ML20213F880
| ML20213F880 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 05/13/1987 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Hale P AFFILIATION NOT ASSIGNED |
| Shared Package | |
| ML20213F883 | List: |
| References | |
| NUDOCS 8705180028 | |
| Download: ML20213F880 (7) | |
Text
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UNITED STATES P
NUCLEAR REGULATORY COMMISSION f,,
f WASHINGTON, D. C. 20556 May 13,1987
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Mr. Paul Hale g -fff_.
12912 E. 24th Streets Tulsa, Oklahoma 74134
Dear Mr. Hale:
This is in response to your letter which expressed your concern regarding tur-bine maintenance and balancing at the Wolf Creek Generating Station Iceated near Burlington, Kansas.
You further'inaicated that you were concerned about the adequacy of the corrective measures implemented by the licensee because the plant has tripped subsequent to returning to operation.
Large rotating equipment, such as turbine generators, normally experience small vibrations as they operate.
The turbine generator at Wolf Creek is equipped with instruments that measure these vibrations and alert the opera-tional staff if they become excessive.
At Wolf Creek these instruments also tripped the turbine generator off-line if these vibrations exceeded seven mils (seven thousandths of an inch).
The Wolf Creek turbine generator had been in commercial operation for a)proxi-mately one year at Wolf Creek prior to the scheduled refueling outage t1at began in mid-October 1986.
During this period of operation turbine generator vibration was acceptably low, typically in the three mils (0.003 inch) range.
During the October 1986 refueling outage the licensee, at the suggestion of the turbine generator vendor, modified the turbine generator to exciter alignment by approximately seven mils to avoid vibration problems that the vendor had observed at other facilities.
However, when the plant was returned to service in December 1986 the turbine generator vibration, as measured at the #12 bearing at the exciter, had increased to the five to six mils range.
On January 17 the reactor was shut down for a planned outage to rebalance the turbine generator.
Following return to operation on January 20 the turbine tripped on high vibration in the turbine generator causing a reactor trip.
Additional balancing weights were added during the January 20 shutdown but the vibration continued.
On January 31 the reactor was again shut down to permit an inspection of tur-bine generator mechanical tolerances and alignment of rotating components.
Minor misalignment was measured in the turbine generator to exciter coupling.
The turbine generator vendor and licensee believe that this misalignment, rather than an imbalanced rotor, is causing the vibrations and plans have been made to re) lace the coupling during the next refueling outage currently sche-duled for r ll 1987.
a During these investigations it was determined that the magnitude of the vibra-tions was influenced by the temp,erature of in the vicinity of the exciter with 8705180028 870513 i
PDR ADOCK 05000482 H
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o Mr. Paul Hale smaller vibrations occuring when the temperatures were lower.
The licensee has air conditioned the exciter housing as a temporary corrective measure and the vibrations have been reduced to approximately four to five mils with some readings as low as 3.2 mils.
The original design of the Wolf Creek turbine generator included a turbine trip on high vibration (greater than seven mils).
This trip does not serve a reactor safety function.
It was installed to alert the operators to vibrations that could damage the turbine generator and result in financial loss to the owners.
The turbine generator is located in a separate building from the reactor and serves no safety related purpose.
No equipment that is required to safely shutdown or cool the reactor is located in the turbine building.
The NRC staff has reviewed the potential failure mechanisms of the turbine and has concluded that a turbine generator failure will not result in damage to reactor system components necessary for safe shutdown and cooling of the reactor.
In consultation with the turbine generator vendor, the licensee has eliminated the turbine trip on high vibration that previously was installed and replaced it with a turbine vibration alarm at the same level of vibration seven mils).
TheNRCstaffdoesnotrequirethataturbinetriponhighvibrat(onbein i
place and the licensee followed the applicable requirements of the Code of Federal Regulations,10 CFR 50.59, in analyzing the acceptability of removal of the turbine trip.
The licensee has reported the reactor shutdowns and the reactor trip caused by the turbine generator vibrations and has informed the NRC staff of the removal of the turbine generator vibration trip.
