ML20049A898
| ML20049A898 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 09/28/1981 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Counsil W CONNECTICUT YANKEE ATOMIC POWER CO. |
| References | |
| TASK-03-06, TASK-3-6, TASK-RR LSO5-81-09-070, LSO5-81-9-70, VYDEC-20B20, NUDOCS 8110020361 | |
| Download: ML20049A898 (8) | |
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Septestcr 28, 1981 Docket No. 50-213 L505-81..09-070 Itr. W. G. Counsil. Vice President nuclear Engineering and Operations Connecticut Yankee Ate:4tc Power Company Post Office Box 270 Hartford, Connecticut 06101
Dear Mr. Counsil:
SUBJECT:
I!ADDAli NECK - SEP TOPIC III-6, " SEISMIC DESIGN CONSIDERATIONS" Our letters to you dated August 4,1980 and April 8,1981 requested in ac-cordance with 10 CFR 50.54(f) of the Comission's regulations that you submit plans and proceed with, a seinic reevaluation program for the Had-dam Meck facility and that you provida justification for your conclusion that operation is justified in the interim until the seismic reevaluation and any necessary upgrading is complete.
We have reviewed your basis for continued operation addressed la your let-ters dated Septerber 15, 1980 end June 11, 1981 and have concluded that continued operation is justified under the following conditions:
- 1) results of seismic analysis are submitted for NRC review on the sched-ule specified in your June 11, 1981 letter; and
- 2) a schedule for completion of the assessment of the structural integrity NW of the plant equipment (mechanical and electrical) be submitted within 30 days of receipt of this letter. The schedule should indicate that the remaining analyses be enmpletM and submitted to the staff no later
' than June 1982; and p 63E [ob
- 3) any modifications shown to be necessary that are not implemented by ADD' January 1,1983 are to ha justified on a case-by-case basis with a g,y schedule specified.
- 7. a,4./.s Enclosed is our Safety Evaluation Report.
Sincerely, 8110020361 810928 PDR AUCCK 05000213 p
PDR Dennis H. 'Crutchfield, Chief AD:SA:DL Operating Reacters Branch No. 5 Glainas
- See previous yellow for additional Division of Licensin9 9/ /81 concurrences.
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Docket No. 50-213 LS05.
Mr. W. G. Counsil. Vice President Nuclear Engineering and Operations Connecticut Yankee Atomic Power Company Post Office Box 270 Hartford, Connecticut 061 01 Dear Mr. Counsil4
SUBJECT:
HADMM NECK - SEP TOPIC III-6, " SEISMIC DESIGN CONSIDERATIONS" Our letters to you dated August 4,1980 and PApril 8,1981 requested in accor-dance with 10 CFR 50.54(f) of the Commission's regulations that you submit plans and proceed with a seismic reevaluation program for the Haddam Neck facility and that you provide justification Jbr your conclusion that continued operation is justified in the interim until the seismic reevaluation and any necessary upgrading is complete.
We have reviewed your basis for continued operation addressed in your letters dated September 15, 1980 and June ll,1981 and have concluded that continued operation is justified under the following conditions: (1) results of seismic analysis are submitted for NRC review on the schedule specified in your June 11, 1981 letter and (2) any modifications shown to be necessary as a result of the seismic analysis which are not implemented by January 1,1983 are justified on a case by case basis with a schedule for implementation.
Enclosed is our Safety Evalpetion Report.
Sincerely, 4
Dennis M. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing
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Docket No. 50-213 LS05 Mr. W. G. Counsil, Vice President Nuclear Engineering and Operations Connecticut Yankee Atomic Power Company Post Office Box 270 Hartford, Connecticut 0(,1 01
Dear Mr. Counsil:
SUBJECT:
HADDAM NECK - SEP TOPIC III-6, " SEISMIC DESIGN CONSIDERATIONS Our letters to you dated August 4,1980 and April 8,1981 requested in accor-dance with 10 CFR 50.54(f) of the Connission's regulations that you submit plans and proceed with a seismic reevaleation program for the Haddam Neck facility and that you provide justification for you conclusion that continued operation is justified in the interim until the seismic reevaluation and any necessary upgrading is complete. We have reviewed your seismic reevaluation program forwarded by your letters dated September 15,1980,and June 11, 1981.
