ML20091C223
| ML20091C223 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 07/30/1991 |
| From: | Tremblay L VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| BVY-91-71, GL-89-10, NUDOCS 9108060090 | |
| Download: ML20091C223 (9) | |
Text
i VERA10NT YANKEE NUCLEAR POWER CORPORATION l
.. A s),
4 Ferry Road, Brattkboro, VT 05301-7002 s(, ( hj/j)
ENGINE ERWG OFFICE
~
=-
n, n s,, -
s ICL f DN !! A (2170 c% ???+ f.7; t July 30,1991 DVY 91-71 United States Nuclear Regulatory Commission A'ITN: Document Control Desk Washington, DC 20555
References:
[See Attachment Al
Subject:
Response to Request for Additional Information Regarding Generic Letter 89-10, Supplement 3: " Consideration of the Results of NRC-Sponsored Tests of Motor-Opemted Valves"
Dear Sir:
By References (j) and (k), Vermont Yankee responded to the requirements of Generic letter 89-10, Supplement 3 l Reference (i)]. By Reference (1), USNRC transmitted to Vemiont Yankee a request for additionalinformation deemed necessary for the Staff to make a safety determination regarding the subject motor-operated valves. Reference (1) was received by Vennont Yankee on July 1,1991 and requested a response within 30 days from letter receipt.
Enclosed please find Attachment B which contains Vennont Yankee's response to Reference (1). We trust that this information is suf6cient for you to complete your review; however, should you have additional questions or require additional infonnation, please contact this office.
Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION SW\\D M 'O p,
Leonard A. Tremblay, Jr.
\\"
Senior Licerning Engineer cc:
USNRC Region 1 Administrator USNRC Resident Inspector-VYNPS USNRC Project Manager - VYNPS i
V 9108060090 910730 a[' J PDR ADOCK 05000271 U
)
I P
ppR
4 i
1 s
Attachnent A
References:
a.
License No. DPR 28 (Docket No. 50-271) b.
letter, USNRC to [ All Licensees], NVY 85 250, dated Novemix r 15,1985 (11ulletin 85-03),
c.
Letter, VYNPC to USNRC, llVY 89-050, dated June 8,1989.
d.
Ietter, USNRC to [ All Licensecs), NVY 89 144, dated June 28,1989 (Generic Letter 89-10).
c.
Letter, VYNPC to USNRC,11VY 89116, dated December 28,1989.
f.
letter, USNRC to VYNPC, NVY 90-109, dated June 11,1990.
g.
Letter, USNRC to l All Licensees], NVY 90123, dated June 13,1990 (Supplement 1 to Generic Letter 89-10).
h.
letter, USNRC to l All Licensecs), NVY 90-148, dated August 3,1990 (Supplement 2 to Generic letter 89 10).
i.
Letter, USNRC to [ All Licenseesl NVY 90198, dated Octoler 25,1990 (Supplement 3 to Generic letter 8910).
i.
Letter, VYNPC to USNRC, BVY 90122, dated December 14,1990.
x.
letter, VYNPC to USNRC, BVY 91-26, dated March 14,1991.
1.
Letter, USNRC to VYNPC, NVY 91-113, dated June 25,1991.
l l
l
. ~..
l Attachment U Additional Information Regarding Supplement 3 to Generic letter 89-10 l
- 1. Provide a description of the "Recirc" valves" discussed in your Determination of Deficiencies.
The Rectre valves discussed are in the Rectreulation System. The 2 53 A and D valves are the Rectre Pump Discharge valves in loop A and D respectively. The 2-54 A and D valves are the Rectre Pump Discharge Valve Dypass valves in loop A and D respectively. The 2 53 A and D valves are 28" Darling Double Disc gate valves. The 2-54 A and B valves are 4" l
Darling Double Disc gate valves.
The present Vermont Yankee LOCA analysis assumes that these four valves close following a break in the suction side of the recirculation loop. The valves are powered from the Untnterruptible Power Supply (UPS) system.
- 2. Identify any mod 111 cations (e.g., torque switch setting adjustments, gearing changes, or motor / actuator replacement) for each MOV with'.n the scope of Supplement 3 to GL 89 10 since June 1990 or planned for the future.
The Reactor Water Clean-up (RWCU) Valves,1215 and 12-18, had the torque switch bypassed 99% to ensure port closure.
'lhe Rectreulation System Valves,2-53 A,0 and 2-54 A,D, had the torque switch bypassed 99% to ensure port closure.
