ML20141F327

Responds to Re Cracked Welds in Plant,Unit 1 Core Shroud & Informs That Based on Insp & Analysis Performed & Mod Made to Tie Rods,Plant Core Shroud Acceptable for Operating.Supporting Documents Encl

ML20141F327
Person / Time
Site:	Nine Mile Point
Issue date:	05/15/1997
From:	Collins S NRC (Affiliation Not Assigned)
To:	Bragman M NEW YORK, STATE OF
References
NUDOCS 9705210280
Download: ML20141F327 (4)

Text

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E WASHINGTON, D.C. 30086-0001 May 15, 1997 j

The Honorable Michael J. Bragman '

The Assembly of the State of Ns!w York Room 436, Capitol Building Albany, NY 12224 i

Dear Mr. Bragman:

I I am responding to your letter of April 20, 1997, forwarding two letters you received recently from Michael Slee of Constantia, New York and Sandra J.

Weston of Fulton, New York, regarding the cracked welds in the Nine Mile Point l; Unit 1 (NMP1)-core shroud.

i i Mr. Slee expresses a preference that a'related meeting between the U.S. '

i Nuclear Regulatory Commission (NRC) and Niagara Mohawk Power Corporation (NMPC) that was scheduled to be held in Maryland should, instead, be held i locally so that residents can voice their opinions and concerns. Both letters

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i express concern for health and safety of the public if NMP1 were allowed to  ;

operate with the shroud in its present degraded condition. '

! In April 1997, NMPC found cracking in shroud welds and problems with tie rod .

assemblies that had been installed in 1995 during the previous outage. The NRC scheduled a meeting with NMPC to discuss NMPC's inspection' findings,

' evaluations, root cause assessment, and* plans for corrective actions regarding the shroud welds and tie rod assemblies. The meeting, which was of interest-to many NRC personnel, was initially scheduled for April 10, 1997, at NRC Headquarters in Rockville, Maryland. However, it soon became apnarent that the shroud was of significant local interest, and the NRC staff ' escheduled r l the meeting for April 14, 1997, in Fulton, New York, to accomodate public interest. The NRC's meeting with NMPC was open for public observation. In i

addition, the NRC scheduled a meeting with the public imediately following j the discussions with NMPC. The meeting with the public lasted about three hours, during which many coments and questions were expressed by the  ;

1 public and answered by the NRC or NMPC. I am enclosing a sumary of the April '

14 meetings that the NRC issued on April 25, 1997 (Enclosure 1).

i i .The NRC staff has considered comments made at the meeting, both by the public 4 L

' and NMPC, and information from several submittals written by NMPC and various  :

contractors, in reaching its conclusions regaraing the acceptability of NMP1

to operate with the existing shroud vertical welds and modified tie rods. I i-am enclosing a copy of the NRC staff's safety evaluation dated May 8,1997 i

4 (Enclosure 2), in which the NRC staff concludes, on the basis of the inspection and analyses performed and the modifications made to the tie rods,

that the NMP1 core shroud is acceptable for an operating period for 10,600 1 hours1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> of hot operation as proposed by the NMPC, provided that NMPC meets i

certain conditions regarding reactor coolant chemistry. Because the shred f' l

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j. will continue to meet the margins specified by applicable codes and standards.

i required by the Comission's regulations during this time, reasonable

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! 9705210200 970515 i f DR ADOCK0500g0

The Honorable M. Bragman May 15c 1997 assurance exists that operation as proposed with the existing ' shroud will not i

endanger health and safety of the public.

/

I trust this information will' help you respond to your constituents. If I can be of further assistance, please contact me.

Sincerely, Odginalsignedipf SamuelJ.CofOns Samuel J. Collins, Director Office of Nuclear Reactor Regulation

Enclosures:

1. Meeting Summary dated April 25, 1997

2. NRC letter dated May 8,1997, with safety evaluation DOCUMENT NAME: G:\NMPl\BRAGMAN.GT *See Previous Concurrence To receive a copy of this document, indicate in the box: "C" - Copy without attachment / enclosure "E" - Copy with attachment / enclosure "N" - No copy 0FFICE PM:PDlal lE LA: POI 1 l DtPDI 1,,f l TECH ED* l D:DRPE* l NAME DHood/rtL T) i @ Slittle A SBajwa h M k RSanders SVarga DATE 05/fj /f7 04/16/9 7A J 05/1% /97 05/12/97 05/12/97 0FF1CE ADP:NRR* D:NRI' / DE/EMCB lWl l NAME RZinsnerman I,SCol Qns' / JStrosnider \ \ j DATE 05/12/97 f 05/ % /T7 6/d/97 //

g Official Record i:opy s

The Honorable M. Bragman May 15,1997 assurance exists that operation as proposed with the existing shroud will not endanger health and safety of the public.

I trust this information will help you respond to your constituents. If I can be of further assistance, please contact me. '

i Sincerely, i

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h famue

.Iollins, Director Office of Nuclear Reactor Regulation

Enclosures:

1. Meeting Summary dated April 25, 1997

! 2. NRC letter dated May 8,1997, with safety evaluation l

DISTRIBUTION: S/0 Enclosures'.unless.noted.

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

ED0 #970319 L. Callan H. Thompson ,

E.~ Jordan P. Norry J. Blaha S. Collins /F. Miraglia '

R. Zimmerman T. Martin W. Travers M. Slosson S. Burns PDI-1 R/F (w/ incoming)

S. Varga B. Sheron S. Bajwa ,

M. Thadani M. Boyle (e-mail only).

0GC OPA OCA SECY # CRC-97-0407 NRR Mail Room (ED0 #970319 w/ ';:c aming)

N. Olson

• C. Norsworthy D. Hood (w/ incoming)(w/enlosures)- ,

S. Little H. Miller, Region I L. Doerflein, Region I ,

R. Bangart  ;

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"Y1 UNITED STATES

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} NUCLEAR RESULATORY COMMISSION j wAsumaron, o.c. menem April 25,1997 LICENSEE: Niagara Mohawk Power Corporation FACILITY: Nine Mile Point Nuclear Station, Unit No. 1 \

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SUBJECT:

SUN %RY OF MEETINGS WITH LICENSEE AND PUBLIC ON APRIL 14, 1997, REGARDINGCORESHROUD(TACNO.M98170) >

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On April 14, 1997, the NRC staff participated in a meeting with Niagara Mohawk l Power Cor meeting, poration (licensee and NMPC) regarding the UnitThe I core shrou public from about 7:45 p.m. to 10:30 p.m. on the same subject. The meetings j were located at the Joint News Center,10' Airport Road in Fulton, New York.

i The agenda and a list of NRC attendees are given in Enclosure 1. Participants for NMPC included Messrs. R. Sylvia, R. Abbott, M. McCormick, C. Terry, and N.

