ML20054H039

Forwards Technical Evaluation Rept, Wind & Tornado Loadings (SEP III-2), & Safety Evaluation as Basis for Comparison W/ 820507 Safety Analysis.Either Plant Mods or Justifying Analyses Must Be Performed

ML20054H039
Person / Time
Site:	Oyster Creek
Issue date:	06/15/1982
From:	Crutchfield D Office of Nuclear Reactor Regulation
To:	Fiedler P JERSEY CENTRAL POWER & LIGHT CO.
Shared Package
ML20054E419	List: ML20054E418 ML20054H039
References
CON-NRC-03-79-118, CON-NRC-3-79-118, TASK-03-02, TASK-3-2, TASK-RR LSO5-82-06-045, LSO5-82-6-45, NUDOCS 8206220516
Download: ML20054H039 (10)

Text

O i f f '" /QAl1 D h l[o June 15, 1982 Docket No. 50-219 LS05 06-045 Mr. P.B. Fiedler Vice President and Director - Oyster Creek Oyster Creek fluclear Generating Station Post Office Box 383 Forked River, New Jersey 08731

SUBJECT:

SEP TOPIC III-2,llIND AND TOR?lADO LOADINGS CYSTER CkEEK NUCLEAR GENERATIhG STATION Enclosed is an evaluation of SEP Topic III-2. This evaluation comoares your facility as described in the Safety Analysis Report you supplied on May 7,1981 and other information on Docket No. 50-219 with criteria used by the staff for licensing new facilities.

This evaluation will be a basic input to the integrated safety assessment of your facility. This topic may be changed in the future if your facility design is changed or if NRC criteria relating to this topic is modified before the integrated assessment is completed.

Sincerely, Dennis M. Crutchfield, Chief Operatinq Reactors Branch #5 Division of Licensing

Enclosure:

As stated cc w/ enclosure:

See next page N

j)sa a v a (c) 8206220516 820615 /fdd*)(ol+44 Y PDR P

ADOCK 05000219 PDR -

, 4

~

d{.[\\ g ,f'i ,

D PBd...... ..DL :SEPB/SL. DL:SEPBQ omcc p ..L : SE ....L

. . . . . . . . . . . . ...DL DL:0RB#

$5'PB/..BC g . ....f,./. . . . . . . . . . . . . . .

Dl BC

. . . . . . . D d /..SA

'"~~>

DPersinko:sh RHermann RFell y ' ' WRussell. . . . JLombard ....DC field ......, G' 'a in a s g,p;gy- ;gy ;gy ymygy- gg g;4 ;yy Qy yyy -

-> . .,. . . .n. .j .c.....s..

g 7.gy-

. yy;gg -

. . . . . . . ..v...... . . .

rom m ohi 66 m OFFICIAL RECORD COPY usam. nu-mm

- . . . . . . . . . - - - .. .. .--w.-...=..i.~......-..-a..l= x. .. d.~ .- .

, ,j 3 Mr. P. B. Fiedler ,

cc G. F. Trowbridge, Esquire Resident Inspector Shaw, Pittman, Potts and Trowbridge c/o U. S. NRC 1800 M Street', N. W. Post Office Box 445 Washington, D. C. 20036 Forked River, New Jersey 08731 J. B. Lieberman, Esquire Commissioner Berlack, Israels & Lieberman New Jersey Department of Energy 26 Broadway 101 Commerce Street New York, New York 10004 Ne.4 ark, New Jersey 07102

,[ . Ronald C. Haynes, Regional Administrator

+

Nuclear Regulatory Commission, Region I 631 Park Avenue King of Prussia, Pennsylvania 19406 J. . Xnubel ,

BWR Licensing Manager GPU Nuclear 100 Interplace Parkway "

Parsippany, New Jersey 07054

"~

Deputy Attorney General' State of New Jersey Department of Law and Public Safety 36 West State Street - CN 112 Trenton, New Jersey 08625 Mayor Lacey Township 818 Lacey Road Forked fiver, New Jersey 08731 U. S. Environmental Protection Agency Region II Office .

ATTN: Regional Radiation Representative 26 Federal Plaza New York, New York 10007

~

Licensing Supervisor Oyster Creek Nuclear Generating Station Post Office Box 388 '

Forked River, New Jersey 08731 e

y - n

u.. _ , ; 2.,___.  :.__ _ ._,a _ _. ~ _ _ ..~. . -._2__.,-- ~ - Lau . m. _. aa. _.

