ML20205C802

Forwards Addl Info Re Structural Design Live Load,Per Nrc/ Util 860723 & 29 Meetings.Proposed Change to Fsar,Including Expanded Definition of Live Load,Also Encl

ML20205C802
Person / Time
Site:	Vogtle
Issue date:	08/11/1986
From:	Bailey J GEORGIA POWER CO.
To:	Youngblood B Office of Nuclear Reactor Regulation
References
GN-1037, NUDOCS 8608130276
Download: ML20205C802 (14)

Text

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F Georgia Fbwer Company

. Fbst Offic] Box 282 Waynesborn Georgi 3 30830 Telephone 404 554 9961 404 724-8114 Southern Company Services, Inc.

Fbst Office Box 2625 Birmingham, Alabama 35202 Telephone 205 870-6011 Vogtie Proj.ect August 11, 1986 Director of Nuclear Reactor Regulation File: X2BQ02 Attention: Mr. B. J. Youngblood Log: GN-1037 PWR Project Directorate #4 Division of PWR Licensing A U. S. Nuclear Regulatory Commission Washington, D.C. 20555 REF: NRC LETTER TO GEORGIA POWER COMPANY DATED JULY 10, 1986 NRC DOCKET NUMBERS 50-424 AND 50-425 CONSTRUCTION PERMIT NUMBERS CPPR-108 AND CPPR-109 V0GTLE ELECTRIC GENERATING PLANT - UNITS 1 AND 2 ADDITIONAL INFORMATION REGARDING V0GTLE STRUCTURAL DESIGN LIVE LOAD

Dear Mr. Denton:

Attached is the response to the NRC staff's request (enclosure of reference) for additional information regarding the Vogtle Electric Generating Plant (VEGP) Structural Design Live Load. Also attached is a proposed change to the VEGP FSAR that expands the definition of live load in accordance with the application of live load on VEGP. This information was discussed with the NRC staff during meetings on July 23, 1986 and July 29, 1986.

Should you have any additional questions, please inquire.

Sincerely,

/ J. A. Bailey Project Licensing Manager JAB /sm Attachments xc: R. E. Conway NRC Regional Administrator R. A. Thomas NRC Resident Inspector J. E. Joiner, Esquire D. C. Teper B. W. Churchill, Esquire W. C. Ramsey M. A. Miller (2) L. T. Gucwa B. Jones, Esquire Vogtle Project File G. Bockhold, Jr.

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8608130276 860811 PDR ADOCK 05000424 A PDR

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ATTACHMENT RESPONSE TO NRC REQUEST FOR l ADDITIONAL INFORMATION REGARDING STRUCTURAL DESIGN LIVE LOAD !

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I. BACKGROUND The following background concerning the use of live load in structural design on VEGP is considered useful before responding to specific requests for additional information.

A. VEGP DEAD LOAD VEGP dead load includes all permanent items or permanently attached items such as:

o Building Structure o Substructures o Platforms o Equipment o Piping and Supports o Raceway _and Supports o Conduit'and Supports o HVAC and Supports o Electrical Control Panels and Consoles B. VEGP LIVE LOAD VEGP live load includes loads that vary with intensity and occurrence depending upon the. load condition, plant status, and the function of a specific area:

o Floor Area Occupancy Loads o Equipment Laydown Loads o Moveable Equipment Loads o Trucks and Other Vehicular Traffic Loads o Fuel Casks and Fuel Cask Equipment Handling Loads o Railroad Equipment Loads o Other Minimum Design Live Loads Such As Snow Loads, Office and Partition Loads, etc.

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C. TYPICAL VEGP STRUCTURAL DESIGN PROCESS In order to establish the specific magnitude'of live load to be used in the analysis and to perform the detailed structural design, the design engineer reviews the level of functional activity anticipated in the various areas of the plant during the different plant conditions.- Next the engineer reviews the loading combination equations (FSAR tables 3.8.4-1,-3.8.4-2 and 3.8.4-3) to determine which equations will govern based on the relative significance of the live loads for the different plant conditions.

listed below:

Pre-fuel load condition:

This' condition includes such things as localized effects of tower crane anchorage, vehicular traffic, temporary storage during construction of bulk materials and equipment, and maximum design live loads for floor area occupancy due to workers, tool boxes, scaffolding and localized cribbing.

