05000280/LER-1992-001, :on 920102,during Control Rod Freedom of Movement Test,Rod H-2 Dropped Due to Personnel Error.Control Rod H-2 Verified to Be in Core by Observing Skewed Core Power Distribution

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:on 920102,during Control Rod Freedom of Movement Test,Rod H-2 Dropped Due to Personnel Error.Control Rod H-2 Verified to Be in Core by Observing Skewed Core Power Distribution
ML18153C895
Person / Time
Site: Surry Dominion icon.png
Issue date: 02/03/1992
From: Kansler M
VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
92-088, 92-88, LER-92-001, LER-92-1, NUDOCS 9202060313
Download: ML18153C895 (6)
v • d • e


LER-1992-001, on 920102,during Control Rod Freedom of Movement Test,Rod H-2 Dropped Due to Personnel Error.Control Rod H-2 Verified to Be in Core by Observing Skewed Core Power Distribution
Event date:
Report date:
Reporting criterion: 10 CFR 50.73(a)(2)(i)
2801992001R00 - NRC Website
v • d • e

text

February 3, 1992 e

. Virginia Electric and Power Company Surry Power Station P. 0. Box315 Surry,_Virginia 23883 U. S. Nuclear Regulatory Commission Document Control.Desk Serial No.:* 92-088 Docket Nos.: 50-280 License Nos.: DPR-32 Washington, D. C. 20555

  • Gentlemen:

Pursuant to Surry Power Station Technical Specifications, Virgi:pia Electric and Power

- Company hereby submits the following Licensee Event Report for Unit*1.

REPORT NUMBER 92-001-00 This report has been reviewed by the Station Nuclear Safety and Operating Committee and will be.reviewed by the Corporate Managenient Safety Review Committee.

Very truly yours, A~c(}_*.

- f"".::, "-

M. R. Kansler Station Manager Enclosure cc:.

Regional Administrator Suite 2900

. 101 Marietta Street, NW Atlanta, Georgia 30323 9~02060313 920203 P~DR ADOCK 05000280 PDR s

I

NRC FORM 366 U.S. NUCLEAR REG_ULATORY COMMISSION

  • 16-891 APPROVED '.JMB NO. 3150-010<

EXPIRES 4/30192 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH TH!S LICENSEE EVENT REPORT (LER)

INFORMATION COLLECTION REQUEST. 50.0 HRS. FORWAR::

COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH IP-5301, !.J.S. NUCLEAP REGULATORY COMMISSION. WASHINGTON, DC 20555. AND TO THE PAPERWORK REDUCTION PROJECT 13150-01041. OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON. DC 20503.

FACILITY NAME (1)

I DOCKET NUMBER (2)

I PAGE (31 S~rry Power Station, Unit 1 01s101010121 81ol1loF 0 15 TITLE (41 Dropped Rod Due To Personnel E_rror Followed By A Required Manual.Reactor Trip EVENT DATE 15!

LER NUMBER (6)

REPORT DATE 171 OTHER FACILITIES INVOLVED"(BI MONTH DAY YEAR YEAR I<<

SEQUENTIAL [:} REVISION MONTH DAY

- YEAR FACILITY NAMES DOCKET NUMBER[SI NUMBER NUMBER 0 I 5 Io I o I o I I

I 0 11 012 9 2 9 ~ -

01 011 -

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OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE RkCUIREMENTS OF 10 CFR §: (Check on* or mor* of th* folfc,w;ng) (11)

MODE (9!

N 20.402(bl 20.405(cl X

S0.73(1)(2)(iv) 73.71(b)

POWER 20.405(1)(1 )(ii 50.38(c)(11 S0.73(1)(2)(v) 73.71(cl LEVEL

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(10) 20.405(1)(1 )(iii 50.JB(c)(2l S0.73(1H2llviil OTHER (Si,ecify,n Abltracr

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S0.7311112Hxl LICENSEE CONTACT FOR THIS LER 1121 NAME TELEPHONE NUMBER AREA CODE t,f R. Kansler., Stat ion Manager 8 0 4 3 16 is I. i2 p IO 11 I

I COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT 1131 REPORTABLE I J :r<!::: 1 ::::: r :

MANUFAC-REPORTABLE w;::: :1!\\:l::::f :::i::j:iJilf I

CAUSE

SYSTEM COMPONENT MANUFAC-

CAUSE

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SUPPLEMENTAL REPORT EXPECTED 1141 EXPECTED,

MONTH DAY YEAR h

SUBMISSION n YES /If YBS, compt*r. EXPECTED SUBMISSION DATE).

