IA-86-778, Trip Rept of 860514-15 Site Visit Re Seismic Design Issues Concerning Cable Trays,Conduit Qualification,Hvac Concerns, CRD Return Lines,Ie Bulletins 79-14 & 79-02 & Nonessential Piping.Request for Addl Info Re Vermont Yankee Encl

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Trip Rept of 860514-15 Site Visit Re Seismic Design Issues Concerning Cable Trays,Conduit Qualification,Hvac Concerns, CRD Return Lines,Ie Bulletins 79-14 & 79-02 & Nonessential Piping.Request for Addl Info Re Vermont Yankee Encl
ML20213F866
Person / Time
Site: Browns Ferry, Vermont Yankee, 05000000
Issue date: 07/31/1986
From:
NRC
To:
NRC
Shared Package
ML20213F817 List:
References
FOIA-86-778 IEB-79-02, IEB-79-14, IEB-79-2, NUDOCS 8611170221
Download: ML20213F866 (8)
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. JUL 311986 Enclosure 1 TRIP REPORT PURPOSE: To Discuss Browns Ferry Seismic Design Issues PLACE: Browns Ferry Plant Site. Decatur, AL.

4 DATE: May 14 and 15, 1986 TEAM: R. Hermann, J. Tsao, S. Kim Engineering Branch, DBL, NRR j During May 14 and 15 1986, the NRC staff, TVA personnel, and TVA consultants met i

at Browns Ferry site to discuss seismic design issues. A list of the meeting attendance is attached (Attachment 1). Attachment 2 is the handouts from TVA.

  • There are currently five issues relating to Browns Ferry seismic design; cable trays, conduit, HVAC, control rod drive return lines and IEB issues (79-14 and 79-02).

s Prior to discussing details of the issue, the staff requested that TVA present a comprehensive background history of the issues leading up to the current reanalysis and fixes. It was apparent that they were not prepared to discuss past history in detail at the meeting. Consequently, the staff requested TVA to provide such background information in all their future submittals at the time of resolution of each issue. They agreed to do so. Also, the staff informed TVA that all the design criteria change and establishment of interim criteria or operability should be discussed with the staff for approval prior to implementation.

TVA and the staff discussed having a meeting at Bethesda to review the overall seismic re evaluation of the plants. We expect the licensee will identify any changes to the building models as well as any other changes to the original l FSAR seismic criteria that are under consideration. TVA pointed out that while cable trays were evaluated based on the original stick model response, the response spectra for the piping analysis (79-14) were derived from a new building structural model. The staff was not aware that TVA has been working on a new building model.

After concluding the meeting on May 15, the staff toured the plant; specific-ally, the cable spreading room and CRD piping arrangement in the reactor bull. ding and. cable trays in the intake structure. It was observed that fire .

retardant spray on cable is a stiff and brittle material. The coating material may have a tendency to increase stiffness of the cable tray system and tends to .

l limit damping by the cable. Considering the increased stiffness, it appears -

that the 7% damping used appears more reasonable than the 15% or 20% damping value for the cable trays analysis at other facilities. -

  • Attachments 1 and 2 not included 8611170221 861112 PDR FOIA CRABEH86-778 PDR

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2 Following is a briof description of each issue. Their resolution efforts are still in progress.

1. Cable Trays United Engineers, a contractor for TVA, presented interim criteria and associa-ted 14 fixes. They plan to complete the fixes prior to projected September 1986

' startup. The staff received a 5 volume submittal transmitted to us by TVA's May 2, 1986, letter to D.R. Muller of NRC. The slides used for the presenta-tion are similar to the ones used in the October 1985, Bethesda meeting. We were told by TVA that there were no seismic design requirements originally for the ceble trays. However, they initiated a backfit program in about 1970 and subsequent inspection revealed that the field implementation of backfit was unsatis factory. TVA hired United Engineers to establish the interim criteria and to fix the cable trays to support startup of Unit 2. We requested that the background information as well as the licensee's intended long term corrective mally.

actions and the schedule for their implementation be provided for-

2. Conduit Qualification Program Erowns Ferry conduits were not designed for earthquakes originally. Several segments of the full size corduits were tested on shaker table at W'yle Labora-tory for DBE, 80% and 100% of table capacity. The table capacity of the shaker is rated at approximately 8 times of vertical DBE and 2.5 times of the horizon-tal DBE. Arrangements of tte conduit tested are provide in the Attachment 2.

None of the conduits failed except two supports of a conduit at 100% table capacity. TVA will provide a submittal to the NRC with a similiar content to that described for the cable trays.

