ML17054A913

Forwards SER Re Completion of Multi-Plant Issues B-24, Venting & Purging of Containment & F-19,Item II.E.4.2, Containment Isolation Dependability. Demonstration of Containment Purge & Vent Valve Operability Acceptable

ML17054A913
Person / Time
Site:	Nine Mile Point
Issue date:	07/24/1984
From:	Vassallo D Office of Nuclear Reactor Regulation
To:	Hooten B NIAGARA MOHAWK POWER CORP.
References
TASK-2.E.4.2, TASK-TM NUDOCS 8408030180
Download: ML17054A913 (14)

Text

July 24, 1984 Docket No. 50-220 Mr. B. G. Hooten Executive Director, Nuclear Operations Niagara Mohawk Power Corporation 300 Erie Boulevard West

Syracuse, New York 13202

SUBJECT:

COMPLETION OF GENERIC ISSUES B-24, "VENTING AND PURGING OF CONTAINMENT" AND F-19, TMI ITEM II.E.4.2, "CONTAINMENT ISOLATION DEPENDABILITY Re:

Nine Mile Point Nuclear Station, Unit No.

1 We have completed our review of the additional information you provided in your letter of May 30, 1984 regarding the equipment qualification portion of MPA B-24.

We find the information submitted demonstrates the ability of the containment purge and vent valves to close against the buildup of contained pressure that could result from a postulated design bases loss-of-coolant accident.

Our supporting Safety Evaluation is enclosed.

Further, in your letter of May 30, 1984, you confirmed that valve closure time would be limited to less than 14 seconds including instrument response time and the modification would be installed at the 1986 refueling outage.

We find this acceptable.

You provided information supporting a request to maintain your current requirements for the elastomer valve seal material.

We have this request under review on a plant specific, basis and 'it will be the subject of separate correspondence.

I Based on the commitment contained in your December 1,

1983 letter to install a containment isolation signal on high radiation in accordance with our position and our enclosed Safety Evaluation, we find that TMI Item II.E.4.2 is complete, since positions 6 and 7 of the item are now satisfied.

We are currently reassessing our position with regard to 'line sizes and should any additional information and/or requirements be found necessary the matter will be handled separately.

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Mr. B.

G. Hooten We request that you review the previous guidance we provided for the vent and purge issue.

In particular, you are requested to provide a Technical Specification change to support your proposed modifications, and to include the valve position blockage at 50', the 14-second closure time as well as the other items included in the guidance including a limit of 90 hours0.00104 days <br />0.025 hours <br />1.488095e-4 weeks <br />3.4245e-5 months <br /> on

purging, as described in our March 19, 1984 Safety Evaluation.

The Technical Specification change should be provided before your next refueling outage.

Sincerely, Original signed by/

Enclosure:

, As stated cc w/enclosure:

See next page DISTRIBUTION C~

NRC PDR Local PDR ORB¹2 Reading DEisenhut OELD SNorris RHermann EReeves ELJordan JNGrace ACRS (10)

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Domenic B. Vassallo, Chief Operating Reactors Branch ¹2 Division of Licensing DL:0 B¹2 DL:$(B¹2 SNo is:ajs RHe ann 07/g9/84 07/gg/84 D

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Mr. B. G. Hooten Niagara Mohawk Power Corporation Nine Mile Point Nuclear Station, Unit No.

1 CC:

Troy B. Conner, Jr.,

Esquire Conner 8 Wetterhahn Suite 1050 1747 Pennsylvania

Avenue, N.

W.

Washington, D.

C.

20006 Robert P. Jones, Supervisor Town of Scriba R. D. ¹4

Oswego, New York 13126 Niagara Mohawk Power Corporation ATTN:

Mr. Thomas Perkins Plant Superintendent Nine Mile Point Nuclear. Station Post Office Box 32

Lycoming, New York 13093 U, S. Environmental Protection Agency Region II Office Regional Radiation Representative 26 Federal Plaza New York, New York 10007 Resident Inspector U. S.'Nuclear Regulatory Commission Post Office Box 126

Lycoming, New York 13093 John W. Keib, Esquire Niagara Mohawk Power Corporation 300 Erie Boulevard West

Syracuse, New York 13202 Thomas A. Murley Regional Administrator Region I Office U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pennsylvania 19406 Mr. Jay Dunkl eberger Division of Policy Analysis and Planning New York State Energy Office Agency Building 2 Empire State Plaza Albany, New York 12223

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UNITEDSTATES NUCLEAR REGULATORY COMMISSION WASHINGTON,P. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION NIAGARA MOHAWK POWER CORPORATION NINE MILE POINT NUCLEAR STATION, UNIT NO.