Rademacher. Contractor personnel included Dr. R. Smith of Altran Corporation,  ;

Dr. M. Manahan, Sr. of MPM Technologies, and Dr. S. Ranganath of General i Electric Nuclear Energy. Both meetings were well attended by state and local I officials, members of the public, and local media. I i , The purpose of the meeting with NMPC was to review the letter to the NRC dated i April 8,1997. To introduce the technt. cal discussions, Mr. Hermann and

! Ms. Kavanagh of NRC provided background discussions, including related generic l

activities by the Boiling Water Reactor Vessel Internals Project (BWRVIP), l descriptions and functions of the core shroud, an explanation of intergranular l strest corrosion cracking, and a review of relevant NMP1 and industry operating experience. Enclosure 2 presents the viewgraph slides and handouts used by Mr. Hernann and Ms. Kavanagh.

In the April letter and meeting, NMPC discussed recent inspection findings of cracking in the heat affected zones of some vertical and horizontal shroud welds, and anomalies associated with the installation and design of the shroud tie rod assemblies. The licensee discussed root cause and corrective actions, reviewed design documentation and analyses regarding the acceptability of the as-found vertical weld cracking for a period of at least 10,600 operating hours, proposed a weld re-inspection schedule, and described actions taken to restore the tie rod assemblies to the as-designed condition. The licensee's corrective actions for the tie rod assemblies include a modification of the lower wedge retainer clip design, for which the licensee has requested NRC approval under 10 CFR 50.55a prior to restart. Details of the licensee's presentations are given in the April 8 letter and are not repeated here.

Enclosure 3 presents the viewgraph slides and handouts used by NMPC and its contractors. ,

CONTACT: D. Hood, NRR 301-415-304g m

Enclosure 1 p%f'; GJ l-jQ /o %. l

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The meeting with the public included introductions of local officials and members of various organizations by Ms. Barbara Brown, Legislator of Oswego County. Numerous questions and expressions of concern for shroud integrity were received and discussed by the NRC staff. Ms. C. Scott of Volney, New York, expressed a preference that the shroud should be replaced before restart and arovided the NRC a signed petition to this end. Mr. P. Guenther stated his i wiief that cracks associated with vertical welds had extended into the '

' base metal of the shroud and felt that this condition represented an j unreviewed safety question. Dr. J. Johnsrud of Pennsylvania State College '

asked questions re regulatory policy.garding aging, operational Some individuals expressed history, concerns managerial for the present attitudes and  !

financial health of NMPC and concerns for the impact that a major accident l I

could have on the local economy. Some employees and union members indicated t their confidence in the licensee's analyses and their support for continued operation with shortened inspection intervals as proposed by the licensee. i i

Asked about the restart plans, Mr. Sylvia replied that although the refueling efforts would probably be completed by the end of April, the unit will not be restarted until the NRC has completed its review and approved the modified

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shroud repair. Several people expressed appreciation for the meeting and i requested that more meetings on issues of local concern be held in the future.  !

1 The meeting was video recorded and copies of the three VCR cassette tapes are available for a fee from the NRC Public . Document Room, the Gelman Building, 2120 L Street, NW., Washin 3343, e-mail pdr9nrc. gov).gton, DC 20555 (phone 800-397-4209, fax 202-634-i stL 00 f

Darl S. Hifod, Senior Project Manager '

Project Directorate I-1 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation j Docket No. 50-220

Enclosures:

1. Agenda and NRC attendees

2. NRC Slides by Mr. Hermann and Ms. Kavanagh

3. NMPC and contractor slides l cc w/encls: See next page 4

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r-,-, - - , ,

Niagara Mohawk Power Corporation Nine Mile Point Nuclear Station Unit No. I cc:

Mr. B. Ralph Sylvia Resident Inspector Executive Vice President U.S. Nuclear Regulatory Commission Generation Business Group P.O. Box-126 and Chief Nuclear Officer Lycoming, NY 13093 Niagara Mohawk Power Corporation Nuclear Learning Center -

Charles Donaldson, Esquire 450 Lake Road Assistant Attorney General Oswego, NY 13126 New York Department of Law 120 Broadway Mr. Richard B. Abbott New York, NY 10271 Vice President and General Manager -

Nuclear Mr. Paul D. Eddy Niagara Mohawk Power Corporation State of New York Nine Mile Point Nuclear Station Department of Public Service P.O. Box 63 Power Division, System Operations Lycoming, NY 13093 3 Empire State Plaza Albany, NY 12223 Mr. Martin J. McCormick, Jr.

Vice President Mr. F. William Valentino, President Nuclear Safety Assessment New York State Energy, Research, and Support and Development Authority Niagara Mohawk Power Corporation Corporate Plaza West  !

Nine Mile Point Nuclear Station 286 Washington Avenue Extension 1 P.O. Box 63 '

Albany, NY 12203-6399' Lycoming, NY 13093 Mark J. Wetterhahn, Esquire Mr. Kim A. Dahlberg Winston & Strawn General Manager - Projects 1400 L Street, NW Niagara Mohawk Power Corporation Washington, DC 20005-3502 Nine Mile Point Nuclear Station P.O. Box 63 Supervisor Lycoming, NY 13093 Town of Scriba Route 8, Box 382 Mr. Norman L. Rademacher Oswego, NY 13126 Plant Manager, Unit 1 Nine Mile Point Nuclear Station Gary D. Wilson, Esquire P.O. Box 63 Niagara Mohawk Power Corporation Lycoming, NY 13093 300 Erie Boulevard West Syracuse, NY 13202 Ms. Denise J. Wolniak Manager Licensing Niagara Mohawk Power Corporation Nine Mile Point Nuclear Station P.O. Box 63 Lycoming, NY 13093 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406

1 I

l AGENDA April 14, 1997 Meeting on Nine Mile Point Nuclear Station Unit 1 Core Shroud I.

NRC SES$10N WITH NIAGARA N0 HAWK POWER CORPORATION (NMPC) 5:00 NRC Opening Remarks Darl Hood Purpose Introduction of Participants .

5:05 Background on Core Shroud Issue Kerri Kavanagh Robert Hermann 5:15 NMPC Review of April 8, 1997, Letter Martin McCormick

. to NRC and Supplemental Information et al. l Introduction Core Shroud Stabilizer Assemblies (Tie Rods)  !

Core Shroud Weld Inspections and Evaluations Conclusions 1 6:30 NRC Questions / Comments 6:50 Break II. NRC SESSION WITH PUBLIC ON CORE SHROUD 7:00 NRC Opening Statements Darl Hood 7:10 Questions / Comments from Audience 9:30 NRC Closing Remarks Singh Bajwa Richard Wessman i

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INCIOSURE 1

1 NRC ATTENDEES I 1

2 l Office of Nuclear Reactor Regulation, Rockv111e, MD:

Richard H. Wessman Chief, Mechanical Engineering Branch  !

