ML17195A846
| ML17195A846 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities, 05000000 |
| Issue date: | 06/17/1985 |
| From: | NRC |
| To: | |
| Shared Package | |
| ML17195A845 | List: |
| References | |
| NUDOCS 8506260745 | |
| Download: ML17195A846 (8) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, 0. C. 20555 SAFETY EVALUATION DRESDEN, UNITS 2 AND 3 DOCKET NUM3ERS 50-237 AND 50-249 QUAD CITIES STATION, UNITS 1 AND 2 DOCKET NUM3ERS 50-254 AND 50-265 DEt-ONSTRATION OF CONTAINr-ENT PURGE AND VENT VALVE OPERABILITY 1.0 R egui rement Denonstration of operability of the contai1111ent purge and vent valves, parti-cularly the ability of these valves to close during a design basis accident, is necessary to assure contairment isolation.
This danonstration of opera-bility is required by BTP CSB 6-4 and SRP 3.10 for containment purge and vent valves* which are not sealed closed during operational conditions 1, 2, 3, and
- 4.
2.0 Description of Purge and Vent Valves The valves identified as the containment isolation valves in the purge and vent sys tan are as follows:
' I Dresden Station Units 2 and 3 Size Valve Unit No.
Valve Number (Inches)
Txpe Location 2
A0-2-1601-21 18 Butterfly Outside con ta i rrnen t 2
A0-2-1601-22 18 Butterfly OJtside containment 2
A0-2-1601-23 18 Butterfly Outside contai1111ent 2
A0-2-1601-2 4 18 Butterfly
. OJtside containment
- 2 A0-2-1601-56 18 Butter fly
- Outside con ta i nnen t
- 2 A0-2-1601-60 18 Butterfly Out s i d e con ta i nm en t
- 2 A0-2-1601 "'.'63 6
Butterfly Outside containnent
- 2 A0-2-1601-55 4
Gate Outside containment 3
A0-3-1601-21 18 Butterfly Outside containment 3
A0-3-1601-22 18 Butterfly Outside containnent 3
A0-3-1601-23 18 Butterfly
.OJtside containment 3
A0-3-1601-24 18 Butterfly Outside containnent
- 3 A0-3-1601-5 6 18 Butterfly Outside containment
- 3 A0-3-1601-60 18 Butterfly Outside contaimient
- 3 A0-3-1601-63 6
Butterfly 0Jtside containment
- 3 A0-3-1601-55 4
Gate*
Outside contaimient
- Valves identified as contairrnent purge and vent valves and added to
.scope of review in Reference A, May 3, 1984 letter from Consoli-dated Edi son (CE) to NRC.
8506260745 850617* *:.-~
PDR ADOCK. 05000237.
p PDR Quad Cities Station Units 1 and 2 Size Valve Unit No.
Valve Number (Inches}
T l'.~e Location 1
A0-1-1601-21 18 Butterfly Outside containment 1
A0-1-1601-22 18 Butterfly Outside contairment 1
A0-1-1601-23 18 Butterfly Outside containment 1
A0-1-1601-24 18 Butterfly Out side con ta i rment
- 1 A0-1-1601-56 18 Butterfly Outside containment
- 1 A0-1-1601-60 18 Butterfly Outside contairment
- 1 A0-1-1601-63 6
Butterfly Outside containment
. *1 A0-1-1601-55 4
G:1te Outside contairment 2
A0-2-1601-21 18 Butterfly Outside con ta i rment 2
A0-2-1601-22 18 Butterfly Outside containment 2
A0-2-1601-23 18 Butterfly Outside contairment 2
A0-2-1601-2 4 18 Butterfly Outside con ta i nmen t
- 2 A0-2-1601-56 18 Butterfly Outside contairment
- 2 A0;..2-1601-~
18 Butterfly Outside containment
- 2 A0-2-1601-6 Butterfly Outside contairment
- 2 A0-2-1601-55 4
Gate Outside containment
- Valves identified as containment purge and vent valves and added to scope of review in Reference A, May 3, 1984 letter fran CE to NRC.
-~:,':
The 18-inch butterfly valves are t1:>del 2Fll valves manufactured by Henry Pratt Ccinpany ard are equipped with Tankins-Johnson actuators (Quad Cities)* and Mi 11 er actuators (Dresden).