DATE 1151 I

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NO ABSTRACT (Limit to 1400 spaces, i.e.. approximatt1ly fiftetm sing/9.spaca typewritten lines) (161 On January 2,

1992 at 1649

hours, with Unit I

at 56%

reactor

power, troubleshooting was in progress for 11B" shutdown bank control rod* E-5 to
  • deter.mine why E-5 had dropped into the core at 0754 that morning during the performance of biweekly. control rod freedom of movement testing.

As "DII control bank was manually stepped out by the operator to control delta flux, a secomt rod, "D" control bank control rod H-2 dropped.

Control Rod H-2 was verified to be in the core and the reactor was manually tripped in accordance with station abnormal proccd ures.

This event occurred as the result of personnel error in that the troubleshooting guide prepared by Electrical Maintenance for rod E-5 did not identify.shared circuitry between rbd E-5 and H-2 which would result in H-2 being dropped if control rods were stepped during troubleshooting.

Following the reactor trip, "A" main feed pump tripped when its recirculation valve failed to open due to a

failed

solenoid, intermediate range nuclear instrumentation indication was erratic due to high voltage power supply problems, steam generator atmospheric rower operated relief valve for "A" steam generator responded poorly while the valves f'or B and.. c.. steam generators did not respond as expected, and the turbine generator cl cctro-h ydraul ic control system indications were erratic.

A four hour non-emergency report was made LO the Nuclear Regulatory Commission in accordance with 1 OCFR50. 72.

NRC Form 366 (6-891 16-891 FACILITY NAME 111 e

U.S. NUCLEAR REGULATORY COMMISSION.

APPROVED 0MB NO. 3150-0104 EXPIRES, 4130/92 LICENSEE EVENT REPORT (LER)

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DOCKET NUMBER 121 REGULATORY COMMISSION, WASHINGTON, OC 20555, AND TO THE PAPERWORK REDUCTION PROJECT 13150-01041. OFFICE OF M_ANAGEMENT AND BUDGET. WASHINGTON. DC 20503..

YEAR LER NUMBER 161

.;-;.:.;,:. SEQUENTIAL '.:{::::: REVISION NUMBER

-: NUMBER PAGE 131 Surry Powe~ Station, Unit 1 0 I 5 IO IO IO 12 I 8 JO 9J 2 -

0 IO I 1 -

0 p O I 2 OF O I 5 TEXT /ff more-ce ;, mquir&d, u/UJ *ddmonel NRC Form ~*,11171

1. () DESCRIPTI()N OF THE EVENT On January 2. 1992 at 1649 hours0.0191 days <br />0.458 hours <br />0.00273 weeks <br />6.274445e-4 months <br />, with Unit 1 at 56% reactor power, troubleshooting was in progress for "B" shutdown bank control rod E-5 [EllS-AA,ROD]. E-5 had dropped into the core at 0754 that morning during the*

performance* of the monthly control rod freedom of movement testing.

As the reactor operator manually adjusted control rods to control delta nux v*ariations associated with the dropped rod, a second rod ("D" control bank control rod H-2) dropped.

The operator promptly veri ficd control rod H-2 to be in the core by observing a skewed core power distribution, and the reactor was ma*nually tripped in accordance with station abnormal procedure l-AP-1.00, "Rod Control System Malfunction."

All rods were verified to be on the bottom i"ollowing the

trip, operators performed the appropriate station procedures, and the Shift Technical Advisor (STA) monitored the critical safety function status trees to ensure that plant parameters remained within safe bounds.