Division of Engineering l l Singh S. Bajwa Acting Director Project Directorate I-1 a

1 Darl S. Hood Senior Project Manager j Project Directorate I-1 Robert A. Hermann Senior Level Advisor-Materials Science l

Materials and Chemical Engineering Branch

{ Division of Engineering

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Kerri A. Kavanagh Reactor Systems Engineer j

Reactor Systems Branch i l

{ Division of Systems Safety and Analysis i

William H. Koo Senior Materials Engineer j Materials and Chemical Engineering Branch Division of Engineering l

} Jai Raj H. Rajan MechanicaiEngineer Mechanical Engineering Branch Division of Engineering Region I, King of Prussia, PA:

1 i Lawrence T. Doerflein Chief, Project Eranch 1 Division of Reactor Projects Barry S. Norris Senior Resident Inspector i

Nine Mile Point Nuclear Station

! Diane P. Screnci i

Senior Public Affairs Officer Public Affairs Staff i

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MEETING ON CORE SHROL D CRACKISU AT

SBE MILE POINT UXIT -

1 i April 14,1997 ,

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Robert A. Hermann, Senior Level Advisor g Division of Engineering y Office of Nuclear Reactor Regulation

BACKGROUND -

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o Core Shrotid Cracking ,

-+ first detected in U.S. plants in 1993 , l'

-+ GL 94-03, "Intergranular Stress Corrosion Cracking of Core Shrouds in Boiling Water .

Reactors," issued July 25,1994

-+ all responses evaluated and SERs issued t

. I o CATEGORY C (22 Plants)

-+ All Category C plants' core shrouds inspected per GL 94-03 (or initiated-preemptive repairs)' .  ;

-+ 13 plants installed core shroud repairs (11 tie-rods and 2 clamps) o CATEGORY B (6 Plants) -

-* All Category B plants core shrouds inspected per GL-94-03, met ASME structural .

integrity criteria for at least one operating cycle

-+ No repairs o CATEGORY A (8 Plants) ~

-* Limited VT inspection performed at 2 plants

' except Browns Ferry 1, which has been in an extended shutdown needetery informatten tenforence April 2, 19 W

STATUS OF BWRVIP REPORT REVIEWS i i

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o BWRVIP-03, Reactor Pressure Vessel and Internals Examination

! Guidelines i l

l 'o BWRVIP-05, BWR Vessel Shell Weld Inspection Recommendations i

i o BWRVIP-06, Safety Assessment of Reactor Internals o BWRVIP-07, Guidelines for Reinspection of BWR Core Shrouds O BWRVIP-14, Evaluation of Crack Growth in BWR Stainless RPV .

Internals 0 BWRVIP-17, Roll / Expansion of Control Rod Drive and In-Core Instrument Penetrations in BWR Vessels 1

Regutetery inferention conference 3 April 2, 199T  ;

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l STATUS OF BWRVIP REPORT REVIEWS (con't3 .

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l 0 BWRVIP-18, Core Spray Internals Inspection and Flaw Evaluation' Guidelines o BWRVIP-19, Internal Core Spray Piping and Sparger Repair Design Criteria i

t o BWRVIP-25, Core Plate Inspection and Flaw Evaluation Guideline o BWRVIP-26, Top Guide Inspection and Flaw Evaluation Guideline t

t o BWRVIP-28, Assessment of BWR Jet Pump Riser Elbow to Thermal Sleeve Weld Cracking -

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stesdetery Informatten conference 4 April 2, 1997

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i INTERGRANULAR STRESS CORROSION CRACKING (IGSCC) MECHANISM

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NINE MILE POINTNUCLEAR STATION UNIT 1 .

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EEll Agenda l

l- NRCWelcome . . . . . . . . . . . . . . B. R. Sylvia NRC Summary for .

the Public . . . . . . . . . . . . . . . NRC l Introductions . . . . . . . . . . . . . . . M. McCormick Purpose . . . . . . . . . . . . . . . . . . . M. McCormick Summary of Results . . . . . . . . . ,

M. McCormick Core Shroud Stabilizer (Tie Rod Findings) . . . . . . . R. Corieri/G. Deaver .

Core Shroud Vertical Weld Assessment . . . . . . . . G. Inch / Dr. R. Smith Dr. M, Manahan/Dr. S. Ranganath Summary . . . . . . . . . . . . . . . . . M. McCormick Closing Remarks . . . . . . . . . . . R. B. Abbott c

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ERII Meeting Purpose The purpose of the meeting is to:

e Discuss the details of recent inspections of the core shroud and stabilized assemblies (tie rods).

e Discuss the analyses supporting the 10CFK50.55a

submittal for proposed tie rod retainer clip modification.

e Discuss analyses which demonstrate that the shroud and tie rods were operable and safe during the previous cycle.

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EElll Shroud Repair Background e The BWRVIP developed industry standardized shroud repair criteria which was approved by t l the NRC. The NMP1 repair was designed to '

t meet standardized criteria.

o NMPC evaluated the industry experience related to core shroud horizontal weld cracking and concluded that the NMP1 core shroud could be susceptible to similar cracking.~

e INMP1 took a pro-active approach with this issue '

and decided to install a shroud repair during the i Spring 1995 refuel outage.

EEll Summary o Results )

. i e The Unit 1 Core Shroud Stabilizers have been restored to the as-designed condition.

e Redesigned lower spring wedge retainer clips have been installed to improve tie rod operation.

e Steady state and transient thermal expansion has been analyzed and proper function of the tie rods and their components is assured.

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EEll Summaryof Results e Abaseline inspection of the shroud vertical welds has been completed. -

l e The as-found condition has been analyzed, taking no credit for the integrity of the horizontal welds and applying conservative crack growth rates, and demonstrates the continued structuralintegrity of the shroud. ,

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EEll Recommended

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Re-inspection Schedule -

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e NMPC requests operation for at least 10,600 hours0.00694 days <br />0.167 hours <br />9.920635e-4 weeks <br />2.283e-4 months <br /> (141/2 months) before re-inspection.

e A safety evaluation, based on conservatism with regard to analytical parameters, concludes no unreviewed safety questions with regard to tie rod repairs and vertical weld integrity.

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EElll ShroudRepairDescription l

e Shroud repair designed to structurally l replace the shroud circumferential welds.

e Four tie rod assemblies are placed around the shroud (azimuths 90 ,166 ,270 ,350 ).

o Vertical restraint is provided by an alternate load path between the top of shroud and shroud support cone.

e Horizontal restraint of the shroud is provided through the use of linear springs and limit stops.

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Spring 1997 Shroud Repair Inspection Plan

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e Prior to the 1997 refueling outage, NMPC submitted its shroud repair inspection plan to the NRC for approval.

e The plan was in accordance with the BWRVIP-07 guidance.

e Visualinspection of all four stabilizer assemblies to:

- Verify the general mechanical and structural condition.

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EElll .

As-Found Condition e Tie Rod Assemblies '

- The tie rod assemblies were found to be in place and functional at the time of theirmpilon with some anomalies.

e Tie Rod Nuts l Allnutlocking devices wereintact. .

