05000387/LER-2003-007, Regarding Common Cause Inoperability of Multiple Core Spray Channels

Regarding Common Cause Inoperability of Multiple Core Spray Channels

ML040020345
Person / Time
Site:	Susquehanna
Issue date:	12/19/2003
From:	Richard Anderson Susquehanna
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
PLA-5700 LER 03-007-00
Download: ML040020345 (6)

LER-2003-007, Regarding Common Cause Inoperability of Multiple Core Spray Channels

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(v), Loss of Safety Function
3872003007R00 - NRC Website

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I R. L Anderson Vice President - Nuclear Operations PPL Susquehanna, LLC 769 Salem Boulevard Berwick, PA 18603 Tel. 570.542.3883 Fax 570.542-1504 danderson@ppweb.com ppi I

• Te DEC 1 9 2003 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop OPI-17 Washington, DC 20555 SUSQUEHANNA STEAM ELECTRIC STATION LICENSEE EVENT REPORT 50-387/2003-007-00 LICENSE NO. NPF-14 PLA-5700 Docket No. 50-387 Attached is Licensee Event Report 50-387/2003-007-00. This event was determined reportable per 10 CFR 50.73(a)(2)(vii) in that both the Unit 1 and Unit 2 'D' Core Spray pumps were declared inoperable due to excessive oil foaming experienced during quarterly surveillance testing. Contaminants in the oil and inadequate antifoaming additives were responsible for the oil foaming condition observed in both pumps. The loss of one Core Spray pump in both Susquehanna Units under these circumstances constitutes a common cause inoperability of two independent channels designed to mitigate the consequences of an accident. This occurrence did not challenge any plant safety systems. There were no actual consequences to the health and safety of the public as a result of this event.

No new regulatory commitments have been created through issuance of this report.

Richard L. Anderson Vice President - Nuclear Operations Attachment

-- Co Document Control Desk PLA-5700 cc: Mr. H. J. Miller Regional Administrator U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Mr. S. L. Hansell Sr. Resident Inspector U.S. Nuclear Regulatory Commission P.O. Box 35 Berwick, PA 18603-0035 Mr. R. Osborne Allegheny Electric Cooperative P. 0. Box 1266 Harrisburg, PA 17108-1266 Mr. R. R. Janati Bureau of Radiation Protection Rachel Carson State Office Building P. O. Box 8469 Harrisburg, PA 17105-8469

NRC FbRM 366 U.S. NUCLEAR REGULATORY APPROVED BY OMB NO. 3150-0104 EXPIRES 7431-2004 (7.2001)

COMMISSION the NRC may not conduct or sponsor,

~~~~and a person Is not required to respond to, the Information collection.

1. FACILITY NAME

. DOCKETNUMBER

3. PAGE Susquehanna Steam Electric Station - Unit1 05000387 1 OF 4

4. TTLE Common Cause Inoperability of Multiple Core Spray Channels

5. EVENT DATE

6. LER NUMBER

7. REPORT DATE

8. OTHER FACILITIES INVOLVED FACILrTY NAME DOCK(ET-NUMBER MO DAY YEAR YEAR NUMBER NO MO DAY YEAR Susq. SES - Unit 2 05000388 7 +/-

7 JFACILITY NAME DOCKET NUMBER 10 23 2003 2003 - 007 -00 12 19 2003

9. OPE RAnNG

11. THIS REPORT IS SUBMIrTED PURSUANT TO THE REQUIREMENTS OF 10 CFR 5: (Check all that anply)

MODE 1

20.2201 fb) 20.2203(a)(3)(i)

_50.73(a)(2)(Ii)(B) 50.73(a (2)(ix)(A)

10. POWER 20.2201 (d) 20.2203(a)(4) 50.73(a)(2)(iii) 50.73(a)(2)(x)

LEVEL 100

_ 20.2203(a)(1) 50.36(c)(1)(l)(A) 50.73(a)(2)(iv)(A) 73.71 (a)(4) 20.2203(a)(2)l) 50.36(c)(1)(ii)(A) 50.73(a)(2)(v)(A)

_ 73.71(a)(5)

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f 20.2203 a(2(iD 50.36(c)(2) 50.73(a)(2)(v)(B)

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20.2203(a)(2)(10l 0.36(c)(2)(

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$ f ^ A i j _20.2203(e)(2)(i) 50.73(a)(2)(lI) 50.73(a)(2)(v)(D) 20.2203(aX2)(v) 0.73(a)(2)(1(B)

X 60.73(a)(2)(vi)

^20.2203(a)(2)(vi)

_ 50.73(a)(2)(D(C)

_ 50.73(a) 2 (vIl)A)

____v__v_-_________-_____

20.2203(a)(3)(1) 50.73(a)(2)09i(A) 60.73(a)(2)(vli)(B)

______a___i___^_____V

12. LICENSEE CONTACT FOR THIS LER NAME TELEPHONE NUMBER (Include Area Code)

Eric J. Miller - Nuclear Regulatory Affairs 570/ 542-3321MANU-REPORTABLE MN-RPRAL

CAUSE

CP I _________

T 1I 7 TAS SYSTEM COMPONENT FACTURER TO EPIX

14. SUPPLEMENTAL REPORT EXPECTED

15. EXPECTED I MO STH DAY YEAR

______________________________________________l_X SUBMISSION IYES_ fye,cornplete EXPECTED SUBMISSION DAT X

NO DATE I

ABSTRACT

During performance of Core Spray quarterly flow surveillances conducted In October, 2003; the Unit I and the Unit 2 'D' Core Spray pumps were declared inoperable due to an oil foaming condition observed in the upper bearing oil reservoirs for each pump motor. Liquid oil levels dropped below established minimum levels for pump operation as a result of the foaming. In response, oil was drained, the oil reservoirs were inspected, and new Gulfcrest 32 oil was placed in the reservoirs. Oil foaming was not observed during subsequent pump runs and oil levels remained in the normal range.

Oil samples taken from the affected pump motors, when analyzed for foaming tendency and stability levels, were found to exceed Industry standard warning limits. The samples also yielded contaminants that mix with additives contained in the Gulfcrest 32 product to form a salt or soap compound capable of altering the foaming properties of Gulfcrest 32. An oil previously used in the Core Spray application is the probable source of these contaminants. Compatibility between the two oils was not considered during the design change process. Additionally, susceptibility to foaming can occur when anti-foaming additives settle" during long term storage and fail to transfer in proper proportion as the oil is siphoned off for use. The plant Intends to replace the Gulfcrest 32 used in selected equipment, revise change processes to ensure product compatibilities, and adjust inventory levels to reduce settling.

This event is reportable as a common cause inoperability of multiple Core Spray channels per 10 CFR 50.73(a)(2)(vii). There were no actual adverse consequences to the fuel, any plant equipment, or to the health and safety of the public as a result of this event.

- l

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NRC FOiM 366A U.S. NUCLEAR REGULATORY COMMISSION (7.2001)

LICENSEE EVENT REPORT (LER)

1. FACILITY NAME

2. DOCKET

6. LER NUMBER S S. PAGE SEQUENTIAL IREVISION

