Letter Sequence Approval |
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Results
Other: ML20082E320, ML20093M745, ML20093M749, ML20094A277, ML20100C247, ML20101C284, ML20116G049, ML20198A027, ML20204E694, ML20204E706, ML20205B056, ML20205B071, ML20214R856, ML20214R871, ML20235Z262, ML20236H257, ML20262E589, ML20262E593, ML20262E597, ML20262E601, ML20262E606, ML20262E611, ML20262E615, ML20262E619, ML20262E624, ML20262E629, ML20266F484, ML20266F489, ML20266F494, ML20266F498
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MONTHYEARML20266F4841983-04-28028 April 1983
Ft St Vrain 2500 Kva Xfmr Foundations & Details. Sheet 1 of 2.No Rev Date
Project stage: Other
ML20266F4891983-05-0202 May 1983
Ft St Vrain 2500 Kva Xfmr Foundations & Details. Sheet 2 of 2
Project stage: Other
ML20266F4981983-06-17017 June 1983
480V Transformer Fire Protection Sys
Project stage: Other
ML20082E3201983-11-0909 November 1983
Responds to Notice of Deviation Noted in IE Insp on 830801-31.Corrective Actions:Concrete Samples Taken at End of Concrete Pump Discharge Line,Addl Lighting Installed & Number of Concrete Vibrators Increased
Project stage: Other
ML20262E6241984-01-0404 January 1984
Building 10 Walk-Over Structure Roof Plan & Details, as-built
Project stage: Other
ML20262E6291984-01-0404 January 1984
Building 10 Walkover Structure Steel Elevation, as-built
Project stage: Other
ML20262E6191984-01-0404 January 1984
Building 10 Walk-Thru Structure Floor Plans, as-built
Project stage: Other
ML20262E6151984-01-0404 January 1984
Building 10 Steel Framing Plans, as-built
Project stage: Other
ML20262E6111984-01-0404 January 1984
Building 10 Concrete Sections & Details, as-built.Sheet 3
Project stage: Other
ML20262E5971984-01-0505 January 1984
Building 10 Architectural Elevations & Details, as-built
Project stage: Other
ML20262E6011984-01-0505 January 1984
Building 10 Concrete Floor Plans, as-built
Project stage: Other
ML20093M7491984-01-22022 January 1984
Rept of Changes,Test & Experiments Not Requiring Prior Commission Approval Per 10CFR50.59(a) for 840101-22
Project stage: Other
ML20093M7451984-07-20020 July 1984
Forwards Rept of Changes,Tests & Experiments Not Requiring Prior Commission Approval for 840101-22.Anniversary Date of Rept Changed to Correspond W/Submittal of Annual Update to Fsar.Future Annual Repts Will Cover Jan 23 - Jan 22
Project stage: Other
ML20094A2771984-07-25025 July 1984
Responds to NRC 840625 Concerns Re Bldg 10 Const.Concept of Bldg 10 Finalized to Relieve Crowding Conditions & to Accommodate Equipment Replacements Being Planned.Bldg 10 Constitutes Mod Not Requiring Amend to OL
Project stage: Other
ML20262E5931984-09-21021 September 1984
Building 10 Site Plan & Caisson Details
Project stage: Other
ML20262E6061984-09-27027 September 1984
Building 10 Concrete Sections & Details, as-built.Sheet 1
Project stage: Other
ML20101C2841984-11-29029 November 1984
Forwards Hl Brey for Redistribution Due to Error in Ltr Date.Correct Date Should Be 831101
Project stage: Other
ML20100C2471985-03-11011 March 1985
Advises That Attachments A,B,C & D Re Diesel Generator Loading,Battery Sizing,Listing of Encl Drawings & Partial one-line Diagram Forwarded to J Miller,Per 850227 Telcon Request
Project stage: Other
ML20116G0491985-04-12012 April 1985
Informs That Listed Electrical Sys Drawings Sent to J Miller of NRR for Review,Per 840410 & 12 Requests.Copy of Logic Diagrams Being Prepared by I Ahmed Requested
Project stage: Other
ML20133A4141985-07-23023 July 1985
Forwards Request for Addl Info Re Const of Bldg 10 & Associated Walkover Structure,Including Engineering Drawings,Walkover Structure Layout & Spatial Relationship W/Surrounding Bldgs
Project stage: RAI
ML20262E5891985-08-0808 August 1985
Ft St Vrain Plot Plan. Sheet 1 of 1.Drawing Consists of Two Aperture Cards
Project stage: Other
ML20137C4011985-11-21021 November 1985
Requests Addl Info Re Bldg 10,including CN-1255 & CN-1332 for Sys 92 & CN-1294 for Sys 92/45.For Each Cn,Safety Evaluation & Design Criteria & Analysis Required.Info Requested within 30 Days of Ltr Receipt
Project stage: Approval
ML20138P0791985-12-17017 December 1985
Forwards Legible Copy of Safety Evaluation Design Criteria & Design Analysis for Change Notices CN-1255,CN-1332, CN-1294 & CN-1391,per NRC 851121 Request for Addl Info. Future Changes to CN-1391 Cover nonsafety-related Battery
Project stage: Request
ML20205B0711985-12-31031 December 1985
Rev 0 to Evaluation of Structure-Soil-Structure Interaction Effect Between Bldg 10/Walkover Structure & Main Plant
Project stage: Other
ML20153H0731986-02-19019 February 1986
Safety Evaluation Supporting Bldg 10 & Walkover Structure Design,Per FSAR Requirements for Category 1 Bldgs.Lack of Clearance Between Structures Should Be Addressed by Util
Project stage: Approval
ML20153H0571986-02-19019 February 1986
Forwards Safety Evaluation Re 850828 Submittal Concerning Bldg 10 & Walkover Structure.Designs Acceptable,Per FSAR Requirements for Category 1 Bldgs.Confirmatory Analysis, Addressing Lack of Clearance Between Structures,Requested
