ML20027C494

Forwards Request for Addl Info Re Unresolved Safety Issue B-24 Re Operability of Purge Valves

ML20027C494
Person / Time
Site:	Crystal River
Issue date:	09/20/1982
From:	Stolz J Office of Nuclear Reactor Regulation
To:	Hancock J FLORIDA POWER CORP.
References
REF-GTECI-B-24, REF-GTECI-ES, TASK-B-24, TASK-OR NUDOCS 8210180010
Download: ML20027C494 (7)

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DISTRIBUTION (Docket Filpl NRC PDR L PDR Docket No. 50-302 ORB #4 Rdg DEisenhut 0 ELD AE0D Mr. J. A. Hancock IE Vice President ACRS-10 Nuclear Operations SMiner Florida Power Corporation RIngram ATTN: Manager, Nuclear Operations Gray File P. O. Box 14042; M.A.C. H-2 EBlackwood St. Petersburg, Florida 33733 H0rnstein GBagchi

SUBJECT:

CRYSTAL RIVER UNIT 3 (CR-3) - REQUEST FOR ADDITIONAL INFOR-MATION ON OPERABILITY OF THE PdRGE VALVES (GENERIC ITEM B-24)

He have reviewed the infomation you submitted to denonstrate the long-term operability of the purge and vent valves at CR-3 From our review, we find that we require additional infomation in order to complete our review. From our review of the infomation you provided and our evaluation of infomation provided on RIA 48" Pratt Valves (same as used at CR-3) by another licensee, we find that these valves may be overstressed even at very low angles of openings.

Therefore, we require the infomation requested in Enclosure 1 in order for us to conclude there is adequate justification for allowing operation at power with your purge valves partially blocked open (interim position), pending denonstration of long term operability of i

these purge valves. To demonstrate long-tem operability of the purge valve, we require the infomation requested in Enclosure 2 Please provide the information requested in Enclosure 1 within 30 days of receipt of this letter and the infomation requested in Enclosure 2 within 60 days of recefpt of this letter. If the infomation cannot be provided within the time requested, please provide within 7 days of receipt of this letter, a schedule for submission of the information.

The reporting and/or recordkeeping requirements contained in this letter affect fewer than ten respondents; thereforo, 02 clearance is not required under P.L.96-511.

Si Acerelyn syg3g3p mr. snm..-

John F. Stolz, Chief Operating Reactors Branch #4 l

Division of Licensing l

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!o 50-302 Crystal River Unit No. 3

.a Florida Power Corporation cc w/ enclosure (s):

tir. S. A. Brandimore Florida Power Corporation Mr. Robert B. Borsum Vice President and General Counsel Babcock & Wilcox P. O. Box 14042 Nuclear Power Generation Division St. Petersburg, Florida 33733 Suite 220, 7910 Woodmont Avenue Bethesda, Maryland 20314 Mr. Wilbur Langely, Chairman Board of County Commissioners Mr. Tom Stetka. Resident Inspector Citrus County U.S. Nuclear Regulatory Commission Iverness, Florida 36250 Routsi #3, Box 717 Crystal River, Florida 32629 Regional Radiation Representative Mr. T. C. Lutkehaus Nuclear Plant Manager EPA Region IV Florida Power Corporation 345 Courtland Street, N.E.

Atlanta, Georgia 30308 P. O. Box 219 Crystal River, Florida 32629 Bureau of Intergovernmental Relations 660 Apalachee Parkway Crystal River Public Library Tallahassee, Florida 32304 668 N. W. First Avenue Crystal River, Florida 32629 Administrator Department of Environmental Regulation Power Plant Siting Section State of Florida 2600 Blair Stone Road Tallahassee, Florida 32301 Attorney General Department of Legal Affairs The Capitol Tallahassee, Florida 32304 Mr. James P. O'Reilly, Regional Administrator U. S. Nuclear Regulatory Commission, Region II 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303

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CRYSTAL RIVER UNIT 3 50-302 REQUEST FOR ADDITIONAL If:FORl1ATION The following information is required in order to make an evaluation on continued operation in the interim position for these valves.

1. 'The analysis for these valves appears to'take credit for the pressure rise versus time into the accident, and the valve closure time is critical to the qualification of these valves.

Therefore, provide the closure time, the lag time, and the delay ~

to signal' time used to qualify the valve. In addition, verify by test that these times are within the actual valve closure and lag times.

Signal delay time should be verified by calibration of the alarm. Data taken during testing or maintenance on these valves within the last six months is acceptable provided no work has been performed on this equipment since.

Qualification times and actual times should be submitted, 2.

The actual piping configurations in which these valves were installed were not identi-fied. Since upstream piping configuration can have a significan,t effect on the dynamic, torques subiit sketches for each of the p' urge' valve installations showing the following detail:

a) distance from upstream bends or elbows up to 15 pipe diameters upstream b) shaft orientation with respect to the elbows c) disc closure direction with respect to the elbows d) flow direction during a LOCA (out of containment) i j

e) hub or flat side of disc downstream f) distance between valves.