We have reviewed these reports and conclude that operation without the turbine generator trip is acceptable and will not represent any undue risk to the health and safety of the public.
Sincerely, 1 Fl Dennis M. Crutchfield, Director DivisionofReactorProjects-III,IV, V and Special Projects Distribution Docket 4 tle' DCrutchfield FSchroeder JACalvo P0'Connor PNoonan DMossburg, PMAS NRC PDR (w/ incoming)
TMurley/JSnieznek FMiraglia RStarostecki JFunches J81aha PShea
- SEE PREVIOUS CONCURRENCE PD4*
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PO4*
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P0'Connor:as PNoonan JACalvo FSchroeder DCrutchfield 5/07/87 5/07/87 5/07/87 5/07/87 5/ 3 /87
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smaller vibrations occuring when the temperatures were lower.
The licensee has air conditioned the exciter housing as a temporary corrective measure and the vibrations have been reduced to approximately four to five mils with some readings as low as 3.2 mils.
The original design of the Wolf Creek turbine generator included a turbine trip on high vibration (greater than seven mils).
This trip does not serve a reactor safety function.
It was installed to alert the operators to vibrations that could damage the turbine generator and result in financial loss to the owners.
The turbine generator is located in a separate building from the reactor and serves no safety related purpose.
No equipment that is required to safoly shutdown or cool the reactor is located in the turbine building. -The NRC staff has reviewed the potential failure mechanisms of the turbine and has 4
concluded that a turbine generator failure will not result in damage to reactor system components necessary for safe shutdown and cooling of the reactor.
In consultation with the turbine generator vendor, the licensee has eliminated the turbine trip on high vibration that previously was installed and replaced it with a turbine vibration alarm at the same level of vibration (seven mils).
The NRC staff does not require that a turbine trip on high vibration be in place and the licensee followed the applicable requirements of the Code of Federal Regulations,10 CFR 50.59, in analyzing the acceptability of removal of the turbine trip.
4 The licensee has reported the reactor shutdowns and the reactor trip caused by the turbine generator vibrations and has informed the NRC staff of the removal of the turbine generator vibration trip. We have reviewed these reports and conclude that operation without the turbine generator trip is acceptable and will not represent any undue risk to the health and safety of the public.
Sincerely, 4
Dennis M. Crutchfield, Assistant Director Project Directorate - IV Division of Reactor Projects - III, IV, V and Special Projects Distribution Docket File DCrutchfield P fkc%
FSchroeder JACalvo P0'Connor PNoonan DMossburcl PMAS NRC POR (w/ incoming)
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,E WASHINGTON, D. C. 20555 Hay 13,1987 Mr. Paul Hale 12912 E. 24th Streets Tulsa, Oklahoma 74134
Dear Mr. Hale:
This is in response to your letter which expressed your concern regarding tur-bine maintenance and balancing at the Wolf Creek Generating Station located You further indicated that you were concerned about near Burlington, Kansas.
the adequacy of the corrective measures implemented by the licensee because the plant has tripped subsequent to returning to operation.
Large rotating equipment, such as turbine generators, normally experience small vibrations as they operate.
The turbine-generator at Wolf Creek is equipped with instruments that measure these vibrations and alert the opera-tional staff if they become excessive.
At Wolf Creek these instruments also tripped the turbine generator off-line if these vibrations exceeded seven mils (seven thousandths of an inch).
The Wolf Creek turbine generator had been in commercial operation for a)proxi-mately one year at Wolf Creek prior to the scheduled refueling outage t1at began in mid-October 1986.
During this period of operation turbine generator vibration was acceptably low, typically in the three mils (0.003 inch) range.
During the October 1986 refueling outage the licensee, at the suggestion of the turbine generator vendor modified the turbine generator to exciter alignment byapproximatelysevenmIlstoavoidvibrationproblemsthatthevendorhad observed at other facilities. However, when the plant was returned to service in December 1986 the turbine generator vibration, as measured at the #12 bearing at the exciter, had increased to the five to six mils range.
