IR 05000344/1982012

IE Insp Rept 50-344/82-12 on 820316-0430.Noncompliance Noted:Emergency Diesel Inoperability

ML20054G617
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	05/10/1982
From:	Malmros M, Zwetzig G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To:
Shared Package
ML20054G612	List: IR 05000344/1982012 ML20054G611
References
50-344-82-12, NUDOCS 8206220139
Download: ML20054G617 (6)

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U.S. NUCLEAR REGULATORY COMMISSION

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REGION V

Report No.

50-344/82-12 Docket No.

50-344 License No.

NP F-1 Safeguards Group Licensee:

Portland General Electric Company 121 S. W. Salmon Street Portland, Oregon 97204 Facility Name:

Trojan Inspection at:

Rainier, Oregon Inspection conducted:

March 16 through April 30, 1982

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Inspector: bY

2 M.~H. Malmros, Senior Resident Inspector

' Date Signed Approved by: h INdy /8, /7/1

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i GO B. [petzig/, Chief, Reactor Projects Section 1 06te signed Reactor Operations Projects Branch Summary:

Inspection on March 16 - April 30, 1982 (Report No. 50-344/82-12)

Areas Inspected:

Follow-up on Licensee Event Report No. 82-01.

The inspection involved 32 inspector-hours by the NRC Senior Resident Inspector.

Results:

One item of noncompliance related to corrective actions and one item of noncompliance related to emergency diesel inoperability were identified.

(Both Severity Level III).

No deviations were identified.

RV Form 219(2)

8206220139 820604 PDR ADOCK 05000344 G

PDR

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DETAILS 1.

Persons Contacted

• C. P. Yundt, General Manager R. P. Barkhurst, Manager, Operations and Maintenance

• C. A. Olmstead, Manager, Technical Services D. R. Keuter, Operations Supervisor A. S. Cohlmeyer, Unit Supervisor, Plant Engineering D. S. Walters, Nuclear Plant Engineer H. E. Williams, Electrical Engineering Branch Manager G. A. Zimmerman, Licensing Branch Manager D. J. Modeen, Associate Nuclear Engineer The inspectoralso interviewed and talked with other licensee employees during the course of the inspection. These included shift supervisors, reactor and auxiliary operators, maintenance personnel, plant technicians and engineers, and quality assurance personnel.

• Denotes those attending the exit interview.

2.

Licensee Event Report (LER) Follow-up The circumstances leading to and the corrective action taken by the licensee as related to LER 82-01 were examined by the inspector.

The LER had been reviewed by the cognizant persons and groups within the licensee:s organization and had been reported to the NRC withir. the required reporting interval. The results of the examina-tion by the Senior Resident Inspector are as follows:

a.

Background During a plant refueling outage on May 30, 1977, a periodic surveillance test was initiated by a loss of off-site power followed by actuation of the safety injection system. As a result of the test, the licensee's operators identified a problem with the emergency diesel generator output circuit breaker.

It was observed that the breaker would fail to close and permit loading of the diesel generator.

The breaker would repeatedly close and trip open while attempting to perform the surveillance test.

The cause of this problem was attributed to the electrical lineup then in use.

Specifically, one of the preferred instrument buses (Y24) was being fed from the alternate power source (YO2) because the inverter for Y24 was out of service.

The alternate source (YO2) is a nonpreferred instrument bus fed from the safeguards electrical buses. With this lineup, the preferred instrument bus would be deenergized upon the loss of offsite power until reenergized when the safeguards buses are powered from the emergency diesel generato _

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-2-Design characteristics were such that the reenergization of Y24 from the diesel-generator caused the trip of the diesel generator output circuit breaker. -Based on this experience, facility standing orders issued by the Operations Supervisor stated that the emergency diesels would be declared inoperable anytime the preferred instrument -buses were powered from their alternate sources (Y01 or YO2) and not from the preferred I

i instrument bus inverter.

