ML17156A157
| ML17156A157 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 04/22/1985 |
| From: | Wagner D Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8504290226 | |
| Download: ML17156A157 (14) | |
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- Docket No. 50-387 UNITEDSTATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 APR 2 2 t985 LICENSEE:
Pennsylvania Power
& Light Company (PP&L)
FACILITY:
Susquehanna Steam Electric Station
SUBJECT:
MEETING
SUMMARY
- CRACKING DISCOVERED IN A STEAM DRYER SUPPORT BRACKET On April 9, 1985, a meeting was held at the Susquehanna site to.discuss recently discovered cracks in a steam dryer support bracket.
A list of meeting attendees is included as Enclosure l.
At Susquehanna, the steam dryer is supported by four steam dryer support brackets located at azimuths 4','94', 184'nd 274'.
These brackets are essentially blocks attached to and extending from the reactor pressure vessel wall to support the steam dryer via the steam dryer. support ring and the seismic blocks.
The brackets themselves are positioned on Inconel pads.
The installation of the brackets and.the corresponding Inconel pads.- was performed onsite-.
Attached to the steam dryer support ring are four seismic-.&locks corresponding to the brackets.
These seismic blocks restrict the movement of themteam dryer during seismic events and are used to prevent the st0am dryer from rocking.
Figures 1-3 of Enclosure 2 depict the general arrangement of the mentioned-components.
During removal of the steam dryer for refueling of Unit 1, the licensee noticed that the 184'racket was cracked.
Subsequent dye penetrant testing confirmed the cracks..
Maps of the cracks are included herein as'nclosure 3.
The licensee was investigatingithe cause of the cracking but had not arrived at any conclusions.
- However, upon removal of the steam dryer, the licensee noted that the contact point of the cracked (184') bracket with the steam dryer was via the steam dryer support ring - the uncracked brackets contacted the steam dryer via the seismic blocks.
Support via the steam dryer support ring would put the contact area farther from the vessel wall than if it were supported by the seismic block.
The licensee is currently underway repairing. the bracket.
Plans call for removing the bracket by cutting it about 3/8" from the vessel wall, leaving a stub.
Any cracks remaining in the stub will be chased to their crack tip.
'ased on ultrasonic examinations, the licensee believes the crack does not extend into the Inconel
- pad, however this will not be positively known until the bracket is removed.
After removal of the bracket, a replacement will be welded on..
PP&L stated that the minimum remaining Inconel pad thickness for rewelding is 1/8". If the crack(s) extend into the pad such that this 1/8" minimum thickness cannot be maintained, the licensee will pursue another repair plan as yet unannounced.
The repair of the bracket is being done as an ASME Section XI repair.
Approximately 25 procedures will be implemented in the course of the repair.
Bracket removal and replacement will take 7 - 10 days.
An NRC-Region 1 inspector will be available onsite to observe the bracket removal.
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Following. discussions with the-licensee,'the staff requested additional infor-mation which would aid in the further-investigation of the bracket cracking.
Regarding the Susquehanna repair,.the staff requested that:
1 1.
PP&L'eep the staff informed on status of repair, III
- 2. 'a 'photograph after removal of bracket be taken which shows explicity the crackapex, I
3.
PP&L provide the staff with a written or pictorial description of the loading pattern on each bracket, and 4.
PP&L make a videotape of the seismic block fillet welds to the support ring.
Regarding the investigation of the cause of the cracking, the staff requested the additional information identified in Enclosure 4.
Enclosures:
As stated Original signed by:
Dave Wagner, Project Manager Licensing Branch No.
2 Division of Licensing cc:
See next page Distribution:
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'ollowing discussions with the licensee, the staff requested additional infor-mation which would aid in the further investigation of the bracket cracking.
Regarding the Susquehanna repair, the staff requested that:
1.
PPSL keep the staff informed on status of repair, 2.
a photograph after removal of bracket be taken which shows explicity the crack apex, 3.
PP&L provide the staff with a written or pictorial description of the loading pattern on each bracket, and 4.
PPSL make a videotape of the seismic block fillet welds to the support ring.
Regarding the investigation of the cause of the cracking, the staff requested the additional information identified in Enclosure 4.
Enclosures:
As stated Dave Magna-, Project Manager Licensiog+ranch No.
2 Division of-Licensing cc:
See next page
""~Eh Mr. Norman W. Curtis
'ice President Engineering and Construction Pennsylvania Power 5 Light Company 2 North Ninth Street Allentown, Pennsylvania 18101 Jay Silberg, Esq.
Shaw, Pittman, Potts, 5 Trowbridge 1800 M Street, N.
W.
Washington, D.C.
20036 Edward M. 'Nagel, Esq.
General Counsel and Secretary Pennsylvania Power 5 Light Company 2 North Ninth Street Allentown, Pennsyl vania 18101 Mr. Will.xaam 'E. Barberich Manager-Nuclear Licensing Pennsylvania Power S. Light Company 2 North Ninth Street Allentown, Pennsylvania 18101 Mr. R. Jacobs Resident Inspector P.O.
Box 52 Shickshinny, Pennsylvania 18655 Mr. E. B. Poser Project Engineer Bechtel Power Corporation P. 0.
Box 3965 San Francisco, California 94119 Mr. Thomas M. Gerusky, Director Bureau of Radiation Protection Resources Commonwealth of Pennsylvania P. 0.
BOx 2063 Har r.isburg, Pennsyl vania 17120 Mr. N. D. Weiss Project Manager Mail Code 391 General Electric Company 175 Curtner Avenue
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San Jose, California 95125 Robert W. Alder, Esquire Office of Attorney General P. 0. Box 2357 Har risburg, Pennsylvania 17120 Mr. William Matson Alegheny Elec. Cooperative, Inc.
=212 Locust Street P. 0.
Box 1266 Harrisburg, PA 17108-1266
Enclosure 1
APPLICANT:
Pennsylvania Power
& Light Company (PPEL)
FACILITY:
Susquehanna Steam Electric Station
SUBJECT:
'RACKING IN STEAM DRYER SUPPORT BRACKET DATE:
April 9, 1985 R. Paley S. Reynolds, Jr.
R. Jacobs L. Willertz J. Gutshall T. Oldenhage S. Cantone W. Hazelton D. Wagner W. Barberich AFFILIATION PP8L NRC-Region 1
NRC-Resident Inspector PPSL PPSL.
PPLL PPSL NRC-NRR --
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Enclosure 4
2.
Complete CBKI welding history of welding and PWHT of-a.
shell course weld (SA533) b.
inconel weld pad c.
bracket attachment weld d.
any special post weld mechanical finishing Detailed water chemistry history summary including highlights of unusual events 3.
Tubing materials for-a.
condenser b.
5.
c.
HP FWH's Known occurrences of unusual air leakage and-source of problem Preliminary and final failure analyses repoWs based on fracture study 6.
Description of steam dryer instrumentation to be installed 7.
8.
Chemistry data on sulphurous species in feedwater Steam dryer skirt fabrication information