The 6-inch butterfly valves are manufactured by Henry Pratt Company, and the 4-inch gate valves are manufactured by Crane.
Valve and actuator model num-bers are not furnished *.
3.0 Demonstration of Operability 3.1 Commonwealth Edison (CE) has provided purge and vent valve operability denonstration infonnation for Dresden, Units 2 and 3 and Quad Cities, lklits 1 and 2 in the foll owing submittal s:
A.
May 3, 1984 letter, B. Rybak (CE) to H. R. Lenton {NRC).
B.
Decenber 21, 1983 letter, B. Rybak (CE) to H. R. Denton {NRC).
C.
Novenber 4, 1983 letter, D. M. Crutchfield (NRC) to D. L. Farrar (CE).
D.
July 6, 1981 letter, T. J. Rausch (CE) to G. C. Lainas (NRC).
C".....
F.
G.
February 27, 1981 letter, R. F. Janecek (CE) to G. C. Lainas (NRC).
August 22, 1900 letter R. F. Janecek (CE) to G. C. Lainas (NRC) *.
April 1980 NUREG/CR-0891, "Seismic Review of Dresden f'tlclear Power Station for Systenatic Evaluation Program."
~
3.2 Commonwealth Edison's (CE) dyncmic torque (To) predictions for the sub-ject 18-inch valves stem from dynamic torque coefficients (Cr) developed from a 6-inch (1/3 scale) model valve bench test program as docunented in Appendix A of Reference F.
The inlet piping configuration used in the test progrcm was configured to establish unifonn approach fl ow to the test valve.
Flow tests were conducted with the valve disc set at fixed opening angles ranging from 8° to 78° (90° =full open) in 10° increnents.
Valve inlet_
pressures of 20 psi a, 38 psi a and 63 psia were established for each disc
- setting. Torque data measured at the 6-inch valve shaft was sealed to predict torques d ev eloped_ in the 18-i nc h in-service valve.
In that the bench test progran did not include inlet pi ping configurations in-volving elbow type fittings, CE provided additional infonnation to show that the torque values used for the 18-inch valve stress analysis were conservative regardless of the valve installation configuration.
CE reviewed each in service valve installation to determine if the piping in-volvej an upstrean elbow fitting (within 10 pipe dianeters) and to detennine the orientation of the valve shaft relative to the plane of the elbow.
The results of CE's review is stmnarized in the table below.
Pl ant Dresden-2 Dresden-3 Quad Cit ie s-1 Quad Ci ties-2 Valve Number*
-21
.-22
-23
-24
-21
-22
-23
-24
-21
-22
-23
-24
-21
-22
-23
-24 El bow Upstrean Shaft in Plane x x x x x
x El bow-Upstrean Shaft Out of P_lane x
x x
N:> El bow Effect x
x x
x x x To account for the el bow-shaft out of plane installation configuration (\\'rorst case configuration relative to To prediction) CE effectively increased Cr (unifonn flo\\'1) by a factor of 1.283 to establish the torque loads.
In their stress analysis, CE identified the valve shaft as the critical valve part based on the stress at the disc to shaft pin location.
The maximun stress at this location was calculated to be 11,256 psi re~ulting in a safety factor of 1.33 \\'then using an allowable stress of 15,000 psi.
CE al so canpared the valve torque 1 oads to the actuator torque output cap ability and concluded that the actuators are capable of closing the va'lve dur-ing the OONLOCA.
3.3 Recent additions (see Reference A and valves marked with* in Section 2.)
of this report) to the 1 i st of containment purge and vent valves being re-viewed include 6-inch and 18-inch butterfly valves and a 4-inch gate valve.
Attachnent 2 to Reference A contains general operability denonstration infor-mation for ball, gate, and globe valves as follows:
Ball and gate valve discs slide closely past the valve seat \\tilen the valve is open.or shut.
Globe valve discs move perpendicular*to the valve seat.
Butterfly valves combine these two basic disc motions and it is th.is canbina-tion of disc motions that results in a hydrodynanic lift effect.
Ball, gate, and globe valves are not subject to the hydrodyni!nic 1 ift effect associated with butterfly valves.