(As defined in Trojan Nuclear Plant Administrative Order A0-3-8, standing orders are issued to advise the operating staff of activities of general interest, but do not supersede the~ Plant Operating Manual procedures).

A plant Request for Design Change (RDC-77-093) was initiated on June 23, 1977, to correct the design deficiency which resulted in the inoperable emergency diesel generator under

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the' conditions ' described above.

Examinations of the RDC by the inspector revealed that the design change had been prepared and was in the review process up through approximately November 21,

1977, when the facility staff's review comments were submitted

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to the engineering organization.

The review comments indicated that the proposed design change was unduly complex and costly, and made recommendations for simplification of the proposed design change.. Until the recent occurrence identified in LER 82-01, RDC-77-093 had remained open with a low' priority

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for completion." It~ was generally believed by licensee personnel

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interviewed by the inspector that the conditions under which the design' change wasi needed were seldom experienced, and that the Technical Specifications provided sufficient time (72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />)

in which to. perform ~ preferred instrument bus inverter maintenance.

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.The facilit'y operated under these conditions throughout 1978, 1979,'1980, and most of 1981.

On flovember 21,s1980, a Training Information Bulletin (TIB)

was issued to explain why the emergency diesel generators were

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declared inoperable' when the preferred instrument buses were powered from their alternate supply.

The author of the TIB researched the. situation and, based on information received from the facility electrical engineer who had reviewed the RDC for Train "A" implementation, indicated that only preferred instrument buses Y11 and Y22 were responsible for emergency diesel inoperability when fed from their alternate source.

It appears that the reference to Y22 instead of Y24 was based on the plant design wherein a Train " A" function on Y11 is normally redundant in Train "B" on Y22.

In addition, the TIB author

was aware of information contained in an Instrument Bus Failure Effects Analysis done in 1980, in response to IE Bulletin 79-27.

This analysis indicated that the emergency diesels would be inoperable should Y11 or Y22 fail to provide power to relays needed for the starting of the diesels and the closing of the generator output circuit breaker. The affected relays are

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-3-l shown on Figure 8.3-43 oi~ the FSAR.

The analysis failed to include the effect of a loss of Y24 since only a sustained loss was considered; a sustained loss of Y24 does not result in the breaker pumping action.

On or about July 30, 1981, a revised Standing Order based on information in the TIB was issued by the Operations Supervisor that stated as follows:

"20.

When Y11 or Y22 are energized from a non-preferred source, or the DC input to Inverter #1 or #2 is open, the emergency diesel generator associated with that source shall be considered to be inoperable."

As a result of the above information, it was apparent that plant personnel were not aware of the emergency diesel opera-bility problems when preferred instrument bus Y24 was fed from its alternate source.

Examination of facility records, including plant logs, inverter machinery history and maintenance requests, by the inspector, found that Technical Specification requirements were met, however, throughout the period from identification of the problem in May of 1977 until the recent occurrences when failures of the Y24 bus inverter occurred during November and December 1981, and January 1982.

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Criterion XVI^of 10 CFR 50, Appendix B, and 16.3.1 of the PGE Nuclear Projects Quality Assurance Program for operation address measures provided to ensure effective corrective actions., Trojan Nuclear Plant Quality Assurance Procedure QAP-5-1 also required appropriate precautions to be included in facility procedures.

Effective corrective action to prevent emergency diesel generator inoperability could have been taken by implementing an appropriate facility design change or incorporating appropriate precautions into facility procedures.

Failure to complete either of these or other actions constituted apparent noncompliance with Section 2.c(7)

of the facility operating license, which requires quality-related activities to be accomplished in accordance with the Quality Assurance Program for Operation.

(82-12-01)

b.

0 currence The LER describes the details of the occurrence.