A torque check on the 270 degree tie rod nut identified a lack of the original installation mechanicalpreload.

The torque check determined that an axial clearance in the tie rod assembly on the order of 0.08" existed.

e LowerSpring Wedge andLatch 90*: latch fractured and lower wedge re-positioned down on wedge guide 166*: latch and lower spring wedge normal 270*: latch potentially damaged and lower spring wedge normal

- 350*: latch damaged and lower spring wedge = 1/8" below normal position 12

. l' EEll AdditionalInspections t

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e Based on the as-found conditions, additionalinspections

were determined to be required.

e A comprehensive procedure was developed to interogate the condition of each of the tie rod assemblies.

e Remote operated underwater tooling and inspection equipment was designed and fabricated to implement the ,!

procedure. -

e The procedure was also intended to obtain data to validate the root cause theories associated with the degraded latches and the lack of preload in the 270 tie rod.

e As a result it was determined that the tie rod assemblies at  !

the 90,166 and 350 degree azimuths also had some amount of axial clearance which ranged from 0.054" to 0.151".

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f EEll Root Cause '

e The evaluation of the as-found condition shows that both the latch -:

failure and the loss of tie rod preload were related.

e The design of the lower spring contact implicitly assumed that the lower spring contact would slide along the Reactor Pressure Vessa i (RPV) wall. -

e Them were two conditions causing differential movement that were not expected: .

l - The lower support assemblies were able to shift up the sluoud cone i j toward *he shroud due to originalinstallation clearances between the toggle bolts and the cone holes. The impact of the clearances ,

was not recognized.

- Differential motion could also be caused by the deflection of the C-spring under tie rod load for heat up. This could also cause stresses in the latch, although somewhat less than in the previous i case.

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ERll Consequence of Tie Rod Anomalies

'During the Past Operating Cycle  ;

e No plant operational anomalies noted during the past cycle.

e All plant operating design cases evaluated.

- All stresses are within ASME Code limits.

l - Bypass leakage does not affect plant operation or safety functions. l

- Core cooling operability unaffected.

- Safe shutdown capability unaffected.

e Flow induced vibration did not occur. l e As found shroud horizontal weld conditions were safe without tie rod repair in place.

e

Conclusion:

no safety concern; no adverse affect on tie rod repair hardware.

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EEll Corrective Actions  :

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e Removed clearance between the lower support toggle bolts and the shroud side of the cone holes.

e Re-torqued the tie rods to their original designinstallation torque.

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e Installed new modified latches which are more tolerant of differential vertical i displacement. .

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EEll Latch Design Objective ,

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G. Deaver .

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EEll Latch Design Objective e Supportlower wedge dead weight loads l e Accommodate potentialvertical l displacements betweenlower wedge .

and lower spring -

l e Prevent release of the lower wedge and l loss oflower spring contact

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EElll Potential Sliding Cases-o Only sliding at vessel wall / lower wedge 4

interface.

i e Only sliding at lower wedge / lower spring interface.

o Combination of the above.

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EElll Lower Wedge / Lower Spring Sliding Scenario Event Surface Assumed to Latch Displacement

Slide (inches) e Initialheatup and SpringInterface 0.042 i hydrotest l

Remainder of heatup SpringInterface 0.090 ,

to fullpower operation Loss of Feedwater SpringInterface 0.132 Heating i

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EEE Combined Sliding Scenario i t

t Event Surface Assumed to Latch Displacement Slide (inches)

Initialheatup and SpringInterface 0.042 hydrotest Remainder of heatup SpringInterface 0.090 l to full power  !

operation ,

. Cooldown to VesselInterface -0.115*

Ambient (70*F)

Heatup to FullPower SpringInterface 0.182 Operation Ioss of Feedwater SpringInterface 0.224 Heating

• Maximum displacement is limited by the amount of travel down the 5 degree angle of the spring.

21

EEll Stress Analysis Results .

t Sliding Plant Displacement Cakulated Stress Condition Operating +

Condition Allowable Stress Sliding only at Normal .090"* 33 %

lower Operation wedge / lower  ;

spring interface  :;

LOFWH .132" 43 %

Operation Sliding at both Normal .182" 60 %

interfaces Operation LOFWH .224" 73 %

Operation

• '1he stress results reported are for a 0.100" displacement, whichis conservative. -

P i

EEll Stress Corrosion Evaluation i

t e Stress Rule Index Methodology utilized. -

! e For probable sliding case, stress corrosion will not occur for remaining t life of plant. .

e For worst case sliding, stress corrosion will not occur in the next operating cycle.

p

EEll Comparison ofLatch Designs

~

e The improved latch design stresses are 8 to 12 times lower than the original design

- membrane + bending ratio = 8.6 i

- membrane + bending + peak ratio = 12.8 .

o No permanent deformation in new latch l

design even under worst case conditions i

EElll Core Shroud Vertical Weld Inspection and Evaluation G. B. Inch j

~

INMPC Engineering n

t EElll Expanded Shroud Inspection Goals l

e Baseline shroud vertical and horizontal welds.

L e Obtain comparison between vertical and horizontal IGSCC cracking patterns

- Horizontal cracking at the H4 location consistent with other BWR-2 cracking and NMP1 H4 analysis predictions.

e Obtain H8 UT re-inspection data

- Re-inspection of H8 confirms no significantIGSCC cracking which could impact core shroud support function. -

' i Structural capability assured based on irspection

- Sample inspection of H9 with EVT shows no indications.

zo

EER Expanded Shroud Inspection Goals e Determine actual core shroud structural margin presentin horizontal welds. .

1 e The tie rod installation assumed horizontal

~

i welds not present. -

- Inspection shows significant margin.

o Based on structural capability of H4 and H5 establish the margins associated with vertical weld crackmg

EEll Additional Assessment Initiatives j e Obtain comprehensive material condition assessment using all available inspection tools (enhanced visual examination / ultrasonic volumetric examination).

e Assessment of the shroud vertical cracking performed by severalindependentIGSCC experts to compare cracking to other industry shroud cracking.

e Advanced computer modeling of the fabrication process to better define the most probable residual stress state which could explain OD dominant cracking.

e Obtain metallurgical sampling of vertical welds (two boat samples).

i

EEE Additional Assessment

~

Initiatives ununuem o More refined analysis of the vertical weld l crackingis expected to increase the l

inspection interval to one operating cycle.

o Re-inspection of vertical weld cracking most probably will show deeper cracking is arrested.

l e The industry has never seen through wall cracking. -

l l

g 1

EEE Basisfor Vertical Weld Analysis Loads e Welding residual stresses and the welding process fitup related induced stress in the weld create built in stresses which drive IGSCC cracking. -

e Pressure stress dominates fracture.

e The pressure stresses are defined by j reactor internal pressure difference calculations. j

~

EEll Root Cause ofCracking

~

e Verticalweld crackingis IGSCC.

e Potential for irradiation enhanced material sensitization in the HAZ, which, coupled with enhanced stress relaxation, can affect. crack growth. ,

e All findings show that IGSCC consistent with basis for BWRVIP established and NRC approved methods for analyzing core shroud cracking and establishing re-inspection requirements.

e Conclusion is that the BWRVIP core shroud 1 inspection and evaluation guidance applies to the y NMP1 vertical weld cracking.

