ML20195G581
| ML20195G581 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 06/13/1988 |
| From: | Pleniewicz R, Walter W COMMONWEALTH EDISON CO. |
| To: | Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| BYRON-88-0592, BYRON-88-592, NUDOCS 8806280058 | |
| Download: ML20195G581 (3) | |
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'm} Ccmmtnw:alth Edis:n 2? Byron Nuclear Station V
4450 North Gerrnan Church Road Byron, Illinois 61010 s
June 14, 1988 LTR BYRON 88-0592 Mr. A.
Bert Davis Regional Administrator Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Dear Sir:
This report is submitted in ar.cordance with Byron Station Unit 1 Operating License NPF-37 Appendix A, Technical Specification 4.8.1.1.3, reporting of diesel generator failurec.
This report addresses one nonvaliC test and failure experienced on the IB Diesel Generator (DG). The criteria to determine valid and nonvalid tests and failures is in accordance with Section C.2.e of Regulatory Guide 1.108.
Attachment A, DVR 6-1-88-076, is a summary of the current 1B DG nonvalid test and failure. This problem is not a valid failure per the criterion established in Regulatory Guide 1.108, and as such does not affect the testing interval requirements established in the Byron Technical Specifications, g.
w R. P1 ni wicz Gtation Manager B,rron Nuclear Power Station l
RP/.IC/Wt/JY/bb (2107M/0122M)
Attachment cca P. Brochman, NRC Senior Resident Inspector
'.f.S. NRC Docuent Control Desk, Washington D.C.
IN1 ') Record Center CP0o distribution List 8f106280058 880613 PDR ADOCK 05000454 S
,DCD j
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ATTACINENT A DE/IATION INVESTIGATION REPOR7 TITLE PAGE FAILURE OF 18 DS TO PROPERLY CONTROL LOAD 1 10Fl 0 12_
EVENT DATE DIR NUMER REPORT DATE
//
I O t1Q.MTH DAY YEAR STA UNIT YEAR j/j SEQUENTIAL /j/ REVISION
/
NUMER j//
NUMBER MONTH DAY YEAR 1
POWER
_Q1_f Il 6 81 8 01 6 Ol 1 81 8 0 17 1 6 0IO O#
l3 8l 8 LEVEL i
01 91 8 CONTACT FOR THIS DIR NAME TELEPHONE NUMER AREA CODE
_ arren Walter. Asst. Tech Staf f Supervisor Ext. 2244 8l1 15 2l3i4l-l5l4 14l1 W
COMPLETE ONE LINE FOR EACH COMPONEN A LURE DESCRIBED IN THIS REPORT CAUSE SYSTEM COMPONENT MANUFAC-REPORTABLE CAUSE SYSTEM COMPONENT MANUFAC-REPORTABLE TURER TO NPRDS TURER TO NPRDS X
EIN l Rl Ll V Gl01810 Y
j l l l l l l I
l l l 1 l l l
l l l l SUPPLEMENTAL REPORT EXPECTED EXPECTED SUBMISSION l
^
I YES (if ves. conolete EXPECTED SUBMISSION DATE)
X l NO TEXT A.
PLANT CONDITIONS PRIOR TO EVENT:
Event Date/ Time _5/J6/88 / 0838 Unit 1 MODE 1
- Awer Oceration Rx Power 98%
RCS (AB] Temperature / Pressure.586 F/2235 PSI Unit 2 MODE 1
- Power Ooeration Rx Power 94%
RCS (AB] Temperature / Pressure _565 F/2235 PSI B.
OESCRIPTION OF EVENT:
On 5/16/88, at Od38, the IB lIlesel Generator (EK) (DG) was started per Byron Monthly Operability Surveillance, IBOS 8.1.1.2.a-?..
Following a successful start and warmup pe. lod, the Nuclear Station Operator (NS0) (Licensed) closed the output breaker. The IB DG issnediately began to load uncontrollably.
When the generator output reached 5500 kilowatts (KW), the NSO attempted to reduce load with the Governor control switch. Generator load rapidly reduced to 0 KW at which time the NSO tripped the output breaker to prevent a reverse power trip. Lis.iting Condition for Operation Action Requirement (LC0AR) IBOS 8.1.1-la was initiated at 0845. Subsequent troubleshooting indicated failure of the 3IMX relay. At 0415, on 5/17/88, following replacement of the 3IMX relay, the IB DG was started for a maintenance run. No abnormal conditions were observed. At 0757, oi 5/17/88, the IB DG operability surveillance was completed and LC0AR IBOS 8.1.1-la was exited. There were no systems or components inoperable prior to this event that contributed to the event. All operator actions taken for this event were correct.
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DEVIAVION INVESTIGATION REPORT TEXT CON 71NUATION VITLE DIR NUMBER PAGE SEQUENTIAL REVISION STA UNIT YEAR NUMBER HUMBER FAILURE Of 18 DG TO PROPERLY CONTROL LOAD 01 5 11 6 81 8 0I716
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0 10 2
0F 0l2 TEXT C.
CAUSE Of EVENT:
The root cause for this event is intermittent failure of the normally deenergized 31MX relay. Following the failure, the 1B DG was started for a maintenance run. Prior to.the start, jumpers with closed test switches were installed across the two sets of normally closed contacts on the 3IMX relay. The engine was then started and synchronized to the grid. No abnormal conditions were observed. Next, the test switches were opened to check the continuity of the normally closed contacts. When the test switch connected across contacts 5 and 6 was opened, the engine began to pick up load uncontrollably. When the test switch was reclosed, generator load stabilized. Subsequent testing verified that the relay was deenergized, which is I
the normal condition, and that contacts 5 and 6 were the only intermittent contacts. The relay was then removed, bench tested, and inspected. All contacts functioned properly during cycling of the relay. No foreign material was detected on the relay contacts. In addition, a procedure to test the relay outlined in General Electric Service Advice letter 188.1 dated 11/14/86 was performed on the relay. Again, no abnormal conditions ware observed. Based on the above testing Byron Station has concluded that the failure was intermittent.
D.
SAFETY AHALYSIS:
There were no safety consequencos as a result of this event. This failure had no effect on the emergency operation of the diesel generattr. The failure affected the synchronizing portion (test mode) of the electronic governor only.
E.
CORRECTIVE ACTIONS:
The 3IHX relay was removed and replaced with a new relay. Due to the nature of the.oot cause, no long term cnrrective actions are deemed necessary.
F.
EREVIOUS OCCURRENCES:
There have been several instances of urttable load control on the Byron diesel generators. However, none of the events were attributed to intermittent operation of the 31HX relay.
DVR NUMBER TITLE NONE G.
COMPONENT FAILURE DATA:
a)
MANUFACTURER NOMENCLA TURE tjQQEL NUteER MFG PART NUMBER General Electric 125 VDC Relay 12HFA151A2H b)
RESULTS OF NPRDS SEARCH:
An NPRDS search found no similar occurrences.
c)
RESULTS OF NWR SEARCH:
None found I
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