SYSTEMATIC EVALUATION PROGRAM TOPIC III-2 OYSTER CREEK TOPIC: III-2, Wind and Tornado Loadings I. INTRODUCTION The safety objective of this review is to assure that safety-related structures, systems and components are adequate to resist wind and tornado loadings including tornado pressure drop loading.

II. REVIEW CRITERIA The review criteria governirig this topic is General Design Criteria 2, design bases for protection against natural phenomena.

III. RELATED SAFETY TOPICS AND INTERFACES

1. Tornado missiles are reviewed in SEP Topic III-4.A.

2. Structures which are considered safety-related are given in SEP Topic III-l.

3. Wind and tornado parameters are given in SEP Topic II-2.A.

4. Design codes, criteria and load combinations are reviewed in SEP Topic III-7.B.

IV. REVIEW GUIDELINES The currently accepted design criteria for wind and torrado loadings is outlined in Standard Review Plan Sections 3.3.1, 3.3.2, 3.8 and Regulatory Guides 1.76 and 1.117. Codes and standards used for the review of structures at the Oyster Creek facility are given in Enclosure 1 to this SER.

Site specific windspeed and tornado parameters were developed in Topic II-2.A and the appropriate values were identified for use as input to the wind and tornado loading analyses. Structures important to safety were reviewed in this topic to determine their ability to withstand these values from Topic II-2.A. Appropriate values for the Oyster Creek site are a 250 mph windspeed (corresponding to 160 psf dynamic pressure) and a 1.5 psi (216 psf) differential pressure. The evalua-tion and conclusions are based on a Safety Analysis Report supplied by the licensee, information available on Docket No. 50-219, and the information developed by the staff given in Enclosure 1 to this SER.

Structural capacities were determined 'and are given in terms of strength and corresponding windspeed.

4

_ , _ .  ? _ _ _ . _ . . . _ . _ . . _ _ _ _ _ _ _ _ _

w a~.;t.ua.;d u l }

V. EVALUATION Enclosure 1 is a report entitled " Wind and Tornado Loadings" presenting our contractor's findings concerning the Oyster Creek facility. The report identifies limiting structural elements and their associated windspeed. No analyses were performed for safety-related systems and components. Systems and components important to safety not housed within safety-related structures should be addressed by the licensee.

Original Design and SAR Conclusions According to the Safety Analysis Report supplied by the licensee on May 7,1981, structures at the site were designed for windspeed of 100 rrph from 0-50 feet above grade and 125 mph from 50-150 feet above grade. This corresponds to a building pressure of 40.3 psf and 62.8 psf respectively as given in response dated 12/19/67 to staff questions.

These values are total applied building load which include a gust factor of 1.1 and a shape factor of 1.3 (.8 windward + .5 leeward face).

Excluding shape factors and back calculating from the values given results in an upstream pressure of 31 psf below 50 feet above grade and 48 psf from 50-150 feet above grade. Although not specifically stated, it is assumed that 31 psf and 48 psf were used in the design of the wall panels since this would be in agreement with normal wind design procedures.

Allowable stresses were increased by 1/3 for load combinations of ^

dead load, live load, and wind load. The load combination involving wind was dead load plus live load plus wind load.

Although the facility has not been designed for tornado loads the .,

licensee has given maximum permissible wind velocity and depressuriza-tion loads based on maintaining stresses less than 90% of yield for reinforcing steel and 85% of the ultimate concrete strength and including cead loads plus normal operating Icads. These values are given below.

Structure Wind (mph) Pressure (psi)

Reactor building - exterior conrete walls 300 2.0 Reactor building - insulated metal siding 160 0.53 Reactor building - roof decking 280 0.68 Reactor building steel for craneway enclosure 190* 0.68 Control room - north wall 160 0.53 remainder 300 2. 0 Intake structure 300 2.0 Ventilation stack 180 2.0 Diesel generator and oil tank vaults ** 300 2.0

- . . . , , . . ~ . . . . . ~ , u. . w .u ....... . . = - . . . a..- ~.u.a :a. .aa.m. . : ac. . .a .a

-2a-Based on siding drag - without siding, steelwork can withstand 300 mph.

Based on other information provided by the licensee dated April 30, 1982, the licensee states that the north and south walls of the diesel generator building are capable of withstanding a 240 mph tornado wind; the east and west walls can withstand 168 mph; and the roof can withstand 88 mph. These values include the effect of tornado missile loading. The values will be higher for wind loading considered separately. No values are given for differential pressure.