On January 17 the reactor was shut down for a planned outage to rebalance the Following return to operation on January 20 the turbine turbine generator.
tripped on high vibration in the turbine generator causing a reactor trip.
Additional balancing weights were added during the January 20 shutdown but the vibration continued.
On January 31 the reactor was again shut down to permit an inspection of tur-bine generator mechanical tolerances and alignment of rotating components.
Hinor misalignment was measured in the turbine-generator to exciter coupling.
The turbine generator vendor and licensee believe that this misalignment, been rather than an imbalanced rotor, is causing the vibrations and plans have made to re) lace the coupling during the next refueling outage currently sche-r ll 1987.
i duled for a
During these investigations it was determined that the magnitude of the vibra-tions was influenced by the temperature of in the vicinity of the excitu with
Mr.' Paul Hale smaller vibrations occuring when the temperatures were lower.
The licensee has air conditioned the exciter housing as a temporary corrective measure and the vibrations have been reduced to approximately four to five ails with some readings as low as 3.2 mils.
The original design of the Wolf Creek turbine-generator included a turbine trip on high vibration (greater than seven mils).
This trip does not serve a reactor safety function.
It was installed to alert the operators to vibrations that could damage the turbine generator and result in financial loss to the The turbine generator is located in a separate building from the owners.
reactor and serves no safety related purpose.
No equipment that is required to safely shutdown or cool the reactor is located in the turbine building.
The NRC staff has reviewed the potential failure mechanisms of the turbine and has concluded that a turbine generator failure will not result in damage to reactor system components necessary for safe shutdown and cooling of the reactor.
In consultation with the turbine generator vendor, the licensee has eliminated the turbine trip on high vibration that previously was installed and replaced it with a turbine vibration alarm at the same level of vibration sevenmils).
The NRC staff does not require that a turbine trip on high vibrat(ion be in place and the licensee followed the applicable requirements of the Code of Federal Regulations,10 CFR 50.59, in analyzing the acceptability of removal of the turbine trip.
The licensee has reported the reactor shutdowns and the reactor trip caused by the turbine generator vibrations and has informed the NRC !.taff of the removal of the turbine generator vibration trip.
We have reviewed these reports and conclude that operation without the turbine generator trip is acceptable and will not represent any undue risk to the health and safety of the public.
Sincerely, f r/
Dennis M. Crutchfield, Director DivisionofReactorProjects-III,IV, VandSpecialProjects Distribution Docket File DCrutchfield FSchroeder JACalvo P0'Connor#
PNoonan DMossburg,PMAS
<QGC PDR (w/incomingD THurley/JSnieznek FMiraglia RStarostecki JFunches JBlaha PShea
- SEE PREVIOUS CONCURRENCE PD4*
PD4*
PD4*
AD4R*
P0'Connor:as PNoonan JACalvo FSchroeder DCrutchfield 5/ 3 /87 5/07/87 5/07/87 5/07/87 5/07/87
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UNITED STATES
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g NUCLEAR R:.GULATORY COMMISSION 3
-l WA 3HINGTON, D. C. 20655 s.,...../
FR0H: PAUL HALE ORIG. DUE DATE:
TICKET NO.: 879118 D0C. DATE: UNDTD T0:
NRC 5/20/87 NRR REC'D DATE: 4/29/87
- YELLOW **
FOR SIGNATURE OF:
(/LLNbfYkffY DESCRIPTION:
cc: MURLEY/SNIEZEK MIRAGLIA h
CONCERNS RE WOLF CREEK STAROSTECKI FUNCHES u
BLAHA MOSSBURG REFERRED T0: DRSP DATE: 4/29/87 CONTACT: \\ CRtHCHFIELD I
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PLEASE REVIEW THE DUE DATE IP91EDIATELY:
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IF THE DUE DATE DOES NOT ALLOW ADEQUATE TIME TO RESPOND TO THIS TICKET, YOU MAY REQUEST A REVISED DUE DATE. THE REQUEST MUST INCLUDE A VALID JUSTIFICATION AND Z
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