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I 3.

Discussions with Pratt on August 5, 1982 indicate Pratt has not tested the R1A valves in other than straight line flow.

Please identify and describe what tests have been performed on the 48" purge valves to determine the worst case installat!on effects.

4.

Calc.ulate the following stresses for a valve closing from a 55* position in the worst case installation, disc stresses key way stress key stress disc to shaft connection (i.e. pins)

Shear stress, combined stress, and bearing stress should be determined where applicable and the loads applied should be the combination of seismic, aerodynamic torque, pressure, and normal operating loads. Provide the analysis and the results for our review.

5.

Provide the minlmum available torque for the air operators and state at which angle this minimum occurs.

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The following additional information is required to continue the long term review of the 48" R1A Pratt Purge Valves at Crystal

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1.

Verification of the delay, lag, and closure timcs of these valves should be..done on a periodic basis not to exceed 6 months. _,,

Incorporate this requirement in the Technical Specifications for CR-3 if 'the time vs. pressure method 'is to be used to qualify these valves. Technical Specifications

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presently require these valves to be closed within 60 secrmds.

If Technical Specifications are not to be changed a closure

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time of 60 seconds should be assumed in the analysis.

2.

Two tables of torque values were provided in your

' submittal. The first table assumed the valve was initially in the full power (90 ) position and was fully closed in 5 seconds plus a 1 second delay time. This table indicated a maximum dynamic torque of 465,275 in-lbs. at 72.

The maximum dynamic torque at 55 was 292,741 in-lbs. and at 40 was 142,284 in-lbs. The second table assumed the valve was initially at 35 from the closed position and closed within 2 seconds.

A one second delay time was assumed. The maximum dynamic torque was 34,116 in-lbs. at seating.

The table indicates the analysis for which these stress levels were calculated was performed for a valve with 435,000 in-lbs.

of torque. These valves are blocked to 40 or 55 depending on which operator is used.

The stress analysis submitted includes a summary table of stress levels and stress allowables.

The stress tables use ASME allowa-bles for valve body pressure boundaries and a combination of Sm values and 90% of yield for other components of the valve.

The stress tables indicate 2 components, the valve shaft and the l

keyway, to be overstressed. The shaft allowable is.9 Sy =

27,000 psi. The shaft actual stress is 38,937 psi. The keywrf i

allowable bearing stress is.9 Sy = 27,000 psi.

The keyway actual bearing stress is 60,870 psi. The valve shaft is ASTM A-479, Type 304 material.

The keyway-is ASTM A-35, Gr.LF-1.

The purge valve stress analysis report was completed in 1970.

It discusses methodology and provides equations used to determine stress levels but did not include the actual calculations. The analysis includes static seismic loads of Sg in 3 directions but neglected',the aerodynamic loads, The only torsional loads included i,n.t.he methodology for shaf t analysis were seating loads. Seati.09. torsion is combined with seismic loads and pressure were combined with seismic loads for the shaft analysis, but seating torsion, i

seismic and pressure were not combined together.

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_2 The. Hub Bfock Assembly stress analysis methodology has been revised to include a dynamic torque of 435,000 in-lbs. but

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it appears to be the only area where dynamic torque was ceasidered in the analysis.

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Since the stres's tables included in the submittal indicate the valve is overstressed in the condition analyzed, the stress report should be revised to reflect the loads the valve q

would experience in a LOCA following appropriate modifi-G cations (i.e., blocking).

Provide, a revi. sed stress report that.

1 combines seismic, pressure,. and torsional loads (as well as any additional loads experienced by the valve) for all j

applicable parts. In addition, provide. the stress levels for all interface hardware (bolting, bonnet, ect.) that are calculated for the combined LOCA 'sYlsmic loads.

3.

Since static se'ismic loads are being used to show operability qualification of this valve, conf.irm that these valve assemblies have been verified by test to be rigid.

4.

Pratt has indicated in discussions with the NRC on August 5, 1982 that model tests for the R1A valve have only been performed for straight pipe installations.

Therefore confinn that all of the 43" purge valves are located'in straight pipe installations or demonstrate

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by test that the torques used in the qualification analysis envelope the worst case installation config-l uration at Crystal River.

5.

Provide a comparison of the ' torque"l'evels. calculated for. the

.nodified ' valves in the as-installed configurations at all angles with the available operator torque. The available operator torque for the Bettis operators will vary with disc angle.

6.

Verify that torque limit switch settings are compatible with' the new cilculated loads for ~the Liriftorque operators. Available torquas for the"Limitorque operators should be determined at minimum available voltages. Changes in closing I

time of the valve due to reduced voltages should be considered.

7.

If handwheels are used on these valves describe the means used to assure that these valves are not left in a manual mode.

8.

If these valves are to be permanently limited to a maximum opening of les.s than 90 in operating modes, submit a description, of..hqw the valve will be_ blocked to prevent opening the. valve beyond the required limit as a long-term modification.

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Describe the qualification of the equipment and/or systems used to assure these valves will not have increased leakage in ambient temperatures of 60*F or less.

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