IR 05000413/1988020

Insp Repts 50-413/88-20 & 50-414/88-20 on 880516-20.No Violations Noted.Major Areas Inspected:Emergency Diesel Generator Operations & Surveillance Testing,Maint & Corrective Actions

ML20155J082
Person / Time
Site:	Catawba
Issue date:	06/03/1988
From:	Jape F, Scott Sparks, Taylor P NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:
Shared Package
ML20155J070	List: IR 05000413/1988020 ML20155J068
References
50-413-88-20, 50-414-88-20, NUDOCS 8806200427
Download: ML20155J082 (6)

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Report Nos.: 50-413/88-20 and 50-414/88-20 Licensee: Duke Power Company . 422 South Church Street Charlotte, NC 28242 Docket Nos.- 50-413 and 50-414- License Nos.: NPF-35 and NPF-52 , Facility Name: Catawba 1 and 2 Inspection Conducted: May 16-20, 1988 Inspector: b. b. b%% 6/5/88 5. E. Sparks Date Signed ! b .1. $::%4 L/3/3A > hA- P. A. Taylori Date Signed Approved by: M b 6[8/ Frank Jape, Section Chie~f Date Signed ; Test Programs Section . Division of Reactor Safety i SUMMARY l Scope: This routine, unannounced inspection was in the areas of emergency l diesel generator operations and surveillance testing, maintenance, l and corrective action Results: The licensee has identified problem areas with diesel generator reliability, and has implemented ongoing activities and corrective actions in the form of increased preventative maintenance frequencies and design modifications aimed at improving reliability, Paragraph In the areas inspected, no violations or deviations were identifie '

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l REPORT DETAILS Persons Contacted Licensee Employees

* B. Barron, Superintendent, Operations W. Beaver, Performance Engineer L. Blankenship, Operations Engineer
* Cote', Compliance Specialist W. Green, I&E Engineer R. McElwee, Supervisor, Mechanical Maintenance
*T. Owen, Station Manager
* F. Wardell, Superintendent, Technical Services Other licensee employees contacted during this inspection included engineers, mechanics, technicians, and administrative personne NRC Resident Inspectors
* VanDoorn - Senior Resident Inspector
* Lesser - Resident Inspector
* Attended exit interview Complex Surveillance, Diesel Generator Reliability - Units 1 & 2 (61701)

' The objective of this inspection was to review the licensee's diesel generator testing program, with emphasis placed on identifying corrective actions, if any, taken as a result of recent diesel generator failure , l The inspection effort was divided into the following areas, each of which . is addressed in separate report details: I

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Review of Diesel Generator Testing Records 1

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Operations and Surveillance Testing l

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Diesel Generator Maintenance and Corrective Actions  !

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Diesel Generator Inspection Requirements per License Amendment Review of Diesel Generator Testing Records l The inspector reviewed portions of the testing logbooks for diesel generators (DG's) 1A,18, 2A, and 28. The logs described all start attempts in sufficient detail to determine statistical validity. The ! purpose of each start attempt, i.e. operability performance test, trouble shooting test, or air roll test, was adequately identifie The testing logbooks reviewed appeared to be complete and up to date, I l l _

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with one exceptio The inspector questioned the classification of DG.1A Test #627 as an invalid ' failure. During this test, the licensee had begun the test to determine DG operability, in which performance test procedure PT/1/A/4350/02A, Diesel Genera 6or "1A" Operability Test, was used. After DG 1A had been loaded for 14 minutes, it. tripped on overcurrent, which is an emergency mode tri Discussions with the licensee led to the reclassification of OG 1A Test #627 as a valid failure. The reclassification is consistent with Regulatory Guide 1.108, Periodic Testing of Diesel Generator Units Used as Onsite Electric Power Systems at Nuclear Power Plant The licensee has revised the acceptance criteria of Operations Management Procedure OMP 2-28, Diesel Generator Logbook, which is used to classify DG start attempts. OMP 2-28 was revised such that once the operability performance test has begun (PT/1/A/4350/02A), the test is subject to normal success / failure criteria as identified in OMP 2-2 Results of DG testing completed through May 19, 1988, . revealed the following number of failures and therefore testing frequency per Technical Specification (TS) Table 4.8-1: Failures in Failures in Testing last 100 tests last 20 tests Frequency DG 1A 8 5 *7 days DG 1B 5 0 7 days DG 2A 3 2 7 days DG 28 4 2 7 days

 *At the time of the inspection, the licensee was voluntarily testing DG 1A once every 3 days, although TS Table 4.8-1 requires testing every seven days, Operational and Surveillance Testing The inspector witnessed DG 1A Start Attempt #700 and DG 1B Start Attempt #79 The controlling procedure for DG testing is PT/A/4350/02A, Diesel Generation "1A" Operability Test. The inspector verified that this procedure was in use at the time of the test for both DG 1A and 18. Each DG started and accelerated to at least 441 RPM in < 11 seconds, and voltage and frequency were at I least 4150 1 420 volts and 6011.2 Hz within eleven seconds after l the start signal. Both DG's were started using a manual start l signal. The inspector observed that the licensee delayed loading of i the DG's approximately five minutes after the start signal to obtain I equilibrium conditions. The licensee explained that this delay 3 minimized induced stresses during startup. After this delay, the !

