IR 05000382/1993034

Corrected Pages 6,7,10 & 11 of Insp Rept 50-382/93-34

ML20059K355
Person / Time
Site:	Waterford
Issue date:	01/28/1994
From:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
To:
Shared Package
ML20059K309	List: IR 05000382/1993024 IR 05000382/1993034
References
50-382-93-34, NUDOCS 9402020050
Download: ML20059K355 (4)

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-6-2. Trip of Essential Chiller A On December 8, while the inspectors were in the control room, they observed the trip of Essential Chiller A on low chilled water flow. Essential Chiller B had been out-of-service since December 7, to repair a refrigerant leak which placed the plant in Technical Specification 3.7.12. Since Essential Chiller AB was not available to backup Essential Chiller A due to the failure of its guide vane cycle timer, no essential chiller was available and the plant entered Technical Specification 3.0.3, which required the '

problem to be resolved within one hour or commence a plant shutdown. The control room staff responded to the loss of the essential chiller systems and returned Train B to operable status in a timely and appropriate manne i

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Fifty-nine minutes af ter Essential Chiller A tripped, Train B was recovered, l l

declared operable, and Technical Specification 3.0.3 was exite l l

Essential Chiller AB was returned to service after the cycle timer was repaired and Technical Specification 3.7.12 was exited. A thermography camera was used in the troubleshooting process to identify a spot on the B phase electrical overload block on Essential Chiller A that was approximately 100 degrees hotter than the other blocks. Electrical maintenance determined that the bolt connecting this block to the overload heater was approximately one turn loose. The overload block was replaced and the bolt tightene These connections in the other two chillers were checked to ensure that there were no additional hot spots. The licensee verified the tightness of all connections on the buses every other refueling outage. A note was to be added to the appropriate procedures to ensure these connections were checked during .

this effor Licensee Event Report 93-10 and Condition Report 93-302 were to !

be issued to document and determine the root cause for this even l 2.2 Sound Event Durina LPSI Pump A Run On November 10, the inspectors noted that there had been an unexplainable sound event during the post-maintenance test of LPSI Pump A on November 9, 1993. The system was walked down by operations personnel immediately following the event and no damage was found. The licensee issued Condition Report 93-229 and formed an event review team to determine what had happened. The inspectors also walked down Train A of the LPSI system and found no sign of damag .

The review team contacted personnel who witnessed the test, walked down the 3 system and, again, found no damage. Interviewers determined that a sound was heard in the control room, but this was later thought to be the closing of breaker right below the control room. The sound at the pump was suspected to be the closing of Check Valve CS-117A. The inspectors questioned why the pump was not run again under observation to allow the collection of additional data. The event review team leader explained that it was the Train B week for maintenance, and the delay gave them additional time to collect and review the data they had already accumulate PDR ADOCK 05000302 G PM

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-7-On November 16, tae inspectors observed as LPSI Pump A was run as required by Surveillance Prrcedure OP-903-30, Revision 2, " Safety Injection Pump Operability Verification," to see if the event recurre Containment Spray Valve CS-125A was closed in preparation for the test as it was suspected to be a contributor in the cause of the noise. The inspectors noted that when the pump started there was a loud noise and that the containment spray riser line moved one to two inches. Licensee personnel were stationed at the pump and on the -35 foot level of the containment penetration area in the vicinity of LPSI system pipin Personnel stationed at the pump found that the movement was not out of the ordinary, while the individual in the wing area saw what he felt was excessive movement but identified no concerns with the containment '

spray system. All involved personnel felt that some form of transient had occurred, and design engineering was assigned to investigate. On November 19, the pump was run again and up to one inch of movement was noted in the vicinity of Valve SI-139A. Based on the above information, a design engineering evaluation found that a hydraulic transient had occurred, but that '

the movement was not unacceptable and would not affect the operability of the system. The operations superintendent was present at the pump during the November 19, run and had the system vented after the run was complete. Air was vented upstream of the flow control valve.

On November 30, the pump was run again under observation as a part of the ;

closure process for the condition report to check to see if the event recurred. The observers noted a small amount of movement, much less than had .

been noted previously, and heard no noise. The licensee planned to observe i the next scheduled surveillance pump start in approximately a month to ensure the event does not recur. The source of the air was still being researched by the event review team. At the time it was suspected that the vent procedure used on Train A of containment spray during the investigation of the recent .

problem with Valve CS-125A was a possible source of the air intrusio l 2.3 Essential Chiller History >

Since the onset of colder weather, the inspectors noted an increase in the ,

number of essential chiller trips. This concern and the problems with the chilled water pumps (discussed in Section 4.1) caused the inspectors to review the chiller equipment history with system engineering. The inspectors found a ,

complete set of logs regarding the system's operation and problems, and that -

the system was walked down on a regular basis.

