ML20212D222

Special Rept:On 860606,determined That Inadequate Assurance Existed Re Use of Qualified Grease in All Limitorque Operators.Appropriate Programs Not Updated to Reflect Revs. Lubrication Records Reviewed

ML20212D222
Person / Time
Site:	Oconee
Issue date:	07/29/1986
From:	Tucker H DUKE POWER CO.
To:	Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
IEB-79-01, IEB-79-1, NUDOCS 8608120441
Download: ML20212D222 (7)

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DUKE POWER GOMPANY P.O. BOX 33180 CHARLOTTE, N.C. 28242 HAL B. TUCKER ML3' NOM

==ree. men (704) GM801 nuotsaa racotwson July 2', 1986 ,

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'3 Dr. J. Nelson Grace, Regional Administrator 7, U. S. Nuclear Regulatory Comunission E-3 Region II --

101 Marietta Street, NW, Suite 2900 cr.

Atlanta, Georgia 30323 C~

Subject:

Oconee Nuclear Station Docket Nos. 50-269, 270, 287

Dear Dr. Grace:

Please find attached a Special Report concerning the utilization of unqualified lubrication within in-containment Limitorque Valve operators. j This Special Report is being submitted pursuant to a comunituent made by Duke to j provide a report regarding this event.

Very truly yours, b J Hal B. Tucker PFG/40/ sib Attachment xc: Mrs. Helen Pastis Office of Nuclear Reactor Regulation l

U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Mr. J. C. Bryant NRC Resident Inspector Oconee Nuclear Station n

8608120441 860729 PDR ADOCK 05000269 p Np M /c)

l DUKE POWER COMPANY  ;

OCONEE NUCLEAR STATION SPECIAL REPORT

, Utilization of Unqualified Lubrication Within In-Containment Limitorque Valve Operators i

Abstract On June 6,1986, at 1130 hours0.0131 days <br />0.314 hours <br />0.00187 weeks <br />4.29965e-4 months <br />, Units 1, 2, and 3 were operating at 100% full power when it was determined by NRC Inspectors that adequate assurance did not exist that qualified grease was being used in all Limitorque Operators required to be environmentally qualified.

The immediate corrective action was to review lubrication records of the equipment in question, determine the type of grease being used, and submit j justification to the NRC for continued operation.

i This event is classified as a Management / Quality Assurance Deficiency in that

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appropriate Duke documents, manuals and procedures were not updated to reflect a revision that occurred to a vendor manual (Limitorque Operator Manual) and that the original Limitorque Qualification test report and maintenance manual were not interpreted to be restrictive concerning lubrication substances.

1 For complete valve operability, under all postulated conditions, i environmentally qualified lubrication is a requirement. Although the qualification of the lubrication used was not clearly substantiated, Duke's evaluation has shown that the combinations of grease will provide the necessary lubrication, and thus, will not degrade the capability of the valve to perform its safety-related function. Therefore, the safety and health of j the public were not affected by this incident.

BACKCROUND i

! Environmental qualification of electrical equipment in nuclear power plants is specified by 10 CFR 50.49, which requires each nuclear power plant to develop j a program for qualifying certain electric equipment installed in postulated j harsh environments. Certain valve operators are environmentally qualified as

) a unit, which includes the grease in the gear box.

1 i Specification Number CS-3-27-1 dated October 25, 1967, and written by Babcock j and Wilcox (B&W) required radiation, temperature, humidity, and pressure effects on the lubricant to be considered in selecting the gear train l lubricant.

} Exxon Nebula EPO and EP1 was the grease tested in Limitorque Valve Operators.

Test Report OM-245-0979 described the grease as being serviceable and

, acceptable after testing, but did not specify the type of grease being used in the test. It was learned from other records that Exxon Nebula was the only grease tested. Other gresses were tested and qualified for other Limitorque j operator applications such as limit switch gear train and motor bearings.

j On June 6, 1986, all three units were operating at 100% full power. An NRC

team of inspectors was on site. During this review the NRC team discovered

that Duke could not demonstrate that the qualified lubricant was being used to lubricate the main gear train of Limitorque Valve Operators required to be j environmentally qualified.

