ML17199F666
| ML17199F666 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities, 05000000 |
| Issue date: | 02/28/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17199F665 | List: |
| References | |
| NUDOCS 8603110157 | |
| Download: ML17199F666 (5) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR RE~ULATION DEMONSTRATION OF CONTAINMENT PURGE AND VENT VALVE OPERABILITY COMMONWEALTH EDISON COMPANY IOWA-ILLINOIS GAS AND ELECTRIC COMPANY DRESDEN NUCLEAR POWER STATION, UNIT NOS. 2 AND 3 QUAD CITIES NUCLEAR POWER STATION, U~ITS 1 AND 2 DOCKET NOS. 50-237/249/254/265 1.0 INT~ODUCTION
- 1. 1 Regli1 rement Demonstration of operability of the containment purge and vent valves, parti-cularly the ability of these valves to close during a design basis.accident, 1s necessary to assure containment. isolation.* This demonstration of opera-bility is required by BTP CSB 6-4 and SRP 3.10 for containment purge and vent v*alves which are not sealed c.losed during. operational conditions 1, 2, 3, and
- 4.
~.
1.2 Description of Purge and Vent Valves
~....,.
The valves identified as the containment isolation valves 1n the purge and vent system are as follows:
Unit No.
2 2
2 2
2 2
2 2
3 3
3 3
3 3
3 3
Dresden Station Units 2 and 3 Valve Number A0-2-1601-21,
A0-2-1601-22 :
A0-2-1601-23 :
A0-2-1601-24 !
A0-2-1601-56
- A0-2-1601-60*
.A0-2-1601-63 A0-2-1601-55:
A0-3-1601-21*
A0-3-1601-22*
A0-3-1601-23' A0-3-1601-24 A0-3-1601-56*
A0-3-1601-60*
A0-3-1601-63 A0-3-1601-SS Size (Inches) 18 18 18 18 18 18 6
4 Valve Type Butterfly Butterfly Butterfly Butterfly Butterfly Butterfly Butterfly Butterfly Location Outside containment Outside containment Outside containment Outside containment Outside containment Outside containment Outside containment Outside containment 18 Butterfly Outside containment 18 Butterfly Outside containment 18 Butterfly Outside containment 18 Butterfly Outside containment 18 Butterfly Outside c6ntainment 18 Butterfly Outside containment 6
Butterfly Outside containment 4
Butterfly Outside containment L
[~~~1l~r~-f~1?J.
e Quad Cities Station Units l and 2 Size Type Unit No.
Valve Number
~Inches}
Tlpe Location 1
A0-1-1601-21 18 Butterfly Outside containment 1
A0-1-1601-22 18 Butterfly Outside containment 1
A0-1-1601-23 18 Butterfly Outside containment 1
A0-1-1601-24 18 Butterfly*
Outside containment 1
AO~l-1601-56 18 Butterfly Outside containment 1
A0-1-1601-60 18 Butterfly Outside containment 1
A0-1-1601-63
- 6 Butterfly Outside containment 1
A0-1-1601-55 4
Gate Outside containment 1
A0-2-1601-21 18 Butterfly Outside containment 1
A0-2-1601-22 18 Butterfly Outsid* cont~inment 1
A0-2-1601-23
. 18 Butterfly Outside containment 1
A0-2-1601-24 18 Butterfly Outside containment 1
A0-2-1601-56
.JS Butterfly ~*
Outside containment 1
A0-2-1601-60 is--
Butterfly Outside containment 1
A0-2-1601-63 18 Butterfly
-Outside containment 1
Ao-1-1601..:ss 4
Gate Outside containment The 18-inch butterfly valves at Dresden and Quad Cities are Model 2Fll valves manufactured by Henry Pratt Company and are equipped with Pratt operators (8-1 nch diameter cylinders).
The 6-inch diameter butterfly valves are also Pratt Model 2Fll valves equipped with Pratt operators (3-l/4inch diameter cylinders). The 4-inch diameter wafer sphere butterfly valves are Jamesbury Model 8126 equipped with type ST-60MSB operators. The 4-inch diameter gate valves are Crane Model No.
47-l/2V valves equipped with Chicago Fluid operators (8-inch diameter cylinders).
