ML20203E728

Responds to to W Travers & Submitted Pursuant to 10CFR2.206,requesting That NRC Convene Public Hearing to Consider Revocation of Operating License for Nine Mile Point Nuclear Station,Unit 1.Petition Does Not Meet Criteria

ML20203E728
Person / Time
Site:	Nine Mile Point
Issue date:	02/11/1999
From:	Zwolinski J NRC (Affiliation Not Assigned)
To:	Gunter P NUCLEAR INFORMATION & RESOURCE SERVICE
Shared Package
ML20203E731	List: ML20203E728 ML20203E829
References
2.206, NUDOCS 9902170298
Download: ML20203E728 (12)

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p k UNITED STATES )p -ggg:> l g } NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 30seH001 l February 11, 1999 l Mr. Paul Gunter, Director l Reactor Watchdog Project Nuclear Information and Resource Service 142416* Street, NW, Suite 404 Washington, DC 20036

Dear Mr. Gunter:

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in a letter dated December 14,1998, to Dr. William Travers, signed by you and representatives of several organizations in New York and Massachusetts (Petitioners), and submitted pursuant to 10 CFR 2.206, you request that the U.S. Nuclear Regulatory Commission (NRC) convene a ,

l public hearing to consider revocation of the operating license for Nine Mile Point Nuclear Station, Unit 1 (NMP-1) located in Oswego County, New York, and operated by Niagara Mohawk Power Corporation (NMPC). You base your request upon information about the  !

degraded core shroud and core intemals that you consider to be new information.  !

You will recall that the NRC staff conducted a meeting near the NMP-1 site to hear from the public on April 14,1997, before acting upon NMPC's request that NRC approve restart and  ;

operation for 10,600 hot operating hours with the existing shroud. The NRC staff approved  ;

that request by letter and safety evaluation (SE) dated May 8,1997. Similarly, the NRC staff  !

I conducted a meeting near the site on September 24,1998, to hear from the public before acting upon NMPC's request to defer the mid-cycle reinspection of shroud vertical welds until 14,500 hours0.00579 days <br />0.139 hours <br />8.267196e-4 weeks <br />1.9025e-4 months <br /> of hot operation. The NRC staff approved the extension request by letter and SE dated November 2,1998.

We have rev! awed your letter of December 14,1998 (the Petition), and find that the issues raised in the Petition have been discussed in the two meetings with the public, in the NRC staff's letters and SEs addressing NMPC's associated requests, or in SEs addressing related topical reports regarding the inspection and evaluation of boiling-water reactors (BWR) core shrouds and other vesselintemals. The NRC staff has previously considered the nature and

! implication of the core shroud cracking at NMP1. Therefore, the Petition does not meet the criteria for consideration under 10 CFR 2.206 or for convening a public hearing. The issues raised in the Petition and the NRC's comments on its previous consideration of these issues are enclosed.

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Thank you for expressing your concerns to the NRC. I trust this letter has been responsive to those concerns. We are forwarding copies of this letter to each of the Petitioners whose mailing address is indicated with their signatures. Please forward copies to Petitioners H.

Siegfried and K Rabin whose addresses are not given in the Petition.

Sincerely, e h

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John . Zwolinski, Acting Director Division of Reactor Projects - t/11 Office of Nuclear Reactor Regulation

Enclosure:

As stated l

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February 11,1999 ,

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? P. Gunter l Thank you for expressing your concems to the NRC. I trust this letter has been responsive to those concerns. We are forwarding copies of this letter to each of the Petitioners whose mailing address is indicated with their signatures. Please forward copies to Petitioners H.

Siegfried and K. Rabin whose addresses are not given in the Petition.

Sincerely, Original signed by:

John A. Zwolinski, Acting Director l Division of Reactor Projects -i/II l Office of Nuclear Reactor Regulation

Enclosure:

As stated DISTRIBUTION:

See next page l

l DOCUMENT NAME: G:\NMP1\GUNTER.WPD *See Previous Concurrence To receive a copy of this document, indicate in the box: "C" = Copy "E" = Copy "N" = No copy 0FFICE PM:PDI 1 lE LA:PDI1,0Q l D:PDI-1 /g f f l TechEd* l lEMCB:BC* l NAME DHood/rst 'D j N _ SlittlmW SBajwa X BCature ESuttivan I DATE 0),tl0/99 ok/ Ilf 4i ($/ ll /99 09f l bf 99" ' ' 01/25/99 D1/27/99

, OFFICE D:DRPE:NRR(A)T l E l l l l I NAME JZwotinski /b DATE 02/ll/99 _

Official Record Copy 1

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February 11,1999 P. Gunter Thank you for expressing your concerns to the NRC. I trust this letter has been responsive to those concerns. We are forwarding copies of this letter to each of the Petitioners whose mailing address is indicated with their signatures. Please forward copies to Petitioners H.

