ML20058G068
| ML20058G068 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 07/28/1982 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-82 10CFR-050.55E, 10CFR-50.55E, NUDOCS 8208030189 | |
| Download: ML20058G068 (3) | |
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TENNESSEE VALLEY AUTHORITY CH ATTANOOGA. TENNESSEE 37401 400 Chestnut Street Tower II
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2 :c July 28, 1982 CS
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BLRD-50-439/82-32
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U.S. Nuclear Regulatory Commission T
i Region II Attn:
Mr. James P. O'Reilly, Regional Administrator 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303
Dear Mr. O'Reilly:
BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - OPERATIONAL DEFECTS IN HIGH-PRESSURE INJECTION N0ZZLES AND THERMAL SLEEVES - BLRD-50-438/82-35, BLRD-50-439/82 SECOND INTERIM REPORT The subject deficiency was initially reported to NRC-0IE Inspector Don Quick on April 29, 1982 in accordance with 10 CFR 50.55(e) as NCR BLN NEB 8206. This was followed by our first interim report dated June 1, 1982. Enclosed is our second interim report. We expect to submit our next report by March 1, 1983 We consider 10 CFR Part 21 applicable to this deficiency.
If you have any questions concerning this matter, please get in touch with R. H. Shell at FTS 858-2688.
Very truly yours, TENNESSEE VALLEY AUTHORITY DSK= ~
L. M. Mills, Manager Nuclear Licensing Enclosure cc:
Mr. Richard C. DeYoung, Director (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555 Mr. James McFarland (Enclosure)
Senior Project Manager Babcock & Wilcox Company P.O. Box 1260 Lynchburg, Virginia 24505 UFFICIAL COPY 8208030189 820728
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An Ecual Opportunity Employer
ENCLOSURE BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 OPERATIONAL DEFECTS IN HIGH-PRESSURE INJECTION N0ZZLES AND THERMAL SLEEVES NCR BLN NEB 8206 BLRD-50-438/82-35, BLRD-50-439/82-32 10 CFR 50.55(e)
SECOND INTERIM REPORT Description of Deficiency
-Recent inspections at several B&W operating plants revealed defects in the makeup /HPI nozzles and their thermal sleeves and in the nakeup piping upstream of these nozzles. The nozzles are located on each reactor coolant cold leg between tne reactor coolant pump and reactor vessel. The nozzles and sleeves are supplied by B&W under the Nuclear Steam Supply System (NSSS) contract. The defects include:
through-wall circumferential crack at the welded joint between the nozzle safe end and the first check valve upstream of the safe end loose thermal aleeves
. missing or worn thermal sleeve retaining buttons The loose thermal sleeves and missing or worn retaining buttons remove the mechanical restraints which were designed to avoid expos,ing the nozzle and pipe to a thermal shock condition by preventing sleeve movement in the upstream direction.
Although the degraded components at the affected plants were the same, the resulting damage was not identical. Accordingly, B&W is investigating this concern to determine its cause and to determine if it has generic implications for other B&W plants, including Bellefonte. The Bellefonte nozzle configuration is similar to that at the affected plants except that it is a one-piece construction while the nozzles for the affected plants have a welded safe end.
B&W has notified TVA of no similar potential deficiencies in the past for other Bellefonte NSSS nozzles. There are no implications for other TVA plants.
Interim Progress 4
TVA has forwarded the nonconformance report to B&W for corrective action.
TVA has advised B&W that any necessary corrective action is to be implemented before plant startup.
B&W has advised TVA that investigative work is proceeding for the operating plants to determine the cause of the problem, with the end date scheduled for December 1982. The following information is applicable to the nozzles and thermal sleeves at Bellefonte.
The design of the Bellefonte nozzle and thermal sleeve is similar to the design used on several of the operating plants. The nozzle material is different, however. The operating plants use a carbon steel nozzle with an A336CFL8M stainless steel safe end. The nozzles at Bellefonte are one piece Ni-Cr-Fe SB-166 (Inconel). The operating plants use A336CLF8M stainless steel thermal sleeves, while Bellefonte has type 304 stainless steel.
Installation and attachment techniques are similar in all plants.
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The basic cause of the problem has not been determined at this time. The crack initiation and propagation is apparently because of thermal stress fatigue based on existing information. The problem may be the result of makeup. flow oscillation beyond those expected in the design and thermal sleeve roll " tightness" at beginning of life.. Based on information as of
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_this date, it is possible that the problems which have occurred on several operating plants could oecur at Bellefonte also.
B&W is not recommending any corrective action until the basic cause of the problem is determined. B&W does recommend taking some dimensional. data from the installed nozzle ends and thermal sleeves. These data will guide l
B&W in determining corrective action. Presently, B&W is contemplating rerolling the thermal sleeves to closer tolerances which are yet l
unspecified.
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