Information Notice 1996-12, Control Rod Insertion Problems

Control Rod Insertion Problems

ML031060255
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	02/15/1996
From:	Crutchfield D M Office of Nuclear Reactor Regulation
To:
References
IN-96-012, NUDOCS 9602090161
Download: ML031060255 (10)

UNITED STATES NUCLEAR REGULATORY

COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555-0001 February 15, 1996 NRC INFORMATION

NOTICE 96-12: CONTROL ROD INSERTION

PROBLEMS

Addressees

All holders of operating

licenses or construction

permits for nuclear power reactors.

Purpose

The U.S. Nuclear Regulatory

Commission (NRC) is issuing this information

notice to alert addressees

to recent events during which rod control cluster assemblies

failed to insert fully. It is expected that recipients

will review the information

for applicability

to their facilities

and consider actions, as appropriate, to avoid similar problems.

However, suggestions

contained

in this information

notice are not NRC requirements;

therefore, no specific action or written response is required.Description

of Circumstances

South Texas Project On December 18, 1995, with South Texas Unit 1 at 100 percent power, a pilot wire monitoring

relay actuation

caused a main transformer

lock out which resulted in a turbine trip and reactor trip. While verifying

that control rods had inserted fully after the trip, operators

noted that the rod bottom lights of three control rod assemblies

were not lit; the digital rod position indication

for each rod indicated

six steps withdrawn.

Boration of the reactor coolant system was occurring

with the charging pump suction having been transferred

to the refueling

water storage tank. One rod did drift into the fully inserted rod bottom position within one hour, and the other two rods were manually inserted later. During subsequent

testing of all control rods in the affected banks, the rod position indication

for the same three locations

as well as a new location indicated

six steps withdrawn.

As compared to prior rod drop testing, no significant

differences

in rod drop times were noted before reaching the upper dashpot area for any of the control rods. Within an hour after the rod drop tests, two of the rods drifted to rod bottom position and the other two were manually inserted.

All four control rods were located in fuel assemblies

that were in their third cycle with burnup greater then 42,880 megawatt days(MWD)/metric

ton uranium(MTU).

CPf\ j45T OcA7(ce-~

cW~4oI2- o 9602090161

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IN 96-12 February 15, 1996 Wolf Creek On January 30, 1996, after a manual scram from 80-percent

power, five control rod assemblies

at Wolf Creek failed to insert fully. Two rods remained'at

six steps withdrawn, two at 12 steps, and one at 18 steps. Three of the affected rods drifted to fully inserted within 20 minutes, one within 60 minutes, and the last one within 78 minutes. After the scram, the licensee initiated emergency

boration, as required, because all rods did not insert fully. The five rods were all in 17x17 VANTAGE 5H fuel with burnup greater than 47,000 MWD/MTU.Discussion

At both South Texas units, a 14-foot active fuel length core design is used.Several differences

between the standard 12-foot active fuel design and the 14-foot one are as follows: the 14-foot fuel design is approximately

76.2 cm[30 inches] longer than the standard fuel assembly design, it has 10 mid grids compared to 8 and the dashpot region is 25.4 cm [10 inches] longer and comprises

a double dashpot. The control rod radial clearances

above and in the dashpot region of the 14-foot fuel assembly are similar to those of the standard design. The South Texas core contains three different

17x17 fuel types--Standard

XL, Standard XLR, and VANTAGE 5H--all of which are designed and fabricated

by Westinghouse.

This was the first operating

cycle with VANTAGE 5H fuel. The core also contains 57 silver-indium-cadmium

rods. The four affected rods were found in twice-burned

Standard XLR fuel assemblies.

During subsequent

testing, the rod drop traces revealed no significant

change in dashpot entry time; however, the affected rods did not show recoil on the rod drop trace. Recoil is a dampening

affect that is normally seen in the traces due to control rod assembly spider hub spring contact against the fuel assembly.

When similar rods in Unit 2 were tested, the results revealed no adverse indications.

One rod did show the "no recoil" effect but inserted fully into the core.At Wolf Creek, subsequent

cold, full flow testing of all of the control rod assemblies

indicated

that eight control rods, including

the five control rods that did not fully insert following

the January 30, 1996, reactor trip, did not fully insert when tripped. One control rod, H2, paused at 96 steps, stopped at 90 steps, and slowly inserted to 30 steps over the next 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.The control rod was then manually inserted.

The 7 other affected rods stopped at various heights in the dashpot region, 5 of which fully inserted within 22 minutes. One of the other two drifted to the bottom within one and a half hours while the remaining

rod needed to be manually inserted.

The remaining 45 rods fully inserted when dropped, although a number of the rods did not exhibit the expected number of recoils. Of the total 53 control rod assemblies, H2 (thie only rod slowing outside the dashpot region) is a hafnium control rod, while the remaining

are silver-indium-cadmium

control rod assemblies.

The licensee retested all rods that stuck, as well as those rods that failed to recoil more than twice, and the results were similar to the previous testing.

I IN 96-12 February 15, 1996 Westinghouse, Westinghouse

Owners Group, and the respective

licensees

are pursuing the root cause identification

of these events. Possible root causes are as follows: debris (foreign matter), control rod or drive line degradation, corrosion

products, thimble tube bow, fuel assembly bow and/or twist, reduction

in thimble tube diameter, adverse alignment

of guide tube cards, and/or design tolerances.

Some foreign reactors have also experienced

slow and/or stuck control rod assemblies.

