ML20041E766
| ML20041E766 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse, Oconee, Arkansas Nuclear, North Anna, Crystal River, Midland, Bellefonte, 05000000, Washington Public Power Supply System, Crane |
| Issue date: | 03/05/1982 |
| From: | Taylor J BABCOCK & WILCOX CO. |
| To: | Deyoung R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| References | |
| NUDOCS 8203110345 | |
| Download: ML20041E766 (3) | |
Text
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a Babcock & Wilcox suci.ar Power Generation Division a Mcoermott company 3315 Old Forest Road P.O. Box 1260 Lynchburg, Virginia 24505 March 5, 198,
Mr. Richard C. DeYoung, Director RECEWto Office of Inspection and Enforcement
-k "gU.O ID U. S. Nuclear Regulatory Conmission Egy Washington, DC 20555 ru
Dear Mr. DeYoung:
/
Babcock & Wilcox is hereby informing youof informa -
we have recently received which may have generic safety implications.
According to information provided to us, recent inspections at Crystal River 3, Oconee 2 and Oconee 3 have revealed the following:
At Crystal River 3, a thru-wall circumferential crack at the welded joint between the normal makeup nozzle safe end and the first check valve upstream of the safe end was discovered (see attached Figure 1). A loose thermal sleeve was discovered in the makeup nozzle; however, the retaining buttons on both sides of the tnermal sleeve were functional. This event was reported to the Region II Office by Florida Power Corporation in LER 82-003/0lT-0 dated February 12, 1982.
At Oconee 3, it was discovered that the thermal sleeve for one of the makeup nozzles was loose, the thermal sleeve retaining buttons on the safe end side were missing, the thermal sleeve had moved in the upstream direction approximately 5/8", and that there were crack indications in the safe end and in the attached makeup /HPI piping.
The other makeup nozzle has been examined by UT and radiography and showed no indication of cracking or a degraded thermal sleeve.
l At Oconee 2, preliminary indications from a radiography inspection are that the thermal sleeve in one of the makeup nozzles may be loose and the retain-ing buttons on the safe end side are missing. The other makeup nozzle has been examined by radiography and showed no indication of a degraded thermal sleeve.
In the inspections made to date, the thermal sleeves have not been observed to have moved a sufficient distance to expose the knuckle region of the nozzle to a thermal shock condition. However, the apparent loose fit of thermal sleeves and the absence or wearing of the sleeve retaining buttons at Oconee 2 and 3 removes the mechanical restraints which were designed to prevent sleeve move-ment in the upstream direction.
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r Babcock &Wilcox Mr. Richard C. DeYoung March 5, 1982 ECCS analyses have shown that a rupture of the HPI line up to complete severance of the terminated end of the nozzle can be mitigated within the criteria of 10 CFR 50.46.
The spectrum of analyses performed for postulated cold leg ruptures demonstrates that a break equivalent to the nozz!e base end area will also be i
mitigated within the criteria of 10 CFR 50.46. Analyses of mechanistic breaks which might occur within the nozzle have not been performed.
Although the degraded component at the affected plants was the same, the resulting damage was not identical. Accordingly, the generic implications of this concern have not been established for the other B&W plants.
According to B&W information the basic Makeup /HPI nozzle configuration as shown on Figure 1 is typically representative of that used on all of the following plants:
1 Oconee I*,
II, III TMI I, II Crystal River 3 Midland I, II Arkansas Nuclear One, Unit 1 Rancho Seco Davis Besse 1 North Anna 3, 4 Supply System 1, 4 Bellefonte 1, 2 PGE (undesignated site) l
- 0conee I has a unique double-sleeve design l
All B&W operating plants have been informed of the findings at Crystal River 3 and Oconee.
Repair work has been completed at Crystal River 3 and plans are underway to repair the affected components at Oconee 3.
V *y truly yours,
),nbW
'2 e
J. H. Taylor Manager, Licensing Note: A telephone report of this information was made to Mr. Doug Sly, Duty Officer Headquarters, Bethesda, MD., at 8:45PM, March 4, 1982, by Mr. George Geissler of my staff.
l cc:
R. B. Borsum - B&W Bethesda Office l
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