ML20235Z131
| ML20235Z131 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 03/03/1989 |
| From: | Shelton D TOLEDO EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 1633, IEB-88-011, IEB-88-11, TAC-72128, NUDOCS 8903150175 | |
| Download: ML20235Z131 (3) | |
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s' TDLEDO Docket Number 50-346 EDISON
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License Number NPF-3 Serial Number 1633 DONALD C. SHELTON Vce Fvendent-Nuck 4ar (419] P49-P300 March 3, 1989
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United States Nuclear Regulatory Commission Document Control Desk Vashington, D. C.
20555 Subj ect: Toledo Edison's (TE) Initial Response to NRC Bulletin Number 88-11 (TAC Number 72128)
Gentlemen:
NRC Bulletin Number 88-11, " Pressurizer Surge Line Thermal Stratification",
(Log Number 1-1988 dated January 3,"1989), discusses a larger-than-expected surge line displacement observed at Trojan and Beaver Valley 2 caused by thermal stratification. The Bulletin also addresses concerns that the thermal stratification phenomenon (which includes thermal striping) could occur in all Pressurized Vater Reactor (PVR) surge lines and may invalidate the analyses supporting surge line integrity.
Paragraph 1.a of the Bulletin requests that a visual inspection be performed.
The paragraph specifically states:
" Licensee are requested to conduct a visual inspection (ASME,Section XI, VT-3) of the pressurizer surge line at the first available cold shutdown after receipt of this bulletin which exceeds seven days.
This inspection should determine any gross discernible distress or structural damage in the entire pressurizer surge line, including piping, pipe supports, pipe whip restraints, and anchor bolts."
Toledo Edison initially became aware of the NRC's concerns at a Babcock and Wilcox Owner's Group (BV0G) presentation in Rockville, Maryland on September 29, 1988, while Davis-Besse was in cold shutdown for the Fifth Refueling Outage (SRFO). A program was immediately developed and implemented
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to assess the condition of the surge line and verify that the unit could be safely returned to power. No gross discernible distress or structural damage to the surge line, including piping, pipe supports, pipe whip restraints and
$o anchor bolts was discovered as a result of implementing this program.
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purpose of this letter is to report the results of those actions taken to no date, actions which TE believes meet the full intent of the request in Paragraph 1.a of the Bulletin.
o> o n2 The program included:
- 1) a review of the surge line configuration and design D8 bases, 2) a visual inspection of the surge line and supports, 3) a review of snubber maintenance history and restraint clearance history, 4) a review of Inservice Inspection data, which included a number of key velds inspected
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'M THE TOLEDO EDlSCN COMPANY EDISON PLAZA 300 MAD! SON AVENUE TOLEDO, OHIO 43652
Docket Nu2bar 50-346 License Number NPF-3 Serial Number.1633 Page 2 during 5RF0, 5) a piping flexibility sensitivity study (using Huelheim-Kaerlich experience and the ANSYS thermal analysis code) to determine stress and moment data, 6) an evaluation of the surge line's remaining service life in terms of. fatigue usage, and 7) deflection measurements taken during the heatup prior to resuming power operation.
The visual inspection, conducted by TE Engineering personnel, detected no gross discernible distress or structural damage to the surge line, piping supports or restraints. The results of the program's other actions support the conclusion of the visual inspection:
that the integrity of the surge line, as it is affected by the thermal stratification phenomenon, is not presently in doubt.
Toledo Edison believes that the actions taken to date confirm the surge line, including piping, pipe supports, pipe whip restraints, and anchor bolts, to be free of any gross discernible distress or structural damage, and that these-actions meet the full intent of the actions requested in Paragraph 1.a of NRC Bulletin 88-11.
Toledo Edison is presently addressing the Bulletin's remaining requested actions, both independently and in conjunction with the B&V Ovner's Group. As discussed in a BV0G letter to Mr. Charles E. Rossi of the NRC's Division of Operational Events Assessment, dated February 24, 1989, which was submitted on behalf of all the B&V Owners including TE, it is the Owner's Group position that the impact of thermal striping upon surge line integrity cannot be adequately evaluated in the four months allotted by Paragraph 1.b of the Bulletin. Therefore, the Ovner's Group proposed an alternative schedule of October 31, 1989, for submission of the results of the thermal striping evaluation. The results of the bounding analysis requested in Paragraph 1.b (though probably not complete in the area of thermal striping) vill still be submitted in accordance with the requirements of the Bulletin.
Please contact Mr. R. V. Schrauder, Nuclear Licensing Manager, at (419) 249-2366 if there are any questions.
Very truly yours, x /
CFM/dlm-Enclosure P. M. Byron, DB-1 NRC Resident Inspector cci A. B. Davis, Regional Administrator, NRC Region III T. V. Vambach, DB-1 NRC Senior Project Manager
.sDockat'Nu2ber 50-346-
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Lic;nsa Nu;b2r NPF-3 Serial' Number 1633 Enclosure Page l
RESPONSE TO NRC BULLETIN 88-11,
" PRESSURIZER SURGE LINE THERMAL STRATIFICATION",
FOR DAVIS-BESSE NUCLEAR POWER STATION UNIT NO. 1 This letter is submitted in conformance with Atomic Energy Act'of 1954 Section 182a, !n response to NRC Sulletin 88-11 "Pressuri7er Surge Line Thermal Stratification".
Fort D. C. Shelton Vice President Nuclear By: T. J. My rs Technical Services Director Sworn and subscribed beft.re me this 3rd day of March, 1989.
Owx/
e9 tary Public, State of Ohio JUDITH HIRSCH Notary Public State Of ONo My Commission Excites June 30,1942
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