Project stage: Approval
ML20266F4941986-03-15015 March 1986
Bus Duct Layout and Location of Bus Duct Supports
Project stage: Other
ML20204A2161986-05-0101 May 1986
Forwards Request for Addl Info Re Bldg 10 Electrical Mods, Including Confirmation That All Class 1E Power,Control & Instrumentation Cables in Bldg 10 Qualified for Environ of 120 F
Project stage: RAI
ML20197F6541986-05-0707 May 1986
Summary of 860423-24 Meetings W/Util,Ga Technologies & S&W at Site Re Fuel Block Cracking,Bldg 10 Const,Seismic Instrumentation,Pcrv Tendons & Integrated Leak Rate Testing. Attendance List & Viewgraphs Encl
Project stage: Meeting
ML20198A0271986-05-12012 May 1986
Responds to NRC 860219 Questions Re Bldg 10 & Walkover Structure.Walkover Structure & Bldg 10 Designed Such That Structural Elements Will Not Impact on Adjacent Bldgs During Seismic Event
Project stage: Other
ML20204E7061986-06-19019 June 1986
Forwards Addl Info Re Bldg 10 Electrical Mods & Essential Power Bus Upgrades,Per NRC 860501 Request
Project stage: Other
ML20199J0261986-06-25025 June 1986
Requests Addl Info Re Structural Evaluation of Bldg 10 & Walkover Structure,Discussed at 860423 & 24 Meetings.Ltr Inadequately Addressed NRC Concerns
Project stage: Meeting
ML20204E6941986-07-25025 July 1986
Forwards Resubmittal of Addl Info Re Bldg 10 Electrical Mods & Essential Power Bus Upgrades to Include Attachments Not Received by NRC
Project stage: Other
ML20205B0561986-07-28028 July 1986
Forwards Addl Info Re Structural Analysis of Bldg 10 & Walkover Structure,Per 860625 Request,Including Seismic Model Used for Bldg & Rev 0 to SAD-481, Evaluation of Structure-Soil-Structure..
Project stage: Other
ML20214R8561987-03-0606 March 1987
Forwards EGG-NTA-7607, Technical Evaluation Rept Evaluation of Bldg 10 Electrical Mods Fort St Vrain Nuclear Generating Station, Informal Rept
Project stage: Other
ML20205R1561987-03-31031 March 1987
Forwards Request for Addl Info Re Seismic Design of Bldg 10, for Nrc/Bnl Review.Site Visit to Review Response to Encl Questions,To Insp Bldg 10 & to Audit Supporting Structural Matl Recommended within 60 Days of Ltr Receipt
Project stage: RAI
ML20214R8711987-03-31031 March 1987
Technical Evaluation Rept Evaluation of Bldg 10 Electrical Mods Fort St Vrain Nuclear Generating Station, Informal Rept
Project stage: Other
ML20215F9631987-05-29029 May 1987
Forwards Response to NRC 870331 Request for Addl Info Re Bldg 10,per 870527 Telcon.Supporting Matl for Bldg 10 Structural Analyses Available in Util Ofc for Review
Project stage: Request
ML20235Z2621987-07-0808 July 1987
Requests Addl Info from Util Re Bldg 10 Seismic Design, Including Descriptive Matl for PILAY2 Computer Code & Sketches or Drawings Showing Caisson/Slab/Wall Configurations
Project stage: Other
ML20236H2571987-07-28028 July 1987
Requests Addl Info Re Seismic Design of Bldg 10,based on Util 870529 Submittal.Response Requested within 45 Days of Ltr Date
Project stage: Other
ML20234D8091987-09-0909 September 1987
Responds to NRC 870728 Request for Addl Info Re Bldg 10, Including Descriptive Matl for PILAY2 Computer Code & Sketches or Drawings of Caisson/Slab/Wall Configurations. Sketch of Configuration & Wall Stiffness Calculation Encl
Project stage: Request
ML20150C4541988-03-10010 March 1988
Safety Evaluation Concluding That Seismic Analysis Methods for Bldg 10 & Walkover Structure Conservative.Gaps Provided Adequate to Accommodate Relative Motions Which Occur Between Subj Structures & Walkover Structure & Turbine Bldg
Project stage: Approval
ML20150C4441988-03-10010 March 1988
Forwards Safety Evaluation Re Seismic Analysis of Bldg 10 & Walkover Structure.Seismic Analysis Methods Used Conservative Relative to FSAR & Acceptable
Project stage: Approval
1985-07-23
[Table View] |
Text
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Enclosure FORT ST. VRAIN BUILDING 10 SAFETY EVALUATION Building 10 at Fort St. Vrain is a 4 story nuclear Class 1 safety related reinforced concrete structure which houses a battery room, electrical equipment, two computer rooms, an office and a training room. The building is located about 10 feet east of the Turbine Building and about 10 feet south of the Technical Support Building. The space between Building 10 and the Turbine Building is bridged by a Walkover Structure along a portion of the Building 10 west wall. Building 10 is 30 by 41 feet in plan and is 63 feet tall. The outer walls are 12 inch thick reinforced concrete. The structure is founded on 6 reinforced concrete caissons 4 feet in diameter and approximately 58 feet long. The caissons are keyed into the underlying rock a minimum of 6 feet. The floors are 6 inch thick reinforced concrete slab supported by steel beams, except for the top floor slab, which is I foot 3 inches thick. The roof slab is 1 foot thick reinforced concrete also supported by steel beams. The first
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floor is a reinforced concrete slab on grade.