~~~~~~~~~~~~~~~YEAR A

UBER INUMBER Susquehanna Steam Electric Station - Unit 1 05000387 2003 007 00 2

OF 4

17. NARRATIVE (ff more space Is required, use additional copfes of NRC Form SW6)

EVENT DESCRIPTION

During performance of Core Spray (EIIS Code: BM) quarterly flow surveillances performed on July 17 (Unit 1) and July 18, 2003 (Unit 2); visible oil foaming was observed in the upper motor bearing sight-glass during both the Unit 1 'D' (1 D) and Unit 2 'D' (2D) Core Spray pump runs. Because oil levels were reported to be in the operating range during these runs, the 1 D and 2D Core Spray pumps were considered to be operable following the surveillance. Subsequent routine lube oil analysis did not identify abnormalities. Planned actions to drain the upper motor bearing reservoir for inspection, originally scheduled before the next Core Spray surveillance runs required in October, were postponed due to conflict with other station work activities.

With both Unit 1 and Unit 2 in Mode 1 at 100% power, the Core Spray quarterly flow surveillances were performed again on October 21 and 23, 2003 for Unit 2 and Unit 1, respectively. Once again, the oil foaming condition was observed during both the Unit I and Unit 2 'D' pump runs. During the Unit 1 run conducted on October 23, oil level for the 1 D Core Spray motor dropped below the minimum level.

The pump was shutdown and declared inoperable at 1330 hours0.0154 days <br />0.369 hours <br />0.0022 weeks <br />5.06065e-4 months <br />. While oil level for the 2D Core Spray motor was characterized as being "at or slightly below" the minimum level during its October 21 run, the 2D pump was not declared inoperable at that time based on discussions with General Electric.

However, subsequent evaluation combined with the oil level response observed during the 1 D pump operation also resulted in an inoperable declaration for the 2D pump on October 23. Although the 1 D and the 2D Core Spray pumps were conservatively'declared inoperable, it should be noted that motor bearing temperature and pump vibration levels were normal during all the aforementioned pump runs.

This suggests that the oilfoam mixture was providing adequate lubrication for the pump motors. There were no actual component failures or detrimental effects that occurred as a result of the observed foaming condition.

In response, oil was drained to facilitate upper motor bearing reservoir inspections for both the I D and 2D Core Spray pumps. No abnormalities were found. On October 24, 2003, after new oil was placed in the 1 D and 2D oil reservoirs, quarterly flow surveillance runs were successfully performed on both' Core Spray pumps. A 4-hour extended run was also performed on the 1 B (previously unaffected by oil foaming) and the 1 D Core Spray pumps. No foam was observed during either the surveillance or extended runs and liquid oil level remained in the normal range. Accordingly, the pumps were restored to operable status on October 24.

Oil samples taken from the 1 D and 2D Core Spray pump motors were shipped to two independent laboratories and the manufacturer for evaluation. The foaming tendency and stability levels were found to exceed industry standard warning limits. Oil in the upper bearings of the two Core Spray motors was also contaminated with low levels of zinc, calcium and phosphorus. While these additives are commonly used in anti-wear (AW) oils, they are not required for the Core Spray application and are not intentionally Introduced in the oil used therein (Gulfcrest 32).