The design of the ball, gate, and globe valves and the actuators was based on standard design considerations for these types of valves. A detailed review of a typical valve has been perfonned aoo the results indicate that the valve will renain operable under the following conditions:
- 1.
Maximum differential pressure across the valve seat - 225 psi.
2 *. Maximum static pressure.
-* 225 psig@ 300°F.
Based on the above detail.ed review, the ball, gate, and globe valves directly connec.ted to the primary con ta inrnent atmosphere have sufficient design margin to with stand the effects of a DB A/LOCA.
4.0 Evaluation 4.1 Reference C trangnitted to the 1 icensee on Novenber 4, 1983, contains the staff findings shown below regarding To (dyni!nic torque) predictions for the 18-inch M:>del 2Fll Pratt valves at Dresden and QJad Cities.
The To values predicted by CE for the 18-inch 2FII valves in the Dresden and C)Jad Cities plants are very low in canparison to To*
values given by H. Pratt for the 18-inch 2F II valves in the Prairie Isl and purge and vent systen.
The staff believes that the conditions for canparing valve loads under LOCA conditions at Prairie Island and Dresden - Quad Cities are reasonably similar.
Canparing the maximum To values predicted, CE predicts*a.maximurn To of 2,600 in-lbs where H. Pratt's prediction is approximately 18,000 in-lbs.
In addition to the Prairie Isl and infonnation, torque information avail able for other valve designs al so indicates that CE's To pre-dictions are low for an 18-inch valve.
Based on the above, the staff finds that the T[)S predicted by CE for the subject valves are not conservative, and therefore not acceptable to the staff.
CE' s response (Reference A, Attachnent 1, page 1 and 2) to the staff's concern with the large difference between maximlJTI dynamic torques (18,000 in-lbs versus 2,600 in-lbs) is that Pratt's torque predictions are based on an analytical approach and are not appropriate for use on Dresden and QJad Cities, since specific test values are available frOTI.the Fluidyne tests (Reference F) for Dresden and ~ad Ci ties.
The staff's understanding of the Pf"att torque analysis for the 18-inch 2Fll valves at Prairie Island, is that the dynamic coefficients are based on data obtained from model tests and therefore the torque predictions by Pratt fo_r the 2Fll valve can be canpared with CE's valves.
Section 4.2 of this report provides more detail concerning the licensee's use of All is Olalmers model* test data (Test 21 and 24) to obtain torque factors based upon similarity of the Allis Chalmers and Fluidynemodel test valve discs.
In order to obtain an additional canparison with the Fl uidyne and Pratt maximun dynanic torques, the staff calculated the torque of an Allis Chalmer disc scaled up from the data for the Alli~ Olalmer's 6-inch test disc shown in Test 24 as shown below.*
Using the max imlJTI To (dynamic torque) value of 49. 5 ft-lbs from All is Chalmer's VER-0209 Test ~mber.24 with a 60 psi inlet and scaling up to an 18-inch diameter disc frOTI the 6-inch Allis Chalmer model test disc, results in a To for the 18-inch disc as follows:
To
=To (diameter ratio)3 x 12 in/ft.
(18)
(6)
To
= 49.5 x (18/6)3 x 12 (18)
= 16,038 in-lbs The staff finds that the maximun To of 2,600 in-lbs predicted by CE for the 18-inch 2Fll Pratt valves is unacceptable W'len canpared to the Pratt predic-tion of approximately 18,000 in-lbs for the 2Fll valves installed at Prairie Isl and and the estimated 16, 000 in-lbs obtained by sealing up from an All is Chalmer's 6-inch model test valve.
4.2 CE (in Re.ferences A and D) refers to a similarity in upstrean disc shape and aspect ratio of the Pratt 6-inch valve used in the Fluidyne model tests, with the Allis Chalmer 6-inch test valve used in Test 21 and 24 of the Allis Olalmer test progrcnn (VER-0209) conducted to confirm the design adequacy of t he p urge and v en t v a 1 v e s in st a 11 ed at t he La C ro s se BW R
- Based on the similarity between the valves, CE uses the data from the Allis Chalmers test nunber 21 and 24 to establish a factor of 1.283 to account for the increase in torque from a valve shaft in plane with an upstream elbow configuration to valve shaft out of plane with an upstrean elbow confi g ur atio n.
