ML17059C082
| ML17059C082 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 06/10/1998 |
| From: | Hood D NRC (Affiliation Not Assigned) |
| To: | NRC (Affiliation Not Assigned) |
| Shared Package | |
| ML17059C083 | List: |
| References | |
| NUDOCS 9806160119 | |
| Download: ML17059C082 (16) | |
Text
~
~
June 10, 1998 1
LICENSEE: Niagara Mohawk Power Corporation FACILITY:
Nine Mile Point Nuclear Station, Unit No. 2
SUBJECT:
SUMMARIES OF RESULTS OF SHROUD WELD INSPECTIONS AND ANALYTICALAPPROACH On June 9 and 10, 1998, I received the enclosed facsimile and electronic mail transmissions from Mr. Steven Leonard of Niagara Mohawk Power Corporation providing summaries of the latest inspection results regarding the horizontal and vertical welds of the core shroud at Nine Mile Point Nuclear Station, Unit No. 2 and plans for analyses.
Apart from these summaries, and in accordance with the Boiling Water Reactor Vessel and Internals Project's (BWRVIP's) "BWR Core Shroud Inspection and Flaw Evaluation Guidelines" (BWRVIP-01), Revision 2, the licensee willsubmit to the NRC within 30 days, a report on the final inspection results of all inspected welds (including vertical welds V12 through V17 which were not required by the BWRVIP inspection guidelines) and the analytical analyses of horizontal welds H4 and H5. Enclosure 1
discusses the licensee's analytical approach to determine the structural integrity of welds H4 and H5 based upon linear elastic fracture mechanics (LEFM) analyses.
Darl S. Hood, Senior Project Manager Project Directorate I-1
>,'ivision,of Reactor Projects - I/II
" Office of Nuclear Reactor Regulation Docket No. 50-410 f
Enclosures:
- 1. Fax dated June 9, 1998 (2 pages)
- 2. Electronic mail dated June 10, 1998 (2 pages)
~ ',
cc w/encls: See next page f
DISTRIBUTION: See next page.
DOCUMENT NAME:G:)NMP2(SHROUD.FAX To receive a copy of this document,'indicate in,the box: "C" = Copy without attachment/enclosure
. "E" = Copy with attachment/enclosure "N" = No co I
OFFICE PM:PDI-1 HAHE DHood E
I.A:PDI-1 D:PDI-1.
SLItII S8a wa DATE 6/
/98 6/I
/98 6/
/98 Official Record Copy 9806i60iiq 9806i0 PDR ADQCK 050004i0 P
~ RK CRM %@V.
DISTRIBUTION:
HARD COPY. (with enclosures)
PUBLIC PDI-1 Reading OGC ACRS J. Zwolinski (A)
S. Bajwa D. Hood S. Little L. Doerflein, Rl G. Lainas E. Sullivan R. Hermann W. Koo
DISTRIBUTION:
HARD COPY (with enciosures)
~
Docket File PUBLIC PDI-1 Reading OGC ACRS J. Zwolinski (A)
S. Bajwa D. Hood S. Little L. Doerflein, RI G. Lainas E. Sullivan R. Hermann W. Koo
June 10, 1998 LICENSEE: Niagara Mohawk Power Corporation FACILITY:
Nine Mile Point Nuclear Station, Unit No. 2
SUBJECT:
SUMMARIES OF RESULTS OF SHROUD WELD INSPECTIONS AND ANALYTICALAPPROACH On June 9 and 10, 1998, I received the enclosed facsimile and electronic mail transmissions from Mr. Steven Leonard of Niagara Mohawk Power Corporation providing summaries of the latest inspection results regarding the horizontal and vertical welds of the core shroud at Nine Mile Point Nuclear Station, Unit No. 2 and plans for analyses.
Apart from these summaries, and in accordance with the Boiling Water Reactor Vessel and Internals Project's (BWRVIP's) "BWR
'Core Shroud Inspection and Flaw Evaluation Guidelines" (BWRVIP-01), Revision 2, the licensee willsubmit to the NRC within 30 days, a report on the final inspection results of all inspected welds (including vertical welds V12 through V17 which were not required by the BWRVIP inspection guidelines) and the analytical analyses of horizontal welds H4 and H5. Enclosure 1
discusses the licensee's analytical approach to determine the structural integrity of welds H4 and H5 based upon linear elastic fracture mechanics (LEFM) analyses.
Darl S. Hood, Senior Project Manager Project Directorate l-1 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Docket No. 50-410
Enclosures:
- 1. Fax dated June 9, 1998 (2 pages)
- 2. Electronic mail dated June 10, 1998 (2 pages) cc w/encls: See next page DISTRIBUTION: See next page DOCUMENT NAME:G:>NMP2(SHROUD.FAX To receive a copy of this document, indicate in the box: "C" = Copy without attachment/enclosure "E" = Copy with attachment/enclosure "N"= No co OFFICE PM:PDi-1 E
LA:PDi-1 D:PD1.1 MAME DHood SLittl SBa wa DATE 6/
/98 6/I
/98 6/
/98 Official Record Copy
p'8 R500
~o Cy Cl0 I
0
++*++
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 June 10, 1998 LICENSEE:
Niagara Mohawk Power Corporation FACILITY:
Nine Mile Point Nuclear Station, Unit No. 2
SUBJECT:
SUMMARIES OF RESULTS OF SHROUD WELD INSPECTIONS AND ANALYTICALAPPROACH On June 9 and 10, 1998, I received the enclosed facsimile and electronic mail transmissions from Mr. Steven Leonard of Niagara Mohawk Power Corporation providing summaries of the latest inspection results regarding the horizontal and vertical welds of the core shroud at Nine Mile Point Nuclear Station, Unit No. 2 and plans for analyses.