We have reviewed your basis for continued operation and have concluded that continued operation is justified under the following conditions:- (1) results of seismic analysis are submitted for NRC review on the schedule specified in your June 11, 1981 letter and (2) any modifications shown to be necessary as a result of the seismic analysis which are not implemented by January 1,1933 l
are justified on a ::ase by case basis with a schedule for implementation.
Enclosed is our Safety Evaluation Report.
(
Sincerely, l
Dennis M. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing
Enclosure:
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HADDAM NECK Docket No 50-213 Mr. W. G. Counsil CC Day, Berry & Howard Counselors at Law c3 One Constitution Plaza Hartford, Connecticut 06103 Superintendent Haddam Neck Plant RFD #1 Post Office Box 127E East Hampton, Connecticut 06424 Mr. Richard R. Laudenat Manager, Generation Facilities Licensing Northeast Utilities Service Company P. O. Box 270 Hartford, Connecticut 06101 J
Russell Library 119 Broad Street Middletown, Connecticut 06457 Board of Selectmen Town Hall Haddam, Connecticut 06103 Connecticut Energy Agency ATTN: Assistant Director Pesearch and Policy Development Department of Planning and Energy Policy 20 Grand Street Hartford, Connecticut 06106 U. S. Environmental Protection Agency Region I Office ATTN: EIS C0ORDINATOR JFK Federal Building Boston, Massachusetts 02203 o
Resident Inspector Haddam Neck Nuclear Power Station c/o U. S. NRC East Haddam Post Office East Haddam, Connecticut 06423
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BASES FOR CONTINUED OPERATION INTERIM SEISMIC SAFETY FOR HADDAM NECK PLANT Docket No. 50-213, A01629 1.
INTRODUCTION In accordaace with the Commission Regulation 10 CFR 50.54(T), letters were issued on August 4,1980 (Reference 1) and April 8,1981 (Reference 2) to Connecticut Yankee Atomic Power Company (CYAPCo) requesting the licensee to submit plans and proceed with a seismic evaluation program for the Had-dam Neck facility and to provide justification for continued operation for the interim until the seismic reevaluation program is complete.
In res-ponse to these letters, the licensee submitted its basis for continued operation on September 15,1980 (Reference 3) and June 11, 1981 (Reference 4).
The staff's evaluation of the basis for continued operation during the time period for the seismic reevaluation program follows.
II.
SEISMIC HAZARD CONSIDERATION The original seismic design of the Haddam Neck facility was 0.179 zero period acceleration (ZPA) Housner spectra.
The licensee has initiated a seismic reanalysis program based upon their own site specific spectra (Refercnce 5).
In its letter dated August 4,1980, the staff directed the licensee to pro-ceed with its seismic reevaluation program and recommended use of the NRC developed preliminary site specific spectrum (0.219 peak ground accelera-tion) as the free field ground mc: ion for the Haddam Neck plant site (Reference 1).
This preliminary spectrut uas associated with earthquake return periods of the order of 1,000 to 10,000 years.
This site spectrum was finalized by the staff on June 17, 1981 (Reference 6).
in Reference 3, the litansee provided a comparison of the 0.179 ZPA ground spectrum being used for the Haddam Neck studies with the 0.21g ZPA NRC-recommended site specific ground spectrum. The licensee's spectrum is more conservative than the NRC's spectrum except for frequencies around 15H.
Based upon the methods being used for seismic reanalysis of struc-z tures, systems and components and the small differences between NRC recom-mended spectra and CYAPCo spectra, the staff concluden that CYAPCo spectrum is appropriate for seismic reanalysis.
III.
SEISMIC RESISTANCE CAPACITY OF STRUCTURES, SYSTEMS AND COMPONENTS As stated previously, most of the safety related structures, systems, and components were originally designed for a seismic input of 0.179 Housner spectra. As part of the Systematic Evaluation Program (SEP), the licensee began its seismic reevaluation program in 19/9 using the 0.179 site specific
, spectra.
