ML20029B382
| ML20029B382 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 03/04/1991 |
| From: | Devine J GENERAL PUBLIC UTILITIES CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20029B383 | List: |
| References | |
| 5000-91-2006, C320-91-2035, NUDOCS 9103070176 | |
| Download: ML20029B382 (2) | |
Text
A GPU Nuclear Corporation
.M Ma nMan, One unne,eond nooo 1
4 HMwswuB Darsippany, New Jersey 07054 201 316-7000 TELEX 136 482 Writer's Direct Dial Number:
March 4,
1991 5000-91-2026 C320-91-2035 U.
S. Nuclear Regulatory Commission Att Document Control Desk Washir.gton, DC-20555 Gontlement Subjects Oyster Creek Nuclear Generating Station (OcttGS)
Docket No. 50-219
?teense No. DPR-16 Oyster Creek Drywell Containment
References:
(1) GPUN letter dated December 5, 1990 - Drywell Structural Reports and Wator Intrusion Summary In the Reference 1 letter, GPUN committed to provide to you the structural design reports supporting drywell sand removal at Oyster Creek.
As you know, our investigations indicate strongly that the presence of sand is a major contributor to the high corrosion rates observed in the sandbed region (clevation 8'-11" to 12'-3") of the drywell; for that reason we consider sand removal to be nn-important element in our program to eliminate the corrosion threat to drywell integrity.
Attachment I to this letter provides this information in the form of GE Reports Index No. 9-3 and 9-4, "An ASME Section VIII Evaluation of the Oyster Creek Drywell for_Without Sand Case Stress and Stability Analysis." This two (2) part report covers the structural analysia of the Oyster Creek drywell with the sand cushion removed and conservatively assumes a uniform drywell sandbod region corroded thickness of 0.736" at the end of cycle 13 operation.
The report-demonstrates that if the sand cushion were removed the drywell would remain in full compliance with ASME Code requirements.
Further measurements of the drywell shell thickness are being made during the current 13R outage and will serve as a basis for refined corrosion rate projections.
Assuming that these updated corrosion rate projections are consistent with the Attachment I analys!.e, GPUN plans to proceed with the removal of the drywell sand cushion during Cycle 13 operation as a prudent and positive step in arresting corrosion at Oyoter Creek.
9103070176 910304 s
PDR ADOCK 05000219
+\\
P PDR
)
RZ:0202035
, s 1
GPU Nuclear Corporation is a subsid:ary of General Pubhc UMbes Corporahon 4
,W WW
- ji
1 C330-91-2035--
-l Drywell' Containment Page 2--
If you have any questions or comments on this s.ubmittal or the overall drywell corrosion' program, please contact Mr. Michael Laggart, Manager, corporate Nuclear Licensing at (201) 316-7960.
Sincerely, f
i 1
.- 4,
- &YUs.G c
]
J. C.
DeVine, Jr.
)
Vice President, Technical Functions Attachment JCD/RZ/p1p i
l cci Administrator, Region 1 i
Senior NRC Resident Inspector Oyster Creek NRC Project Manager I
d
=I
-- 1
~
l l
RZ C3202035 l
. ~.. __
..