The Reactor Core Isolation Cooling (RCIC) Valve,13 15, had the torque switch bypassed 99% to ensure port closure.
At this time, there are no modifications planned for the future.
l l
l l
- 3. Provide the actuator and motor sizes, and information necessary to confinn motor adequacy for each MOV within the scope of Supplement 3 to GL 89-10.
Valve ID 23-15 System 11PCI Manufacturer Walworth Actuator SMB-0/40 4GO V AC Diameter 12Z5 Orifice fL25 Pitch 1/2 dP 1Q80 lead
.1/3 Unit Ratio
.4DJf5 Stall Efr. 4 Motor RPM
.1200 The stem factor is based upon a p=0.20 Using SEL 3 from Limitorque the max motor output at stallis 52448.5 lbs.
This is for the undervoltage condition up to 10% undervoltage.
The motor output is above the close thrust at torque switch trip of 28135 lbs.
The close thrust at torque switch trip yields an effective valve factor of 0.40.
Valve ID 23-16 System 11PCI Manufacturer Walworth Actuator SMB-1/40 115 V DC Diameter 1.875 Ortflee fL25 Pitch lla dP 1930 lxad lja Unit Ratio 5111 Stall EIT. 3 Motor RPM
.120Q The stem factor is based upon a p=0.20 Using SEL 3 from Limitorque the max motor output at stall is 60568.0 lbs.
This is for the undervoltage condition up to 10% undervoltage.
The motor output is above the close thrust at torque switch trip of 28339 lbs.
The close thrust at torque switch trip yields an efTective valve factor of 0.41.
Page 2
Valve ID 13-15 System RCIC Manufacturer Walworth Actuator SMB-000/5 460 V AC Diameter
.LQ Oriflee 2.624 Pitch
.lu dP 1080 Lead JB Unit Ratto SQ3 Stall Eff. J Motor RPM JZQQ The stem factor is based upon a p=0.20 Ustng SEL 3 from Limitorque the max motor output at stall is 9042.8 lbs.
This is for the undervoltage condition up to 10% undervoltage.
The motor output is above the close thrust at torque switch trip of 8000 lbs.
l De close thrust at torque switch trip yields an elTective valve factor of 1.05, 1
Valve ID la-l.Q System ECIC Manufacturer Walworth Actuator SMB-000/5 115 V DC i
Diameter
,LQ Orifice 2.624 Pitch 1/3 dP 1Qfl0 Lead 1]A Unit Ratio iQ Stall Eff. J Motor RPM 100Q l
The stem factor is based upon a p=0.20 Using SEL 3 from Limitorque the max motor output at stall is 9909.9 lbs.
This is for the undervoltage condition up to 10% undervoltage.
The motor output is above the close thrust at torque switch trip of 7780 lbs.
The close thrust at torque switch trip yields an effective vahr factor of 1.02.
l l
i l
I Page 3
Valve ID 12-15 System RWCU Manufacturer Wm. Powell Actuator SMB-000/ 5 4GO V AC Diameter
.L25 Ortfice 3.693 Pitch 145 dP 1Q82 Lead 215 Unit Ratio 02 3 Stall EIT. J Motor RPM
.l.ZQQ The stem factor is based upon a p=0.20 Using SEL 3 from Limitorque the max motor output at stallis 11017.0 lbs.
'Ihis is for the undervoltage condition up to 10% undervoltage.
Because the TS is bypassed 99%, the motor output is equal to the close thrust.
The close thrust (max motor output) yields an effective valve factor of 0.70.
i i
Valve ID 12-18 System RWCU Manufacturer Wm. Powell Actuator SMB-000/5 125 V DC l
Diameter 1 25 Ort.
3.693 Pitch 145 dP JDJiil Lead 245 Unit Ratio 21Q Stall Eff. J Motor RPM 1900 The stem factor is based upon a p=0.20 Using SEL 3 from Limitorque the max motor output at stallis 13221.2 lbs, This is for the undervoltage condition up to 10% undervoltage.
Because the TS ts bypassed 99%, the motor output is equal to the close thrust.
The close thrust (max motor output) yields an effective valve factor of 0.89.
l l
l
\\
i-l Page 4
~. -
Valve ID 2-53 A.D System Recirculation Manufacturer Darling Actuator SMB 2/60 460 V AC Diameter 215 Orince
.LQ2.5 14tch
.11.2 dP 23Q Lead
.1/.2 Unit Ratio d332 Stall Eff. J5 Motor I@M 3.105 The stem factor is based upon a p=0.20 Using SEL 3 from Limitorque the max motor output at stallis 5G029.4 lbs.