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DESCRIPTION OF OCCURRENCE Initial environmental qualification requirements were provided in 10 CFR 50 Appendix A in 1967. In 1968, B&W supplied Limitorque Operators with Exxon Nebula EPO or EP1 grease, qualified by tests for valve operators located in harsh environments. Exxon Nebula is a general use grease and was listed in the Limitorque Operator Manual (1966-1971), along with several other brands, including MarFak 0, as an acceptable lubricant for the Limitorque Operator main gear train. When Duke Power started the lubrication and maintenance program at Oconee, Texaco products were selected as an acceptable. grease for the main gear train of Limitorque Valve Operators.

Maintenance and operations used Limitorque Operator Manual-(1966-1971) to develop a Repair Procedure and a Lubrication Manual respectively. Texaco grease was the specified grease in both of these applications. A compatibility study and laboratory tests was judged to be sufficient to l qualify the Texaco grease as an acceptab3e substitute for in-containment valves.

Subsequently, Texaco was requested to do compatibility studies, laboratory testing and make recommendations for substitute greases for Oconee. The study and tests were completed by Texaco in 1975, and recommendations were made for substitute greases. Texaco lubricants were then selected for use in Limitorque Valve Operators at Oconee. The Oconee lubrication program met the grease requirements as stated in the Limitorque Manual dated 1966-1971.

Prior to Texaco completing the requested compatibility studies and laboratory testing, a Maintenance procedure was written in 1974, to repair Limitorque Operators, which referenced the Limitorque manual dated 1971. This manual gave grease specifications but did not distinguish between grease brands.

In 1975, a new safety related Limitorque Operator Repair Procedure, was developed referencing Texaco products as lubricants for the main gear train of the Limitorque Operators. At this time it was perceived that the grease requirements as stated in the Limitorque Manual (dated 1966-1971) were being met.

On February 8,1979, the NRC Office of Inspection and Enforcement issued IE Bulletin (IEB) 79-01 " Environmental Qualification of Class IE Equipment".

This bulletin, together with IE Circular 78-08, issued on May 31, 1978, required Duke to perform reviews to assess the adequacy of their Equipment Environmental Qualification programs.

The NRC issued orders, dated August 29, 1980, requiring licensees to' provide a report by November 1,1980, documenting the qualifications of safety-telated electrical equipment.

An Equipment Qualification Criteria Manual was developed by Duke to define the harsh environments in which the equipment was located in. All equipment affected by this bulletin were verified to be qualified or were to be replaced with qualified equipment.

During the course of Duke's correspondence with the NRC concerning IEB 79-01

, A, B, it was stated by Duke that the lubricating grease used in the main gear power train of the Limitorque Operators at Oconee Nuclear Station was Chevron SRI-2 and that this grease had been tested in a continuous-run motor type

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test. However, this was in error because the grease initially supplied in the Limitorque Operators main gear train was Exxon Nebula EPO or EP1 and, as indicated earlier, Texaco products were r,ubsequently selected as an acceptable substitute. It should be noted that Chevron SRI-2 is the permanent grease used in the bearings of the reliance motors supplied with limitorque motor operatored valves.

A new Limitorque Operator Manual (1982) was issued by Limitorque, which was approved by Duke and stamped QA condition 1 on March 15, 1984. This manual ,

had specific guidance for types of grease to be used in Limitorque Operators, '

with Exxon Nebula listed as the only acceptable lubricant for in-containment applications. All appropriate Station Lubrication Programs were not updated to reflect the new information contained within the new Limitorque Operator Manual.

