ML17207A885
| ML17207A885 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 02/25/1980 |
| From: | Eisenhut D Office of Nuclear Reactor Regulation |
| To: | Robert E. Uhrig FLORIDA POWER & LIGHT CO. |
| References | |
| NUDOCS 8003140421 | |
| Download: ML17207A885 (19) | |
Text
Dr. Robert Uhrig Because of the general nature of the information sought in Enclosure 2 we are transmitting a copy of this enclosure to Westinghouse by separate letter.
As discussed in the December 17, 1979 meeting Me urge you to address the generic aspects of this problem and to coordinate your responses through an owner's group.
Sincerely, Darrell G. Eisenhut, Acting Director Division of Operating Reactors
Enclosures:
1.
IE Information Notice No. 79-37 With Errata Sheet 2.
Request for Information Related to Turbine Disc Cracks - 20 Day Response cc:
v/enclosures See next page
- SEE PREVIOUS YELLOW FOR CONCURRENCES OFFlCEP SURNAME OAVE P ORBb'4:DOR*
PErickson/cb 1/24/80 C-ORB)4:DOR RReid*
1/24/80 A-R D
Ut 1/25/80 21@~0 A-AO-ORP:DOR WGammi 1 1 "
ORBlmJ'1'DOR MRoss
$gg 2/P)/80, NRC FORM 318 (9 76) NRCM 0240 4V.S. GOVERNMENT PRIN flNG OFFICE: 1979.289 369 6 QPal40
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~a Likewise, you are requested to provide and address the safety significance of the information in Enclosure 3 within 60 days of the date of this letter.
Because of the general nature of the infornIation sought, in Enclosures 2 and 3 we are transmitting a copy of these enclosures to ftestinghouse by separate letter.
As discussed in the December 17, 1979 meeting we urge you to address the generic aspects of this problem and to coordinate your responses through an owner's group.
Sincerely, Darrell'G. Eisenhut, Acting Director Division of Operating Reactors.
Enclosures:
l.
IE Information Notice t/o. 79-37 With Errata Sheet 2.
Request for Information Related to Turbine Disc Cracks - 20 Day Response 3.
Request for Information Related to Turbine Disc Cracks - 60 Day Response cc:
w/encl osures See next page OFFICE )>
SURNAME OATF P
~ i ORBN:DOR PErickson i~jYio" C-ORBS'4:DOR 1jr~0 A-AD-RP:
OR A-D:DOR DEtsenhut t
1/
/80 NRC FORM 318 {9.76) NRCM 0240'V.S. GOVERNMENT PRINTING'FFICE: 1979 289 369
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Fl,orida,Power 5 Light pany CC:
Robert Lowenstein, Esquire Lowenstein, Newman, Reis 5 Axelrad 1025 Connecticut Avenue,'.W.
Washington 0.
C.
20036 Norman A. Coll, Esquire McCarthy, Steel, Hector 8 Davis 14th Floor, First National Bank Building Miami, Florida 33131 Mr. Jack Shreve Office of the Public Counsel Room 4, Holland Bldg.
Tallahassee, Florida 32304 Indian River Junior College Library 3209 Virginia Avenue Fort Pierce, Florida 33450
~~ UNITED STATES
-.;: ISIHS RQ.:
~70
'. hUC~REGULATORY CONQSSION
".'," Accession No..-
'--'='.- ~'- OFFICE OF INSPECTION ANO EHFORCEHENT
'=,
. 7910250525
.,"": '.. - - MASHIHGTQH, D.C.
20555 December 28, 1979
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IE Information Notice Ho. 79-37 V
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CRACKIHG IH LOV 'PRESSURE TURBINE DISCS:
r Description of Circumstances=
An anonymous letter was received by the Director-of the Office of Inspection and--",-;--'=-,-.-'-
Enforcemen. -on November 17, 1979 Mich a1leged possible violation of Part 10 CFR 50.55e and/or 10 CFR.21 Regula ions concerning reportability of recently discovered stress corrosion cracking in Ves inghouse 1800 rpm low pressure turbine discs.
4'estinghouse had rade a presen ation on the turbine disc cracking to electric utility executives on October 30, 1979 Telephone discussions between the HRC staff and westinghouse's Turbine Division on November 20, 1979 established tha cracking, attributed to stress corrosion phero.",ena, had been found in the keyway areas of several LP turbine discs at operating plants and that inservice inspection techniques (i.e., in situ ultra-soni= e"a-.ination) for crack detec ion have been developed and are being imple-uen o."'n he field.