The Walkover Structure provides access from the Turbine Building into Building 10 at two floor levels. The Walkover Structure is approximately 10 by 20 feet in plan dimension and'is approximately 52 feet tall. The building is constructed of braced structural steel with metal siding on the north and south walls. The east and west walls are provided by Building 10 and the Turbine Building respectively. Thestructurfhastwo
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5602280598 860219 l
DR ADOCK O 27
- - " - - - - ^ - - - - - -
intermediate reinforced concrete floor slabs and a reinforced concrete roof supported on steel beams. The steel columns that suppoit the structure are founded on reinforced concrete footings that are in turn supported by the soil. The first floor is a reinforced concrete slab on grade.
The licensee stated in a letter (Lee to Hunter dated August 28,1985) that the two structures were designed and constructed in accordance with the following building codes.
1.
AISC Manual of Steel Construction; 8th edition 1980 2.
Uniform Building Code (UBC) 1979 3.
ACI 318 1977 4.
ACI 349 1976 5.
AWS D1.1
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The results of the seismic analysis of Building 10 and the Walkover Structure were reported by the licensee in the August 28, 1985 letter.
The response spectrum technique was used where the north-south and vertical direction or the east-west and vertical direction motions are combined using the absolute sum method. The stresses that result from earthquakes are combined with loads from other sources according to the combination equations described in the FSAR. The stresses computed using the load combination equations were compared with the allowa61( stresses and were reported to be below these allowables.
3-The deflections of the Turbine-Reactor Building and the Walkover Structure and Building 10 were provided by the Licensee in the August 28, 1985 letter. The largest computed absolute differential displacement in the direction of concern (east-west) was 0.81 inches for the Design Basis Earthquake (DBE).
It is not clear from the information provided whether the licensee means that this is the sum of the deflections for the Turbine Building - Walkover Structure or the Walkover Structure -
Building 10 movements or the relative movements of the building pairs.
This item should be clarified in responding to our question below.
l The detailed sections on the drawings provided show a 1 inch clearance at the foundation and a 2 inch clearance at the roof of the Walkover Structure.
The information provided on drawing B-453 Section L shows the clearance 4
of the checkered plate on the intermediate floors in the Walkover Structure to be 1/4 inch. This is less than the calculated required clearance of 0.81 inches. Therefore, it is possible to have collision between the Walkover Structure and Building 10 at elevations 4811 and 4829 feet and collision between the Walkover Structure and the Turbine Building at the same elevations.
l The licensee stated in the August 28 letter that both structures were designed to withstand the tornado specified in the FSAR. The tornado missile used for the design was a 4 x 12 inch by 12 feet fir plank weighing 105 pounds. The licensee also reported that an impact analysis of the Building 10 walls was performed which indicated that they could 4
. resist the postulated missiles without penetration or spalling of the concrete. The metal siding on the Walkover Structure was qualified by.a topical report by H. H. Robertson, the manufacturer of the siding.
(The final acceptance of this topical report is still pending.) Building 10 was designed to withstand an external pressure drop of 3 psig in 3 seconds.
4 The Walkover Structure was qualified by the licensee by showing that the building would depressurize in 0.2 seconds by venting the internal air
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through openings in the corners of the structure, and the siding could withstand the reduced pressures.
EVALUATION The staff has examined the information provided in the FSAR Section 1.2.2.2 and in a Public Service Company of Colorado letter from Lee to Hunter, NRC, Region IV, dated August 23, 1985 with attached drawings.
The staff finds that Building 10 and the Walkover Structure were designed
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in accordance with the requirements specified in the FSAR for Category I buildings. However, the staff is concerned about the apparent lack of clearance between the Walkover Structure and Building 10.
It appears that these two structures could impact each other during the postulated i
earthquake. This apparent impact potential should be addressed by the utility.
Reviewer:
H. Polk l
l 1
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