05000483/LER-1995-001, :on 950501,manual Reactor Trip Initiated as Result of Shutdown Bank A,Group One Dropping Into Core During Replacement of Rod Control Sys Firing Cord.Procedure ITM-ZZ-00015 Revised to Provide Addl Guidance
| ML20084F279 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 05/25/1995 |
| From: | Affolter R, Bono H UNION ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| LER-95-001, LER-95-1, ULNRC-03218, ULNRC-3218, NUDOCS 9506020130 | |
| Download: ML20084F279 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv), System Actuation |
| 4831995001R00 - NRC Website | |
text
I Callaway Plant Past O!fce Bor 620 futtan, Mascun 65251 Eu{r.b4 ION nuc b'E May 25,1995 U. S. Nuclear Regulatory Commission Document Control Desk Washington, D. C. 20555 ULNRC-03218 Gentlemen:
DOCKET NUMBER 50-483 CALLAWAY PLANT UNIT 1 FACILITY OPERATING LICENSE NPF-30 LICENSEE EVENT REPORT 95-001-00 MANUAL REACTOR TRIP AS A RESULT OF SHUTDOWN BANK A, GROUP ONE DROPPING INTO TIIE CORE DURING REPLACEMENT OF ROD CONTROL SYSTEM FIRING CARD The enclosed Licensee Event Report is submitted pursuant to 10CFR50.73(a)(2)(iv) for an event or condition that resulted in manual actuation of a reactor trip.
I r
R. D.
ffolter Manager, Callaway Plant o$4r Y RDA/HDB/JDN/trj Enclosure cc: Distribution attached 310005 p
9506020130 950525 I )
a PDR ADOCK 05000483 S
+
l cc distributica for ULNRC-03218 Mr. J. B. Martin Regional Administrator.
4 U. S. Nuclear Regulatory Commission Region III 801 Warrenville Road Lisle, Illinois 60532-4351 Mr. L. Raynard Wharton (2 copies)
Licensing Project Manager U. S. Nuclear Regulatory Commission OWFN - Mail Stop 13E21 Washington, D. C. 20555 Manager, Electric Department Missouri Public Service Commission P. O. Box 360 Jefferson City, MO 65102 Records Center Institute of Nuclear Power Operations 700 Galleria Parkway Atlanta, GA 30339 Mr. Steve Wideman i
Supervisor, Licensing j
Wolf Creek Nuclear Operating Corporation P. O. Box 411 Burlington, KS 66839 Mr. M. J. Farber Chief, Reactor Projects Section ill A U. S. Nuclear Regulatory Commission Region Ill 801 Warrenville Road Lisle, Illinois 60532-4351 Mr. Thomas A. Baxter Shaw, Pittman, Potts & Trowbridge 2300 N. Street N.W.
Washington, D.C. 20037 NRC Senior Resident Inspector
i
..e LICENSEE EVENT REPORT (LER)
FACILIT f NAME II)
DOCKE I NUMBE R (21 PAGE (33 l oF l o l 3 Callaway Plant Unit 1 o ls lo lo lo l4 l8 l3 1
Manual Reactor Trip As a Result of Shutdown Bank A, Group One Dropping Into the Core During Replacement of Rod Control System Firing Cord E VENT DATE di LER NUMBER for HEPORT DA TE 171 UTHER FACILITIES INVOLVED 18)
M0;mt DAY YEAR YEAR SEQUENTIAL REV.
MONTH DAY YEAR FACILITY NAMES DOCKET NUMBERISI NUMBER NO.
olslololol l I ois oli s
s sls ololi olo ols 21s sls otslololol l l ODE (
THIS REPORT is SUBMIT 7ED PURSUANT TO THE REOUIREMENTS OF 10 CFR :ICheck one or more of the /b//oweg)1111 2
20.402101 20.405tcl X
50.13(aH21ovl 73.7 t tel POWE R 20.405taH 110) 50.36tcHil 50.73(aH2Hvl 73.71(c)
LEVEL (101 0 l0 l0 20.405t H11w 50.38tc)t2)
So.73(aH2iten)
OTHER (Specify in 20.405f alt tituel 50.73(aH2Hil 50.73(aH2HvmHAl Abstract below andin 20.405t alt 1 Hav) 50.73(aH2Hn) 50.73(aH2HvmHB)
Text, Mtc form 36 sal 20.405f aH11M
$0.73taH2Hml 50.73(aH21tx)
LsCENSEE CONTACT FOR THis LER 112)
NAME TELEPMONE NUMBER AREA COUE H. D. Bono, Supervising Engineer, Site Licensing 3ltl4 6l7l6l-l4l4l2l8 COMPLITE ONE LNE FOR EACH COMPONENT FAILURE DESCRIBED W THl4 REPORT 113)
CAUSE
SYSTEM COMPONENT TU E TO NPRD
CAUSE
SYSTEM COMPONENT TURE TO NPRD X
AlA is l C l li l D Wl 1 l 2 l 0 N
l l l l l l l l
l l l l l 1 I
I I
I I I
$UPPLEMENT AL REPORT E AFEC TED 114)
MONTH DAY l YFAR EXPECTED l
SUBMIS$10N
~' ~
DATE (151 l
l
[
YE S Uf yes. compiate EXPECTED SUBMi$Sf0N DATfl NO ABd TRAC T tunut to 1400 spaces, re. approximatesy hfteen single space typeveretten kneeH 161 On 5/1/95 at 1617 hours0.0187 days <br />0.449 hours <br />0.00267 weeks <br />6.152685e-4 months <br /> CDT, startup physics testing was in progress while the plant was in Mode 2 with reactor power at 1.0 E-7 amps. At this time, a Rod Control Urgent Failure (RCUF) annunciator alarmed. Utility Instrumentation and Control (I&C) personnel investigated the condition in accordance with procedure ITM-ZZ-00015, Rod Control Troubleshooting Guidelines, and determined the cause to be a failed stationary firing card for Control Bank C, Group One. In addition, the stationary firing card for Shutdown Bank A, Group One, was determined to have a degraded voltage.