The license has not submitted dimensional data verifying the similarity be-tween the Pratt and Allis Chalmers model test valve discs, therefore, the staff cannot accept the 1.283 torque factor.
Additionally, CE states {page 3, Attachnent 1 of Reference A) that the All is Chalmer' s test data shows that valves with shaft in plane with upstrean el-bo\\<6, require no correction factor for torque, when canpared to valves with straight pipe inlet.
It is understocx1 that the Allis Chalmer' s test data -
referred to by CE does not include data for a straight pipe inlet configura-tion, therefore, the preceding assllTlption for valves with shafts in plane with upstream elbo\\<6 is unacceptable.
4.3 CE has not provided sufficient infonnation to evaluate the operability of the following valves:
A0-1601-56, ro {18-inch butterfly valve)*
A0-1601-63 (6-inch butterfly valve)*
A0-1601-55 {4,;.inch gate valve)*
4.4 'Based on the discussions in Section 4.1, 4.2, and 4.3 of this report, CE has no.t denonstrated that the critical valve parts have sufficient design mar-gins to withstand the pressure-related loads of the DBA/LOCA.
4.5 Based on the discussions in Section*4.l, 4.2, and 4.3 of this report, CE has not denonstrated.that the actuators are capable of stroking the valve closed during the DBA/LOCA nor has CE denonstrated that the actuators are structurally capable of withstanding the resultant torque loads ~ere those loads act to close the valve disc (butterfly valves only).
4.6 CE states in Reference A that the valves _are not seismically qualified, however, the sen*ior seismic review team from Lawrence Livermore Laboratory has concluded on a generic basis in their SEP report (NUREG/CR-0891 entitled "Seismic Review of Dresden rticl ear Power Station - Unit 2 for the Systematic Evaluation Program") that based on. design redundance and their experience with respect to functioning of equipnent in earthquakes throughout the \\t!Orld and under military requirenents, the systens required for safe shutdoW"I will re-main functional during a seismic event.
Demonstration of valve seismic qual i-fication is to be addressed under the unresolved safety issue A-46 "Seismic
()Jal ification of Equi pnent in (\\:>erating Pl ants."
- Valves identified as contairment purge and vent valves and added to scope of revi2w in Reference A, May 3, 1984 letter from CE to t-RC.
-_, 5. 0 Summary We have canpl eted our review of the infonnation submitted to date concerning operability of the valves use:i in the containnent purge and vent systens for Dresden, Lhits 2 and 3 and ().lad Cities, Lhits 1 and 2. *we find that the infonnation sub'nitted did not denonstrate that these valves have the ability to close against the buildup of pressure in the event of IBNLOCA from the full open position.
Sections 4.1, 4.2, 4.3, 4.4, and 4.5 of the evaluation are the basis for these findings.
~
~ Enclosure 2 OPEN ISSUES DRESDEN, UNITS 2 AND 3 QUAD CITIES STATION, UNITS 1 AND 2 DEt()NSTRATION OF CONTAINM:'.NT PURGE AND VENT VALVE OPERABILITY
- 1.
The large differences indynanic torque predictions between similar 18-inch valves at other plants with the Pratt 18-inch 2Fll valves at Dresden - Quad Cities neerl to be re solved (see Section 4. 1 and 4.2 of attached TER ) *
- 2.
Depending on the resolution of (1) above, for the 18-inch valves the stress analysis for critical valve parts and the structural/torque capability of the valve operator may have to be reexanined.
- 3.
Operability denonstration *infonnation needs to be furnished for the A0-1601-56, -60, -63, and -55 valves.
Since the 4-inch gate valve A0-1601-55 does not experience the hydrodynanic lift loads that the butterfly valves (-56~ -60, and -63) are subject to, the review areas typically for this t~ of valve are as follows:
- o Seismic qualification data o
Static pressure an al ysi s o
Closure analysis (denonstrating the operator capability).
- ..)he 18-inch butterfly valves (-56 and -60) and the 6-inch butterfly valves.
- (-.63) require operability denonstration infonnation for review as follows:
o M:?thodology used in dynanic torque predictions and torque analysis
- results.
o Stress analysis results (dynanic and static) for critical valve parts including load canbinations used, stress allowables and applicable c oo e s/ stand a rd s
o Seismic qualification data.