ML20198L300
| ML20198L300 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 01/08/1998 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20198L306 | List: |
| References | |
| NUDOCS 9801150223 | |
| Download: ML20198L300 (2) | |
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UNITED STATES g
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,j NUCLEAR REGULATORY COMMISSION o
WASHINGTON, D.C. 9066H001 l
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMLNDMENT NO. 223 TO FACILITY OPERATING LICENSE NO. DPR-51 AND AMENDMENT NO.19910 FACILITY OPERATING LICENSE NO. DPR-69 BALTIMORE GAS AND ELECTRIC COMPANY CALVERT CLIFFS NUCLEAR PCWER PLANT UNIT NOS. I AND 2 DOCKET NOS. 50-317 AND 50-318
1.0 INTRODUCTION
By letters dated November 30, 1995, March 15, 1996, March 6, 1997, and June 27, 1997, Balt ore Gas and Electric Company (BGE), the licensee, submitted a request ') change " Technical Specifications (TSs) at Calvert Cliffs Nuclear Power Plant, Unu Nos. I and 2.
The proposed changos would incorporate reTerences to a new Combustion Engineering, Inc. topical report describing steam generator tube sleeves, incorporate sleeve / tube inspection scope and expansion criteria, establish a plugging limit for a CE sleeve as 28% of the nominal sleeve wall thickness, and incorporate a post weld heat treatment of free span welds.
The updated CE Topical Re) ort, CEN-630-P, Rev. #01, " Repair of 3/4" 0.D. Steam Generator Tubes Using Lea ( Tight Sleeves," dated November 1996, addresses issues identified in 1996 at Prairie Island Unit 1.
At issue, were indications detected in weld joints of CE sleeves resulting from inadequate cleaning.
Because the bulk of the technical and regulatory issues for the present request are identical to those reviewed in other previous Safety Evaluations (SEs) inclusion based on current experience., this SE discusses only amplification or Details of prior staff evaluatiens of CE sleeves may be found in the SEs for Waterford Steam Electric Station, Unit 3, Docket No. 50-382, dated December 14, 1995; Byron Nuclear Power Station, Units 1 and 2 and Braidwood Nuclear Power Station Units 1 and 2, Docket Nos. 50-454, 50-455, 50-456, and 50-457, dated April 12, 1996. These evaluations relate to the proposed Calvert Cliffs license amendment. The March 15, 1996, March 6, 1997, and June 27, 1997, letters provided clarifying information that did not change the initial proposed no significant hazards consideration determination.
2.0 BACKGROUND
AND
SUMMARY
OF PREVIOUS REVIEWS The proposed er cleeve types are an expansion transition zone (ETZ) sleeve and a tube support....sve.
An ETZ sleeve is designed to restore the portion of a 9001150223 900108 PDR ADOCK 05000317 P
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Code minimum material properties in accordance with staff positions. Removal of tubes and/or sleeves from service when degradation reacges a pluggine limit of 285 provides assurance.that the minimum acceptable wall thickness will not 4
be violated during the next subsequent cycle of operation. Adoption of the 285 plugging limit is reflected in the proposed wording for TS 4.4.5.4.a 7.c.
and is acceptable.
3.4 Post Weld Heat Treatment 4
Accelerated corrosien tests confirm that a post weld heat treatment (PWHT)
I significantly improves the intergranular stress corrosion cracking resistance of the alloy 600 parent tube materisl in the weld zone.
In its June 27, 1997, submittal, the licensee committed to performing PWHT of the welded joints in i
accordance with the CE generic sleeving report and the NRR staff position.
l e
This commitment is reflected by proposed revision to plant TS 4.4.5.4.a.10.b.
and the TS change is acceptable.
3.5 Adoption of Revised Inservice Inspection Expansion Criteria The licensee has proposed, through the incorporation of TS Table 4.4-3, to a minimum 20% (with expansion criteria) inservice inspection of all sleeved i
tubes in accordance with industry guidelines. The staff finds this inspection sample acceptable.
3.6 Staff Conclusions-i The staff concludes the proved Seving repairs, as described in the new CE sleeve topical report, can a accomplished to produce sleeved tilbes of i
acceptable structural-integrity, leak tightness and corrosion resistance. The-staff also finds-the proposed preservice inspection methods for examining the conditions'of the welds are acceptable.
The NRC staff concludes the repair of SG tubes using welded sleeves designed 4
by CE is acceptable, as discussed above and reflected by TS revisions, to:
- 1) install welded CE sleeves in accordance with CE Topical Report CEN-630-P, Rev. #01, " Repair of 3/4" 0.D. Steam Generator Tubes Using Leak Tight Sleeves," dated November 1996, 2) performing PWHT of the free span weld joints, 3) incorporating 15 table 4.4-3 for sleeve inservice inspection sample size and expansion criteria, and, 4) establishing a sleeve plugging limit to 28% of the sleeve wall. thickness. The bases have also been modified consistent with-these TS changes.-
4.0 STATE CONSULTATION
iln accordance with the commission's regulations, the Maryland State official I
Lwas notified of the proposed issuance of. the amendments.
The State official had no comments.
5.0 ENVIRO MENTAL CONSIDERATION The amendaants change a requiren,ent with respect to installation or use of a i
- facility component-located within the restricted area as-defined in 10 CFR t
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