ML20082B527

Part 21 Rept Re Notification 9505 Automatic Switch Co Pilot Solenoid Valve Model NP8323A20V.Caused by Failures of MSIVs to Close to Asco Pilot Solenoid Valves.Subj Valves Replaced W/Valcor 3-way Solenoid Valves

ML20082B527
Person / Time
Site:	LaSalle
Issue date:	03/28/1995
From:	Querio R COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
REF-PT21-95 NUDOCS 9504050191
Download: ML20082B527 (5)

Text

comnu,nweanh niison compiny labile Generating station 2&)I North list Road mrwilles. 11.61361 9757 Td Hl5M7 6"61 March 28,1995 United States Nuclear Regulatory Commission Washington, D.C. 20555 Attention:

Document Control Desk

Subject:

LaSalle County Station Units 1 and 2 10CFR Part 21 Notification 9505

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Automatic Switch Company (ASCO)

Pilot Solenoid Valve Model # NP8323 A20V NRC Docket Numbers 50-373 and 50-374.

Enclosed in Exhibit B is Comed's 10CFR Part 21 Notification of the deficiency of ASCO Dual Solenoid Valve Model # NP8323 A20V, manufactured by the Automatic Switch Company and in use at LaSalle Station.This notification is submitted in accordance with the requirements of 10CFR 21, Section 21.l(b),21.3a(3), and 21.3d(4).

If there are any questions or comments concerning this letter, please refer them to me at (815) 357-6761, extension 3600.

Respectgl,1y, R. E. Querio Site Vice President LaSalle County Station i

cc:

J. B. Martin, Regional Administrator, Region Ill W. D. Reckley, Project Manager, NRR P. G. Brochnun, Senior Resident Inspector, LaSalle D. L Farrar, Nuclear Regulatory Services Manager, NORS Central file 040135 9504050191 950328 PDR ADOCK 05000373 f[$,g S

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Exhibit B ENC-QE-40 Revision 9 Page 1 of 3 To:

Nuclear Licensing Manager

Subject:

Part 21 Notification 9505-Regarding Automatic Switch Company (ASCO) Pilot Solenoid Valve Model # NP8323A20V LaSalle Site Support Engineering has evaluated the subject document and determined that the defect / noncompliance is reportable under the requirements of 10CFR Part 21. The attached report has been prepared for submittal to the NRC, and should be submitted by 3'2D 0 to the NRC Operations Center.

Questions regarding this report should be directed to William C. Kirchhoff x2927.

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-/fb NED Engineer

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3 2 ; 9f NED Suptf/ Supe b/rf~/ s-2 7-9 s NED Manager President and Chief Operating Officer Senior Vice President, Nuclear Operations Vice President BWR Operations Vice President PWR Operations Vice President Nuclear Engineering and Construction General Manager Nuclear Services General Manager Quality Programs and Assessments i

Nuclear Station Managers Nuclear Engineering Manager Safety Assessment Manager Manager of Quality Assurance / Nuclear Safety Part 21 Coordinator ENC Regulatory Assurance Supervisor 1

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Exhibit B ENC-QE-40 Revision 9 Page 2 of 3 10CFR 50 Part 21 Notification Deficiency of ASCO Dual Solenoid Valve Model # NP8323A20V, Manufactured by the Automatic Switch Company and used at LaSalle County Station Part 21 file # 9505

• Applicability This notification is submitted in accordance with the requirements of 10CFR 21, Section 21.1(b),

21.3a(3), and 21.3d(4).

• ldentification of Facility and Component This defective component was identified only at Commonwealth Edison's LaSalle County Station.

The effected solenoid valves are used on Main Steam Isolation Valves (MSIV) 1(2)B21-F022 A/B/C/D and 1(2)B21-F028 A/B/C/D as part of the actuating mechanism.

• ldentification of Component Manufacturer The ASCO Dual Solenoid Valve Model #NP8323A20V is manufactured by the Automatic Switch Company (ASCO).

• Nature of Defect 2

The ASCO Model # NP8323A20V valve is a dual coil, three-way solenoid valve used at LaSalle as a pilot valve which controls the opening and closing of the MSIV's. A root cause investigation i

has attributed two recent failures of the MSIVs to close to the ASCO pilot solenoid valves. In particular, intemal sticking of the "B" core assembly to the plugnut, which prevented the valves from changing state. It is believed that a foreign material acted as an adhesive film. This substance was determined to be Nyogel 775A grease it is unknown how the Nyogel 775A came to this location. According to information provided by ASCO, Nyogelis used in the valve. Entry of Nyogel 775A from sources extemal to the valve were investigated and considered implausible.

