ML19305B461
| ML19305B461 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 02/27/1980 |
| From: | Hannon J Office of Nuclear Reactor Regulation |
| To: | Ippolito T Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8003190694 | |
| Download: ML19305B461 (4) | |
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o UNITED STATES
!T NUCLEAR REGULATORY COMMISSION gh
- E WASHINGTON, 0. C. 20SSS f
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s Mr. G. Carl Andognini Boston Edison Company M/C NUCLEAR 800 Boylston Street Boston, MA 02199 Mr. Paul b. McGuire Pilgrim Station Acting Manager Boston Edison Company RFD #1, Rocky Hill Road Plymouth, Massachusetts 02360 lathony Z. Roisman Natural Resources Defense Council
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917 15th Street, N. W.
Washington, D. C.
20005 Henry Hermann, Esquire Massachusetts Wildlife Federation 151 Tremont Street Boston, Massachusetts 02111 Plymouth Public Library North Street Plymouth, Massachusetts 02360 l
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Docket File V. Noonan NRC PDR G. Knighton lj Local PDR D. Ziemann ORB!3 Rdg P. Check NRR Rdg G. Lainas H. Denton D. Crutchfield E. Case F. Pagano D. Eisenhut.
R. Clark B. Grimes OELD W. Gannill 01&E (3)
R. Vollmer S. Sheppard L. Shao Project Manager J. Miller ACRS (16)
T. Ippolito NRC Participants R. Reid TERA A. Schwencer 8003190 6 %-
o UNITED STATES 8"
NUCLEAR REGULATORY COMMISSION y
- E WASHINGTON, D. C. 20555 February 27, 1980 MEMORANDUM FOR:
T. A. Ippolito, Chief Operating Reactors Branch #3, D0R FROM:
J. N. Hannon, Project Manager Operating Reactors Branch #3, D0R
SUBJECT:
MEETING
SUMMARY
A meeting was held with representatives from BECo (the licensee) and GE in Bethesda, Maryland on February 25, 1980. The purpose of the meeting was to discuss the Pilgrim Unit 1 GE Turbine inspection findings. A list of meeting attendees and a GE to BECo letter dated February 13, 1980 provided at the meeting are enclosed.
GE presented technical information to support their preliminary conclusions which were outlined in the February 13 letter.
Briefly, they believe that the indications found during the keyway / bore inspection of the "B" low pressure rotor are attributable to local moisture erosion (water cutting).
GE has reconmended that the LP "A" rotor be inspected during the current outage.
BECo committed to provide the NRC with the LP "A" rotor inspection schedule in advance, so that NRC personnel would be able to witness testing in progress.
BECo is presently evaluating the GE proposal to reinspect the LP "B" rotor after 9-12 months of operation. Pending the results of the LP "A" rotor inspection, BECo will supply data to support the continued safe operation of the facility subsequent to the current refueling outage.
The following technical information was supplied during the discussion:
Crit' cal Crack Depth 2.96" Crack 1rowth Rate 0.1-0.3 in/yr Inspection Down Time 3 weeks Turbine Gperating Hours 43,64 Burst Probability
~10 g to 10-5 2rvM9W John N. Hannon, Project Manager Operating Reactors Branch #3 Division of Operating Reactors
Enclosures:
1.
Attendees 2.
GE to BECo ltr dated 2/13/80 cc w/ encl:
See next page
MEETING WITH BOSTON EDIS0N C0itPANY RE:
GE TURBINE INSPECTIONS 2/25/80' Name Representing John N. Hannon NRC/ DOR /0RB #3 R. J. Placek GE-LST-G, Schenectady R. S. Couchman GE-LSTG-Schenectady J. J. Hintney GE-LSTG-Schenectady K. P. Roberts NRC/I&E Region I Res. Insp.- Pilgrim D. V. Kehoe NRC/I&E Region I Project Inspection Millard L. Wohl NRC/NRR/ DOR /EEB C. D. Sellers NRC/NRR/ DOR /EB Harold Walker NRC/NRR/ DOR /EB Catherine Kieffer NRC/NRR/ DOR /EB R. W. Klecker NRC/NRR/ DOR /EB M. L. Boyle NRC/ DSS /MTEB T. J. Grady GE-I&SE-Wellesley, Ma.
Jack Fulton Boston Edison - Licensing H. T. Watanabe GE-San Jose W. J. Ross NRC/ DOR R. A. Hermann NRC/IE T. A. Ippolito NRC/ DOR W. Hazelton NRC/ DOR
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February 13, 1980 Mr. G.C. Andognini Manager of Nuclear Operations Boston Edison Company
SUBJECT:
Boston Edison Pilgrim #1 170X341 During the wheel boresonic test of the LP-B rotor of Turbine 170X341 (Boston Edison-Pilgrim #1), two sonic indications were detected at the keyway on the upstream side of the fourth stage turbine end wheel. These sonic indications are located near each corner of the approximately rec-tangular keyway and appear to be 0.100"-0.140" deep (radial extent). They appear to extend axially approximately 1.5" from the hub face..
Considerable local moisture erosion was noted o'n the wheel hubs, including the fourth stage turbine end wheel.
Such water cutting is not uncommon on non-reheat units. Moisture water cutting grooves were visible at the hub periphery approximately in line with the keyway sonic indica-tions.
Fiber optics disclosed that these grooves extended radially inward from the hub periphery toward the keyway. 'Thus, it is possible that the keyway sonic indications are due to the existence of water cut grooves axially into the corners of the keyway.
This explanation suggests the interaction of the involved physical parameters such that small changes are significant (manufacturing tolerance, pressure, temperature, etc.)
l because no sonic indications were noted in the fourth stage generator end wheel.
l l-Stress corrosion cracking is generally associated with a concentrating mechanism such as that which occurs adjacent to the early moisture region.
This is a non-reheat unit, and this wheel operates in the wet steam region at all times and hen:e there is no apparent mechanism for concentrating corrodants.
Thus, there is a low likelihood of stress corrosion cracking in this wheel.
Feedwater chemistry control on the unit appears to have been ' good since startup.
Further, no indications were found in any of the other wheels including the fourth stage generator end wheel which has similar proper-ties (approximately 120 KSI T.S.) and was produced by the same forging vendor.
After the British experience'at Hinkley Point, follow-up studies by the CEGB showed that cracks could propagate even in non-contaminated steam. To assure that these indications are not growing cracks, we recommend that this wheel be reinspected after 9-12 months of additional operation and that the LP-A rotor be inspected during the current outage. The inspection interval
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lir. G.C. Andoinini I;;; 2
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February 13, 1980 is based.upon a final crack size yielding a low probability of burst under the worst case con 6ition (cold start).
The final crack size was based upon
- the upper bound CEGB crack growth data in non-contaminated turbine steam.
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