"::== !

Ni

--______--__-_____-___________-___--______-________)

EEll ThermalHydraulics Assessment i

~

e Potentialverticalweld through-wallcracking could result in i negligible) diverted core flow.

e Anticipated transients (potentially increased carryunder has favorable effect on thermal l

limits). -

i eLOCA

- Potential leakage has no impact on core spray flow. -

t l

- Core cooling is assured through core spray.

l' k

I EElll Vertical Weld V9 and V10 Crack Growth Margins e Uncertainty associated with variables like stress intensity, neutron fluence are 4

basis for bounding crack growth rates of Se-5 inches / hour.

e Detailed crack growth analyses which account for all the above variables ,

define V9 and V10 crack site specific growth rates which demonstrate that Se-5 inches / hour is conservative.

33 j

4 EElli Evaluation o Cracking in Vertical Welds i i

\

i i t

i i t

l Dr. R. Smith

Altran

, e 4

l N i i

l

8 EEll .

Purpose 1

e Careful examination of cracking patterns and other information.

e Develop a plausible explanation of l what happened. .

l l

l.

l l

_=_ __-__

EElll f e

l Cracking Patterns Provide i

Evidence o the Reasons or Cracking i

i

\ EEll Observations @ V9 and V10 l t

. e Cracking characteristics typical for ~

shroud '

i e Cracking predominantly on OD e Cracking remains axial predominantly in the weld HAZ i e Cracking density favors one plate e Cracking deeper at top /more shallow towards bottom j i

5/ j

EEll Considerations o Parameters for IGSCC are wellknown J o Welding and fabrication practices alter residua 1 stresses e

e

~ '

EElll Residual Stress Sources a

e Welding i

e Surface metalworking e Fabrication and fitup i

EEll! Welding Residual Stresses e Extensively studied e Predicted by FEM .

~

e Confirmed by measurements .

O

EElll Through ' Wall Stress Pattern e Depends on heat input and weld sequence e High OD stress predicted for low heat input welds e Fitup shaping adjustments (diameter squeeze) e Combination produces a stress pattern ,

thatis consistent with the cracking observations t

41

=-_ _=-_ _ _ _

EEll Time Dependent Irradiation Effects e Increase electrochemical potential (ECP) e Enhances material susceptibility .

e Reduces residual ~ stresses by a creep mechanism l

~

h

EEll Core Flux Pattern Suggests a Possible Reasonfor Crack Depth -

Dfferences Top to Bottom

~

d5

EEII Conclusion -

l l e Shroud fabrication practices provide a i plausible explanation of vertical weld i cracking observations ~

e Time dependent irradiation effects can help explain crack depth profiles top to bottom a ,

. .a - .

_j

EElll Analysis ofShroud Weld V9 and Weld V10 Cracking l

l i

Dr. M. P.' Manahan, Sr.

l MPM Technologies,Inc.

l

]

6 l I

ERII Introduction The analyses have focused on:

e Contributing to the determination of the root cause of cracking at V9 and V10 from a stress field, crack growth, and cracking m.echanism perspective

< o Explaining why cracking along V9 and V10 is l predominantly OD (this behavior would not be expected from examination of double V-groove weld I stress fields)

! e Providing a realistic estimate of the allowable future operating time based on a conservative, but accurate l model l

do

=

EElll Qualitative Characterization o

~

V9 and V10 Cracking e Tlie cracking is almost exclusively on the OD side of the weld within the HAZ e Most of the cracks run longer in the axial direction and am connected to a short horizontalcrack segment e The axial cracks (driven by hoop stmss) am deepest near the H4 weld where the fast neutron flux is highest e Both the left and right sides of V10 am cracked e The left side of V9 is cracked with little cracking on the right side

.e The depth of cracking cormlates with fast (E > 1 MeV) neutron fluence

Conclusion:

The evidence suggests that the cracking mechanism is l irradiation enhanced - intergranular stress corrosion cracking (IE-l- IGSCC).

l l

l l

b)

~

EEll Cause ofPredominant OD Cracking at V9/V10 Nretrospective analysis of the cracking observed has been performed to obtain an in-depth understanding of the fabrication processes which contributed to the observed cracking behavior. The approach involved the followmg:

o weldingsimulations(WELD 3) e shoploadsimulations(ALT 3D) e weld repair. simulations (ALT 3D)

Conclusion:

It can be demonstrated that a combination oflow heat input and a diametral squeeze (dead weight and/or '

jacking) produce a stress field which would explain the cracking behavior.

b

EEll StructuralMargin Assessment o V9 or Continued Operation Model Description ,

e Credit was not taken for crack armst e LEFM, EPFM, and limit load calculations wem performed e Crack gmwth rates wem calculated using GE fluence dependent model e Initial crack depths which bound the measumd depths wem used e Variation of fluence through the wall was modeled using plant-specific fluxes -

e K vs. a data were calculated using finite element methods for a representative stress field o Cracks initiate under axial stmss, grow 0.3 to 0.5 inches deep, and then grow under hoop stmss e Cases with, and without, credit for integrity of the H4 and H5 welds wem analyzed

~

EEll Structural Margin Assessment of V9for Continued Operation Conclusions e The bounding 5 x 10-5 in/hr crack growth rate is conservative e The analyses show that safe operation can be ensured for at least an additional 2 years of hot operation .

EER Structural Evaluation of the Shroud Vertical WeldIndications Dr. S. Ranganath i

1 GENE 9

.~

, 5. '.-

y

EEllImpact o Vertical Weld Cracking on the Tie Rod Func~ tion l e Tie rod repair design basis does not require vertical welds to be crack free t

- Any flaws should be within the allowable size

- No credit for horizontalwelds l e Structural analysis of NMP1 vertical weld indications based on i i

separate stand-alone cylindrical model 1

- Acceptability demonstrated assuming horizontal welds to be fully cracked ~

- No adverse effect on the tie rod repair function Vertical Weld Cracking does not lead to t Violation of Tie Rod Repair Design Basis u ;

EElll Effect ofTie Rod Loading on the Vertical Weld Cracking e Xnalysis performed to determined whether tie rod loading.can cause stresses which could cause crack growth in the vertical welds

- 3D finite elementmodeling e Results confirm that the stresses due to tie rod loading are negligibly small l

t Tie RodRepair has noImpact on Vertical Weld Cracking

'i j a\!

EEll Structural Evaluation ,

i e Two types of evaluations performed; with conunon features: .