NRC FORM 386A(7.2001)

NRCFORhM 366A U.S. NUCLEAR REGULATORY COMMISSION (7-2001)

LICENSEE EVENT REPORT (LER)

1. FACLITY NAME

2. DOCKET

6. LER NUMBER

3. PAGE

[-

l SEQUENTIAL REVISION j

YEAR l

NUMBER I NUMBER Susquehanna Steam Electric Station - Unit 05000387 2003 007 00 3

OF 4

17. NARRATIVE Jfl/mre space Is require, use addiioal copies of NRC Fonn MA)

CAUSE OF EVENT

Contamination of the oil has been identified as a cause for this event. While there are several ways the oil could have become contaminated, it is believed the contamination was most likely caused by a Core Spray application change from Gulf Harmony 32 AW to Gulfcrest 32. Calcium sulfonate additives present in the anti-wear Gulf Harmony oil can mix with the acidic additives found in Gulfcrest 32 to form a salt or soap compound that can alter the foaming properties of Gulfcrest 32. The station did not evaluate compatibility of these oils and did not appreciate the potential for this reaction upon mixing of Gulf Harmony 32 AW and Gulfcrest 32.

Inadequacy of antifoam additives present in Gulfcrest 32 has also been identified as a cause for this event. As is discussed in ASTM D 892 Standard Test Method for Foaming Characteristics of Lubrication Oils.." these additives can be adversely affected by product quality and storage practices. In inactive systems (such as a storage drum), these additive tend to agglomerate and will settle-out or cling to contaminants over time. Methods for dispensing oil (i.e. 5 gallons removed from a 55 gallon drum) may also reduce the effectiveness of the antifoam additive present in the Gulfcrest 32 product. When oil is dispensed In this manner, additives that may have usettled" during long-term storage may not transfer In proper proportion with the oil.

EXTENT OF CONDITION Similar oil foaming problems could exist In any component using Gulfcrest 32. However, components that originally used Gulf Harmony 32 AW and have been changed to Gulfcrest 32 are more vulnerable. At Susquehanna, Core Spray pumps and the Residual Heat Removal Service Water pumps (EIIS Code: BS) are the only safety related components that have undergone this change. It should be noted that there are no other reported foaming issues associated with Gulfcrest 32.

REPORTABILITY/SAFETY CONSEQUENCES ANALYSIS This event was determined to be reportable under 10 CFR 50.73(a)(2)(vii) In that multiple Core Spray channels were rendered inoperable via common cause.

Actual: This event had no detrimental consequences on the Core Spray system. Surveillance history, including the October 2003 surveillances where oil level dropped below the minimum operating range, indicate all pump and motor performance parameters (motor bearing temperature and vibration) were normal. The lack of elevated temperatures suggests that adequate lubrication occurred through the oilffoam mixture.

The potential for bearing degradation is monitored using vibration analysis during surveillance runs.

Following the oil change, no changes in vibration were detected as a result of this event.

Potential: Inadequate lubrication can lead to mechanical failure of lubricated components. If inadequate lubrication exists, bearing metal temperature would Increase and, if left unchecked, could result in bearing failure. In the event of a Core Spray pump failure, the redundant Core Spray division would still be capable of providing desln injection flow for the system.

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(It more space Is required, use additionlI copies of NRC Forn 366A)

CORRECTIVE ACTIONS

The following corrective actions for this event have been completed:

The 1 D and 2D upper motor bearing reservoirs were drained and inspected. Oil ports were verified to be properly sized and unobstructed.

The 1 D and 2D upper motor bearing reservoirs were re-filled with new oil.

Surveillance and extended runs were performed on multiple Core Spray pumps with no foaming observed.

Oil samples were analyzed and evaluated by the manufacturer and two Independent laboratories.

The following corrective actions are planned:

The purity of Gulfcrest 32 used in selected plant equipment will be ensured through replacement.

Oil receipt inspection and used oil testing will be reviewed against ASTM D 6224 "Standard Practice for In-Service Monitoring of Lubricating Oil for Auxiliary Power Plant Equipment"and ASTM D 4378 "Standard Practice For In-Service Monitoring of Mineral Turbine Oils for Steam and Gas Turbines"to identify and realize oil program Improvements.

Inventory levels of Gulfcrest 32 will be adjusted to reduce the potential for settling" of additives associated with long-term storage of this product.

Benchmarking will be performed to Identify Industry best practices in the areas of lubricant control, dispensing, usage tracking and product selection. Gathered information will be used as the basis for the potential establishment of a formal Lubrication Program" at Susquehanna.

The modification process will be revised to ensure all critical characteristics are reviewed and documented as part of the design change package. Compatability between new and existing components such as lubricants, gaskets and 0-rings must be addressed by this revised process.

ADDITIONAL INFORMATION

Failed Component Information:

None

Previous Similar Events

None NRC FORM S66A (7201)