DG's were loaded to >5600 KW but < 5750 KW in < 60 seconds after ! being synchronized, and operated f6'r at least 60 minutes. The two DG l l l l

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tests witneued were correctly classified as valid successe The operators observed during. the tests seemed knowledge 1ble of acceptance criteria, limits and precautions, and recorded DG operating parameters per PT/1/A/4350/02 The inspector performed a walkdown of the exterior portions of the starting air system, fuel system, lube oil system, as well as the diesel engine before and during the tests, and found the general appearance to be free of noticeable corrosion or wea In addition, the inspectors reviewed the completed test results for the 18 month diesel generator testing required by TS 4.8.1.2.g. This series of tests includes Engineering Safety Features (ESF) actuation with and without a loss of offsite power and a loss of offsite power only. Unit I testing was conducted in October 1987 and Unit 2 in December 1987, in accordance with PT-4200/09. Unit 2 testing did not document any diesel generator test failures. Unit 1 experienced four failures identified as pneumatic air control system pressure sensor - shuttle value malfunctions associated with diesel generator low lube oil tri Modification to these components were accomplished and the 18 month tests completed satisfactorily. The inspectors reviewed Unit 1 diesel generator load sequencer test results (PT 1/A/4350/04A) and inspected the sequencer panel. No discrepancies were identifie c. DG Maintenance and Corrective Actions Based on the inspectors review of DG Special Reports and discussions with licensee personnel, the licensee has experienced several recent DG failures which can be attributed to tha starting air system. The starting air system also supplies instrument air for the pneumatic control system, which has also been a contributor to recent DG failures. The licensee had implemented several corrective actions aimed at improving the quality of the air in the starting air system, many which involve increasing maintenance activities. The inspectors verified the following corrective actions have been implemented:

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Increased blowdown frequency of the starting air system compressor aftercoolers from once to twice per shift. This is inter.ded to reduce the amount of carryover moisture entering the air dryer Increased preventative maintenance inspection and servicing of the starting air dryer, including the prefilter and afterfilter, from semi-annually to quarterly. In addition, the frequency of servicing the starting air dryer desiccant has been increased from annually to semi-annuall Increased frequency of testing dew point of air in the starting air receivers from semi-annually to weekly (however, the licensee's dew point instrument is currently being repaired and calibrated). In addition, oil and particulate monitoring of the air system is being performed weekly.

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The licensee is preparing a separate procedure for inspection of pneumatic trip valve internals on six month interval The licensee has installed per Nuclear Station Modification CN-11151/00 a nitrogen control air system for DG 1A due to the number of pneumatic air problems DG 1A has experienced. This modification consists of six nitrogen cylinders, pressure regulating valve, a filter, and associated piping and tubin The cylinders supply nitrogen at 2500 psi which is controlled by the pressure regulating valve to provide 70 psi of control pressur The nitrogen system is connected to a shuttle valve inside the control panel such that if the nitrogen system malfunctions, the shuttle valve automatically switches to a uackup control air system, which is the normal air starting syste The nitrogen supply system is seismically qualifie In addition, the licensee is currently evaluating alternative electrical DG trip systems for Emergency Mode trips (low-low lube oil pressure trip and engine overspeed trip), and for non-emergency mode trip The inspector also reviewed a 10 CFR Part 21 submittal from IMO Delaval Inc. regarding a potential problem with certain engine control devices in the air start, lube oil, jacket water, and crankcase system The components were manufactured by California Controls (Calcon), and include three air start valves, a low pressure lube oil trip sensor, a high temperature jacket water trip sensor, l and high crankcase pressure trip sensor. IMO Delaval Inc. identified ! a failure in the implementation of their Quality Assurance program with regard to product testing in that there was no objective evidence that product testing was performe The licensee has ! experienced DG trips on low-low lube oil pressure (an Emergency Mode

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trip), which were suspected of being caused by the Calcon pressure sensor. On May 7, 1988, a Calcon representative visited the licensee to investigate the pressure sensor problems. It was confirmed that a i design flaw consisting of an improper tolerance stackup existed with j certain pressure sensors. The flawed pressure sensors include (as 1 indicated on pneumatic schematics CNM 1301.00-0031 and CNM 1301.00-0032) three low-low lube oil pressure sensors, one low-low lube oil trip switch, one low lube oil pressure sensor, one low turbocharger oil pressure sensor, and one turbocharger oil pressure senso These pressure sensors were subsequently replaced by the licensee with ones that did not contain the design fla d. Diesel Generator Inspection Requirements per License Amendment The inspector reviewed activities related to Amendment #18 of the Unit 2 Operating Licensee (NPF-52). This amendment contains additional requirements related to Transamerica Delaval Inc. (TDI) diesel engines in the inspection, maintenance, and surveillance are The following activities were verified by the inspectors:

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Turbocharger rotor axial clearances were measured during the most recent Unit 2 refueling outage, and found to be in compliance with TDI/Elliott specifications under Work Requests 4352MNT (DG 2A) and 4359MNT (DG 28).

- Spectrographic and ferrographic engine oil anal performed monthly for all DG's (1A,18, 2A, 28)toysis are being provide early evidence of bearing degradation. High copper levels could signify turbocharger thrust bearing degradation. However, no unusual copper levels have been found to dat Main Bearing No. 7 of DG 2B was disassembled and visually inspected during the last outage under Work Request 3799MN In addition, liquid penetrant testing was also performed per Work Request 5738MNT. No indications of bearing distress were foun Within the areas inspected, no violations or deviations were foun . Exit Interview The inspection scope and results were summarized on May 20, 1988, with those 3ersons indicated in Paragraph The inspectors described the areas 'nspected and discussed in detail the inspection result Proprietary information is not contained in this report. Dissenting comments were not received from the licensee.

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