The details have been verified by the inspector through a review of facility records. As a result of the failure to recognize the inoperability of the Train

"B" emergency diesel generator when the Y24 preferred instrument bus was powered from its alternate source (Y02), certain limiting conditions for operation and action steps of the technical specifications were not met as follows:

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-4-During the period November 8).1981 through November 12, 1981, L

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for a' total time of 87 hours0.00101 days <br />0.0242 hours <br />1.438492e-4 weeks <br />3.31035e-5 months <br />; and during the period December 1, 1981 through January.4,1982, for a total of 34 days and three hours, the Train "B" emergency diesel generator was inoperable while maintenance was performed on the Y24 inverter with the alternate source (Y02) providing power to the Y24

. preferred instrument bus. This was in apparent noncompliance with the requirements of Technical Specification 3.8.1.1.in that the requirements of Action Step "a" were not met since the 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> time limit was exceeded and no surveillances were conducted in accordance with Technical Specifications 4.8.1.1.1.a and 4.8.1.1.2.a.5.

(82-12-02)

On December 8,1981, during the period from 0750 hours0.00868 days <br />0.208 hours <br />0.00124 weeks <br />2.85375e-4 months <br /> to 1725 hours0.02 days <br />0.479 hours <br />0.00285 weeks <br />6.563625e-4 months <br />, for a total of nine hours and 25 minutes, the Train "A" emergency diesel generator was made inoperable for routine maintenance and the Train "B" emergency diesel generator was inoperable since the Y24 preferred instrument bus was energized from its alternate source (Y02).

Although not clearly in noncompliance with the action statement requirements in Technical Specification 3.8.1.1, the simultaneous inoperability of both emergency diesel generators left the plant without an emergency power source, and therefore represented a matter of substantial safety concern.

During each of the periods described above, the facility was in Mode 1 with the reactor at or near full power.

c.

Corrective Action Corrective actions taken by the licensee pursuant to LER 82-01 consisted of the following:

(1) The Standing Orders were revised to indicate that the emergency diesel generator for Train "B" must be declared inoperable should preferred instrument bus Y22 or Y24 be powered from its alternate source (YO2). A revision to Operation Instruction 01-1-7, 120 Volt A.C. Preferred Instrument Bus Operation, was also initiated to incorporate these precautions.

(2) RDC 82-13 was prepared which incorporates the design change proposed in RDC 77-093 and additionally changes the power supply for the diesel generator start under-voltage relay (144-D1) and the diesel generator output circuit breaker close on auto start relay (106-D1) from the preferred instrument buses (ref. FSAR Figure 8.3-43)

to the respective train DC bus. As a result of this design change, the emergency diesels will be operable independent of any failures of a preferred instrument bus. This design change is scheduled for installation during the current 1982 refueling outag _ _ _ - _ _ - _ _ - _ - _ _ - _.

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-5-(3) The licensee requested that the architect-engineering design organization (Bechtel) review this occurrence for potential generic design applicability to other facilities.

(Bechtel later aavised the licensee that the power supply configurations were not generic with respect to other plants).

Two items of noncompliance were identified by the licensee as described in LER 82-01 and discussed above.

No deviations were identified.

3.

Exit Interview The inspector met with licensee representatives (denoted in para-graph 1) on April 12, 1982. The inspector summarized the scope and findings of the inspection related to the follow-up of LER 82-01.

During the meeting, the inspector confirmed with the licensee the following items:

a.

RDC 82-13 was in the final review process and would be implemented and tested prior to the completion of the 1982 refueling outage scheduled for July 9,1982.

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Recent discussions with Bechtel indicate that the power supply configurations which led to LER 82-01 (Ref:

PGE letter %.

PD-11188 to Bechtel Corporation, dated February 12,1%2) are not generic with respect to other plant designs.

c.

The revised LER 82-01, submitted to the NRC on February I?,1982, contains an error on page two.

In the second line of the first paragraph, "Y22" should be changed to "Y24."

The licensee indicated that the LER would be resubmitted to the NRC to correct the error and clarify the discussion of diesel inoperability with respect to Technical Specification compliance.