• Safety Significance Failure of the ASCO NP8323A20V pilot solenoid valve to shift position when de-energized would prevent the automatic or manual fast closure of the main steam isolation valves. The safety function of the MSIVs as described in LaSalle's Technical Specification Basis Section 3/4.4.7 Main Steam Line Isolation Valves describes the safety function as minimizing potential leakage paths from the containment in case of a steamline break to limit release of fission products and to ensure that the core is not uncovered following line breaks. The MSIV's function is also described in the Technical Specification Basis 3/4.6.3 Primary Containment isolation Valves to i

Exhibit B ENC-QE-40 Revision 9 Page 3 of 3 ensure that the containment atmosphere will be isolated from the outside environment in the event of a release of radioactive material to the containment atmosphere or pressurization of the containment.

' Time of Discovery February 18,1995

• Corrective Actions Unit Two

• Outboard ASCO Pilot Solenoid valves have been replaced with Valcor 3-way solenoid valves as had been previously scheduled for this current outage (L2R06).

• Inboard ASCO Pilot Solenoid valves have been replaced with new ASCO valves assembled without grease.

Unit One

• Engineering has performed an operability evaluation and recommended increasing the testing frequency of the MSIV'c to 60 days. The cycling of the valves is believed to break the cohesion (binding formation) which decreases the sticking probability. Operating has chosen a more conservative testing frequency of 30 days.

• LaSalle plans for next Unit One refueling outage include the replacement of the inboard ASCO valves with new ASCO valves assembled without grease and the replacement of the outboard ASCO valves with Valcor solenoid valves.

• Number and Location of All Defective Components The effected solenoid valves are used on Main Steam isolation Valves (MSIV) 1(2)B21-F022 A/B/C/D and 1(2)B21 F028 A/B/C/D.

• Technical Contacts William C. Kirchhoff, LaSalle Site Support Engineering Charles J. Bohan, LaSalle Site Support Engineering Questions Pertaining to this notification should be addressed to:

Eric Stockhan NETS Part 21 Coordinator Commonwealth Edison Company 1400 Opus Place, Suite 400 Downers Grove, IL 60515 (708) 663-7437

s'

.o PART 21

SUMMARY

SHEET In acccidance with Part 21 you, as an officer of CECO, are being informed of the following situation:

A defect in the ASCO NP8323A20V Dual Solenoid valve manufactured by the Automatic Swich Company was identified. These ASCO valves are used at LaSalle as a pilot valve which controls the opening and closing of the MSIVs. A root cause investigation has attributed two recent failures of the MSIVs to close to the ASCO pilot solenoid valves. In particular, internal sticking of the "B" core assembly to the plugnut, which prevented the valves from changing state.

It is believad that this foreign material acted as an adhesive film. This substance was determined to be Nyogel 775A grease. It is unknown how the Nyogel 775A came to this location.

According to information provided by ASCO, Nyogelis used in the valve. Entry of Nyogel 775A from sources extemal to the valve were investigated and considered implai'sible.

LaSalle is the only user in the CECO system that uses this model valve. Failure of the ASCO NP8323A20V pilot solenoid valve to shift position when de-energized would prevent the automatic or manual fast closure of the main steam isolation valves Corrective Actions:

Unit Two

• Outboard ASCO Pilot Solenoid valves have been replaced with Valcor 3-way solenoid valves as had been previously scheduled for this current refueling outage (L2R06).

' Inboard ASCO Pilot Solenoid valves have been replaced with new ASCO valves assembled without grease.

Unit One

• Engineering has performed an operability evaluation and Operating has increased the testing frequency of the MSIVs to every 30 days. The cycling of the valves is believed to break the cohesion (binding formation) which decreases the sticking probability.

• LaSalle plans for next Unit One refueling outage include the replacement of the inboard ASCO valves with new ASCO valves assembled without grease and the replacement of the outboard ASCO valves with Valcor solenoid valves.

If you require further information regarding this notification, please direct them to William C.

Kirchhoff, LaSalle Site Support Engineering, extension 2927.

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CECO Compa Officer Informed

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