In parallel with the issuance of the new manual by Limitorque, the Equipment Qualification Reference Index (EQRI) Manual was developed by Duke in September 1984. The purpose of the EQRI manual was to clarify qualification mandated maintenance requirements for nuclear safety related equipment located in postulated harsh environments.

The manual contained equipment qualification sheets that listed specific maintenance requirements co maintain equipment qualification, including those for Limitorque Operators. In the remarks column of the qualification sheet for Limitorque Operators, the original OM-245-0979 Test Report referenced did  ;

not contain specific grease requirements. The Test Report did describe the grease as being serviceable and acceptable after testing. The specific guidance provided within the new Limitorque Operator manual ragarding which grease to be used for in-containment applications was not specified within the EQRI Manual.

Subsequently, upon implementation of the EQRI Manual, the grease requirements were not identified and were not considered.

On June 6, 1986, an NRC team discovered the possible use of unqualified grease in the environmentally qualified Limitorque Valve Operators.

CAUSE OF OCCURRENCE This incident has been classified as a Management / Quality Assurance deficiency in that appropriate programs were not updated to reflect revisiona made by Limitorque to their operator manual, which provided specific guidance on the type of grease to be utilized for in-containment environmentally qualified valve operators and that the original Limitorque Qualification test report and maintenance manual were not interpreted to be restrictive concerning lubrication substance. In addition, existing administrative controls were not adequate at the time, to assure that the changes to the Limitorque Operator Manual was properly reviewed and incorporated into the EQRI Manual and into appropriate operations and maintenance procedures. The following three factors also contributed to the root cause of the above identified deficiency.

(1) The Limitorque Operator Manual (1966-1971) did not restrict which Lubricants could be used as is the case in the new Limitorque Operator Manual. The initial Manual provided a list of acceptable Lubricants, which included MarFax 0.

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(2) The compatibility studies and laboratory tests were judged to be sufficient to qualify the selected Lubricant as being acceptable due to the information provided in the initial operator manual issued by Limitorque, (as noted in Item 1, above) .

(3) Test report OM-245-0979 described the grease as beirs serviceable and acceptable after testing, but did not state the type of Lubricant used in the test. It was learned from other records that Exxon Nebula grease was the only grease tested.

In regard to the error concerning the use of Chevron SRI-2 as reported in Duke submittals to NRC in response to IEB 79-01, the cause was due to a misunderstanding of terminology.

CORRECTIVE ACTIONS The immediate corrective action was to review Lubrication records to determine the type of grease used. In addition, a " Justification for Continued Operation" (JCO) was prepared and submitted to the NRC by a Duke letter dated June 6, 1986. A number of accessible in-containment Limitorque Operators were, also, visually inspected for grease condition.

Duke has initiated a valve refurbishment program, and upon recommendations of a consultant, has also, elected to use Exxon Nebula exclusively in all Limitorque Operators. Subsequently, many valve operators have been completely rebuilt with use of Exxon Nebula grease.

The following are corrective actions that Duke intends to pursue in response to this incident:

e All Limitorque Valve Operator Procedures will be revised to state the exact type of grease to be used and a clear description of where it should be used.

e The Equipment Qualification Reference Index Manual (EQRI) will be revised to identify, within the manual, the exact type of grease to be used in each application, and to reference only documents that are available in Oconee site document control.

e Lubrication in all in-containment environmentally qualified Limitorque Valve Operators will be replaced with qualified grease (Exxon Nebula EPO) during any cold shutdown outage which begins after September 1, 1986.

e Lubrication in all outside containment environmentally qualified Limitorque Valve Operators will be replaced with qualified grease (Exxon Nebula EPO) during each unit's next scheduled refueling outage.

e The Oconee Valve Lubrication Program will be reviewed for accuracy and completeness by September 1, 1986.

e Vendor Document Upgrade Program with a scheduled completion date of 1987 is i

currently ongoing. The program will have provisions to insure changes to Equipment Manuals are flagged to the appropriate personnel. This program was initiated in response to an Action item within Generic Letter 83-28.