A number of problems had plagued this syste The hot gas bypass system did j not initially work well and was not used as a result of its inadequacy. The ;

system was repaired on all chillers last year and worked fine for one winter, but started malfunctioning again this winter. Troubleshooting revealed that one of the setpoints in the controls for the hot gas bypass valve had drifted ;

in the conservative direction, preventing the valve from opening.when i require These setpoints were reviewed, raised approximately two degrees, I

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-10- Installation of Chilled Water Pump AB On November 9, 1993, and several times later in the week,.the inspectors observed different stages of the installation of new Chill Water Pump AB. The pump was installed using Design Change DC-3251 and WA 99003251. This work was to correct a history of packing seal leaks and multiple occurrences of shaft ,

failur The original supplier could no longer supply qualified replacement parts and new enhanced design pumps were purchased from a qualified supplie The design change utilized the existing motor, modified the pump's foundation, and installed the new pum After the modification was complete, operations personnel noted that they had to fill the oil reservoir (bubbler) several times a day. The oil, in some cases, would drain into the bearing casing soon after the pump started. (Oil ,

was also found to be leaking out of the casing, but not at the same rate.)

The same problem had been identified on Chill Water Pump A, but they found that they did not have to add oil as often as they did on Chill Water Pump A According to the manufacturer this type of pump had this problem in the past and the solution was to remove the oil slinger pin (1 of 2) closest to the bubbler penetration. The spinning pin had a tendency to create a void that

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pulled all the oil in the bubbler into the casing. The manufacturer stated that removal of the pin would not affect the shaft balanc While checking the balance on a similar pump from the warehouse before and after removing the pin, the licensee found etching on the shaft surface where the lip seal of the bearing casing contacted the shaft. An additional pump from the warehouse had the same etching. The licensee shipped the two shafts from the warehouse back to the manufacturer for rework. Once returned, these shafts were scheduled for installation in Chill Water Pumps AB and A. The shafts removed would then be sent back for modification and later installation in the two disassembled pumps from the warehous .2 Indeterminate Status on Battery Chargers On November 19, the inspectors observed the breaker in Battery Charger AB2 being replaced in accordance with WA 01115444. While replacing the breaker in Battery Charger AB1, a technician noted that although the charger technical manual called for a Model LAB 2400 breaker, a Model LAB 2700M breaker was installed. Condition Report 93-260 was completed to determine the root cause, and the licensee entered Site Directive W4.101, Revision 0,

"Nonconformance/ Indeterminate Analysis Process," for all six safety-related i battery chargers. The licensee had previously identified that the Model LAB 2700M breaker was installed in one of the other chargers several months prior and completed a nonconformance identification. There was a long 1

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-11-lead time in procuring the LAB 2400 breakers and they were not in stock in the warehouse. The licensee had no records of previous replacements and they concluded that the breakers had been installed by the manufacturer. The manufacturer indicated that either breaker could be used. The licensee has had a history of problems with one charger tripping as the other charger in the train was brought on line. The LAB 2400 breaker had both thermal and magnetic trips instead of just a magnetic trip that breaker LAB 2700H had and a higher amperage range (2000-4000 amps versus 350-700 amps.) The lower amperage range of the installed LAB 2700M breaker was a-possible cause of the tripping problem, so the licensee replaced all six breaker The maintenance personnel performing the task on Charger AB2 followed the work package instructions and used good electrical practice .3 Controlled Ventilation frea-System (CVAS) B Outage On November 23, the inspectors observed as mechanical maintenance technicians cleaned and lubricated couplings and bearings for the CVAS B blower. The inspectors noted that WA 0111427u was cocoleted, and that the task was performed in accordante with the instruct'ons. After cleaning the bearings, quality assurance was contacted to verify cleanliness before the bearings were repacked and to observe as the bearing and coupling casings were torqued. The inspectors verified that the correct lubricants were used and that the torque wrenchos were calibrate .4 .nclusions Electrical technicians were noted to use good electrical practices. A poor maintenance practice was noted in that adequate lighting was not set up for '

the replacement of Chill Water Pump A BIMONTHLY SURVEILLANCE OBSERVATION (61726)

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The inspectors observed the surveillance testing of safety-related systems and components listed below to verify that the activities were being performed in accordance with the licensee's programs and the Technical Specification ; Emergency Feedwater Pumo A Surveillance i

On November 22, 1993, the inspectors observed the operation of Emergency -

Feedwater Pump A. The pump was started to verify that it developed a discharge pressure greater than or equal to 1298 psig on recirculation flow and to inspect the oil slinger ring The inspectors noted that the pump ran smoothly at normal temperature The technicians found no problems with the oil slinger ring Following the test, the inspectors verified with a control room operator that the discharge pressure met the acceptance criteria, t

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