Siegfried and K. Rabin whose addresses are not given in the Petition.

Sincerely, Original signed by:

John A. Zwolinski, Acting Director Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation

Enclosure:

As stated DISTRIBUTION:

See next page DOCUMENT NAME: G:\NMP1\GUNTER.WPD *See Previous Concurrence To r;ceive a copy of this document, indicate in the box: "C" = Copy "E" = Copy "N" = No copy OfflCE PM:PDI-1 lE LA:PDI-1,() Q l D:PDI 1 A ff l TechEd* l l EMCB:BC* l NAME DHood/rst D .) N _ Slittl& W SBajwa E BCalure ESullivan DATE 0),tl0 /99 ppffdqy ($/ ll /99 09f)b /99' 01/25/99 01/27/99 I 0FFICE D:DRPE:NRR(A) T E l l l l

! NAME JZwol inski /b DATE 02/l /99 Official Record Copy

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DISTRIBUTION - GREEN TICKET #G19980733:

Docket File (50-220) w/ original incoming PUBLIC (w/ incoming)

EDO #G19980733 EDO R/F W. Travers i M. Knapp F. Miraglia R. Zimmerman P. Norry J. Blaha S. Burns B. Sheron i D. Matthews j Docket File PUBLIC PD l-1 R/F J. Zwolinski  !

S. Bajwa 1 S. Little l

D. Hood j R. Subbaratnam  ;

K. Cyr, OGC J. Goldberg, OGC ACRS OPA OCA NRR Mail Room (EDO #19980733)

H. Miller, Region i A. Blough, Region i D. Screnci, Region I L. Doerflein, Region I G. Hunegs, Region 1 J. Strosnider E. Sullivan R. Hermann W. Koo i

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. DISTRIBUTION - GREEN TICKET #G19980733:

l Docket File (50-220) w/ original incoming PUBLIC (w/ incoming) i EDO #G19980733 l EDO R/F I

W. Travers i M.Knapp l

F. Miraglia R. Zimmerman l P. Norry i J.Blaha l S. Burns l B. Sheron i D. Matthews l Docket File I PUBLIC l PD l-1 R/F l J. Zwolinski S. Bajwa l S. Little D. Hood R. Subbaratnam K. Cyr, OGC

, J. Goldberg, OGC l

ACRS OPA OCA NRR Mail Room (EDO #19980733)

H. Miller, Region i i A. Blough, Region l l D. Screnci, Region I L. Doerflein, Region i G. Hunegs, Region I i J. Strosnider l

E. Sullivan R. Hermann W. Koo l

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Identical Letters Sent To:

David Radley Heidi Siegfried j Student Environmental Action Coalition Oswego Valley Peace and Justice Council l

Syracuse University 124 West 7* Street '

Syracuse, NY 13244 Oswego, NY 13126 Kyle Rabin Jackie Abrams

• Environmental Advocates 245 Moore Ave., Apt.1K 353 Hamilton Street Syracuse, NY 13210 Albany, NY 12210 7

l l Michell Ridell Safe Legacy 173 Huguenot Street New Paltz, NY 12561 ,

Susan Griffin Chenango North Energy Awareness 345 Center Road South Plymouth, NY 13844 Wendy Harris Syracuse Anti-Nuclear Effort 234 Salt Spring road Syracuse, NY 13224 Tim Judson l Syracuse Peace Council 924 Bamet Avenue Syracuse, NY 13203 -

l Andrew Roth Wells The Green Party of Greater Syracuse 732 Westcott Street Syracuse, NY 13210 l

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Diane Swords -

Peace Acton of Central New York 658 West Onondaga Street Syracuse, NY 13204 Deborah Katz Citizen Awareness Network P.O. Box 83 Shelbume, MA 01370 i

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1 I- NRC's Comments on Petition of Deceeber' 14. 1998

1. The utility method forpredicting the crack growth rate of the core shroudis nort- ,

conservative [ Petition at pages 3-4]. ,

NRC Comment

, The Petitioners assert that Niagara Mohawk Power Corporation's (NMPC's) method for .