Apart from these summaries, and in accordance with the Boiling Water Reactor Vessel and Internals Project's (BWRVIP's) "BWR Core Shroud Inspection and Flaw. Evaluation Guidelines" (BWRVIP-01), Revision 2, the licensee willsubmit to the NRC within 30 days, a report on the final inspection results of all inspected welds (including vertical welds V12 through V17 which were not required by the BWRVIP inspection guidelines) and the analytical analyses of horizontal welds H4 and H5. Enclosure 1
discusses the licensee's analytical approach to determine the structural integrity of welds H4 and H5 based upon linear elastic fracture mechanics (LEFM) analyses.
Docket No. 50-410 Darl S. Hood, Senior Project Manager Project Directorate I-1 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation
Enclosures:
- 1. Fax dated June 9, 1998 (2 pages)
- 2. Electronic mail dated June 10, 1998 (2 pages) cc w/encls:
See next page.
Niagara Mohawk Power Corporation co:
Mr. John H. Mueller Chief Nuclear Officer Niagara Mohawk Power Corporation Nine Mile Point Nuclear Station Operations Building, Second Floor P.O. Box 63 Lycoming, NY 13093 Regional Administrator, Region I U. S. Nuclear Regulatory Commission 475 Ailendale Road King of Prussia, PA 19406 Mr. Jim Rettberg NY State Electric 8 Gas Corporation Corporate Drive Kirkwood Industrial Park P.O. Box 5224 Binghamton, NY 13902-5224 Supervisor Town of Scriba Route 8, Box 382 Oswego, NY 13126 Mr. Richard Goldsmith Syracuse University College of Law E.I. White Hall Campus
- Syracuse, NY 12223 Mr. John V. Vinquist, MATS Inc.
P.O. Box 63 Lycoming, NY 13093 Nine Mile Point Nuclear Station Unit 2 Resident Inspector Nine Mile Point Nuclear Station P.O. Box 126 Lycoming, NY 13093 Charles Donaldson, Esquire Assistant Attorney General New York Department of Law 120 Broadway New York, NY 10271 Mr. Timothy S. Carey Chair and Executive Director State Consumer Protection Board 5 Empire State Plaza, Suite 2101 Albany, NY 12223 Mr. F. William Valentino, President New York State Energy, Research, and Development Authority Corporate Plaza West 286 Washington Avenue Extension Albany, NY 12203-6399 Mark J. Wetterhahn, Esquire Winston 8 Strawn 1400 L Street, NW.
Washington, DC 20005-3502 Gary D. Wilson, Esquire Niagara Mohawk Power Corporation 300 Erie Boulevard West
- Syracuse, NY 13202
f
,IUN-09-98 TOE 08:69 Atf HSING FAX NO, 53491400 V NIAGARA Ld MOHAWK P.
01 NINE MILEPOINT NUCLEAR STATION P.O. BOX 63, LYGOMING,NEW YORK l3093 NINE MILE POINT UNIT 2 EEU2Ml:
FAX TELEPHONE NUMBER:
{315l 349-1400 NAME: ~WEE/IK.
4RS Ai DEPARTMENT:
LICENSING/ENVIRONMENTAL TELEPHONE NUMBER:
O'0 f Q(5 -2..to TOTAL NUMBER OF PAGES FAXED {INCLUDINGCOVER LETTER):~
DATE:
~ + ~+ TiME:
O '
MESSAGE:
(C~n g Enc1osure 1
0
)
~
L I
. JUN-09-98 TUE 08'59 N L
ING FN NO.
491400 P.
02 NMPC has almost completed the inspection ofthe Unit 2 core shroud welds. Below is a table providing a summaiy ofthe inspection findings to date and a description ofNMPC's analytical approach which w'alt be used to demonstrate the structural integrity ofthe welds with significant flaws, Consistent withthe BWRV1P guidelines, NMPC willsubmit the finalinspection results and the results ofthe H4 and H5 weld analyses within30 days ofthe end ofthe current refueling outage, forNRC approval.
n i
Inspection ofvertical welds is underway.
IIorizontal weld inspection results as of.6/7/98.
lVeld No.
H7 H8
% of%eld Length Examined 56.03 56.03
, 70.58 77.14 79.94 50.67 79.31 79.89
% ofExamined
'ength Flawed 4A2 3.01 2.13 71.45 52.71 40.85 8.10 Max. Depth ofFlaw (inches) 0.5 0.4 0.33 0.65 0,65 0.6 0.35 The analysis ofthe structural integrity ofthe horizontal weld H4 and HS welds is performed consistent with the requirements identified in the SWRVF-01 flaw evaluation and analysis guidelines.
The cracking on these weids exists over a signiQcant pcrcentagc ofthe circumference such that the simplified Lmin uncracked ligament analysis was not possible.
Since these welds require LCManalysis, thc limitingcondition is created by the assumption that regions which could not be inspected are through wall cracked.
The analyses which are required forH4 and HS qualify as detailed analyses wherein the methods wliichare typically discussed and applied to establish an Lmin are not sufficient. The detailed analyses performed are consistent with the guidance in BWRVIP-01 to the extent that the methods are
'iscussed.
The LEPM analyses ofthe part through wall 360 degree crack, combined with the through-wall assumption in regions which could not bc inspected, require the stress intensity factor calculated with thc DLLconputcr program to h'c.increased by a factor reflecting the presence of360 degree cracking, In addiYion,'finite element modeling ofthe 360 degree cracking has been performed which has validated the scaling factor applied to the DLLsolution. %hilc not explicitlyaddressed inB%RVIP-Ol, these analysis methods are consistent with other 8%R core shroud analyses of360 degree part through wall cracking, previously submitted and reviewed by thc NRC.
~(~~~ >~mw ~
c~
<qg, 4
0 t