This is for the undervoltage condition up to 10% undervoltage.
Decause the TS is bypassed 99%, the motor output is equal to the close thrust.
The close thrust (max motor output) yields an elTective valve factor of 0.G1.
Valve ID 2 54 A.D System Recirculation Manufacturer Darling Actuator SMB 000/5 460 V AC Diameter 1.375 Orifice 4.0625 INich
.11.3 dP 230 lead
.1/_3 Unit Ratio AfLQ Stall Eff. J Motor RPM 1700 The stem factor is based upon a p=0.20 Using SEL 3 from Limitorque the max motor output at stall is 8741.7 lbs.
This is for the undervoltage condition up to 10% undervoltage.
Because the TS is bypassed 99%. the motor output is equal to the close thrust.
The close thrust (max motor output) yields an che t!ve valve factor of 1.88.
Page 5
.... =.
I
- 4. Ilas the leakage rate with an MOV closed 99% been determined? Does the leakage rate exceed the limits in Appendtx J or the ASME Code?
'the leakagn ite of an MOV closed 90% has not been detennined. Ilowever. this has no bearing on the testing requirements of Appendix J. The Appendix J leak rate test requires the valve to be closed by nonnal operation. These valves are nonnally closed using the torque switch. The 99% closed torque switch bypass is elTectively used as a close Ifmit switch and only comes into play during a llEll3. The purpose of this valve under line break conditions is to lignit the energy release. Closing the valve 90%. which covers the port of the valve. limits the gross flow through the valve. Slight leakage would not significantly influence the EQ analysis. In addition, with two valves in series the differential pressure across the valve is reduced such that one valve may close campletely, becoming leak tight. The ASME Code (as it pertains to leakage passed the seat) does not apply to the Vermont Yankee valves within the scope of Gl. 89-10 Supplement 3.
- 5. Are thennal overload protection devices installed and used?
Thermal overload protection devices are installed and used in all GL 8910 Supplement 3 valves. 'Ihe thennal overloads are in both the open and close circuit regardless of initiating event (manual or automatic actuation).
Two different methods are used to size thennal overload (kwices at Vennont Yankee.
Method 1 sizes the thermal overloads to 300% fullload current. Method 2 sizes the thermal overloads to a minimum of 3 times the stroke time and, when possible, to 10 seconds locked rotor curTent for AC powered valves or 8 seconds locked rotor current for DC powered valves. Vennont Yankee originally sized thennal overloads to Method 1.
The following table shows the method used to size thennal overloads for the valves within the scope of GL 8910 Supplement 3:
Valve Method 12-15 2
12-18 2
13-15 2
13 16 1
23-15 1
23-16 1
2-5'l A.13 1
Will be resized to Method 2 during the next refueling outage.
2 54 A.Il 1
Page 6
- 6. Provide justification for the use of the MOVA% database, i
The justification for the use of the MOVATS database is currently ongoing. A comparison of the thrusts derived from the database against the INE!, sponsored tests shows that the MOVATS database provides a higher effective valve factor for Walworth valves. The MOVA~IS database uses actual test data from valves tested in their true configuration (in situ).
The MOVATS database is inherently conservative since it contains valves fmm several manufacturers 8-Ms been shown via NRC sponsored testing that these valves generally require more thruhi sor a given differential pressure than do Walworth valves. Walworth valves comprise the majority of Vennont Yankee valves.
A differential pressure test was perfonned at Ve mont Yankee on a Walworth valve, identical in size and model to the liPCI 15 and la isolation valves, and in the same steam line downstream of these valves. 'The thrust required to close this valve during the ditTerential pressure test was less than that called for by using the MOVATS database.
This demonstrates the conservative nature of the MOVATS database when compared to the standard industry equations.
At this time, the MOVATS database uppears to be the best data available.
- 7. Ilow have you addressed the rate ofloading phenomenon in MOV sizing and torque switch settings?
Vermont Yankee has not addressed the rate ofloading phenomenon directly At this time there is no method to accurately address this issue or detennine which valves may be subject to this phenomenon, llowever, by using the MOVATS database, part of the effect of rate ofloading is indirectly included, since the MOVATS database is comprised of actual in situ test data of valves that actually close fully under test conditions. As industry experience and more data becomes available, especially from EPRI, Vennont Yankee will incorporate this infonnation.
I Page 7
- -. - -