- Fracture and Limit Load considered i

- ASME Code safety factors included.

e Screening Criteria Approach

- Assumes through wallcracking

- Analysis for 16,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> e Detailed Analysis using UT Depth Data

- Creditfor uncrackedligaments

- Maximum period of operation based on allowable K i

' A

EElll Crack Growth Rate Assessment t

e Several predictive models evaluated

- BWRVIPcorrelation

- GE PLEDGE model i

- SKI crack growth model

- NRC crack growth rates

! e NRC accepted growth rate of 5 x 108 in/hr is bounding .

- Irradiation effects are bounded by the NRC curve

~

- BWR shroud field cracking data confirms that actual growth rates are lower; 2 x 108in/hr bounds data j

- NMP1 water chemistry during the last cycle has been excellent (less than 0.1 micro-siemen/cm) i i

NMP1 Crack Growth Rates Expected to be Much Less than the Bounding Crack Growth Rate used in the Analysis

1  :

EEll Screening Criteria Analysis Technical Approach e

'Ciracks assumed through wallin all uninspected regions e

Where indications found (UT/VT), through wall flaw assumed e LEFM and Limit Load analysis e ASME Code safety factors

- 3.0 Normal and upset;1.5 Emergency and faulted e Uncertainty factors for UT and VT included e Evaluations performed for 16,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br />

- Crack growth rate of 5 x 104in/hr

- Indications acceptable if finallength less than allowable value All Welds except V4, V9 and V10 shown acceptable by the ScreeningCriteria Analysis

EElll Detailed Evaluation of V9, V10, and V4 Welds e Detailed evaluations for the V9, V10, and V4 indications

- Credit for remaining ligament after crack growth of 5 x 104 in/hr and inspection uncertainty factors 1

- LEFM and limit load analysis with ASME code safety factors

- Covers normal / upset and accident conditions

- Acceptable period for continued operation determined e Analysis shows that continued operation is justified for at least10,600 hours0.00694 days <br />0.167 hours <br />9.920635e-4 weeks <br />2.283e-4 months <br /> 4

i EElll Structural Analysis Conclusions t

i i

! e tie rod repair design basis maintained even with the observed verticalweld cracking l - No credit taken for horizontal weld integrity e Structural margin demonstrated for continued operation for atleast10,600 hours0.00694 days <br />0.167 hours <br />9.920635e-4 weeks <br />2.283e-4 months <br />

- ASME Code safety factors maintained t

- Bounding crack growth rates used

- Conservative flaw sizing assumed Required Structural Margins Maintained t

i t

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Showing the Effect of Diametral Squeen on the Stresses l

HAZ Surface Stress Summary (Baseline Weld Heat)

Hoop Stress (ksi) Axial Stress (ksi)

[ ID OD ID OD '

as welded 19.8 -3.7 39.9 42.6 welded + operating 1E.6 -2.8 29.1 32.7 weld + 4" squeeze + op 9.0 -1.9 19.5 25.5 HAZ Surface Stress Summary (0.75 Baseline Heat Weld)

Hoop Stress (ksi) Axial Stress (ksi)

ID OD ID OD as welded 29.4 0.2 37.1 43.8 welded + operating 23.6 0.0 26.0 33.6 weld + 2" squeeze + op 17.2 0.7 20.2 26.4 weld + 4" squeeze + op 8.4 0.4 13.4 26.0 weld + 6" squeeze + op -2.6 0.7 8.1 14.0 HAZ Surface Stress Summary (0.5 Baseline Heat Weld)

Hoop Stress (ksi)

Axial Stress (ksi)

ID OD- ID OD as welded 38.8 11.0 27.7 50.3 welded + operating 28.4 8.5 19.6 38.8 weld + 2" squeeze + op 15.3 7.1 13.8 31.7 weld + 4" squeeze + op 6.2 5.4 10.4 28.7 weld + 6" squeeze + op -5.0 5.2 7.0 19.4

Weld V9 OD Fluence and Crack Depth Profiles (left side of V9) ,

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- ;- as MAR 31 1997

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PREP 7 El.EMENTS TYPE NUM

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• DIST-144.627

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Figures, tables, and Appendix C from General Electric Nuclear Energy Document SE-NE-B13-01869-043, Revision 0.

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s Summary of Reesat Skrond Vertical Wald Inspeedons (RFO 14) weld Weld Inspeciosa j Strood Esas Type Fisw Langth langth Coverage

• 3DOD M -

l V.3 31.25 15" LsA i .

OD UT 3.5" ID, Right HAZ 15' *W 0.8" OD,Itight HAZ V4 31.25 22"!** OD UT 22"ID14A MAZ, 11* Right l . IJ'ID Right !!AZ 1

V $ rtns Not '=M NA NA NA V 6 ring Not +' ==4 8 NA NA NA V.7 18J 9" LaA OD UT No]ndsdiens It

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r vm over 90% op i

OD right HAZ l Minorerasidas en ODisAside

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80" and onID both sides -

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Twoadner8sws anID,Right

{ V 10 90.12 HAZ 100 % ID and i EC" ! C. ams on OD, Right HAZ' i

OD Considag onID,LaA and Right 84" MAZ

}

OD -

UT Fisws detected on > 80% on j OD,Right HAZ Fisws desacted on > 10% on V.!! OD,14A HAZ 63.5 100% OD ID and EVT.! No w-a 50%!D OD .

V 12 63.5 100% OD IDand EVT.) 4" OD, Right HAZ ~

$0%ID OD V.15 22.13 1I" L4A OD -

UT 6" . ID, LaR HAZ -

11" Right V.16 2.2"ID, Right HAZ 22.13 100% OD , EVT.1 .75" OD, LsA HAZ 10.5" 14A OD ~ UT 20" Right

• Sa ID tmA HAZ 4'ID Right HAZ 3'IDLeA HAZ 9em right side exam hspection coverage assy be less iban indicased, but has bee aisenant hagih. .

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Appendix C ShroudInspection Summary 0

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' The following is a weld by weld namnary daattia the ach of 8Wons and results of the stuoud examinations perfonned to date.

WaldV3 Perfonned nitrasonic ====landon of approximately 15 inches of each side of the weld from the shroud OD surface. Approximately 1.5" of flaw was detected on the ID surface and 0.g" of flaw on the OD surface. .

Wald V-4 Perfonned ultrasonic ev=iandon ofappra 8-* ly 11" of the lea HAZ and 22" of theiright HAZ.

- ID flaws were detected over the entire ausmined length of the lea HAZ and 1.5" of flaw was deteceed on theID ofthe right HAZ.

Wald V-7 Performed ultrasonic ====ination of approximately 9" of the lea HAZ and 11" of the right HAZ.

No flews were detected during the examination. .

Wald V 8 Perfonned ultrasonic -v=iandon'of approximately 5.5" of the lea HAZ and 9.5" of the right HAZ. No flaws were detected during the ===iantion.