The Of,ice o. inspection and Enforcement was also notified ol tiove DeT 20, 1979 tha duri ng the curr ent overhaul of Commonwealth Edi son s
Z',on Unit 1 LP turbine, ul resonic examination revealed embedded cracks locaed on the inlet side on the disc bo".e area where no cracks had been previously observed.
Ultrasonic measurem n~s indicate this disc bore cracking is of greater depth than tho keyNay cracks found to date.
According to westinghouse these bore cracks have been metallurgically examined and preliminary findings show them nci to be typical of classical stress corrosion cracking observed in the keyways.
The probable cracking mechanism and impac on disc integrity is being further evaluated. by westinghouse.
A mee.ing was held on December 17, 1979 between the HRC staff, westinghouse and u ility represen etives to discuss the disc cracking problem, repair aler-
- riatives, urbine =issile evaluation, inspection techniques and plan inspection priorities.
In response to he smffs'equest, Westinghouse provided the
- staf, an ~ada ed report on Decker 21, %79 regarding the curren. iield inspection program that included a list of nuclear power plants already inspected, recom-menced inspection schedules and pertinent information related to LP tur'bines where "racks have been observed.
Inspections to date have identified turbine disc c-. acks at Surry Unit 2, Point Beach Unit 2, Palisades, Indian Point Unit 3 and Zion Unit 1.
All units except Point Beach Unit 2 will make repairs before the plants return to power.
Point Beach returned to power on Oecember 23, 1979 vi h z smell crack in the Ho.
2 disc of LP Turbine Ho. 2.
An analysis by Vestin"ho se indicated the the observed crack will not attain critical dimensions during 28 additio".al non hs of'rbine operation.
The NRC staff is evaluating the turbine inspection results and analysis by Mestinghouse.
4 Q
I gE information Notice No.
7...
'cember 28,3979"-"--
Pane 2 of 0 P
a of a
, J.
- eq-v y
-'estinghouse a1so notified the staff that extrapolation of information ob+~ined from Indian Point Unit 3 inspection and analysis indicates that disc cracking-
-could be significant at Indian Point Unit 2 and the turbines should be >nspecteQ sooner than the spring outage of 1980.
The HRC staff is currently reviewing,
-~ Consolidated Edison's plans for prompt evaluation of this potential prob1em
.~
%san ~,." lists the PMR plants having Westinghouse l500/1800 rpm 4urbines.'-
The AA category represents those turbines which appear to have the.earl%est need for inspection..
With the exception of Yankee Rowe, Westinghouse has
. reconaended to utilities that, inspection of these ma'chines be completed by the Spring'3.980 outage period."
The Rowe unit is uninspectable by the present.
vlt-asonic techniques
'due to its design.
Westinghouse has recommended the, remaining machines of the Category A plants be inspected as their service periods approach five years or in the event significant corrosion problems become.
~ evident during this 'time.
The HRC staff is currently reviewing the need for inspe-tion of those PMR plants having other interfacing turbine designs shown in =n"losure '2.
Changes to the forementioned inspection s"hedules proposed by Mes inghouse may be necessary as new technical information becomes available.
Frc... the information available to the hRC 'staff at this ti.-.e it. appears that c-.a=king may be more generically widespread in turbine discs (e.g.,
key<<.ays and bore areas) than previously observed.
'It is important to note that the UT inspections performed by Westinghouse thus far were essentially limited to the ke~ays (disc outlet) of selected discs whereas the Zion Unit 1 inspection results indicate that examination of the disc bore section must be taken into account Also, Westinghouse is currently re-evaluating their previously estimated turbine missile energies based on recent missile test results from mode1 syne ric and non-symmetric missile impact tests.
Their preliminary findings, altjiough sub iect to change, now indicate possibl e hi gher mi ssi 1 e exit energi es in some cases h~n previously expected.
This Information Notice is provided as an early notification of a possibly s-c-..i ican ma ter, the alleoations and the oeneric sa e y implications of which a-e c -rre;=ly undergoing review by the HRC staff.
It is expected that recipients
~ill revie~ the information applicable to their facilities. If HRC evaluaions so =.r."-ica e, further licensee actions ray be requested or required.