On February 21 and 22,1979, a site visit was made by the staff and its consultants to discuss the progress being made on the seismic studies for the facilities.
The scope of initial seismic reevaluation program includes containment structure, Reactor Coolant System (RCS) piping, RCS components and their supports, and other structures which house equipment necessary for a safe shutdown (screenwell, primary auxiliary building, control room, auxiliary feedwater. pump room) following a seismic event and coincident loss of offsita power. The generation of floor response spectra for all structures mentioned above was also included.
Our letters of August 4,1980 and April 8,1981, requested the licensee th include in its seismic reevaluation program the following:
- 1) The integrity of the reactor coolant pressure boundary;
- 2) The integrity of fluid and electrical distribution systems related to safe shutdown and engineered safety festures, and;
- 3) The integrity of mechanical and electrical equipment and engineered safety features.
In its response to NRC letters, the licensee revised the program scope and-schedule for the seismic reevaluation (References 4 and 7-).
The licensee has completed the analyses and evaluations of Containment Shell, Containment Interior Structures, Screenwell, and Auxiliary Feedwater Structure. The analyses and evaluations of Service / Turbine Building, Primary Auxiliary Buildings and the Reactor Coolant System are in progress. The licensee's analysis to dare has identified some structural modifications to the Turbine /
Service Building and minor structural modifications to the Primary Auxiliary Building and Screenwell (Reference 7).
In general, design margins of at least 2 to failure typically exist in design codes and inherent seismic design conservatisms for nuclear power plant structures. Based upon the methods being used for seismic reanalysis of structures, systems, and components and the small differences between NRC recommended spectra and CYAPCo spectra (i.e. less than 20% at frequencies above 15 H.) the staff concludes thatithe increase in input motion due to z
the difference in spectra is small and is easily accomodated by the inherent seismic resistance capacity of structures, systems, and components. Our consultant, Dr. W. J. Hall, has reviewed the up-to-date information available to him and reached similar conclusions. (See Enclosure 1)
In response to NRC letters of January 1 and July 28, 1980, on " Anchorage and Support of Safety-Related Electrical Equipment" issues, the licensee ident-ified 36 items which required evaluation.
Calculations have been performed to demonstrate the adequacy of either the original support configuration or the modified support configurations,as appropriate. All required modifica-tions were completed by January 31, 1981.
3-Based upon the original design and the analyses and evaluations conducted to date, it is clear that the original design of structures, systems, and components resulted in seismic capabilities beyond their original design.
IV. ACTIVITIES TO IMPROVE SEISMIC RESISTANCE OF THE FACILITIES In Reference 4, the licensee indicated that CYAPCo is approximately 90%
complete with the analyses and evaluations of the following plant struc-tures:
Containment Shell, Containment Interior Structure, Screenwell, Auxiliary Feedwater Structure, Auxiliary / Turbine Buildings, and Primary Auxiliary Building.
In addition, assessments of the seismic adequacy of the new diesel generator building and spent fuel building will be performed and completed by January 1,1982 and July,1982, respectively.
CYAPCo is approximately 90% complete with the modeling of the reactor coolant system and has developed as-built: piping isometrics and complied necessary information for the seismic reanalyses of safety related pip-ing systems. The modeling of several piping systems is in progress. The scheduled completion date for all required seismic analyses is July 1982.
The installation of any modifications shown to be necessary to assure adequate safety margins is scheduled prior to startup from the 1984 re-fueling outage.
V.
CONCLUSION Based upon the above considerations, the Haddam Neck plant can continue to operate with no undue risk to the health and safety of the public dur-ing the time required to complete the seismic analysis under the follow-ing conditions:
- 1) results of seismic analysis are submitted for NRC review on the sched-ule specified in your June 11, 1981 letter; and
- 2) a schedule for completion of the assessment of the structural integrity of the plant equipment (mechanical and electrical) be submitted within 30 days of receipt of this letter. The schedule should indicate that the remaining analyses be completed and subuitted to the staff no later than June 1982; and
- 3) any modifications shown to be necessary that are not implemented by January 1, 1983 are to be justified on a case-by-case basis with a schedule specified.
