ML20072E277
| ML20072E277 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 03/01/1983 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-83 10CFR-050.55E, 10CFR-50.55E, NUDOCS 8303210630 | |
| Download: ML20072E277 (2) | |
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TENNESSEE VALLEY AUTHORITY CH ATTANOOGA. TENNESSEE 374ot 400 Chestnut Street Tower II March 1, 1983 BLRD-50-438/82-35 BLRD-50-439/82-32 II.S. Nuclear Regulatory Commission Region II Attnt Mr. James P. O'Reilly, Regional Administrator m
w 101 Marietta Street, Suite 2900 Atlanta, Ooorgia 30303 3
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Dear Mr. O'Rotlly:
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-BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - OPERATIONAL DEFECTf. IN HIGHm a '1 l
t'9 PRESSURE INJECTION N0Z2LES AND THERMAL SLEEVES - BLRD-50-438/82-35, -
IMy BLRD-50-439/82 THIRD INTERIM REPORT' w
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E" The subject deficien::,y 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 folloded by our interim reports dated June 1 and July 28, 1982. Enclosed is our third interim report. We expect to submit our next report by April 18, 1983 We consid6r 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 t
L. M. Mills, Manager Nuclear Licensing Enclosure Mr. Richard C. DaYoung, Director (Enclosure) 00:
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
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8303210630 830301 DR ADOCK 05000 3 g
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An Equal Opportunity Employer
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ENCLOSURE BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 OPERATIONAL DEFECTS IN HIGH-PRESSURE INJECTION NOZZLES AND THERMAL SLEEVES NCR BLN NEB 8206 BLRD-50-438/82-35, BLRD-50-439/82-32 10 CFR 50.55(e)
THIRD INTERIM REPORT l
Description of Deficiency Recent inspections at several B&W operating plants revealed defects in the makeup /HPI nezzlee and their thermal. sleeves and in the makeup piping upstream of these nozzles. The nozzles are located on each reactor coolant cold leg between the 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 sleeves
. 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 exposing the nozzle and pipe to a thermal shock condition-by preventing sleevo 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 tot other Bellefonte NSSS nostles. There are no implications for other TVA pla'nts.
Interim Progress B&W has determined that there is no safety concern unless there is a cracked or loose thermal sleeve. With respect to nozzles that have not been degraded, failures are assumed only at the weld between the RC pipe and ths nozzle forging and between the nozzle forging and the connecting HPI' pipe.
Energency core cooling system analyses have shufn that ruptures in these locations can be mitigated within the criteria to 10 CFR 50.l!6. Failures are not assumed within the nozzle forging itself becauss the forgihgs are heavily reinforced. Thus failures within the forging are considered to be a sufficiently low probability as to not require evaluation.
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a, This design basis (i.e., no failure within the forgings) assumes that the thermal sleeves within the nozzle remain in place as designed and that there is no loosening or cracking of the sleeve that would allow hot primary coolant, cool makeup, or HPI fluid to flow between the thermal sleeve and the nozzle body. Thermal sleeve problems and subsequent nozzle failures will be prevented at Bellefonte by establishing sleeve tightness.
The Bellefonte HPI nozzle thermal sleeve will be hard rolled into the 2-1/2-inch end of the nozzles and contact rolled at the 28-inch end. The contact roll will be done such that the collar on the sleeve is in line contact with the nozzle inner wall. This second roll will stabilize the sleeve with respect to flow induced vibration. Four small holes will be drilled through the collar from the 28-inch pipe side to allow the venting of fluids from between the rolled areas.
B&W has documented the field work required to implement this fix in a field change package (FCP). The fix requires access to the inside of the RC piping.
Access to this area is available only through the reactor vessel when the internals have been removed. The internals are to be removed and the field work to implement the fix is scheduled to begin by March 4,1983 The work is scheduled to be completed by May 3, 1983 TVA will submit a final report on this deficiency upon review, and concurrence with B&W's FCP.
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