Erbedded c
a king in key~ays and disc bore areas have been observed only in Westinghouse LP urbines thus far.
- However, the HRC staff believes tha turbines of oker'anufacturers should be included in consideration of this p'oblem.
Ho ~itten response to this Information Notice is required.
If you have any questions regarding this matter, please contact the Director of the app-.opriate H?C Regiona.l Office.
Enc1osures:
As stated
Enclosure 3.
UTILITY
- Florida, PQ.
Consolidated EO.
PASMY -="
. YEPCO Carolina P&L.
So. Calif. Ed.
Yankee A.P.
Misc. Hich. Pwr.
Consumers Pwr.
Cumonweal th Ed.
Co~nweal th Ed.
Florida PE L Hebraska PPD Misc. Hich.
Pwr.
Yiaine Yankee Ro"hester QE Horthern States Misc. P.S.
STATIOH Turkey Point Indian Point
- Indian Point
=-
Russel lville..
Surry Robinson San Onofre Rove Point Beach Pal isades Zion 3.
Zion 2 Turkey Point Cooper Point Beach Bailey Point Ginna Prairie Island Keweunee 1
4 1
2 1
1 1
1
\\
p 4
~nclosure 1 (Continued)
Page 2 of 3 CATEGORY A UTILITY STATION UNET Alabama Power Alabama Power Baltimore QL, Carolina PEL Carolina PQ Carolina PQ Carolina P8L Cincinnati ERE Farley
= Farl ey "1
,Calvert Cliffs Harris Harris-Harris Harris Zimmer 1;
23-Commonweal th Ed.
Cormonweal th Ed.
Commonweal th Ed.
Commonwealth Ed.
Byron Byron Braidwood Biaidwood 1
2 1
2 Connecticut Yankee Haddam Heck Dvke Po er Dvke Power HcGvir e t'cGvi re 1
2 Dvqvesne Lt.
Duquesne Lt.
Dvquesne Lt.
Shippingport Beaver Yalley Beaver Yalley Flordia Power Corp.
Flordia Power 5 Lt.
Flordia Power 6 Lt.
Crystal River St.
Lucie St.
Lucie 1
2 Ho ston LE P Houston LRP So.
Texas So.
Texas Louisiana P8L Y.etropol itan Ed.
Horthern States Pw"..
Vaterford Three Yii-le Island Prairie Island Pvb.
Service EM Pub.
Ser vice EK Sal em Salem 1
2 Pacific HE Paci ic GEE Diablo Canyon Diablo Canyon 1
2
V slnsvre I (OonÃnved) v CATEGORY A llTILITT P S Indiana P 5 Indiana Puget Sound PhL
. SHUD TVA 7VA 1%A Tm V"PCO YEPCO VEPCO YEPCO V=PCO V?PSS 4'PPSS
%GPSS
~~PSS M?PSS STATION Harbl e Hi1l Harbl e Hill.
. Skagit,~.
Rancho Seco Sequoyah Sequoyah Matts Bar watts Bar North Anna North Anna North Anna North Anna North Anna Hanford Mhp3 MNPS MNPS MHPS UHI:T. '
1 1
2 3
2 2
1 3
5 e
'V
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Enclosure 2
.0 UTILITY Duke Power Co.
Duke Power Co.
Duke Power Co.
OPPO Baltinore Electric 8 Gas Metropol itan Edison Indiana 8 Michigan Electri c Indiana 8 Michigan Electri c Nor heast Utilities Por 1 and Gener al Toledo Edison Arkansas Power E
Light i 'PPZS 5TATIOM Oconee Oconee Oconee-Ft. Calhoun Calvert Cliffs Three HHe Island D C.
Cook D.C.
Cook Mil1 stone Trojan Davis Besse Arkansas Nuclear One Han> ord UNIT 2'
1 1
2 1
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Errata Sheet For IE Information thtice Ho. 79-37 4
Page 1
~ragrag 2, line 9:
Change "inlet" to "outlet" 4
. Page 1
paragraph 3, lines 9 and 10:
Change "Point Beach Unit 2" to Point Beach Urit 1"..
