ML20010G248
| ML20010G248 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 09/04/1981 |
| From: | Curtis N PENNSYLVANIA POWER & LIGHT CO. |
| To: | Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, PLA-922, NUDOCS 8109150485 | |
| Download: ML20010G248 (6) | |
Text
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@ Pennsylvania Power & Light Company Two North Ninth Street
- Allentown PA 18101 + 215 / 770 5151 Norman W. Curtis Vice President-Ergineering & Construction-Nuclear 215 / 770-5381 4
September 4, 1981 Mr. R. C. Haynes Director, Region I U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 g% l 5.,.
SUSQUEHANNA STEAM ELECTRIC STATION k
FINAL REPORT OF A DEFICIENCY RELATING TO IMPROPER QUALITY CLASSIFICATION OF SOLENOID
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$[7 bOI h PILOT VALVES e.
ERs 100450/100508 FILES 840-4/900-10
- N 7 g roer 6/
PLA-922 d
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References:
PLA-588 (dated 12/16/80)
/
PLA-515 (dated 7/23/80) 4 / l,t d,\\
PLA-483 (dated 5/13/80)
Dear Mr. Haynes:
This letter serves to provide the Commission with a final report of a deficiency relating to the improper safety classification of pilot solenoid valves. This deficiency was originally reported in PLA-483 and the information contained herein is submitted as a final report pursuant to the provisions of 10 CFR 50.55(e).
The attachment to this letter contains a description of tr.e problem, its cause, safety implications and thc ccIrective action taken and planned to preclurla recurrence.
We trust the Commission will find the information forwarded by this etu r to be satisfactory.
Very truly yours, N. W. Curtis
}
Vice President-Engineering & Construction-Nuclear J
FLW:sab Attachment 8109150485 810904 PDR ADOCK 05000387 S
Mr. R. C. Haynes cc:
Mr. Victor Stello (15 copies)
Director-Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission Washington, D.C. 20555 Mr. G. Mcdonald, Director (1)
Office of Management Information & Program Control U. S. Nuclear Regulatory Commission Washington, D.C. 20555 Mr. Gary Rhoads i
U. S. Nuclear Regulatory Commission P.O. Box 52 Shickshinny, PA 18655 i
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ATTACHMENT TO PLA-922 SUBJECT Failure to apply the correct safety relate <1 designation (quality classification) to Solenoid Pilot Valves.
Description of the Deficiency The deficiency involves the incorrect quality classification of solenoid pilot valves. The subject solenoid valves, used as pilot valves for functional safety-related process valves, should have been classified by the designer as functional safety-related.
Cause The cause of the deficiency was an oversighton the designer's (Bechtel Project Engineering) part. The safety /non-safety boundaries were not correctly identified.
In this instance, the system design review process did not ensure that the safety /
non-safety identification process was properly and consistently applied.
Analysis of Safety Implications Improper classified pilot solenoid valves and associated equipment could hypothetically prevent safety system process valves from failing in their safe-positions as the lack of formal QA program controls during their manufacture and installation renders the quality of these components indeterminate.
Examples of potential failure modes are 1.
Non-seismic tubing (connecting pilot solenoid valves and associated valve operators) could be crimped during a seismic event, preventing venting of the air operator pressure.
2.
Non-Q solenoid pilct valves could theoretically fail in the position that prevents venting of the air operator pressure.
3.
Non-Q control circuits could theoretically act in such a way as to improperly energize the solenoid pilot valve, thereby improperly admitting pressure to the valve operator and incorrectly positioning the process valve.
Any of the above three conditions may result in an undesirable valve lineup in a safety related system. The specific valves and systems are delineated in Table 1.
The affected systems are the Emergency Core Cooling System (ECCS) and ECCS auxiliaries. A specific failure scenario is given below for valve SV-15626 showing safety impact:
l.
The Non-Q control circuit fails in such a way as to kmproperly energize solenoid valve SV-15626, pilot valve for valve HV-E41-lF026.
2.
Valve HV-E41-lF026 improperly opens.
Page 1 cf 4 4
r ATTACHMENT TO P'LA-922 3.
Reactor coolant is lost as a result of valve HV-E41-lF026 improperly opening if valve HV-E41-lF025 is not manually closed.
Safe shutdown of the plant could be made more difficult in such an instance.
The deficiency will require extensive rework and replacements to establish the adequacy of these systems to perform their intended safety functions. Therefore, this condition is considered reportable under 10 CFR 50.55(e).
l Corrective Action A review of the circumstances surrounding this deficiency have resulted in a conclusion that this occurrence is unique and would not be expected to recur.