3. HVAC Concerns TVA has initiated a program to review seismic design of the HVAC. As was the case for the etnduits the HVAC ducts were not originally seismically designed but were later backfit. The licensee has instituted a program to identify discrepancies beteeen the installed system and the backfit design. TVA is currently developing a program to resolve this issue and will provide it to the staff for review and approval.
4. Control Rod Drive (CRD) Return Lines As a result of an NRC information notice, TVA hired a contractor, IMPELL, to re-evaluate the seismic design of the CRD piping. TVA is using 5% damping factor in the seismic re-analysis of the CRD piping. The staff requested TVA to provide their bases for this damping value, a summary of the results of the analysis, a list of intended modifications, and a schedule for their completion.

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5. I & E Bulletin 79-14 And 79-02 TVA presented the plan of attack to resolve the I & E Bulletin 79-14 and 79-02.

Three phases have been planned: Phase I is the initial "walkdown" of the existing piping system to obtain the inspection data of the existing piping and ascertain " operability" of the system.

Phase II is the reanalysis of the piping system. TVA stated that it intends to use Section III,1971 and 1973 addendum of the ASME Code to analyze thermal, dead weight, and seismic effects for the piping system. However, TVA did not specify whether they will analyze for the seismic anchor movement or LOCA loads. It was unclear from the meeting if TVA intends to change the floor response spectra and damping factors for the reanalysis. TVA did provide a draft copy of their current reevaluation interim report. -

Phase III is the modification phase using the results from the piping stress analysis.

The staff expects TVA to provide a concise description of their re-evaluation criteria and identify any changes from that described in the FSAR, a statement confirming that all operability evaluation are complete, and a schedule for completion of Phases I, II & III of the program.

6. Non-essential Piping Test TVA initiated a vibration test program for the non-essential piping to deter-mine if the piping would survive a DBE. This work was intended to resolve the issue of class II piping damaging class I piping and components as a result of a severe earthquake.

Pipes with 2, 4 and 6 inch diameter were supported on a simulated concrete wall and were placed on the shaker table. From the results of the tests, the j non-essential piping system configurations appear to have a significant inherent capability to withstand seismic excitation. I l

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. JUL 81586

. Enclosure 2 Browns Ferry Nuclear Plant Seismic Design Issues Reques_t for Additional Information The numbered items in the following request are consistent with the meeting summary (enclosure 1) transmitted by the same letter:

1. Cable Trays - please provide background information, the TVA long term corrective actions and the implementation schedule regarding the seismic design of the cable trays.
2. Conduct Qualification Program - please provide information similar to item 1 above for the conduct qualification program.
3. HVAC Concerns - please provide the program to identify discrepancies between the installed system and the backfit design for staff review and approval.
4. Control Rod Drive (CRD) Return Lines - please provide the basis for the 5% damping factor used in the seismic reanalysis of the CRD piping, a summary of the results of the analysis, a list of intended modification and a schedule for completion of the modifications.
5. IE Bulletins 79-14 and 79 please provide a concise description of the reevaluation criteria for the piping system with identification of changes from the FSAR, a statement confirming that all operability evaluations are complete, and a schedule for completion of Phases I, II and III of the program.

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ENCLOSURE i

REQUEST FOR ADDITIONAL INFORMATION FOR VERMONT YANKEE RELATING TO HIGH DENSITY RACK - 5 PENT ' FUEL POOL EXPANSION ,

DOCKET NO. 50-271 l

Reference:

" Vermont Yankee Spent Fuel Storage Rack Replacement Report" April, 1986.

1) There are three load combinations provided in the report; pages 20, 71 and 88. Please discuss why there exist variations among three combinations and state which one was used for the rack design . Currently, the staff review is based on 1979 NRC position paper together with ASME Section III, subsection NF,1980 for stress limits. .

-2) It appears that there are errors in stress limits associated with the load combination in page 72. Sy is not allowed for levels A and B stress limits. Please clarify. .

3) Definition of S (section strength) is not clear. Provide an example and a justification for using S as a stress limit. (page 72) l l
4) It is stated that "the nonlinear three-dimensional model adequately represent the effects of impacting, friction and hydrodynamic coupling" (p. 74). Provide mathematical expressions for each component and discuss how such expressions are coded into the enmputer program. Provide experimental evidence that such mathematical expression together with numerical solution employed in the program indeed represent physical behaviors.

l 5) Provide a stability analysis for the nonlinear equation that governs rack dynamic response (p. 75-76). One should demonstrate that small changes in input parameters do not result into large changes in resultant values such as sliding and uplift of the rack. Parameters one should consider are damping, friction or any other major input such as forces and forcing frequencies. Some examples of stability analysis are demonstrated in

, " Nonlinear Vibration" by J.J. Stoker, Interscience Publishers and "

Analysis of Numerical Methods" by Isaacson and Keller, John Wiley.