1 DOCKET NO. 50-220 DEMONSTRATION OF CONTAINMENT PURGE AND VENT VAI VE OPERABILITY 1.D

~R Demonstration of operability of the containment purge and vent valves, partic-ularly the ability of these valves to close during a design basis accident, is necessary to assure containment isolation.

This demonstration of operability is required by BTP CSB 6-4 and SRP 3.10 for containment purge and vent valves which are not sealed closed during oper ational conditions 1,

2, 3,

and 4.

2.0 Descri tion of Pur e and Vent Valves The valves identified as the containment isolation valves in the purge and vent system are as follows:

Valve Ta No.

BFV 201-07 BFV 201-08 BFV 201-17

. BFV 201-16 BFV 201-09 BFV 201-31 BFV 201-10 BFV 201-32 Valve Size (Inches 20 20 20 20 24 24 24 24

~TB Butterfly Butterfly Butterfly Butterfly Butterfly Butterfly Butterfly Butterfly Use Suppression chamber purge and vent.

Drywell purge and vent.

I Location Outside containment Outside containment Outside containment Outside containment Outside containment Outside containment Outside containment Outside containment The butterfly valves are manufactured by Allis Chalmers.

The 24-inch valves are used for purging and venting the drywell and the 20-inch valves purge and vent the suppression chamber.

All lines have two valves in series; with the inboard valves being air operated and the outboard valves motor operated.

All valves are mechanical ly bl ocked for a 50'maximum opening (90'-ful 1 open).

The pneumatic operators are manufactured by Bettis and the electric motor operators are made by Limitorque.

Model numbers for the operators are not furnished in the licensee's submittals.

No information is provided in the 5 Ubmittal s concerning the pilot sol enoid valves

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3.0 Demonstration of 0 erabilit Niagara Mohawk Power Corporation (NMPC) has provided operability demonstration information for the containment purge and vent system isolation valves at their Nine Mile Point nuclear station in the following submittals:

Reference A - NPC letter of January 29, 1982, T.

E.

Lampages to D. B.

Vassallo (NRC).

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Reference B - Niagra Mohawk Power Corporation, letter of December 17,

1979, D.

P.

Disc to T. A. Ippolito (NRC).

Reference C - Allis Chalmers test r eport for containment isolation valves dated August 1,

1980 and attached to Reference A.

Reference D - Niagara Hohawk Power Corporation letter of November 14, 1983,'to D. Vassalo (NRC).

Reference E - Teleconference April 17,

1984, NC, Licensee, Allis

Chalmers, Brookhaven National Laboratory.

Reference F - Niagara Mohawk Power Corporation', letter of Hay 30, 1983, to D. Vassallo (NRC).

3.1 Niagara Mohawk's approach to operability demonstration is based on the Allis Chalmers Operability Analysis Report submitted as an attachment to Ref-erence D.

Thy analysis 'assunes single valve operation with both valves blocked at 50 (90

= full open) and one valve failed at 50 open.

Dynamic torque coefficients (CT) used in the analysis are derived from the manufacturer's model test program; the results of which are presented in the Allis Chalmers report VER-0209.

The ramp-rise approach is used for determining Pl during valve closure based on LOCA contaianent pressure response curves for the drywell and suppression

chamber, furnished by the licensee.

Valve orientation and upstream piping as confirmed by site inspection is the basis for selecting appropriate curves of dynamic torque coefficient (CT} vs closure angle from the model test data.

The predicted loads are based on a

30-second closure time for the valves and the analysis is performed for 0, 1, and 3-second delay times before valve disc motion is initiated.

3.2 A table entitled "Dynamic Torque. Summary" taken from Reference D is shown below and enables a canparison to be made for each valve of minimun operator torques and peak dynamic torques.

