ML20205B307
| ML20205B307 | |
| Person / Time | |
|---|---|
| Site: | Mcguire |
| Issue date: | 07/16/1986 |
| From: | Tucker H DUKE POWER CO. |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-86-265-000 PT21-86-265, PT21-86-265-000, NUDOCS 8608110562 | |
| Download: ML20205B307 (3) | |
Text
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q DUKE POWER GOMPANY P.O., box 33189 W.I b
[qMARLO{TF N.C. 28242 dO ' '
HAL B. *RJCKER TELEPHONE (704) 373-4s31 m......
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July 16, 1986
.Dr. J.-Nelson Grace, Regional Administrator U.S. Nuclear Regulatory Comission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323
Subject:
McGuire Nuclear Station, Unit 2 Docket No. 50-370
Dear Dr. Grace:
Pursuant to 10CFR Part 21 and in followup to the telephone notification of your staff on July 11, 1986, please find attached a report concerning operational problems with valves 2SA-48 and -49 at McGuire Unit 2.
If there are any questions regarding this, please contact us through the normal licensing channels.
Very truly yours, 7
A
/
W Hal B. Tucker RLG/78/jgm Attachments xc:
W.T. Orders NRC Resident Inspector McGuire Nuclear Station Mr. Darl Hood Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Director (3 copies)
Office of Inspection and Enforcement Washington, D.C.
20555 8608110562 860716 PDR ADOCK 05000370
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MCGUIRE NUCLEAR STATION UNIT 2 REPORT - Valves 2SA-48 & -Potentially Reportable Item This report was prepared to document the problems with valves 2SA-48 & -49, described the corrective actions taken, and provide inputs to NPD-Licensing for NRC reporting.
1.
On June 14, 1986, during pre-operational testing, following a refueling outage, valves 2SA-48 & -49 failed to open on actuation.
The valves are located in the steam line of the Auxiliary Feedwater Pump Steam Turbine Drive. Their intended safety function is to open, admitting steam flow to the turbine.
2.
The valve / actuator assemblies were new components, installed by NSM during the preceding refueling outage, replacing an older and less reliable design. The old design had an air-to-open/ air-to-close actuator. The new design featured an air-to-close/ spring-to-open actuator. The source of the failure was improper sizing of the opening spring.
3.
When notified, the vendor (Atwood & Morrill) evaluated the problem, diagnosed the source of failure, and immediately ordered new stronger springs.
4.
The springs were installed and the valve / actuator assemblies were satisfactorily tested on June 17, 1986.
5.
Nuclear Production Variation Notice ME-VN-395 authorized the spring charge on Unit 2.
ME-VN-399 covered the change on Unit 1 (still in refueling).
6.
Design Engineering originated the following documentation to address /
report the problem:
Form Q-1D - Reportability Evaluation Request.
Form 202.1 - Design Nonconformance Report No. DNC-0115.
Form 290.1 - Potentially Reportable Item No. MC-86-03.
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..t The following is a listing of information intended to satisfy the reporting requirements of 10CFR21.
Section 21.21 NOTIFICATION OF FAILURE TO COMPLY OR EXISTENCE OF A DEFECT Paragraph (3)
(1) The NRC was informed of the defect verbally on July 11, 1986, by i
R. L. Gill and T. M. Love of Duke Power Company, 422 S. Church Street, Charlotte, NC 28242.
(ii) The defect was found in Unit 2 of the McGuire Nuclear Station.
The component containing the defect was the steam admission valves to the Auxiliary Feedwater Pump Steam Turbine Drive.
(iii) The valves were designed, manufactured, and supplied by the Atwood & Morrill Co., Inc., 285 Canal Street, Salem, MA 01970.
(iv) The source of the failure.was inadequate actuator spring force to open the valve. Duke Power Company feels that no substantial safety hazard was created as proper function of the valves is required prior to plant operation.
(v) The defect was found on 6/14/86.
(vi) The subject valves form a redundant and parallel path for steam flow to the AFWP Turoine. They are specialized components and are unique to the application.
There are two valves per unit.
4 (vii) The corrective action consists of replacing the opening springs with those of greater force capability. The replacement was handled by the manufacturer (see para. iii), with the exception of installation, which was performed by Duke personnel at the vendor's direction.
Replacement was completed on June 17, 1986, for an approximate duration of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
(viii) The manufacturer has been instructed to evaluate operator sizing criteria for air / spring operators.
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Note:
It should be taken into consideration that the subject valves were newly installed, custom-engineered components and that their failure to operate could only be found during in-place testing.
Corrective action was simple and was effected without damage or risk.
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