ML20059F879
| ML20059F879 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 11/01/1993 |
| From: | Denton R BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML19311B173 | List: |
| References | |
| NUDOCS 9311050139 | |
| Download: ML20059F879 (3) | |
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BALTIMORE I
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GAS AND
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ELECTRIC/,
1650 CALVERT CLIFFS PARKWAY. LUSBY, MARYLAND 20657-4702 6
ROBERT E. DcNTON j
VtCE PRE 5fDEseT NUCLEAR cNERGY (4to) 260-4455 f
November 1,1993 U. S. Nuclear Regulatory Commission Washington,DC 20555 i
A'ITENTION:
Document Control Desk i
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2: Docket Nos. 50-317 & 50-318 Request for Authorization to Utilize an Alternative Repair Technique for Pressurizer Inconel 600 Sleeve Nozzle i10 CFR 50.55afaV3 Vill j
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REFERENCES:
(a)
ASME Boiler and Pressure Code,Section XI,1983 Edition through Summer 1983 Addenda l
(b)
Ixtter from Mr. G. C. Creel (BG&E) to NRC Document Control Desk, dated September 20, 1989, Submittal of Basis for Determination Pursuant to 10 CFR 50.55a(a)(3)(i), Baltimore Gas and Electric Company (BG&E) hereby submits a request for authorization to utilize an alternative to the requirements set forth in 10 CFR 50.55a(g).
Paragraph 50.55a(a)(3)(i) allows the use of alternatives to the requirements of Paragraph 50.55a(g),
that provides an acceptable level of quality and safety, when authorized by the Director of the Office of Nuclear Reactor Regulation. Paragraph 50.55a(g) states, in part, that components which are part of the reactor coolant pressure boundary shall meet the requirements for Class 1 components in ASME Code,Section XI. Article IWA-4000 of ASME Code,Section XI (Reference a) requires a cracked pressure boundary leak to be repaired by welding. Baltimore Gas and Electric Company proposes to use an alternative roll / plug-type repair should a leak develop through a crack in the Calvert Cliffs pressurizer Inconel 600 heater sleeves or instrument nozzles.
The pressurizer nozzles at Calvert Cliffs Nuclear Power Plant are susceptible to smallleaks due to-primary water stress corrosion cracking (Reference b). These nozzles are mill-annealed Inconel 600 and are of the partial penetration welded sleeve type. Primary water stress corrosion cracking can occur in mill. annealed Inconel 600 nozzles which become susceptible because of stresses induced i
during fabrication and installation. MPR Associates Inc. developed a roll / mechanical plug repair technique for BG&E that provides an acceptable level of quality and safety.
s On September 29,1993, we met with your staff to present the technical justification for the roll / plug j'
repair technique and to discuss strategy for our submittal. 'Ihe two technical concerns raised by the staff at the meeting regarding the hydrostatic leak test criteria and corrosion problem for Inconel 690 crevice geometries are addressed in the attached safety analysis report.
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' Document Control Desk November 1,1993 Page 2 Attachment (1) is the non-proprietary version of the safety analysis report for the roll / plug repair methodology that supports our request for authorization. Attachment (2) is an MPR Associates proprietary affidavit for Attachment (3), pursuant to 10 CFR 2.790. Attachment (3) is the proprietary version of the safety analysis report.
Benefits to BG&E The roll / plug repair technique, if approved, would allow BG&E to respond to pressurizer sleeve nozzle leaks in a timely manner with a minimum of outage time, personnel radiation exposure, and cost. Typically, these roll / plug-type repairs can be performed in one-fifth the time it takes to perform weld repairs. Therefore, this technique reduces cost, exposure to radiation, and outage time by about eighty percent.
Request for Lead Plant Licensine Status I
We are aware of at least three other Combustion Engineering pressurized water reactors where this type of repair can be successfully utilized with minor refinement. The licensees of these plants have expressed interest in using this technique for a similar application, following our lead. Therefore, our i
request for authorization to use an alternative repair method should be considered as a lead plant submittal.
Schedule Our objective is to use the roll / plug repair technique during the spring 1994 Unit I refueling outage in the event we discover any leaking pressurizer nozzles. Before implementing this repair technique, we must complete the required engineering, procure parts and tooling, prepare procedures, and train craft personnel. This preparation takes several months and cannot be completed until NRC approval is obtained.
Hence, we request that you review and approve this lead plant submittal by January 15,1994.
Should you have any questions regarding this matter, we will be pleased to discuss them with you.
Very truly yours, i
RED /GT/gt/dlm Attachments: (1)
Calvert Cliffs Nuclear Power Plant Units 1 and 2 Pressurizer Inconel 600 Sleeve Nozzle - Safety Analysis Report for Alternative Roll / Plug Repairs (Non-Proprietary Version)
(2)
Proprietary Affidavit for Attachment (3)
(3)
Calvert Cliffs Nuc! car Power Plant Units 1 and 2 Pressurizer Inconel 600 Sleeve Nozzle - Safety Analysis Report for Alternative Roll / Plug Repairs (Proprietary Version) f
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Document Control Desk November 1,1993 Page 3 cc:
OVithout Attachments)
D. A. Brune, Esquire J. E. Silberg, Esquire R. A. Capra, NRC T. T. Martin, NRC P. R. Wilson, NRC R. I. McIran, DNR J. H. Walter, PSC i
OVith Attachments)
D. G. Mcdonald, Jr., NRC (5 Copies of Attachments)
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