. . ~ , - -

, _ . . ~._ - . _ - . - -

- - - - _ _ - - - - _ _ .__ _._ - . _- _ --_._.-.__~

The SAR also states that the outdoor service water pumps and startup transformer are capable of withstanding 200 mph winds and 2 psi pres-sure drop. The licensee also concludes that the likelihood of damage l to the spent fuel: pool in the pool area due to tornado effects is ,

small. I The ventilation stack was designed per ACI-505 with a design wind gust velocity of 110 mph at the base and increasing with height in accordance with the relation used in ACI-505.

Discussion Current criteria for straight wind loading'is given in Standard Review Plan 2.3.1 which references ANSI A58.1. Current criteria requifes de-sign for s+.raight wind with a probability of exceedance in one year of 10-2 and 10-7 for a tornado. Straight wind loads differcfrom tornado loads in that straight wind loads are considered in different load combinations, have different load factors in ultimate strength design of concrete and have different acceptance criteria than tornado wind loads. Additionally, straight wind design includes such aspects as gust factors and variation of force with height whereas tornado design does not. Buildings at Oyster Creek were originally designed for 100 mph winds (40.3 psf total load) from 0-50' and 125 mph (63 gsf total load) from 51-150' above grade. ANSI A58.1 specifies a 10-' wind of approximately 103 mph at an elevation of 30' above grade. Per current criteria, load combinations involving dead, live, wind, pipe reactions, and thermal are allowed a 30% increase in allowable stresses for con-crete structures if working stress methods are used and a 50% increase in stress for steel structures if elastic design methods are used. The original design by the licensee utilized working stress design methods for steel and concrete design; therefore, the load Octors used in the original design are the same as current criteria. Tha magnitude of the straight wind-loads, excluding localized effects, used in the original design is comparable to that. required by current criteria. The ANSI A58.1 code requires higher localized forces below 50' above grade and above 75' above grade than used in the original design; however, using the basic 10-2 windspeed identified in Topic II-2.A (78 mph) and using ANSI A58.1 rules for developing forces at various heights results in the original design exceeding these forces for both local and global forces at all elevations. The 1/3 increase in allowable stress does not imply structural failure since increases of 30% and 50% in allowable l

stress above code allowable are permitted for load combinations involving all operating loads (dead load, live load, wind load, operating pipe reaction loads and thermaltloads). Additionally, decreasing the original design loads such that the 1/3 increase in stress is not allowed results l in a load higher than the load applied from the results of SEP Topic II-2. A for a 10-2 wind. This load would be higher for all elevations globally and almost all elevations locally. Since it is uncertain whether pipe reaction loads and snow loads were included in the original design in combination with wind loads, it may be possible to overstress some structural elements if these loads are combined with wind.

Although this is possible, it is unlikely to occur for structures that are able to withstand the design tornado loads since these loads are signiff-cantly more demanding than the wind loads and would, therefore, provide margin to accommodate pipe reaction loads and snow loads with the exception of some roofs. Roof members designed to carry axial loads as a result of wind will have their axial load carrying capacity significantly reduced if vertical loads that induce bending are present. It should be noted that straight wind design criteria relied upon is that presented by the licensee in their Safety Analysis Report and Attachment B to the licensee response to staff questions dated December,;1979 for buildings and Amendment 22 to the FDSAR for the vent stack. The original design straight wind loads applied to the stack are comparable to the requirements of ANSI A58.1, 1972 for a basic windspeed of 103 mph and are in excess of that required based on the site specific windspeed of 78 mph from SEP Topic II-2.A. The staff determined capacity of 164 mph uniformly distributed with height would result in a higher applied load at any section than that cbtained from ANSI A58.1 for a 103 g1ph straight wind at 30' above grade.

The staff has analyzed the reactor building and veit stack to determine its ability to resist the design tornado loads. Although the vent stack was not designed for tornado loads and it is currently not a Category 1 struc-ture from a systems approach, it is a unique structure whose failure can affect Category 1 structures. The results of the analysis are shown below in terms of limiting windspeeds. For elements found to have low tornado wind resistance, the element was examined for straight wind design per the requirements of ANSI A58.1. The wind capacity then reported is based on stress limits for wind design with no allowable stress increase; therefore, there would be additional capacity than that shown:

TABLE 1 Wind Corresponding Cause of** speed Pressure Structure Element

• Failure (mph) (psf)

Reactor building Roof beams 3 68 17 2 61 19 1 102 27 Celumns above operating floor 2 174 154

• The first element identified for each structure is the limiting element.

