ML19309F254
| ML19309F254 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 04/07/1980 |
| From: | Ippolito T Office of Nuclear Reactor Regulation |
| To: | Peoples D COMMONWEALTH EDISON CO. |
| References | |
| NUDOCS 8004290104 | |
| Download: ML19309F254 (4) | |
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April 7,1980 Docket tio. 50-249 Mr. D. Louis Peoples Director of fluclear Licensing Comonwealth Edison Company P. O. Box 767 Chicago, Illinois 60690
Dear Mr. Peoples:
During out continuing review of the Dresden Unit 3 GE turbine inspection findings, we have found it necessary to request that the following infor-mation be supplied on a schedule that will provide for review prior to startup from the current refueling outage.
1.
Description of the turbine disc inspection procedure 2.
Inspection results 3.
Justification for returning to power with UT indications (.1.e.
water cutting) 4.
Responses to the enclosed questions.
Some of this information may have been supplied in a GE submittal dated fiarch 27, 1980. To the extent that it is applicable to Dresden Unit 3, the GE document may be referenced.
Since the basic flRC concern about turbine disc cracking is the potential for interaction with safety related systems and components in case of a turbine failure, it wculd be prudent to perform an assessment of the potential for turbine missile damage at the Dresden Unit 3 facility.
Accordingly, please provide a schedule for your planned submittal of an analysis of strike and damage probabilities with your response to this request for information.
(See Question VI in enclosure.)
Sincerely, 1
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. Ippolito, Chief I
Operating Reactors Branch #3 Division of Operating Reactors
Enclosure:
l Request for Information l
Related to Turbine Discs cc w/ encl:
See next page
Mr. D. Louis Peoples Comronwealth Edison Company.
cc:
Mr. John W. Rowe Isham, Lincoln & Beale Counselors at Law One First National Plaza, 42nd Floor Chicago, Illinois 60603 Mr. B. B. Stephenson Plant Superintendent Dresden Nuclear Power Station Rural Route #1 Morris, Illinois 60450 Morris Public Library 604 Liberty Street Morris, Illinois 60451 Jimmy L. Barker U. S. Nuclear Regulatory Commission P. O. Box 706 Morris, Illinois 60450 Susan N. Sekuler Assistant Attorney General Environmental Control Division 188 W. Randolph Street Suite 2315 Chicago, Illinois 60601
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I.
Provide the foliewin; ir.f:rmaticr. f:r each LP turbir.e:
turbine type
- c..
3.
Number of hours of c;5ratica fcr each LP turbine at time of last turbine inspectica Or if not inspected, postulated to turbine inspection C.
Number of turbine trips and everspeeds D.
For each disc:
1.
type of material including material specifications 2.
tensile properties data 3.
toughness prcperties data including Fracture Appearance Transition Temperature and Charpy u;per steel energy and temperature 4.
keyway temperatures 5.
critical crack si:e and basis for the calculation 5.
calculated bcre and keyway stress at operating design overspeef 7
calculated K;; d!.a 5.
-inirum yielc s ring:n I;icied for each disc
? ovide details of the risults of any ccmplet d inservice inspection :#
'_? turbir.e ro.crs, ir:1_ ding areas examined, sic:e issuance of an c;ert:ine license. For each ir. fica:ica detected, provide details of the loca ic.
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of the indication, its crientatica, size, and pcstulated cause.
II:.
?revide the n:minal witer chemistry conditions for each LP turbine anc describe any condenser inieakages er other significant changes in water chemistry to this point it its c:srating life.
- ycur plant has nc: bee ; i.s:e: e:, describe y:ur :roposed schedule 1.d 1:: cach to ensure that ;;rbir.e cra: king d:es n:: exis in your turbiri, If your plant has bee, 'ni;e: ed ind ?lans to return er has returned i.
- rser with cracks or
- :r.er defects, provide your prc;osed schedule for
?.e next turbine inspec-icn and the basis for this inspection schedule, including postulated defect growth rate.
VI.
Indicate whether an analysis and evaluatien regarding turbine missiles have been performed f:r y:ur plan ar.d provided to the staff.
If such an
- nalysis and evaluati:n his been ;erf:rmed and reported, please provide a: rcariate references :: the available documentatien.
In the vvent tha: such studies hav3 n:- been ide, consideraticn should be given ::
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- heduline such an a::i:n.
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I Enclosure *3 4
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'.'E57IO:;5 - T: Ee C: :le ed in 30 Days
- isc.'ibe what quality c:r.trcl and inspectica procedures are used for the disc bore and key,ay areas.
II.
Pr: vide details of the Ger.eral Electric repair / replacement procedures i:r f aulty discs.
III.
What im ediate and icng term actions are being taken by General Electric
,nimi:e future " water cutting" problems with turbine discs? What a:-icns are being rec:=er.ded to utilities to minimize " water cutting" of discs?
IV.
Discribe fabrication and heat treatment sequence for discs, including
-herni exposure'.during shrinking operations.
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