Due to steam_ generator (S/G) shrink during the transient lEIIS-SB,SG],

the level in the three steam generators decreased to less than 13 %,

which resulted in the start of the three auxiliary feed *water pumps [EllS-BA,P] and the arming of ATWS Mitigation System Actuation Circuit (AMSAC).

At 1650, the "A" main feed pump (MFP). [EIIS-SJ,P] tripped when its recirculation valve failed to open.

Also at 1650, AMSAC timed out and tripped.

The AMSAC trip signal opened the control rod drive,

motor generator set supply breakers [EIIS-AA,MG]

and provided redundanL turbine trip and auxiliary fcedwater actuation signals as designed.

Reactor coolant system [EIIS-AB] average temperature (RCS Tave) decreased below 543° F at 1651.

The pressurizer heater breakers.

[EIIS-AB,PZR] opened and letdown isolated at 1653 due to the low pressurizer level resulting from the cooldown.

RCS Tave stabilized at 5 3 2 ° F, eight minutes following the manual reactor-trip.

At 1659,

  • with reactor power 111 the intermediate range, intermediate range channels N-35 and N-36 [El!S-IG] exhibited erratic behavior with the start up rate meter oscillating from the low to the high end of scale.

At

  • 1700 both source range nuclear instruments energized and indicated a

stable shutdown was in progress.

At _ 1701, after turbine generator speed [EIIS-TL,TGJ had been observed to be 1100 RPM and decreasing, a main turbine vibration annunciator was

received, the operators observed an erroneous main turbine speed indication of 2350 RPM at the ma111 control board, and the electro-hydraulic control system [EIIS-TG]

indications were observed to be erratic.*

In response to the indication, main steam trip valves [EllS-SB.ISV] were closed and an operator was dispatched Lo verify turbine

'16-891 FACILITY NAME (11 U.S. NUCLEAR REGULATORY COMMISSION.

APPROVEO 0MB NO. 3150-0104 EXPIRES. 4130/92 LICENSEE EVENT REPORT (LERI TEXT CONTINUATION

. DOCKET NUMBER 121 ESTIMATEO BUROEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH IP-5301. U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON. DC 20555. AND TO THE PAPERWORK REDUCTION PROJECT (3150-01041. OFFICE

LER NUMBER (61 PAGE 131 Surry Power Station, Unit 1 TEXT /ff more spaet1 is n,qui~, u.., *ddmon*I NRC Form 366A's) (171 speed.

After verifying the four turbine stop valves [EIIS-SB,ISV] were fully. closed, and that turbine speed was decreasing, preparations were initiated to reopen the main steam* trip valves.

The response of the "A" steam generator PORV following

A four hour non-emergency report was made to the Nuclear Regulatory Commission in accordance with* 1 OCFR50. 72. This event is being reported pursuant to 10CFR50.73(a)(2)(i) and (iv).

2. O

SIGNIFICANT SAFETY CONSEQUENCES AND IMPLICATIONS

3.0 This event consisted of a manual *reactor. trip initiated immediately following the full insertion of a second control rod into the core at power.

Plant parameters responded as expected following the trip.

Although the B" and "C" steam generator PORVs failed to open, no safety significance was involved since the plant.is analyzed for a trip..

from full power with no steam generator PORVs operable.

The safety

valve. setpoints were not challenged during the event.

This. event was within the bounds of the accident analysis, thus the health and safety of the public were not affected.

CAUSE OF THE EVENT

This event occurred as the result of personnel error in the preparation of the troubleshooting guide for rod E-5.

An existing procedure which is normally used during refueling was referenced to prepare the troubleshooting instructions.

The

  • instructions directed that the fuses for control rod drive mechanism E-5 be. removed (for personnel protection) to measure the resistance of the mechanism coils.

Because the electricians *

  • preparing the troubleshooting guide did not fully understand the operation of the rod control system and did not consult station drawings, they were unaware that one of the fuses removed was common to the moveable coils for control rods E-5 and
  • H-2.