D namic Tor ue Summar 201-07 201-17 201-08 201-09 201-31 201-10 201-16 201-32 Lsmitorque Limito rque Bettis Limito rque Limitorque Bettis Bettis Betti s

~U1 T

N

~Q Operator Torque Min.*

ft-1bs) 1100 1200 556 1100 1100 1169

556, 1169+

6 476 518 964 964 953 478

880, 464 467 464 476 400 518 964 960 964 960 964 960 478 477 824 853 Max. Dynamic Torque with Delay ft-1 bs

• Hinimun Bettis torque may not occur at the same angle as the maximum dynamic torque.

See graph attached to Bettis equipped valve calculations.

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3 3.3 The valve shafts and disc pins are considered the critical valve parts in determining the structural adequacy of the valve to close under NAFLOCA con-ditionss.

Maximun allowable shaft torques conform to the criteria of AWWA standard C504.

The disc pins in accordance with AWWA C504, are capable of transmitting a minimun of 75% of the maximun shaft torque.

For all valves the allowable torques exceed the'eak dynamic torque predicted for the accident conditions.

3.4 Allis Chalmers and the licensee stated during the Reference (E) telecon-ference that the Nine Mile Point 1 purge and vent valves are bounded by a generic seismic qualification available at Allis Chalmers plant.

Reference (F) is confirmation that the seismic requirements of the valve specifications were met by generic engineering analysis.

4.0 Evaluation 4.1 The staff has reviewed the report entitled "Torque Analysis of Purge and Vent Valves" prepared by Allis Chalmers and submitted as an attachment to Ref-erence D.

Predicted valve loads are based on closure fry the blocked angle (50 open),

and dynamic-torque coefficients (CT) from the Allis Chalmers'odel test program using the installed valve and piping as checked in-situ by the licensee.

A previous error in calculations combining the dynamic and bearing torques reported by the staff has been acknowledged and rectified. The use of the suppression chamber LOCA pressure response curves in predicting dy-namic torque loads for the wet well valves is acceptable even if less conser-vative than using the drywell LOCA response curves for all containment purge and vent valves.

P 4.2 The 24-inch drywell valve assemblies, BFV 201-09,

-31, -10, -32, and two of the 20-inch suppression chamber valves BFV 201-07, and -17 have substantial torque margins as shown below.

Valve Number 201-07,

-17 201<<09,

>>31 201-10 201-32 Torque Margin*

(0-second Delay) ft-lbs 6

136 216 289

• Torque margin

= minimum operator torque-maxsmum dynamic torque.

The torque margins for valve numbers 201-08, and -16 if taken from the torque su+nary table shown in Part 3.2 of this report, are 38 ft-lbs and 78 ft-lbs, respectively based on minimun operator torque'nd maximum dynamic torque,

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without considering the variation in operator torque during closure.

However, using the curves of operator and valve torque versus valve angle found in Ref-erence D, the actual minimus torque margin is found to be 130 ft-lbs (201-08) and 260 ft-lbs (201-16) which the staff finds acceptable.

4.3 Information concerning critical valve part structural integrity is pro-vided in References D and E.

The valve shaft and disc pins are determined to be the most critical and an allowable maximun torque for the 20 and 24-inch valve shafts are determined using AWWA C504 standard allowable stresses.

Ref-erence D gives values of 2050 ft-lbs allowable torque for the 20-inch valve shafts and 2200 ft-lbs allowable torque for the 24-inch valve shafts.

The disc pin allowable torques are given as 75$ of the shaft torques, and are can-pared to the peak dynamic torques below:

Val ve Si ze

~Inches 20 24 Disc Pin Allowable Torque ft-lbs) 1588 1650 Peak Dynamic Torque (ft-lbs) 518 964 Factors of safety for the 20 and 24-inch. valves are 3.1 and 1.7 respectively, and are acceptable to the staff.

4.4 The plant specific seismic loading for these valves at Nine Mile Point 1 is enveloped by the generic loading; the staff finds this acceptable.

5.0

~Summer We have canpleted our review of information submitted to date concerning the operability of contairment purge and vent valves for Nine Mile Point 1.

Sec-tions 4.1, 4.2, 4.3 and 4.4 are the basis for the conclusion~

drawn by the staff.

We find the information submitted demonstrates the ability of the con-tainment purge and vent valves at Nine Mile Point 1 to close against the buildup of contaireent pressure in the event of a DBA/LOCA.

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