1.3 Demonstration of Operability
_ Comon~ealth Edison (CECO) has provided purge and vent' valve operability demonst~ation information for Dresden, Units 2 and 3 and Quad Cities, Units 1 and 2 in the following submittals:
A.
September 30, 1985 letter, J. R. Wojnarowski (CECO) to H. L. Thompson (NRC).
B. July 25, 1985 letter, J. R. Wojnarowski (CECO) to H~ L. Thompson (NRC).
C.
May 3, 1984 letter, B. Rybak (CECO) to H. R. Denton (NRC).
D.
December 21, 1983 letter, B. Rybak (CECO) to H. R. Denton (NRC).
E.
November 4, 1983 letter, D. M. Crutchfield (NRC) to D *. L. Farrar. {CECO).
F. July 6, 1981 letter, T. J. Rausch (CECO) to G. c. Lainas (NRC).
G.
February 27, 1981 letter, R. F. Janecek (CECO) G. C. Lainas (NRC).
H.
August 22, 1980 letter, R. F. Janecek (CECO) to G. C. Lainas (NRC).
I. AprH 1980 NUREG/CR-0891, "Seismic Review of Dresden Nuclear Po"1er Station" The licensee's dynamic torque (To) predictions contained in NUTECH Engineers report COM-83-042 (Reference A) for the 18-inch, 6-inch, and 4-inch butterfly valves at Dresden and Quad Cities are based on Prairie Island valve torque data derived from a torque analysis by the Henry Pratt Company for the same model 18-inch butterfly valve (Model No. 2Fll). The Pratt anaJysis uses dynamic torque coefficients (Cr) based on a test program using a 5-inch dia-meter model valve disc. For the 6-inch Pratt butterfly valves, the 18-inch torque data is scaled down by the cube of the diameter ratio (0 6 inch/Dia inch) 3*
The 4-inch Jamesbury butterfly valve disc does not have the same geometry as the Pratt disc. For this valve, the 18-inch Pratt torque data was modified by two factors. The first factor involved scaling of the 18-i nch. torque data by the cube of the diameter ratio (04 inch/Dia inch) 3*
The second factor involved increasing the 4-inch torque data by the ratio of analytically-determined torque coefficients for the Pratt and Jamesbury disc geometry (Cr4 inch/Cria inch)*
The stress analyiis for cri~ical valv~ parts is ~oniained in the NUTECH Engineers report (Reference A).
Stress values are determined for the critical valve parts (shaft, disc pins, keyways) using maximum torque loads combined with design pressure loads. Allowable stresse~ for the various valve com-ponents are taken from ASME Boiler and*Pressure Vessel Code,Section III appendices.
The largest stress ratio which is defined as the calculated stress divided by the allowable stress was determined.to be 0.90 for the Pratt 18-inch diameter valve disc pin.
The actuator torque margin for the valve assemblies is adequate.in all cases for the 18-inch, 6-inch, and 4-inch butterfly valves. This is demon~
strated by comparing the minimum operator torque with the maximum dynamic torque required to close the valve against the increasing.containment pressure during a LOCA.
The Crane 4-inch Gate Valve utilized in the purge and vent system at Quad Cities 1 and 2 is a 150 lbs class valve designed to ANSI 81634 with a design pressure rating of 225 psig at 300°F. The closure analysis for this valve is provided.fo NUTECH Report No. COM-83-042, dated September 23, 1985 and sub-mitted as an attachment to Reference A.
- 2. 0 EVALUATION...
-~
The 1 i censee (Commonwea 1th Edi son) has chosen to use torque data for its 18-inch Pratt Model No. 2Fll butterfly valves from an analysis performed by Henry Pratt Company for the same size and model number valves at another nu-clear generating station. The maximum dynamic torque predicted by Pratt for the 18-inch valve is 18,302 in-lbs and includes a factor for the increased dy-namic torque resulting from an installation configuration with the valve shaft out of plane with the upstream elbow. *Torque coefficients for both sonic and subsonic flow are derived from analysis of experimental test data* using a 5-inch test model. Conservative assumptions used in the analysis include:
J I*
- Single valve closure with the redundant valve failed in the open position.
