ML20054L959
| ML20054L959 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 07/01/1982 |
| From: | Harstead G, Rothberg O HARSTEAD ENGINEERING ASSOCIATES, INC., NRC, Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20054L951 | List: |
| References | |
| NUDOCS 8207090104 | |
| Download: ML20054L959 (10) | |
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UNIED STAIES OF AFERICA h1ETEAR REGUIAIORY C0tifLSSION BEFORE 11E AlmIC SAETi AND IENSDC BOARD In the M$tter of
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Docket Ibs. 50-327
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CQfK W EAlmi EDISON COMPANY 50-249 (DresdenSt$ tion, Units 2$nd3 )
(Spent Nel Pool lbdific$tions)
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- 1ESTIFONY OF OWEN 0. ROIHBERG AND GUNNAR HARSTEAD REGARDING C01DNWEALTH EDISON'S PROPOSAL
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70 INSTAIL 33 HIGH DENSITY FUEL ~ STORAGE EACKS I,OwenO.Rothberg,dost$teasfollows:.
I $m cuployed by the United St$tes Nucle $r Regbl$ tory Cmmission $s a Strbetbr$1EngineerintheStrbetbralEngineeringBranchofthe Dibision of Engineering. A statment of my professional qE$lific$tions is $ttached as enclosbre.(1) to this $ffid$ hit.
I,Obnn$rHarstead,dost$te$sfollows:
I $m $ consElt$nt to the StrbetEr$1 Engineering Br$nch of the U. S.
NEcle$r Regblatory Ccxtmission. A st$tement of my profession $1 q$$lific$tions is $tt$ched as enclosbre (2) to this testimony.
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Commonwealth Edison Company, the Licensee, originally proposed to increase the storage capacity of the spent fuel pools at Dresden 2 and 3.
This proposal involved replacing the existing spent racks with 33 high-density poisoned racks. A Safety Evaluation Report was issued.on June 6, 1980, the essential conclusion of which was that the proposal was acceptable to the staff. The SEP Branch review of TOPIC IX-1 for Dresden 2 revealed that the seismic cnalysis of the new rack installation conducted by Commonwealth Edison did not adequately address several issues. Subsequently, all but one issue was resolved and the licensee was allowed to install five new racks in the Dresden 2 pool in order to support.a refueling outage.-
The single issue which remained unresolved was that it was not adequately demonstrated that the spent fuel pool floor could withstand the loads, including impact, which would be imparted should all 33 racks rock (tip) during a seismic event and fall back simultaneously. This testimony addresses that issue.
On October 2, L98l, Commonwealth Edison submitted to the staff a report entitled " Evaluation of the Effects of Postulated Rocking of Racks on Spent Fuel Pool Structures of Dresden Station Units 2 and 3."
In that report the results of a non-linear time history analysis of the potential effects of a seismic event, including the modeling.of rack impact on the pool floor due to tipping, were presented. The development of.the pool floor motion time-history used in this evaluation consisted of the following steps:
1.
The building structural model. developed by Lawrence Livermore Laboratory in NUREG/CR-0891 (Seismic Review.of Dresden 2 for.
SEP) was modified for the as-built condition.
2.
USNRC Regulatory Guide 1.60 response spectrum scated to 0.2g was selected as the basis for the input motion at the ground Level.
A synthetic time-history matching this response spectrum was developed.
3.
A time-history response analysis was performed using the building model (Item "1" above) and the synthetic time-history (Item "2" above). A seven preent building structural damping was used per USNRC Regulatory Guide 1.61.
4.
A response spectrum at the spent fuel pool floor level was developed using a two percent equipment damping.
The use of two percent damping is conservative since Regu!atory Guide 1.61 recommends four percent damping, and NUREG/CR-0098 recommends five to seven percent damping.
5.
The floor response spectrum developed as outlined in Item "4" above was smoothenedandpen;k-broadenedbyi 15 percent to account for building modeling and response uncertainties.
6.
A synthetic time-history was developed matching the peak-broadened floor response spectrum (Item "5" above). The peak acceleration for the syn-thetic time-history is about 20 percent higher than the actually computed' peak acceleration. This provided additional conservat. ism in the input motion.
The mathematical model of the rack / pool floor used in the analysis accounted for the non-Linear effects of fuel bundle " rattling" within the cells and of rack tipping on the pool floor. The results of the analysis indicated that the pool floor structure was weLL within its. capacity under simultaneous Loading from 33 racks. On December 14, 1981, the Licensee submitted additional arguments and responses to previous staff questions which supported his choice of seismic loading and method of analysis.
It was found that these presentations demonstrated suitable conservativism in the Licensee's analysis.
A non-linear analysis of the pool and rack -system.for Dresden 2 wa_s performed.
l It was found that'the spent. fuel pool. structure is conservatively capable of withstanding the postulated Loads imposed by the full 33 rack installation.