Post-fuel-load condition:

This condition includes such things as equipment laydown loads, moveable equipment loads, and the maximum anticipated live loads for floor area occupancy.

The live loads used in design for equipment laydown and moveable equipment reflect the actual equipment weight as determined from vendor documents or specific calculations.

-For loading combination equations including earthquake generated loads, the maximum anticipated live loads for floor area occupancy are chosen to reflect 100% of the' live load occupancy level which could be expected to be-present during post-fuel load conditions, and are considered to be no less than 25% the pre-fuel load maximum design live load.for floor-area occupancy. The 25% is used as a_ conservative lower bound in areas that do not have a specific occupancy function, and is based on Bechtel's cumulative experience and judgment acquired by reviewing actual floor area occupancy levels on operating generating stations.

As a design option, in lieu of using the post-fuel load maximum anticipated live load for floor area occupancy, the design engineer may choose.to substitute a more conservative uniformly applied equipment dead load (i.e., dead load greater than the maximum anticipated live load, af ter accounting for load factor differences) on floor areas _not occupied by equipment, to simplify the design process.

An example of this structural design process is shown in Figure 1.

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FIGURE 1 Example of Structural Design Process

1. Structural Element: Reinforced concrete slab panel

2. Identified Live Loads for Different Plant Conditions:

Pre-Fuel Load Condition L g = Tower crane anchorage loads L = Maximum design live load for floor area occupancy due to 2

workers, tool boxes, bulk material laydown, etc.

Post-Fuel Load Condition L3= Equipment.laydown load L - Maximum anticipated live load for floor area occupancy 4

expected to be present during plant operation-(outside designated laydown area), but not less than L /4* 2

3. Governing Load Combination Equations *:

a. Pre-fuel load condition Equation 1: 1.4 D + 1.7 L = 1.4 D + 1.7 (L y + L2) I[ U

b. Post-fuel load condition Equation 3:

1.4 D + 1.7 L + 1.9 E = 1.4 D + 1.7 (L3+L)+ 4 1.9 [(D + L 3 + L4 )a] j[ U where:

a = Seismic design acceleration in "g"'s

• Refer to FSAR Table 3.8.4-3 3

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, II. ' RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION-

} A. REQUEST NO. 1:

i Provide a list of Category I structures and structural elements for g I which the application of " live load" in structural design was

? based on criteria other than those committed to in FSAR Section 3.8.4.3.1.1 and FSAR Tables 3.8.4-1, 3.8.4-2, and 3.8.4-3 l

i (i.e., where live load values of less than 100% of the " maximum j design" live load were applied). Describe chronologically when-such live load criteria was adopted and the design control' procedures and structural reevaluation tasks instituted to ensure.

l that the usage of the less than 100% live load criteria was 4 appropriate.

i j Response:

1 i VEGP criteria for. live load application acknowledges that live load I . intensity varies depending upon the status of plant operation-2 (i.e., pre-fuel load condition versus post-fuel load condition),

j and the level of functional activity for a. specific area. : Tables 1 j- through 4 identify all structural elements by building for which 2 the post-fuel load maximum anticipated live load for floor or roof j occupancy differs from the pre-fuel load maximum design live load j for floor or roof occupancy.- For structural elements not -

identified in these tables, post-fuel load maximum anticipated live load magnitudes are either equivalent to or greater than the pre-j fuel load maximum design live load magnitudes.

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( As can be seen from these tables, the areas where the post-fuel .

load maximum anticipated live loads differ from the pre-fuel load I maximum design live loads are limited to the grating and platforms

! inside the containment, localized roofs of some miscellaneous

} structures or tunnels, the basemats for several structures, columns

! at the lowest elevation of the Auxiliary Building and the NSCW l Valve House structure at all levels. The justification or i disposition of'these differences is provided in.the tables..  ;

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j The VEGP criteria-for live load application in combination with j- seismic induced loads, as summarized in the body of'Section I, was

first issued for use on February 28, 1974. This criteria j specifirally limits the live load intensity in loading combinations including earthquake motion to the live loads expected to be present during plant operation.-~ Subsequent revisions to the

criteria have resulted in only slight variations in the wording.