Wald V-9 Performed ultrasonic ev==landon from the shroud OD surface for approximately the entire len of both the lea and right HAZ: as well as EVT Aom both the ID and the OD. Visual cracking was detected over greater than 90% of the right HAZ on the OD and minimal cracking was detected . on the ID in both the lea an right HAZ . Minor cracking was also detected on the OD in the lea HAZ. .

The cracks detected visually on the shroud ID surface were found to be predominantly tran:, vers to the weld whereas the cracking detected visually on the shroud OD surface was anostly parall -

the weld with components that branched transverse to abe ' weld. Ultrasonic ===inadons of

=== ati=11y the entire length of the weld was performed Dom the shroud OD surface and detected numerous flaws over the length of the lea HAZ =anating froen the shroud OD surface. Two amall fisws on the ID surface were detected in abe right HAZ.

Wald V-10 -

Perfonned ultrasonic ev=instion tom the shroud OD surface for approximately the entire length ofboth the lea and right HAZs as well as EVT Dom both the ID and the OD. Flaws were detected - -

on greater than 80% of the right HAZ on the OD surface and greater than 50% of the lea HAZ sevealed flaws on the OD surface. The EVT ev==iantion revealed cracking in the lea and right

)

,-v .

j ow&stwsaws,an.o HAZ: on the OD surface for snost of the length of the weld and' on the ID in both the lea and right HAZs. The cracks detected visually on the shroud ID surface were found to be v.d=iamatly mansverse to the weld whersas the cracking detected visually on the shroud OD surface was mostly parallel to the weld with wm = = that branched transverse to the weld. .

WMV 11 ,

- EVT ==iantons were performed on the accessible weld length tom both the ID and the OD of L both the lea and right HAZs. No cracking was detected during the ====iamion.

Wald V 12 4

EVT ==minetons were performed on the accessible weld length from both the ID and the OD of both the lea and right HAZs. Ore 6" crack was detected on the length OD surface in the right HAZ. No other cracking was detected.

[

Wald V;15 Ultrasonic examination was perfonned from the abroud OD surface on approximately 11 inches of both the lea and right HAZs. One 6" flaw was detected in the lea HAZ on the ID surface and several ID flaws totaling 2.2" in total length was detected on the ID in the right HAZ. No flaw detected in either HAZ was greater than 10% through wall.

g Wald V 16 Ultrasonic namination was performed from the shroud 00 surface of approxhnstely 10.5" ofleA

. HAZ. Two flaws were detected on the ID surface. One flaw was 5" in length,10% through wall.

The other ID flaw ~in the lea HAZ was detected from the scan on the right HAZ and was 3" long f and 30% through wall. Approximately 22 inches of the right NAZ was namine from the shroud j OD surface. One flaw was detected on the ID which measured 4" in length and 21% through wall.

i of both HAZs 6om the abroud OD surface sevealed one crack in the leh An EVT ===taat on

. HAZ. > ,

Raeent Inspection Rosalts for Shroud Bertaostal Welds ,

In addition to the shroud vertical weld 8Nons, the horizooal welds H 2, H-4, H 5, H-6a, H.

6b, and H 7 were also inspecte( for analytical purposes, to evaluate the overall integrity of the shroud using assumptions . of worst case cre: king of the

~

vertical welds.

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GE.NMIS.Ola69.au. Rev.0

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Wald H.2 Ultrasonic namination was performed 6am the abroud OD swface of approximately 24 inches of sin upper HAZ adjacent to weld V.4. Ary,--

• m=1y 7 inches ofintermittent flaws were detected on the, OD swface, with the deepest area having a through wall depth of.22 inches.

W ald B.4 .

Ukrasonic examinstion 6am the shroud OD seface was performed on approximately 60% of the lower HAZ. ID and/or OD flaws were detected t.i Iti ily throughout the examination area.

Some ID flaws were desacted in the upper HAZ. Arr==J ately 32 inches of the upper HAZ was

. ahrssonically amminad 3 inches ofshallow OD flaws were detected in the upper HAZ and one 6 inch long ID flaw was detected with the maximan through wall depth of.23 inches. . An EVT examination of the OD was performed of over 70% of the upper and lower HAZs. Cracks were detected in both the upper and lower HAZs.

W ald B.5 i

Uhrasonic ammination 6om the shroud OD surface was performed on yy.-- *- "=ly 30% of the upper and lower HAZs. OD and ID flaws were detected in the upper HAZ only. No flaws were detected in the lower HAZ. EVT ofapproximately 60% of the shroud OD surface revealed cracks intermittentjy in both the upper and lower HAZs. Most of the fisws detected visually on the OD surface were oriented perpendicular to the weld. No flaws were detected in the upper HAZ at the intersections ofwelds V9 orV10. .

Wald B4A -

Ultrasonic namination was performed on boIh t the upper and lower HAZs of approximately 30%

of the circumference from the abroud OD surface. Flaws were detected on the OD surface of the -

lower HAZ only. No flaws were detected in the upper HAZ or on the ID of either HAZ.

Wald B4B ,

Uhrasonic examination was performed on both the upper and lower HAZs of.yy.- ' = =ly 30%

of the circumference Dom the shroud OD seface. Fisws were detected on the OD surface of the upper HAZ only. No flaws were detected in the lower HAZ or on the ID of either HAZ.

W ald B .7 ,

Ukrasonic ==alaation was performed for the shroud OD surface on the upper HAZ an I appra t-ly 30% of the circumference. No flaws were detected dwing the ammiantion. I W ald H.8 -

Uhrssonic namination was performed for the shroud OD surface on the lower HAZ on approximately 30% of the circumference. A flaw which was identified by UT during a prior

. c.4 -

- - - - - - - - - - - - - - - - - - - ~ - - - - - - - - - - -

,, , CE.NE.3134186s40. Rev.0 essage was located as well as one additional flaw in the same ersa. His flaw was ultrasonically

, shed to be oflesser through wall depth than in RFO!3. A review'of the previous data indicates abat the previous sizing performed was very conservative. An EVT was performed on approximately 30% of the circunference than the abroud OD surface. Of the five small cracks visually detected during RFOl3 only 1 was visible during this inspection. De inspection in the area of the other four was hampered by the placement of a Tie Rod support which r.. aed a good EVTinspection. Cracks were visually detected in three new locations in the upper HAZ. The largest of these cracks @".12") is located r '-:=wly in the ring segment Upper HAZ and runs into the weld toe and back into the ring segment. .

W ald B 9 An EVT -idon was performed in one area 26 inches long. No indications were acted during the examination.

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Table 52 ABowable Fisw Shes for the Nine MDe Paint Unit 1 .

- Ehrend VarticalWalds (1) Q) Q) (4) {

Stialaus

5) (6)

Wald ten.IJssawst  !

