, intermediate, and upper bound soll modulus) raw IRS for items of equipment under evaluation was determined by your engineer. The raw IRS are the Seismic Margin Earthquake (SME) 5 percent damped IRS, which weree developed in the original Plant Hatch Seismic Margin Assessment (SMA) program .

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3 (Reference 3). With respect to the IRS that you had committed to in Section 4.2.1.2 and Appendix G of the USl A-46 Summary Report (Reference 1), the staff is requesting the following additionalinformation:

a. Provide the plots of the IRS (enveloped three soil cases and broadened by 115 percent) for elevations (EL.) 87 ft (Mass 1),130 ft (Mass 2),158 ft (Mass 3),

188 ft (Mass 4),203 ft (Masses 5,14, and 22) and 228 ft (Mass 6) for the reactor building,

b. Provide the ground response spectrum (GRS) (one-half SME GRS) and a comparison between the GRS and the IRS for the Masses 1,2,3,4, 5, and 22 of the reactor building on the same plot.

c. With regard to the summary of the maximum absolute acceleration that you provided at different elevations of the reactor building in Appendix G of Reference 1, it is the staffs understanding that you refer to the zero period acceleration (ZPA) as the maximum absolute acceleration. From the review, the staff found that all ZPAs from EL. 87 ft to EL. 228 ft are smaller than the peak ground acceleration (PGA) of 0.15g at EL.130 ft. Provide deOlled technical discussions as to why all these ZPAs are smaller than the PGA, since the motions -

at higher elevations are expected to be emplified. Also, discuss the methods and assumptions of your soil-structure interactions (SSI) analysis (i.e., convolution /

deconvolution techniquas used, input motions at foundation level, etc.),

d. Provide the plots of the IRS (enveloped three soil cases and broadened by (

• 15 percent) for EL.112 ft (Mass 2),130 ft (Mass 5),147 ft (Ms,2s 8) and 164 ft (Mass 11) for the control building.

e, Provide a comparison between the GRS and the IRS for Masses 2,5,8, and 11 of the control building on the same plot.

f. Provide detailed technical discussions as to why the ZPAs of Masses 2, 5,8, and 11 of the control building are smaller than the PGA, since the motions at higher elevations are expected to be amplified.

4. In the staffs RAI dated June 27,1996, you were requested to provide the evaluation methodology used for the resolution of the outlier tanks and heat exchangers in your i response (Reference 2) to our RAI, you referenced the SMA methodology described in the report EPRI NP-6041. In using the SMA methodology for ine tank evaluations, the staff has found that this methodology may yield analytical results that arc not as conservative ss those obtained by following the GIP 2 guidelines. Therefore, the SMA methodology is generally not acceptable for the USl A 46 program. Describe the extent to which the method was used in your USl A-46 program. For each deviation from the -

GlP-2 guidelines and in situations where the margin methodology is utilized, identify the nature and the extent of the deviation, and provide a technicaljustification for its acceptance.

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5. If Thermo-Lag panels have been added to cable tray installations, discuss how the appropriate weight and modulus of the Thermo-Lag are included in the evaluations performed to determine the seismic resistance capability of affected cable trays and their supporting systems. ,

6. Indicate whether, dunng the walkdowns, you found any r.nchors of types nc.t covered by the GlP-2 (e.g., lead cinch anchor, or Liebig anchor, etc.). If yes, how did you resolve the finding?

REFERENCES

1. "Edwin 1. Hatch Nuclear Plant: Results of Unresolved Safety l'. sue A 46 Review,"

submitted by Georgia Power Company (GPC) on May 30,1995.

2. Letter, J. Beckham, GPC, to NRC, "Edwin 1. Hatch Nuclear Plant: Respons n to Request for Additional Information: Unresolved Safety lasue A-46," August 23,1996

3. " Seismic Margin Assessment of Edwin 1. Hatch Nuclear Plant, Unit 1," EPRI NR-7217-SL, EPRI, Palo Alto, CA, June 1991.

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