B. REQUEST No. 2:

The definition of live load discussed in_your May 23, 1986 letter,-

I- differed from the definition of live load.as given in FSAR

. Section 3.8.4.3.1.1 in that it broke down the live load into the l " maximum design" live load and " anticipated" live load. Provide 4

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the basis of this redefinition, Also, explain the basis for redefining the live load without amending FSAR Section 3.8.4.3.1.

Response

Our letter of May 23, 1986 (GN-921) addresses the basis for the usage of varying magnitudes of live load expected during different plant conditions. The terms " maximum design" live load and

" anticipated" live load are used to differentiate between these varying magnitudes, i.e. pre-fuel load condition versus post-fuel load condition. The pre-fuel load maximum design live loads for floor area occupancy include such things as temporary storage during construction of bulk materials and equipment, and maximum occupancy due to workers- tool boxes, scaffolding, and localized cribbing. The post-fuel load maximum anticipated live loads for floor area occupancy, pertaining to loading combinations including earthquake generated loads, are live load occupancy levels expected to be present during plant operation.

Because of the confusion surrounding this subject, it is acknowledged that a clarification to the FSAR is warranted. A proposed FSAR amendment concerning live load application in loading combinations including earthquake generated loads is previded in the attachment.

C. REQUEST h0. 3 The articipated live load is defined as 25% of the maximum design live load in some cases. Provide theoretical justification for this assumption. Also, as applicable, discuss and justify other percentages (less than 100% other than 25%) of the maximum design live load which may have been used in other cases.

Response

The maxiwum anticipated live load for floor area occupancy during plant operation is defined as 100% of the live load occupancy level expected to be present during post-fuel load conditions. The actual magnitude of this load can vary from area to area depending upon the level of functional activity imposed by operational requirements. In accordance with established Bechtel practice, the magnitude of the maximum anticipated live load for floor area occupancy is limited to no less than 25% of the pre-fuel load maximum design live load for floor area occupancy. As discussed in section I, the 25% is used as a conservativa lower botind in areas that do not have a specific occupancy function, and is tased on Bechtel's cumulative experience and judgment acquired by reviewing actual floor area occupancy levels on operating generating stations.

It should be noted that the live load reduction identified in Taole 4 for level D columns in the Auxiliary building is based on 5

live load reduction due to the size and number of supported tributary floor areas, as provided for in the design criteria in accordance with the Uniform Building Code.

- D. REQUEST NO. 4:

The anticipated live load, not the maximum design live load, is used in the load combination equations involving earthquake load effects. Provide the basis for the adoption of such design criteria.

Response

The load combination equations defined in FSAR Tables 3.8.4-1, 3.8.4-2, and 3.8.4-3 reflect a broad range of operational,

} environmental and abnormal conditions. The specific load terms (e.g., D, L, E, etc.) used in each equation reflect the condition 4

being investigated and should be compatible with the definition of-the status of the defined condition. The earthquake load combination equations reflect a post-fuel load plant condition, and therefore the maximum anticipated live load for floor area occupancy used in these equations should reflect 100% of the occupancy live load expected to be present during post-fuel load 3 conditions. The VEGP post-fuel load maximum anticipated live load for floor area occupancy reflects 100% of the live load occupancy level expected to be present during post-fuel load conditions, and are the values used in the structural design.

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ATTACRMENT 1 PROPOSED FSAR AMENDMENT SECTION 3.8.4.3.1.1 PRESENTLY STATES:

L Live-loads or their related internal moments and forces, including any movable equipment loads and other loads which vary with j intensity and occurrence, as lateral soil pressures. Live load intensity varies depending upon the load condition and the type of structural element.

, PROPOSED CHANGE:

L Live loads or their related internal moments and forces, including

. any moveable equipment loads and other loads which vary with intensity and occurrence, such as: floor area occupancy loads, moveable equipment loads, equipment laydown loads, nuclear fuel

, casks and fuel cask equipment loads, vehicular traffic loads, railroad equipment loads, and lateral soil pressures. Live load intensity varies depending upon the status of plant operation (i.e., pre-fuel load condition versus post-fuel load condition),

the level of functional activity for a specific area, and the type of structural element. The pre-fuel load maximum design live loads for floor area occupancy include such things as temporary storage during construction of bulk materials and equipment, and maximum occupancy due to workers, tool boxes, scaffolding, and localized cribbing. The post-fuel load maximum anticipated live loads for floor area occupancy, pertaining to loading combinations including earthquake generated loads, are 100% of the live load occupancy levels expected to be present during plant operation, and are considered to be not less than 25% of the pre-fuel load maximum design live load for floor area occupancy.