A5ewable Throegt usu seqstred Avansble WaldID 1magth, incending ersak , Egalvalsat

, ersaklength,la. Ngament,is, As .

greeth (two Elsersaked pears)and' IJgament 12FM IJuikimed

• 328Pession 2degth,la.  :

Useertainty,th V.3, V 4 J1.23 (Note 1)  !

29.97 L28 343

%7, W4 7J (V.3) * '

3840 1)J 87.74 Note 2(%4) .

0.72 3.07 ,

V.9, 9.0 (V.7) 90.12 73.40 5.6 (%3)

V.10 46At 84.72

• ' 87.07 V.ll, ' Note 2(V.9) 4340 38.20 61.03 Note 2(W10)

% 12 JJO 9JO V.13, 31.73 (V.ll) 22.13 - Note 3 ,

' 89J3 2M 25.75 ( % 12)

% 16 4A1  !

Note 4 (V.13)  !

' 5.5 (%16) '

' Notes

1. Based os crack growth of t.6 in, and UTlaspection ascertain!

inch at each crack tip forlength sidag. - *'

2; Meets requirements based on ihrther evaluation reportalin

3. The anlaimas lignment for EVT inspection b narger so.see ascertainty to 2 x 1.2 is. in the visuallaspection. The'antertainty Anator ap

4. He agakalent length after subtreeting ersch growth and insp 1

, ascertainty and thus seesytable. b 2.g9 is.which k greater than the required ligassat of2!  !

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. 32

fy? J"L ACTl0%

D EDO Principal Correspondence Control f

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8 FROM: DUE: 05/16/97 EDO CONTROL: G970319

{

DOC DT: 04/20/97 Michtel J. Bragman FINAL REPLY:

!Stcto of New York (Albany)

' 1 TO:

k l

Chairman Jackson l

FOR SIGNATURE OF : ** GRN **

CRC NO: 97-0407 Office Director

',DESC: -

ROUTING:

CRACKED SHROUD AT NIAGARA MOHAWK'S NINE MILE ONE Callan k

NUCLEAR REACTOR (Michael Slee/ Sandra J. Weston)

Jordan j Thompson t Norry

! Blaha Burns fDATE: 05/02/97 Miller, RI ASSIGNED TO: CONTACT:

NRR Collins

'SPECIAL INSTRUCTIONS OR REMARKS

l CRR RECEIVED: MAY 2,1997 1RR ACTION: DRPE':VARGA

-NRR ROUTING: COLLINS

.MIRAGLIA ACTION IJMMERMAN l .:nARTIN DUE TO NRR D! RECTOR'S OFFICE y

W sc0ss0N.

l EQEl'V BY I 3 17 i i n

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..(- - - . - . - , . . - - . . _ . _ - - .. . ~ . . -_ .. -

• • i OFFICE OF THE SECRETARY 4

q

, CORRESPONDENCE CONTROL TICKET-l PAPER NUMBER: CRC-97-0407 LOGGING _DATE: Apr 30 97 1 i

ACTION OFFICE: EDO AUTHOR: MICHAEL J. BRAGMAN

, AFFILIATION: NEW YORK

] ADDRESSEE: CHAIRMAN JACKSON LETTER DATE: Apr 20 97 FILE CODE: IDR-5 NINE MILE POINT

SUBJECT:

NIAGARA MOHAWK'S NINE MILE ONE NUCLEAR REACTOR ACTION: Direct Reply DISTRIBUTION: CHAIRMAN ,

SPECIAL HANDLING: SECY TO ACK CONSTITUENT:

NOTES:

DATE DUE: May 16 97 SIGNATURE: . . DATE SI'GNED:

AFFILIATION:

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['a THE ASSEMBLY nSn'sy'rU".E EoY13212

} (315)452-1044 STATE OF NEW YORK O Room 926

% ,,jd> ALBANY yds,**

y s, 7y'"ft$2 (518)455 4567 MICHAEL J. BRAGMAN MAJORITY LEADER O Room 436 Capitol Building Albany New York 12224 (518)4554 225 April 20, 1997 shirley A. Jackson Chairwoman United States Nuclear .

Regulatory Commission 11555 Rockville Pike Rockville, Maryland 20852-2738

Dear Shirley:

I have enclosed copies of two recent letters that I have received from Michael Slee, 21 Lower Road, Constantia, New York 13044 and Sandra J. Weston, ESDW AC for Environmental Concerns, Inc., 819 West Third Street South, Fulton, New York 13069-3200. These letters, relative to concerns regarding the cracked shroud at Niagara Mohawk's Nine Mile On,e nuclear reactor, are self-explanatory.

Would you please review this matter and provide me with your comments and recommendations. Subsequent to receiving your response, I will be able to determine what further action on my part is necessary and appropriate.

Thank you for your anticipated cooperation.

Best wish e Very rul yours, U

Mi ael J. Bragman Majority Leader MJB/ key Enclosures cc: Michael Slee Sandra J. Weston

h. .

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I i

From

Sandra J. Weston Date: 'Apri! 9,1997 l To: Honorable Michael Bragman Time:  !

4:10 PM i Company: Assembly Majority Leader FAX #: ~(315) 452 0872 Message:

Residents of Oswego County are very concerned about the bracked Core l i Shroud at Nine Mile Point Unit i lt is our belief that the reactor should not be l restarted without total replacement of the core shroud.

l

)

i We are not only concerned about the nealth and safety of edunty residents but l a valuable end irreplaceab:e natura! resource. Lake Ontario, which adds an economic factor'to consider. -

l We wou!d like to suggest that exper :- riot affiliated with Niag' ara Mohawk, nor  !

company employees, inspect and eva'usite the plant.  !

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VOICE. (313) $92 9731 FAX-(3 t 502 0731 EMail $Westog724@eol.com 1

l E/2*d 2280-2SP 00 FALSOd8 9T:80 46, 10 AOW

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On April 171997,' the NRC will make a decision on allowing

' Niagara Mowhawk Power Authority to re start the reactor at '

Nine Mile One in the town of Scriba NY.

Niagara Mowhawk maintains, that cracks in a shroud around the reactor, will not get any worse for at least [2] years, and wants to re start it with out making any kind of repairs.

The Nuclear Information and Resource Group, maintain, i that the shroud must be replaced be fore the reactor is restarted.

As a resident of Oswego County ware the reactor is located, I find it very distressing that the main meeting with Ni Mo is to be held in Maryland? Why there?

Why don't they want it held locally, so the residents can voice, their opinions and concerns?

Its clear that they ~a re trying to do a restart on a dangerous. .

unit and at the sam 6 time, white wash itin the eys of the public.

They are looking at the dollar side of this, instead of the impact of what may happen if this animal blows and poisons New York State and who knows ware else.

I ask you to please take a stand with us in insisting that the repairs be done safely and properly.This is your state also Thank You sincerely (Ylichae S et 21 Lower Road.

(on5fcwh% MV 13049 l

.pSEQi '

/W.mwr 5 APR 141997 '

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