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REFERENCES 1.
D. G. Eisenhut letter to W. G. Counsil, dated August 4,1980.
2.
D. M. Crutchfield letter to W. G. Counsil, dated April 8,1981.
3.
W. G. Counsil letter to D. M. Crutchfield, dated September 15, 1980.
i 4
W. G. Counsil. letter to D. M. Crutchfield, dated June 11, 1 981.
5.
W. G. Counsil letter to D. M. Crutchfield, dated August 5,'1980.
l 6.
D. M. Crutchfield letter to all SEP Owners (except San Unofre'l),
dated June 17, 1981.
7.
Sunmary of May 21,'1981 meeting by W. A. Paulson, dated June 22, 1981.
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ENCLOSURE 1 Lahvretice Livermore National Laboratory j
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July 31, 1981 SM 81-206 Mr. P. Y. Chen Systematic Evaluation Program Branch Division of Licensing Office of Nuclear Reactor Reg.
U.S. Nuclear Regulatory Commission Washington, D.C.
20555
Dear P. Y.:
I have enclosed two letters from W. J. Hall regarding continucd operation of Yankee Rowe and Haddam Neck plants. The seismic input issue raised in the Yankee Rowe letter is being reviewed by Don Bernreuter of LLNL. He will b6 corresponding with the SEP Branch Staff on this issue in the next few days.
In addition, I am transmitting D. A. Wesley's latest evaluation of Haddam Neck's program plan.
Sincerely, M
Thomas A. Nelson Structural Mechanics Group Nuclear Test Engineering Division TAN /mg 0077m Enclosure I
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CH AMP AIGN. lLLihols 61620 217 35t Ott3 July 23,1981 1
Mr. T. A. Nelson L-90 Lawrence Livermore Laboratory j
P. O. Box 803 Livermore, CA 94550 Re:
Connecticut Yankee Atomic Power Ccmpany -- Haddam Neck Plant Docket No. E0-213 LLL Agreement 1523501
Dear Mr. Nelson:
Comments arising from my review of the Haddam Neck Nuclear Power Plant and in particular its ability to accommodate seismic effects follow.
I'have in hand the following material for review pertaining to this case at this particular point in time.
Matcrial orihinatino from Connecticut Yanket Atonic Power Company or North-east Utilif.ies 1.
Letter of January 9, 1978 (13 pages) -- pertaining to fracture toughness and potential for lameller tearing of the steam generator (SG) and reactor coolant pump (RCP) support materials 2.
Letter dated January 17, 1980 (3 pages with attachment 1) -- per-taining to Systematic Evaluation Prograd - seismic reevaluation 3.
Letter dated August 5, 1980 (2 pages with attachment 1) -- System-atic Evaluation Program - seismic reevaluation 4.
Letter dated September 15, 1980 (5 pages) -- Scismic Reevaluation Program 5.
Letter dated October 14, 1980 (3 pages) -- Seismic Reevaluation i
Program 6.
Letter cated December 30, 1980 (8 pages) -- (EP - Anchorage and Support of Safety Related Electrical Equipmer.:
7.
Letter cated June 11, 1981 (6 pages) -- SEP - SEP Topic III Seismic Design Considerations
r-2 These letters for the most part contain reports of progress pertaining to work carried forward on the seismic reevaluation program.
Material originating from U. S. Nuclear Regulatory Commission 1.
February 2, 1979 (2 pages with enclosure 1 and 2) -- pertainir.: to Heddan. Neck Plant 2.
December 30, 1980 (2 pages with attachments pertaining to anchorage and support of safety related electrical equipment 3.
April 8,1981 (2 pages with attachment 1) -- partaining to SEP topic III-6, " Seismic Design Considerations" 4.
Letter of June 22, 1981 (18 pages) -- Summary of Meeting (May 21, 1981) with CYAPC on Haddam Neck 5.
Report dated March 9,1967 entit'ed " Report to Advisory Committee on Reactor Safeguards in the matter of Connecticut Yankee Atomic Power Company -- Haddam
- % Plant, Report No. 3, Additional Informa-tion" Material originating with Lawrence Livermore Laboratory 1.