(G. Harstead; Report dated 5/19/82.)
i A comparison was also made of the recent Quad Cities spent fuel pool expansion seismic analysis with that used for Dresden2. Both plants are MKI BWR's founded on rock in the same tectonic province. Although the j
Quad Cities plant is arranged somewhat differently than at Dresden; the spent fuel pool structures are identical in dimensions and very sim.ilar in construction. The seismic event postulated for Quad Cities was a 0.22L3 maximum event based on the 1957 Golden Gate Park earthquake time history.
The floor response spectra at the Quad Cities pool floor was developed from this event and used for construction of the plant. The Latest seismic event
used for the Dresden analysis is as described previously.
I Although comparisons are somewhat complex and judgemental, it was considered
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that useful conclusions could be made regarding the adequacy of the proposed 33 rack Dresden installation by studying the results of the analysis performed for Quad cities. The Quad Cities 2 pool structure was found to be conservatively capable of withstanding the loads imposed by 3970 fuel modules which wiLL be
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arranged in 20 racks. The Dresden pools wiLL dach hold 3537 storage locations arranged in 33 racks. Since the Quad cities structures were found to be acceptable, it is considered that this providessome additional assurance, in '
- the form of yet another analysis, that the Dresden spent fuel pool structures
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are adequately constructed to withstand the loads which are postulated for their seismic event under full 33 rack load.
Accordinly, we find that the spent fuel pool expansion as proposed by the Licensee for a full 33 rack installation is acceptable.
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Owen O. Rothberg Structural Engineering Branch Division of Engineering U.S. NRC l
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Gunnar Harstead~
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BETTY LANE TAYLOR NOTARY PUBLIC OF NEW JERSEY My Cornmission Empires Sept. 9,1986 l -
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ENCLOSURE (1)
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OWEN 0. ROTHBERG PROFESSIONAL QUALIFICATIONS STATEMENT STRUCTURAL ENGINEERING BRANCH DIVISION OF ENGINEERING OFFICE OF NUCLEAR REACTOR REGULATION I am a structural engineer for NRC and responsible for rehiew of the safety analysis _ report for the Floating Nuclear Plant. My background is as follows:
1961,-
GraduatedUnihersityofFlorida,BachelorofCihilEngineering.
1962-1964 Graduate courses in naval architecture strength of materials andmathematicsatUnhiersityofCalifonia, Berkeley.
1961-1973 NahalArchitect(Structures)andSuperhisoryNahal Architect (Structures) at the San Francisco Nahal Shipyard.
Designedandsuperhisedthedesignofship structuresforalltypesofnahalsurfaceshipsand conhentionalsubmarines.
Designed and analyzed ' complex steel structures and components.
1973-NahalArchitect(Structures)atM.Rosenblatt& Son, NahalArchitectsandMarineEngineers,SanFrancisco, Ca.
Performedstudiesofproposednahalsurface-effect ship structures and deep ocean mooring projects.
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. 1973-1977 SuperhisoryNahalArchitect(Structures)atMareIsland NahalShipyard,ValljoCa.
Designed;andsuperhised the design and installation, of equipment mounting,and ship structures for nuclear submarines. Designed and analyzed shock and vibration isolated equipment mountings.
-1977-1978-HullEquipmentEngineeratNahalShipEngineeringCenter, Arlington, Va. Designedandsuperhiseddesignofall types of ships hull equipment (doors, hatches, ladders, gratings, partitions, ramps,dahits).
1978-1980 SeniorEngineerforSerhiceCraft,NahalSea' Systems Command Headquarters, Arlington, Va. Project Engineer foralltheU.S.Nahy'sbargesandserhicecraft (about40b)inchargeofoherhaulplanningandcon.
figuration control.
1980-present Structural Engineer at U. S. Nuclear Regulatory Commission, Bethesda, Md.
Performreh,iewandehaluationofnuclear power plant structures iricluding all SEP plants, Floating i
1 Nuclear Plant, Bellefonte and Riher Bend.
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ENCLOSURE (2)
Gunnar A. Harstead Professional Qualifications Statement STRUCTURAL ENGINEERING BRANCH DIVISION OF ENGINEERING OFFICE OF NUCLEAR REACTOR REGULATION I am a consultant for the NRC and have assisted on strdctural audits for Midland, Commanche Peak, Waterford, and Dresden.
My background is as follows; 19'54-Graduated Columbia University, BS 1954-1957 Commissioned officer U.S. Navy c
1957-1959 Structural Detailer of highway bridges and highway systems.
Howard Needles Tammen, and Berenelott 1959-1963 Structural designer of buildings Served Associates 1963
' Graduated Columbia University, MS 1963-1965
'Research Scientist on structural Buckling of beam-columns New York University 6
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. 1965-1967 Senior Engineer on structural systems of nuclear power plants Westinghouse Corporation 1966 Graduated New York University, Ph.D 1967-1974 Sr. Supervising Engineer on nuclear power plants.
Burns and Roe Inc.
1974-1975 Assistant Chief Structural Engineer, J
Stone and Webster 1975-1979 Vice President in charge of mechanical and structural engineering for components of nuclear power plants.
SOBt and Harstead Associates P.C.
1979-Present President, in charge of all engineering which includes many nuclear projects.Harstead Engineering Associates, Inc.
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