Consequently, when the control rods were manually stepped to control delta flux, the moveable coil for H-2 did not energize, the stationary coil for H72 de-energized, and control rod H-2 dropped into the core.

4. O IMMEDIATE CORRECTIVE ACTION<Sl Control rod H-2 was verified to be in the
  • core by observing a skewed core power distribution, and the r.eactor was manually tripped in i6-89J FACILITY NAME 111 e

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LER NUMBER 16)

PAGE 131

. Surry Power Station, Unit L o' 1 s I o I o I O 12 I 8 I o 91 2 _ o I o I 1 _ o I o o I 4 o F o I s TEXT /ff mom space i, rtJquimd, u"" *ddftion*I NRC Form 315!1A'JJ°(17) 5.0 6.0 accordance with station abnormal procedure 1-AP-i.00.

Operators performed the appropriate procedures and the unit was brought to a stable hot shutdown condition.

The STA monitored the critical safety functioi;i status trees to ensure that plant parameters remained within safe bounds.

ADDITIONAL CORRECTIVE ACTION<S}

The coil stack for control rod drive mechanism E-5 was determined to contain a defect that was corrected by bringing the plant to cold shutdown and replacing the coil stack.

The "A" MFP recirculation valve failed due to sticking solenoid operated valve, SOV-I50A, which was subsequently replaced.

The Intermediate Range Nuclear Instrument indication problems were determined to be power supply related and the high voltage power supplies were replaced.

The* erroneous turbine speed indication and problems encountered with the turbine Electro-Hydraulic Control System were caused by a capacitor failure in a + 15 volt power supply which was replaced.

The air supply regulators for the three steam generator POR Vs were replaced.

Component Failure Evaluations were initiated for the intermediate range nu.clear instrument power supplies and the PORY air regulators.

ACTIONS TO PREVENT RECURRENCE This event has been reviewed by personnel in the Electrical, Instrument and Controls,

  • and Operations Departments through inclusion in required reading.

This event will be reviewed in Electrical, Instrument and

Controls, and management continuing training programs as
well, re-empasizing the need to exercise. caution when preparing and* approving -troubleshooting instructions, particularly those instructions associated with equipment that is energized and inservice.

As an enhancement, operator training will be revised to discuss the ramifications of stepping control rods while rod control troubleshooting*. is in progress.

Both the existing Instrument and Controls procedure for troubleshooting the rod control system and the abnormal procedure which governs operation with a misaligned control rod will be changed to alert the operator to the ramifications of stepping.control rods while rod *control troubleshooting is in progress.

A new procedure will -be developed for Electrical Maintenance troubleshooting of an energized and inservice rod control system which will also alert the operator to the ramifications of stepping control rods with troubleshooting in progress.

..16-891 FACILITY NAME 11 I e

U.S. NUCLEAR REGULATOR;( COMMISSION LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION DOCKET NUMBER 121 e

APPROVED 0MB NO 3150-0104 EXPIRES 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH (P-5301. U.S. NUCLEAR REGULATORY COMMISSION. WASHINGTON. DC 20555. AND TO THE PAPERWORK REDUCTION PROJECT (3150-01041. OFFICE OF MANAGEMENT AND BUDGET. WASHINGTON. DC 20503.

LER NUMBER (61 PAGE (JI Surry Power Static~, Unit 1 0 1s IO IO IO 12 Is 1 0 912 -

0 JO I 1 -

01 0 01 5 OF O r 5 TEXT /If moftl 'PDctl is required, uu odditionsl NRC Form 366A's) 1171 7.0 8.0 Finally, enhanced training on the Rod Control System will be provided for technicians responsible for the system.

SIMILAR EVENTS

None*.

ADDITIONAL INFORMATION

Power Designs Inc..

Model UPMD-X54W (IR High Voltage Power Supply)

. Fisher, Mod~.l 67AFR/224 (PORV Air Regulator)

Lambda, Model LMEE15-Y-3820-1

(+15 Volt EHC Power Supply)

Westinghouse Electric Corporation, Mechanism)

Model L-106A (Contrnl Rod Drive

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