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I ATTACHMENT 1 PROPOSED FSAR AMENDMENT

• PRESENT FSAR:

TABLE 3.8.4-1(*)

EQN D L Pa To ..........

Service Load Conditions 1 1.0 1.0 ..........

2 1.0 1.0 ..........

3 1.0 1.0 ..........  !

4 1.0 1.0 1.0 .......... l i

a. See paragraph 3.8.4.3 for definition of load symbols . . . . . . . . . . . . . . . . . .

PROPOSED CHANGE:

EQN D L Pa To ..........

Service Load Conditions 1 1.0 1.0 ..........

2 1.0 1.0 ..........

3 1.0 1.0 ..........

4 1.0 1.0 1.0 ..........

a. See paragraph 3.8.4.3 for definition of load symbols including the definition of L during pre-fuel load and post-fuel load conditions.....

• The footnotes to table 3.8.4-2 and 3.8.4-3 will also be revised as shown above.

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Table 1 CONTAIN'JENT INTERNAL STRUCTURES, DIESEL FUEL OIL STORAGE TANK PUMPHOUSE AND FUEL HANDLING BUILDING +

PRE-FUEL LOAD POST-FUEL LOAD

' STRUCTURE MAXIMUM DESIGN MAXIMUM ANTICIPATED

& LOCATION LIVE LOAD (PSF) LIVE LOAD (PSF) COMMENTS CONTAIPWENT INTERNAL STRUCTURE GRATINGS & PLATFORM 150 37.5 REFLECTS MAXIMUM ANTICIPATED FLOOR AREA OCCUPANCY LEVEL DURING POST-FUEL LOAD CONDITION DIESEL FUEL DIL STORAGE TANK PUMPHOUSE ROOFS (UPPER AND LOWER) 150 37.5 REFLECTS MAXIMUM ANTICIPATED ROOF AREA OCCUPANCY LEVEL DURING POST-FUEL LOAD CONDITION FUEL HANDLING BUILDING LEVEL 3 ROOF 30 30 SLAB THICKNESS CONTROLLED BY (7.5 USED) TORNADO MISSILE CRITERIA.

INHERENT RESERVE CAPACITY EXISTS.

30 PSF LIVE LOAD USED IN LOADING COMBINATIONS FOR TORNADO WIND CONDITIONS.

BASEMAT 100 FLOORS 25 FLOORS FLOORS REFLECT MAXIMUM ANTICIPATED 30 ROOF 30 ROOF FLOOR AREA OCCUPANCY LEVEL DURING (7.5 USED) POST-FUEL LOAD CONDITION FOR EVALUATION OF CONTRIBUTION TO BASEMAT DESIGN. ROOF DIFFERENCE IS INCONSEQUENTIAL. (USED FOR BASEMAT DESIGN ONLY)

• FOR ALL AREAS OF REFERENCED BUILDINGS NOT LISTED, POST-FUEL LOAD MAXIMUM ANTICIPATED LIVE LOAD MAGNITUDES USED WERE EITHER EQUIVALENT TO OR GREATER THAN THE PRE-FUEL LOAD MAXIMUM DESIGN LIVE LOAD MAGNITUDES.

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Table 2 DIESEL GENERATOR BUILDING, NSCW VALVE HOUSE AND TOWER

• PRE-FUEL LOAD POST-FUEL LOAD STRUCTURE MAXIMUM DESIGN MAXIMUM ANTICIPATED

& LOCATION LIVE LOAD (PSF) LIVE LOAD (PSF) COMMENTS DIESEL GENERATOR BUILDING BASEMAT 250 BASEMAT 250 BASEMAT REFLECT MAXIMUM ANTICIPATED FLOOR 100 FLOORS 25 FLODRS AREA OCCUPANCY LEVELS DURING POST-i 30 ROOF 30 ROOF FUEL LOAD CONDITION NSCW VALVE HOUSE ROOF 30 30 SLAB THICKNESS CONTROLLED BY (7.5 USED) TORNADO MISSILE CRITERIA.