The failed card was replaced and additional readings taken. It was then decided to replace the degraded card as a precautionary measure. When this card was removed, current to the associated stationary grippers was interrupted and the control rods dropped. The condition was immediately noted by the utility licensed reactor operator in the Control Room and the reactor was manually tripped at 2031 hours0.0235 days <br />0.564 hours <br />0.00336 weeks <br />7.727955e-4 months <br /> CDT The root cause of the dropped rods was a failure to properly restore from the RCUF on Control Bank C prior to removing the card for Shutdown Bank A. Procedure ITM-ZZ-00015 was revised to provide additional guidance, and appropriate personnel will be trained to prevent recurrence of this event.
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION wwv uxue m oouu uuueen a, us uugego, uao 3, NLMEER NO.
Callaway Plant Unit 1 olslololol4lala sls
- - olol1
. olo ol2 ola or TEXT Uf more space is recpared, use addittorul NAC Form 366 A'el(17)
BASIS FOR REPORTABILITY:
This event is reportable per the requirements of 10CFR50.73(a)(2)(iv) as an event or condition that resulted in manual actuation of the Reactor Protection System.
CONDITION AT TIME OF EVENT:
Mode 2 - Plant startup Reactor Power - 1.0 E-7 amps
DESCRIPTION OF EVENT
On 5/1/95 at 1617 hours0.0187 days <br />0.449 hours <br />0.00267 weeks <br />6.152685e-4 months <br /> CDT, startup physics testing was in progress. The plant was in Mode 2 with reactor power at 1.0 E-7 amps. At this time, a Rod Control Urgent Failure (RCUF) annunciator alarmed. Utility Instrumentation and Control (I&C) personnel investigated the condition in accordance with procedure ITM-ZZ-00015, Rod Control Troubleshooting Guidelines. The cause of the RCUF was determined to be a failed stationary firing card for Control Bank C control rods. In addition, the stationary firing card for Shutdown Bank A, Group One, was determined to have a slightly degraded voltage. The failed firing card was replaced. It was decided to replace the second card as a precautionary measure. When the Shutdown Bank A firing card was removed, electrical current to the stationary grippers was interrupted, thus allowing the release of the four affected control rods. The RCUF alarm, in conjunction with the rod control cabinet Bank selector switch, energizes the Bank stationary and movable grippers to hold the control rods in place. The Shutdown Bank A control rods dropped because the RCUF was not restored from Control Bank C prior to removing the card for Shutdown Bank A. In this event, the Bank selector switch was still selected to Control Bank C when the firing card for Shutdown Bank A was pulled from the cabinet.
This situation was immediately noted by the utility licensed reactor operator and a manual reactor trip was initiated in accordance with Off-Normal Operating procedure OTO-SF-00003, Dropped Control Rod.
8*.e**so LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION MCILf1Y NAME (1)
DOCLk T NUMBtR 12)
LER NUMBER 461 PAGEt3)
YEAR lif NTIAL REV Callaway Plant Unit 1 olslololol4lala sls
- - olol1 olo ol3 ols or TENT tif more space se requwed, use additsonal NRC Form 386A*slH 7)
ROOT CAUSE:
The root cause of the event was cognitive personnel error. Personnel failed to recognize that with the RCUF alarm in and Control Bank C still selected, pulling the firing card for Shutdown Bank A would remove current to the stationary gripper coils and cause control rods to drop into the core.
CORRECTIVE ACTIONS
- 1. Appropriate personnel will be trained to prevent recurrence of this event.
- 2. ITM-ZZ-00015 has been revised to provide additional guidance.
SAFETY SIGNIFICANCE
The ESF systems involved performed as required. At the time of the event, the reactor was critical in Mode 2 at a power level of 1.0 E-7 amps. There was no detrimental effect on plant equipment as a result of this event. All equipment functioned as required by plant design. This event did not pose a threat to the health and safety of the public.
PREVIOUS OCCURRENCES
LER 90-007-00 transmitted on 7/10/90 details a manual reactor trip after four Bank B control rods dropped. Troubleshooting identified a faulty slave cycler counter card for the control rod power cabinet. Although the 7/10/90 manual reactor trip was similar to the 5/1/95 reactor trip, the root cause for LER 90-007-00 was a faulty card. The corrective action taken for LER 90-007-00 was not applicable to this event.
FOOTNOTES:
- 1. System AA, Component-ROD
- 2. System JC
- 3. System JE