The existing procedural requirements, if properly followed, provide proper and adequate program controls. Thus the corrective action will require no change in the present design review process. A plan to correct the improperly classified valves has been prepared.
Detailed corrective action for each specific valve is tabulated in Table 1.
In general, the following steps are to be taken to ensure that the final installation complies with applicable safety criteria.
1.
Solenoid pilot valves purchased without QA requirements / programs are to be replaced with valves manufactured undar a QA program.
2.
All safety-related solenoid pilot valves will have safety-related control circuits, power supplies and safety grade vent tubing, as applicable.
(Note that in some cases when non safety grade tubing was used, corrective action was accomplished by relocation of the solenoid valve and accessories directly on the process valve).
Completion of corrective action will be tracked by NCR 6646 and by Design Change Packages DCP-080.1 and DCP-080.2.
DCP-080.1 describes the action taken for Unit 1 while DCP-080.2 describes the action taken for Unit 2.
A review program has been initiated to assure the clear identification of "Q" designated valves on the Bechtel P& ids.
In order to preclude recurrence of this deficiency, a meeting was held with the I
responsible Bechtel Chief Engineers and Group Supervisors (Control Systems and Mechanical) to discuss existing project engineering procedural requirements for design interface coordination, discipline design reviews of Q boundaries, and Group Supervisor, Project Engineer and Chief Engineer reviews / approvals. The need to clearly identify Q-boundaries and to follow established design review procedures was emphasized.
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TABLE 1 Functionnl Safety-Related Solenoid Pilot Valvas - Installation Stetus Location of Work to i'f Uncorrected' Original Original grade of Correct Ssfety System Tag. No., SV-Originally Installation Control Circuits, Deficiency A f fected; (See Note 6)
Purchased "O"?
(See Note 4)
Power Source (Note 1) p ote 2) 10943A No Valve "Q"
P,I,R; Note 5 A
10943B No Valve "Q"
P,I,R; Note 5 A
11024A No Remote "Q"
P,I,R; Note 5 A
11024B No Reniote "Q"
P,I,R; Note 5 A
4 11274A Yes Valve "Q"
R B
11274B Yes Valve "Q"
R B
14319 No Valve "O"
P,R D
14320 No Valve "Q"
P,R D
14925 Yes Valve "Q"
R F
14926 Yes Valve "Q"
R F
15004 No Valve
,"Q" P,R G
15005 No Valve "O"
P,R G
15122A No Valve "O"
P,R 11 15122B No Valve "Q"
P,R 11 Yes Valve "Q"
R 11 15150A 15150B Yes Valve "Q"
R 11 15151A' Yes Valve "Q"
R 11 15151B Yes Valve "Q"
R 11 15152A Yes Valve "O"
R 11 15152B Yes Valve "Q"
R 11 15188A No Valve "Q"
P,R 11
)
15188B No Valve "Q"
P,R 11 l,,
15189A No Valve "Q"
P,R 11 15189B No Valve "Q"
P,R 11 15191A' No Valve "Q"
P,R 11 15191B' No Valve "Q"
P,R 11 15203A' No Valve "Q"
P,R J
1 15203B No Valve "O"
P,R J
15206A Yes Valve "Q"
R J
15206B Yes Valve "Q"
R J
15528 Yes Valve "Q"
R K
15529 Yes Valve "Q"
R K
_15625 No Valve "Q"
P,R L
- 15626 No Valve "Q"
P,R L
j
. ~E Page 3 of 4
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Notes for Table 1:
1)
P = solenoid valve replaced with a "0" valve.
I = installations of solenoid pilot, air set and lubricator moved to imediately on the process valve / operator.
E = electrical controls upgraded; power source upgraded.
R = revise P&ID and location dwg. to correct "Q" designation.
Refer to discussion of corrective action for reasoning and details.
- 2) Affected systems A
Emergency Service Water B
Reactor Recirculation F
RCIC G
RCIC Turbine I
H RHR J
HPCI L
HPCI Turbine 3)
(Deleted)
- 4) Original installation: Valve = pilot valve nounted on process valve Renote = pilot valve nounted remotely, away frcun process valve Note: Installation information is "as-built", noted in a walkdown by Construction Engineering.
5)
SV-11024A & B were retagged as SV-11024A2, & B2; SV-11024A3, & B3 were purchased. Similar changes were made for SV-10943A & B.
- 6) Only the Unit 1 valves are listed. Designs and corrective actions for Unit 2 counterparts are the same.
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