Page 1. paragraph 3, line 10:
After Point Beach. Unit 1 add ar.
asterisk
("*")footnote and place a note at the bottom of the pace as Vollows:
~Wisconsin Electric Power Company orally notified the NRC project manage-.
on thvember 5 that turbine disc cracking had b
en observed at Po: nt Beach
$nit 1."
En=losurel, 1in':
Change "Russell ville" to "At'0"
.En=losur i, lin. 8:
Change to read:
"Yankee Atomic =lee r:c Yankee Rove" En=1 os ure En=1 osur 1, libras 9 and 15:
Change "Misc Yich hv" to 'Misc =le= Pwr" 1, lia 16:
Change to read "Paine Yankee Atomic hr. thine Yankee"
=n=los r 1,
page 3, line 13:
Dele.e as redundant referen"e tc !nrth Anre 2
k S
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E sure 2
0 1
REQUEST FOR INFORMATION RELATED TO TURBINE DISCS SITE SPE.IFIC GEl!ERAL QUESTIONS - To Bc "om leted in 20 Da s
I.
Provid th following information for each LP turbine:
A.
Turbine type 8
5mb r-of hours of operation for each LP turbine at time of last turbine insp ction or if not inspected, postulated to turbine inspection, C.
H~b r of turbine trips and overspeeds-D.
For each disc:
type of material including material specifications 2.
tensile properties data 3.
toughness properties data including Fracture Appearance Transition Temp rature and upper energy and temperature 4.
keyway temperatures 5.
calculated keyway crack size for turbine time specified in "B" above 6.
critical crack size 7.
ra io of calculated crack to critical crack size S.
crack growth rate calculated bore and key ay stress at operating design overspeed l0.
calculated Klc data ll..-..inim~-... yield strength specified for each disc Provide details of the results of any completed inservice inspection of LP turbin rotors, including areas examine.',
since issuance of an operating license.
For each indic-ion detected, provide details of the location of
-'he crack, it orier
- aration, and size.
Provide -he no-.:nnal water chemistry conditions for each LP turbine ano G seri="-e any condenser inleakag s or other si gnificant changes in secondary w:ater ch ~stry to this point in its operatino life.
Discuss the occurrence of cra-ks in any given turbine as related to history of secondary water chemistry in the unit.
IV.
~ vo r plart has not be n'inspected, describe your proposed schedule and ep-roach to nsure tl at turbine cracking does not exist in your turbine.
V.
YI.
Fyour plant h s been inspected and plans to return or has returned to power with cra=ks, provide your proposed schedule for the next turbine inspection an='he basis =or this insp ction schedule.
Indicate wheth r an analysis and evaluation regarding turbine missiles have be n p=-r onied for your plant and provided to the staff.
If such an analysis an".'valuation has been performed and reported, please provide appropri-ate referenc s to he available documentation In the event that such studies ha;e n t b en made, consideration should be given to scheduling such an action.
IP
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Describe what quality control and inspection procedures are used, for the disc bore and keyway areas.
Provide details of the Mestinghouse repai r/replacenent procedures:;
. -.=.".-, -,....;.-,=.
for the faulty discs.
2 2
%hat imam diate and long term actions are being tak=n by Mestinghouse o minimize future stress corrosion problems with turbine discs?
Mhat..-..
actions are being recottmended to utilities to ni nisi ze stress corrosion cracking of discs?
2 iden i y the impurities known to cause cracking in the low pressure-
=.'.
- turbines, and their sources.
Discuss. the relc ionship between steam gene;a or chemistry and steam chemistry relative t: the introduction of corrosive impurities into the turbine, i~clucin: phosphate,
- AYT, ZST, and BMR chemistry.
Discuss the mechanisr. of eposition of these impuri ies that can lead to their concontraticn ir. certain areas of
- keyways, and bores.
Y.
Vhat role does the refluxing action in the steam s=paration portion of th st a~ generator have on scrubbing corrosive iapuritia5 fron the st~au?
To wna-extent can he buildup o corrcsiv ittourities in the LP turbine be alleviated?
Mhat would be the effects of the following ac ions:
1.
Pumping moisture separa or condensate to corde.ser?
"eriodically moving point cf ccndensation tc t:-event localizeo buildup of corrosivo ir~urities?
y V
Describe fabrication and hea. treamen.
sequer,"e
~r discs, including ther<i exposure during shrinking operations.
VIII.
Discuss the effects of a~v local residual stresses on the cracking nechani sm P
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