Additional elements that have also been found to be inadequate are subsequently listed. Note that this table does not imply that all inadequate elements have been identified or that entries are listed with respect to the most critical loading combination. Structural details not included in this review are windows, doors and roof decks.

• • Key: 1 - tornado dynamic pressure; 2'- differential pressure; 3 -

high wind dynamic pressure. Tangential wind speeds are listed for differential pressure fai Jres.

a __,.__ - - - _: -

w -- -__ u _ _. L ,.2.u. .. ..a.

]

_ l

-S-The results indicate that the reactor building below the operating floor is adequate to withstand the design tornado wind and pressure loads.

Above the operating floor, structural elements were found to be inadequate to withstand the postulated tornado loads with the limiting elements given in Table 1. The concern above the operating floor is the spent fuel pool since there are no other safety-related systems or components above this level. The failure of structural elements on the spent fuel pool need to be considered.

The ventilation stack was analyzed by 1) working stress methods with ACI code allowables and 2) working stress methods allowing stress in the extreme outer steel to reach yield and extreme fiber concrete to reach .85 fc'. The results in terms of windspeed (mph) are given below.

Stack WSD (code allowables) WSD (fy, 85 fe' allowables)

Stack cylinder 138 164 The conclusions reached by the staff agree with values presented by the licensee for the reactor building below the operating floor. Above the operating floor, values for steel capacity obtained by the staff are significantly less than that presented by the licensee.

Ventilation stack capacity obtained by the staff is less than that presented by the licensee (164 mph vs.180 mph).

The staff was unable to perform capacity calculations for other structures due to a lack of information. The staff concludes that there is inadequate

.iustification for some of the conclusions reached by the licensee in the SAR. These are discussed below.

1. The SAR states that " generally, safety-related equipment is enclosed within safety-related structures." The licensee should review com- 1ents not enclosed within safety-related structures to assure that all such components have been identified and their capacity determined.

2. The licensee has not presented information to support their statement that service water pumps and startup transformer are capable of withstanding 200 mph winds and 2 psi depressurization nor has any information been provided to support capacity values for the intake structure, oil tank vaults, control room and diesel generator building.

3. The licensee has not provided bases to support their conclusion that stack failure upon the reactor building would not impair the ability to safely shutdown the reactor. Failure of the stack on the spent fuel pool or other Category 1 structures or components has not been i

. ~. wa._ . ~ . ...=:. . , .~u.. . . .. ..a . ..

+

addressed. Circumferential stresses in the stack were not analyzed.

due to lack of information concerning placement of circumferential reinforcing.

4. The licensee has not determined the consequences on the spent fuel pool of superstructure failure.

5. Capacities for exterior masonry walls have not been given. Since no capacities have been given, any exterior masonry walls should be assumed to fail during a tornado and consequences datennined.

6. The effect of failure of non-Category 1 structures on Category 1 structures (e.g., turbine building on control building) has not been addressed by the licensee.

7. Roof decks have not been analyzed by the staff due to lack of information. It is expected that such roofs will have inadequate ability to withstand internal pressure loads. The licensee should determine consequences of their failure.

VI. CONCLUSIONS It is concluded that some structures and portions of others cannot withstand the postulated tornado loadings of 250 mph and 1.5 psi.

In two cases where the licensee results indicated that structural capacity is less than required to resist design tornado loads (i.e., reactor building above operating floor and vent stack), the staff has calculated capacity less than the value presented by the licensee. For the reactor building below the operating floor, the staff agrees with the licensee that design tornado loads can adequately be resisted.

The licensee should either implement modifications for the following

! structures or demonstrate that the consequences of their failure in i

the event of tornado loads is acceptable:

1. Reactor building structure above the operating floor.

2. Failure of non-Category 1 structures upon Category 1 structures (e.g., turbine building, vent stack).

3. Safety related equipment not inside qualified structures.

l 4. Exterior masonry walls.

5. Roof decks on Category 1 structures.

The licensee should provide a description of the methods and sample calculations used to qualify the following:

1. Service water pumps and start-up transformer.

2. Intake structure and oil tanks.

3. Control building.

4. Diesel generator building.

It should be determined whether snow loads, operating pipe reaction loads and thermal loads were considered with wind in the original design. If these loads were not, the effect of combining then should be addressed.

The need for modifications in order for structures, systems and components to adequately resist wind and tornado loads will be determined during the integrated assessment.

.