Draft report dated January 1979 entitled " Seismic Design Bases and Criteria for Connecticut Yankee Nuclear Generating Ctation, Haddam, CT 2.
Two letters (January 5,1981 and May 12,1981) tc T. A. Nelson (LLL) from D. A. Wesley (S!%) re Haddam Neck review Material originating from N. M. Newmark and W. J. Hall 1.
Letter dated 16 January 1967 (3 pages - proposed draft) -- pertain-ing to Connecticut Yankee Atomic Power Plant - Docket No. 50-213 2.
Letter dated March 9, 1967 (2 pages) -- pertaining to Connecticut Yankee Atom;c Power Plant 3.
Letter dated 24 Marr.h 1967 (4 pages) -- pertaining to Connecticut Yankee Atomic Power Plant In addition to the above material, on February 21 and 22,1979, I made a site visit to the Haddam Neck Plant with the second day being devoted to technical discussions on the progress being made on the Systematic Evalua-tion Program studies.
At the time of that meeting I was provided with a
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number of miscellaneous summary sheets and draft material (mostly undated);
this material is not listed above.
The September 15,1980 Connecticut Yankee letter contains a plot showing the 0.17 g ZPA Haddam Feck seismic response spectrum as employed for the Haddam Neck studies compared to the 0.21 g ZPA NRC-suggested site specific response spectrum.
It is noted that the NRC-suggested spectrum falls close to that specified for use by Connecticut Yankee and, depending upon the margins of safety, it is possible that the assessment of adequacy in retrofitting de-veloped.in the Connecticut Yankee studies can be.showr. to be satisfactory.
Although I appreciate the basis upon which the USNRC site specific spectra were generated, I do wish to note that Dr. Newmark (prior to his death) and
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I expressed Scncern verbally to W. Russell and T. Cheng of USNRC that in some cases (and in this ce;e for the Connecticut Yankee Plant) the amplified velocity region appeared to be low compared to standard Reg. Guide 1.60 or
' NUREG CR/0098 spectra which we normally would recommend for use.
As a re-sult of this observation, and also since 'this is an older operating plant, when reviewing the physical resistance of critical safety systems in such cases as this I recommend particular attention be paid to the margins that may be present to re:ist o/erloading f rom seismic effects.
The letter dated August 5,1980 from Connecticut Yankee with attachments 1, 2 and 3 notes that the structural analysis studies were expected to be com-pleted by January 1981, but later letters suggest the studies may not yet be complete.
It should be,noted that in the letter prepared by Dr. Newmark-dated 16 January 1967 attention was directed to the fact that the steel liner-around the inside of the cylindrical portion of the containment vessel was designed to carry the tangential earthquake shear and that in the original design no provision was made for the shear being carried in the concrete con-tainment walls.
It is my undsrstanding that at about that time, or perhaps slightly later, tests <9re mace by the licensee to obtain demonstration of the resistance that coulc be provided by the concrete cylindrical walls and hopefully an updated summary of such information will be contained in the.
summary report that is being prepared by the licensee.
With regard to the reactor coolant system and component analyses it is in-dicated in the August 5,1980 letter that these are in various stages of
-development and completion.
Stress criteria are presented in Attachment 2.
to the August 5,1980 letter.
It is assumed-that the final report on this topic will contain discussion of the bases of the analyses and calculations that were carried out and provide some comparativ'e measure of the adequacy of highly stressed regions including indication of the nature of the margins that may remain in the event of any potential overloading from seismic effects.
[
It is apparent from the most recent letters and from the minutes of the Ma'y 21, 1981 meeting that the SEP review analyses are going forward promptly with regard to structures, piping and equipment.
It is only fair to note that in i
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light of the original design and the manner in which it was carried out it is clear that the structures for the plant contain some distinct level of inherent seismic resistance.
On this basis, as long as a reasonable program
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schedule is maintained, and the upgrading process for structures, piping and ec.uipment is carried out promptly I see no reason why this' plant should not be permitted to continue in operation while the upgrading program is underway.
Sincerely yours, IU W. J. Hall CC:
W. T. Russell, USNRC i
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