predicting the crack growth rate of the core shroud is non-conservative because the Electric Power Research Institute's (EPRl's) database is based upon unirradiated test samples and  !

relies upon an insufficient number of observations of vertical cracking. The NRC staff was i

aware of the types of data in the EPRI database and this information was considered by the 4

NRC staff along with other factors in approving the crack growth rates used in the integrity )

2 analyses documented in the safety evaluations (SEs) approving continued operation of Nine j Mile Point Nuclear Station Unit 1 (NMP-1) with a degraded core shroud. The NRC staff I recognizes that data for irradiated samples are sparse, but there is a large amount of non-irradiated data available under a wide range of chemical conditions.

The extension of the current operating cycle for NMP-1 to 14,500 hours0.00579 days <br />0.139 hours <br />8.267196e-4 weeks <br />1.9025e-4 months <br /> is based upon the use of a stress intensity factor (K) 1 dependent crack growth rate of 2.2 x 104 inch / hour given in i

Boiling Water Reactor Vesse' d Intemals Project (BWRVIP) document BWRVlP-14

" Evaluation of Crack Growit. 3WR Stainless Steel RPV [ Reactor Pressure Vessel] Intemais,"

, using a database correlatio- model. The use of this crack growth rate was reviewed and 4

accepted in the NRC staff's t i dated November 2,1998. To allow the use of the approaches for the evaluation of crack growth given in BWRVIP-14, the NRC staff specified severallimiting conditions in an SE dated June 8,1998, which are to be met by utilities that apply the methods

of BWRVIP-14. As discussed in the NRC staff's SE of November 2,1998, on NMP-1, the limiting conditions are satisfied for the NMP-1 core shroud vertical welds V-9 and V-10. 'The limiting conditions specify, in part, that (1) the cracking mechanism is to be intergranular stress-corrosion cracking (IGSCC) rather than irradiation-assisted stress-corrosion cracking (IASCC) ,

2 2 i and (2) the neutron fluence should not exceed 5 x 10 n/cm ,

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On the basis of the results of the metallurgical evaluation of the boat samples from vertical ,

welds V-9 and V-10 and the reported fluence measurements, the cracking in the shroud )

vertical welds is determined to be typical of IGSCC because the observed cracking features  !

J are consistent with the cracking mechanism of IGSCC observed in other BWR components.

The key microstructure features for lASCC as shown in a foreign boat sample are characterized by significant grain encirclement, grain fallout, and crack branching, including the j areas at the crack tip. These IASCC features are not observed in the NMP-1 boat samples.

Enclosure 4,

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l The results of NMPC's neutron flux calculation show that the fluence at the remaining ligament

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of vertical welds V-9 ar.d V-10 will not exceed 5 x 102 n/cm2at the end of operating cycle 13 (i.e., after 14,500 hot operating hours). As discussed in the NRC staff's SE of November 2, 1998, the major effects of irradiation upon the austenitic stainless steel are to increase the sensitization and hardening of the base material. The results of the metallurgical evaluation of the boat samples-that there is no evidence of significant sensitization of the grain boundaries in the base material--and the degree of hardening of the base materials are consistent with General Electric's testing results of the austenitic stainless steel materials irradiated to a fluence range of 1 x 102 o n/cm 2 to 3 x 102 n/cm 2(E > 1 Mov).

The threshold fluence value of 5 x 102 n/cm2is established on the basis of the consideration that the sensitization effect (radiation-induced segregation) will not be significant when the fluence is at such a low level. However, the results from an in-reactor test at NMP-1 show no change in the crack growth rate of a C304 stainless steel specimen for radiation levels up to about 5 x 1020n/cm .2 This supports the use of a crack growth rate curve based on unirradiated data for such low influences.'

Accordingly, the NRC staff has previously determined that the use of crack growth data based l upon unirradiated materials for irradiated materials with a fluence level not exceeding the threshold value is conservative and that a sufficient database exists for the analytical model for predicting crack growth rate. The Petition does not (1) present a significant safety issue not previously considered by the NRC staff, (2) present new information on a significant safety issue previously evaluated, or (3) present a new approach warranting reevaluation of a significant safety issue previously evaluated.

2. Cracking outside the heat-affected zone [HA7] constitutes an unreviewed safety question [ Petition at pages 5-6].

NRC Comment ,

The NRC staff specifically addressed the issue of IGSCC outside the HAZ in its SE issued May 8,1997, approving restart and limited operation of NMP-1 with the degraded core shroud.