- Valve closure against peak containment pressure (65 psig~.
- Valve shaft 90° cut of plane with an upstream elbow for every valve.
The staff finds the use by the licensee of the Pratt torque data for the 18-inch valves at Dresden-Quad Cities acceptable.
For the 6-inch butterfly valves, the torque of 18,302 in-lbs.was scaled down by the ratio of the diameters cubed resulting in a maximum dynamic torque of 678 in-lbs.
The 4-inch butterfly valves have a disc geometry dissimiln to the Pratt disc geometry.
In order to account for this difference, the NUTEC analysis (Refer-ence A) determined theoretical torque coefficients for both discs then applied the ratio of these coefficients and the diameter ratio cubed to the 18,302 in-lbs maximum dynamic torque from the Pratt analysis for the 18-inch valve.
D 3
T
= 18,302 x ( 4-i nch J 04-inch D 18-inch x
= 18,302 x ( ~B) 3 x O~~~~B
= 307 in-lbs Diameter Ratio
=
D4 inch Dis inch.
Cr Jamesbury Torque Coefficient = -----
Ratio Cr Pratt C,: ~amesbury C Pratt T
The staff finds the assumptions and methodology used in torque prediction for the 18-inch, 6-inch, and 4-inch valve acceptable.
- .
- The stress analysis for the 18-inch, 6-inch, and 4-inch butterfly valve critical parts is contained in NUTECH Report No. COM-83-042 which is furnished as an attachment to Reference A.
Calculated stresses are compared to allow-able stresses taken from Section III and Appendices of the ASME Boiler and Pressure Vessel Code.
Tables 4.1, 4.2, and 4.3 of the NUTECH report tabulated the stress ratios for the 18-inch, 6-inch, and 4-inch butterfly valve critical parts. The stress ratio is defined as the calculated stress divided by the code allowable stress. The weakest critical part in each valve sizE!- has the largest stress ratio. For the 18-inch butterfly valve, the weakest member.is the disc pin with a stress ratio of 0.9.
The weakest member in the 6-inch
- t..
- 5 butterfly valve is the disc shaft in the pin region with a stress ratio of 0.43.
The weakest member in the 4-inch butterfly valve is the disc shaft in the spline region with a stress ratio of 0.56.
The staff finds the stress analysis results acceptable. Conservative loading assumptions were used and the results demonstrate that the calculated stresses do not exceed stresses allowed by code.
For the demonstration of adequate torque margins, the maximum dynamic torque is compared to the minimum operator torque in the NUTECH analysis. The comparison for each size valve is shown below:
Valve Type 18-inch Butterfly 6-inch Butterfly 4-inch Butterfly 4-i nch Gate Maximum Dynamic Torque (in-lbs) 18,302 678 307 1,404 Minimum Operator Torque (in-lbs) 25,303 2,903 720 2,545 The staff finds that the torque margins for the valves above are adequate and demonstrate the ability of the operator to close the valve against the in-creased containment pressure during a LOCA.
The 150 lbs pressure rating of the valve provides an acceptable margin for structural integrity when compared to the peak containment pressure of 65 psig.
NUTECH furnishes a closure and static pressure analysis for the 4-inch gate valves. The closure analysis determines the force required to close the valve which is created by packing friction and a wedging factor, and compares this with the minimum actuator force.
The analysis results show that the
.actuator has a minimum available spring preload of 2,545 lbs compared to the required force to effect closure of 1,404 lbs. The 150 lbs pressure rating of the valve provides an acceptable margin for structural integrity when compared to the peak containment pressure of 65 psig.
As a valid seismic qualification document is not available, this item must be addressed under Unresolved Safety Issue A-46 (s~ismic qualifica-tion of equipment in operating plants).
3.0 CONCLUSION
We have completed our review of information submitted to date concerning the operability of the 18-inch, 6-inch, and 4-inch containment purge and vent valves at the Dresden Station, Units 2 and 3, Quad Cities Station, Units 1 and
- 2.
We find that the information submitted has satisfactorily demonstrated the ability of the valves to close from the fully open position against the build-up of containment pressure in the event of -a DBA/LOCA.
Principal Contributors:
R. Wright Dated: February 28, 1986