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6) It is ' stated in the report (p. 90) that " Euler bucklin'g load for one storage cell is 105.7k". Provide a calculation for the buckling. load together with a schematic orasing of the mathematical model. Demonstrate that a dynamic effect of dropped fuel assembly is considered in'the buckling calculation.
7) In the report (p. 75), it is stated that "three conditions of fuel storage were analyzed; full, half full and empty. Consider a case where only two or three extreme outer cells are loaded while rest of the cells are empty. Demonstrate that the rack- does not tip over considering the fact that the rack support pads are recessed from the outer edge of the rack.

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v Mr. R. H. Capstick Vemont Yankee Nuclear Power Corporation Vermont Yankee Nuclear Power Station -

cc:

Mr. J. G. Weigand W. P. Murphy, Vice President &

President & Chief Executive Officer Manager of Operations Vermont Yankee Nuclear Power Corp. Vermont Yankee Nuclear Pcwer Corp.

R. D. 5, Box 169 R. D. 5, Box 169 Ferry Road Ferry Road Brattleboro, Vemont 05301 Brattleboro, Vernont 05301 Mr. Donald Hunter, Vice President Mr. Gerald Tarrant . Comissioner Vermont Yankee Nuclear Power Corp. Vermont Pepartment of Public . Service 1671 Worcester Road 120 State Street Framingham, Massachusetts 01701 Montpelier, Vemont 05602 New England Coalition en Nuclear Pollution Hill and Dale Farm Public Service Board R. D. 2 Box 223 State of Yemont Putney, Vemont 05346 120 State Street Montpelier, Vermont 05602 Mr. Walter Zaluzny Chairman, Board of Selectrian Yemont Yankee Decornissionirg Post Office Box 116 Alliance Vernon, Vemont 05345 Box 53 Montpelier, Verront 05602-0053 J. P. Pelletier, Plant Manager Vemont Yankee Nuclear Power Corp.

Post Office Box 157 Resident Inspector Vernon, Vement 05354 U. S. Nuclear Regulatory Corcission Post Office Box 176

{ Raymond N. McCandless Vernon, Verront 05354 Vermont Division of Occupational A Radiological Health Yemont Public Interest Administration Building Research Group, Inc.

10 Baldwin Street 43 State Street Montpelier, Vemont 05602 Montpelier, Yermont 05E0?

Honorable John J. Easton Thomas A. Murley Attorney General Regional Adninistrator State of Vermont Recion I Office

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109 State Street U. S. l'uclear Regulatory Corrission l Montpelier, Vermont 05602 631 Park Avenue l

King of Prussia, Pennsylvania 19406 John A. P.itscher, Esquire Ropes & Gray l 225 Franklin Street .

l Boston, Massachusetts 02110

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  • Mr. S. A. White Browns Ferry Nuclear Plant Tennessee Valley Authority Units 1, 2, and 3 cc: ,

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11. S. Sanger., Jr. , Escuire W. C. Bibb General Counsel Site Director, BFNP Tennessee Valley Authority Tennessee Valley Authority 400 Comerce Avenue Post Office Box 2000 E 11B 330 Decatur, Alabana 35602 Knoxville, Tennessee ~37902 Resident Inspector Mr. Ron Rooers U. S. Nuclear Reaulatory Commission Tennessee Valley Authority Route 2. Box 311 SN 130B Lookout Place ~

Athens, Alabama 35611 Chattanooga, Tennessee 37402-2801 Mr. Donald L. Hi111ans, Jr.

Tennessee Valley Authority -

Chairman, Limestone County Comission 400 West Sumit Hill Drive, U10BB5 Post Office Box 188 Knoxville, Tennessee 37902 Athens, Alabana 35611 Robert L. Lewis,tianaper, BFNP Ira L. Meyers, M.D. Tennessee Valley Authority State Health Officer Post Office Box 2000 State Department of Public flealth Decatur, Alabama 35602 State Office Buildino Montnomery, Alabama 36130 Mr. K. H. Whitt E3A8 400 West Sunnit liill Drive Tennessee Valley Authority Knoxville, Tennessee 37902 Regional Administrator, Region II U. S. fluclear Regulatory Comission l

101 Marietta Street, Suite 3100 Atlanta, Georoia 30303 l

l Mr. Steven Roessler U. S. Nuclear Regulatory Comission Reactor Training Center Osborne Office Center, Suite 200 Chattanoona, Tennessee 37411 1 .

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