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i ANALYSIS OF OCCURRENCE The deficiency in this incident is that the qualification of the grease used for Limitorque Valve Operators was not clearly substantiated. This assessment addresses the operability concern for those valves. The assessment is ,

twofold, with one portion addressing the in-containment valves and the other addressing all other environmentally qualified valves.

l The environmental conditions within the reactor building af ter an accident are

$ of such extreme nature that certain specifications for valve operators are required. High temperature and high radiation conditions are considered to be the most detrimental to lubricants. Therefore, lubricants for valve operators must meet standards regarding dropping temperature (i.e., point at which the base would begin separating from the oil). The lubricants must also withstand high radiation effects.

It is assumed that all Limitorque Operators in all three reactor buildings may  :

have a mixture of Exxon Nebuls EP0/EP1 and Texaco Marfak 0 or Marfak 2. The j operaters could also contain the unqualified Marfak 0 or Marfak 2 entirely.

An investigation has determined that these are the only three types of grease that could be present in the operators. All of these valves are containment j isolation valves whose post-accident position is closed.

4 The containment isolation function is achieved in less than 30 minutes, and these valves have been evaluated to be fully operable during this time period, based on the following:

(a) Exxon Nebula EPO and EP1 is compatible with the Texaco Marfak 0 and 2.

It has been determined that some of the valves in question have both types of grease in the operator.

(b) The total integrated dose 30 minutes post-accident is less than 9.2 ES l rads. The threshold for any radiation effects for the Marfak grease is l 5.5 E6 rads. The initial effects above this threshold are softening {

with no failures of fluids predicted below 1 E8 rads. i (c) The peak post-accident temperature is 286 degrees F. While the Marfak is rated for continuous use at 200 degrees F., the dropping temperature is 320 degrees F.

(d) Oconee's stroke tLse tests for the subject valves have shown no trends that would indicate any lubricant degradation.

(e) The combined radiation and temperature effects, at most, would produce some softening of the grease. Being that the grease is totally i

encapsulated by a sealed gear box, the softening would not adversely affect operation.

Further, two of the in-containment valves are required to be active after an accident, specifically LP-1 and LP-2. These valves are located on the decay heat drop lines which would have to be opened to establish Low Pressure Injection Cooling. The valves on Units 1 and 2 have been replaced during the last refueling outage (Unit 2 - March 85, Unit 1 - March 86), and each have the qualified Nebula lubricant only. The same vales on Unit 3 have Rotork Operators and contain qualified lubricant. All other post-accident in-containment active valves have Rotork Operators with qualified lubricant or are electrical solenoid valves.

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In summary, any unqualified grease is present in only the post-accident passive isolation valves, and, as discussed above, the presence cf the unqualified grease would not adversely affect the capability of the valves

to provide their intended safety function.

For the outside containment valves, this portion of the assessment assumes '

that the environmental conditions within containment would be the most extreme and would bound any conditions possible outside containment.

Therefore the assessment for in-containment post-accident passive valves is viable for the valves outside-containment, provided the types and combinations of lubricants are the same. An investigation has shown this to be the case. The operability of any valves outside the building is not t in question since the environmental conditions are not as severe as inside the building. The fact that the grease in these operators is totally encapsulated and would still be able to provide some lubrication after any softening lends more assurance to the operability of the valves.In addition, any active valves located outside the containment would also be accessible except in the most severe accident conditions which have minimal probability of occurrence.

While it is understood that environmentally qualified lubrication is a requirement for complete valve operability under all pcstulated conditions, this investigation has not found any reason to suspect the present lubrication in any EQ valve will prevent operator function. To the contrary, it has shown that the possible combinations of grease will provide the necessary lubrication to allow the valve to carry out its intended safety function.

Therefore, the safety and health of the public were not affected by this incident.

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