NMPC reported that a few crack indications not associated with the HAZ were found in the base metal. These cracks were initiated from the cold-worked areas resulting from grinding to remove the attachment welds (lugs) during construction. The depth of the cold-worked layer in the base metal resulting from grinding is generally very shallow, and the cracking in the cold-worked areas will also not grow very deep. NMPC also reported that some cracks extended beyond the areas of the HAZ. The extension of the cracking outside the HAZ is promoted by surface cold work. As shown in the metallurgical evaluation of boat samples V-10 and V-9, a surface cold-work layer with a depth of 6 to 7 mil and about 2 mil, respectively, was identified.

P. L. Anderson, F. P. Ford, S. M. Murphy, and J. M. Perks, " State of Knowledge of Radiation Effects on Environmental Cracking in Light Water Reactor Core ' Materials," Proc. of  ;

the 4* Intemational Conference on Environmental Degradation of Materials in Nuclear Power l Systems, NACE Intemational, Houston (1990). j i

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3-The depth was measured by microhardness testing and the appearance of slip lines in the microstructure. This observation supports NMPC's contention that the crack growth in the cold-worked area will not grow very deep because the depth of the cold-worked layers has been shown to be very shallow. Therefore, the cracking in the cold-worked area outside the HAZ will not have a significant impact on the structural integrity of the vertical welds. The cracking in the cold-worked area was also observed in other BWR plants in the past and, as previously discussed herein, such cracking is not expected to result in any significant safety consequences.

Accordingly, the cracking in the cold-worked area outside the HAZ does not constitute a significant safety concem. The Petition does not (1) present a significant safety issue not previously considered by the NRC staff, (2) present new information or: a significant safety issue previously evaluated, or (3) present a new approach warranting reevaluation of a significant safety issue previously evaluated.

3. By deferring its mid-cycle inspection, Niagare Mohawk has contradicted industry advisories 16r more detailed re-evaluations of core shroud cracking as an indicator for cracking in other reactor vesselintemals [ Petition at pages 6-7].

l NRC Comment

. The industry formed the BWRVIP in 1994 to address IGSCC in BWR intemals. All BWR 1 licensees, including NMPC, are implementing the BWRVIP program for examination, j evaluation, and repair of reactor intamal components. Currently, the program consists of 56 j industry reports that contain examination, evaluation, and repair criteria that ensure j maintenance of structural integrity for numerous intamal components, as well as reports that

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provide the safety basis for the priority of the activities. Accordingly, the Petition does not (1) !

j present a significant safety issue not previously considered by the NRC staff, (2) present new I l information on a significant safety issue previously evaluated, or (3) present a new approach j warranting reevaluation of a significant safety issue previously evaluated.

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4. NRC has not calculated and published the risk factors associated with core shroud cracking nor determined to what extent core shroud cracking constitutes an l unacceptable safety risk and thus continued operation of Nine Mile Point Unit 1 constitutes an unqualified safety risk [ Petition at page 7].

NRC Comment The NRC staff has issued SEs addressing integrity assessments and attemative repairs of cracked core shrouds. In all cases, the NRC staff has determined that required safety margins for structural integrity consistent with the American Society of Mechanical Engineers Boiler and Pressure Vessel Code requirements will be maintained during the approved operating interval.

Furthermore, the NRC staff issued an SE dated September 15,1998, containing its review of BWRVIP-06, "BWR Vessel and intamals Project, Safety Assessment of BWR Reactor Intemais," and BWRVIP-09, " Quantitative Safety Assessment of BWR Reactor Intemais,"

addressing risk associated with intamals cracking. Therefore, the Petition does not (1) ,

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present a significant safety issue not previously considered by the NRC staff, (2) present new information on a significant safety issue previously evaluated, or (3) present a new approach j warranting reevaluation of a significant safety issue previously evaluated. l l

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EDO Principal Correspondence Control. .

FROM: DUE: 01/11/99 EDO CONTROL: Gl9980733 DOC DT: 12/14/98 Ecul Gunter FINAL REPLY:

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• Travers, EDO

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i 2.206 -- REQUEST TO REVOKE NIAGARA MOHAWK'S Travers

.' LICENSE TO NINE MINE POINT, UNIT 1 _ Knapp

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Norry Blaha DATE: 12/14/98 Burns

• Cyr, OGC ASSIGNED TO: CONTACT:

Miller D I 8 Goldberg, OGC

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