INHERENT RESERVE CAPACITY EXISTS.

30 PSF LIVE LOAD USED IN LOADING COMBINATIONS FOR TORNADO WIND CONDITIONS MEZZANINE 100 25 REFLECTS MAXIMUM ANTICIPATED FLOOR AREA OCCUPANCY LEVEL DURING POST-FUEL LOAD CONDITION BASEMAT 100 25 REFLECTS MAXIMUM ANTICIPATED FLODR AREA OCCUPANCY LEVEL DURING POST-FUEL LOAD CONDITION NSCW TOWER PLATFORM AT ELIMINATOR 100 25 POST-FUEL LOAD MAXIMUM ANTICIPATED LEVEL FLOOR AREA LIVE LOAD (USED IN OVERALL BLDC. ANALYSIS ONLY)

TOP OF BtHTRESS 100 25 REFLECTS MAXIMUM ANTICIPATED FLOOR AREA OCCUPANCY LEVEL DURING POST-FUEL LOAD CONDITION

• FOR ALL AREAS OF REFERENCED BUILDINGS NOT LISTED, PCST-FUEL LOAD MAXIMUM ANTICIPATED LIVE LOAD MAGNITUDES USED WERE EITHER EQUIVALENT TO OR GREATER THAN THE PRE-FUEL LOAD MAXIMUM DESIGN LIVE LOAD MAGNITUDES.

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Table 3 CATECORY 1 TUNNELS.

PRE-FUEL LOAD POST-FUEL LOAD STRUCTURE MAXIMUM DESIGN MAXIMUM ANTICIPATED

& LOCATION LIVE LOAD (PSF) LIVE LOAD (PSF) COMMENTS D.C. PIPING TUNNEL (T3A & T38) 100 25 DETAILED SAME AS ROOF WHERE SEPARATION FLOOR (0 USED) 250 PSF LL WAS USED D.C. ELECTRIC TUNNEL (T4A & T48)

SHAFT ROOF 30 30 DETAILED SAME AS ANOTHER TUNNEL (7.5 USED) SHAFT ROOF WHERE 124 PSF LL WAS USED

• FOR ALL AREAS OF TUNNELS NOT LISTED AND FOR ALL OTHER TUNNELS, POST-FUEL LOAD MAXIMUM ANTICIPATED LIVE LOAD MAGNITUDES USED WERE EITHER EQUIVALENT TO OR GREATER THAN THE PRE-FUEL LOAD MAXIMUM DESIGN LIVE LOAD MAGNITUDES.

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Table 4 CONTROL BUILDING AND AUXILIARY BUILDING.

PRE-FUEL LOAD POST-FUEL LOAD STRUCTURE MAXIMUM DESIGN MAXIMUM ANTICIPATED

& LOCATION LIVE LOAD (PSF) LIVE LOAD (PSF) COMMENTS CONTROL BUILDING BASEMAT 100 (TYPICAL) FLOORS 25 FLOORS FLOORS REFLECT MAXIMUM ANTICIPATED 30 ROOF 30 ROOF FLOOR AREA OCCUPANCY LEVEL DURING (8 USED) POST-FUEL LOAD CONDITIONS FOR EVALUATION OF CONTRIBUTION TO BASEMAT DESIGN. ROOF DIFFERENCE IS INCONSEQUENTIAL (USED FOR BASEMAT DESIGN ONLY)

AUXILIARY BUILDING LEVEL 'D' COLUMNS ONLY 100 72 LL REDUCTION BY TRIBUTARY AREAS PER UBC PROVISIONS

• FOR AREAS OF REFERENCED BUILDINGS NOT LISTED, POST-FUEL LOAD MAXIMUM ANTICIPATED LIVE LOAD MACNITUDES USED WERE EITHER EQUIVALENT TO OR CREATER THAN PRE-FUEL LOAD MAXIMUM DESIGN LIVE LOAD MAGNITUDES.

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