This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact one of the technical

contacts listed below or the appropriate

Office of Nuclear Reactor Regulation

project manager.a or Division of Reactor P gram Management

Office of Nuclear Reactor Regulation

Technical

contacts:

Margaret Chatterton, NRR (301) 415-2889 Internet:

msc1@nrc.gov

Stephen Koenick, NRR (301) 415-2841 Internet:

ssk2@nrc.gov

Attachment:

List of Recently Issued NRC Information

Notices

K>Attachment

IN 96-12 February 15, 1996 LIST OF RECENTLY ISSUED NRC INFORMATION

NOTICES Information

Date of Notice No. Subject Issuance Issued to 96-11 96-10 96-09 96-08 Ingress of Demineralizer

Resins Increases

Potential Stress Corrosion

Cracking of Control Rod Drive Mechanism

Penetrations

Potential

Blockage by Debris of Safety System Piping Which is Not Used During Normal Operation or Tested During Surveil-lances Damage in Foreign Steam Generator

Internals Thermally

Induced Pres-sure Locking of a High Pressure Coolant Injec-tion Gate Valve Slow Five Percent Scram Insertion

Times Caused By Viton Diaphragms

in Scram Solenoid Pilot Valves Design and Testing Deficiencies

of Tornado Dampers at Nuclear Power Plants Partial Bypass of Shutdown Cooling Flow from the Reactor Vessel Incident Reporting

Require-ments for Radiography

Licensees 02/14/96 02/13/96 02/12/96 02/05/96 01/26/96 01/25/96 01/18/96 01/10/96 All holders of OLs or CPs for pressurized

water nuclear power reactors All holders of OLs or CPs for nuclear power reactors All holders of OLs or CPs for pressurized

water reactors All holders of OLs or CPs for nuclear power reactors All holders of OLs or CPs for boiling water reactors All holders of OLs or CPs for nuclear power reactors All holders of OLs or CPs for boiling water reactors All radiography

licensees and manufacturers

of radio-graphy equipment 96-07 96-06 96-05 96-04 OL = Operating

License CP = Construction

Permit

IN 96-12 February 15, 1996 Westinghouse, Westinghouse

Owners Group, and the respective

licensees

are pursuing the root cause identification

of these events. Possible root causes are as follows: debris (foreign matter), control rod or drive line degradation, corrosion

products, thimble tube bow, fuel assembly bow and/or twist, reduction

in thimble tube diameter, adverse alignment

of guide tube cards, and/or design tolerances.

Some foreign reactors have also experienced

slow and/or stuck control rod assemblies.

This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact one of the technical

contacts listed below or the appropriate

Office of Nuclear Reactor Regulation

project manager.original signed by Dennis M. Crutchfield, Director Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical

contacts: Margaret Chatterton, NRR (301) 415-2889 Internet:

mscl@nrc.gov

Stephen Koenick, NRR (301) 415-2841 Internet:

ssk2@nrc.gov

Reviewed and concurred

on by tech editor 02/01/96 CONCURRENCES

DOCUMENT NAME: 96-12.IN To receive a copy of this document, Indicate in the box: 'C' = Copy without enclosures

'E'*SEE PREVIOUS IOFFICE ITECH CONTS I IC:SPLB l I c: NAME MChatterton*

RJones* AChaffee SKoenick*

L DATE 02/07/96 02/08/96 02/08/96 02/06/96 I ,~- I-T,'T~AI

nrd~r l dflflv UrrtIMaL KLtUKU 6ur l

IN 96-xx February xx, 1996 hafnium control rod, while the remaining

are silver-indium-cadmium

RCCAs. The licensee retested all rods that stuck, as well as those rods that failed to recoil more than twice, and the results were similar to the previous testing.Some foreign reactors have also experienced

slow and/or stuck RCCAs.This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact one of the technical

contacts listed below or the appropriate

Office of Nuclear Reactor Regulation

project manager.Dennis M. Crutchfield, Director Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical

contacts: Margaret Chatterton, NRR (301) 415-2889 Internet:

mscl~nrc.gov

Stephen Koenick, NRR (301) 415-2841 Internet:

ssk2@nrc.gov

Attachment:

List of Recently Issued NRC Information

Notices kkil pv 0. 4,.X- , ka-n.-.. IBIr&T IVAI u.d!

• T'. IUI CT rD CCIV L AWWMLtNI C ; b; %a\n tall In OFFICE PECB/DRPM

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AChaffee DCrutchfield

DATE 2/08/96 12/07/96 2/7/96 2/ /96 See previous concurrence

OFFICIAL RECORD COPY

IN 96-xx February xx, 1996 hafnium control rod, while the remaining

are silver-indium-cadmium

RCCAs. The licensee retested all rods that stuck, as well as those rods that failed to recoil more than twice, and the results were similar to the previous testing.Some foreign reactors have also experienced

slow and/or stuck RCCAs.This Information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact one of the technical

contacts listed below or the appropriate

Office of Nuclear Reactor Regulation

project manager.Dennis M. Crutchfield, Director Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical

contacts: Margaret Chatterton, NRR (301) 415-2889 Internet:

mscl@nrc.gov

Stephen Koenick, NRR (301) 415-2841 Internet:

ssk2@nrc.gov

Attachment:

List of Recently Issued NRC Information

Notices DOCUMENT NAME: G:\IN\IN ST CR.SSK OFFICE PECB/DRPM

I SPLB /DSSA ADM:PUB I SC:SPLBDSSA

1 RIVDRS NAME SKoenick*

MChatterton*

TECH ED* EWeiss*DATE 2/06/96 2/07/96 2/01/96 2/07/96 l 2/08/96 OFFICE IBC:SPLB/DSSA

I ISC:PECB/DOPS-1C/PECB:DOPS

I DRPM I -NAME RJones* EGoodw/ n ( AChaffee DCrutchfeld

DATE 2/08/96 E 12/72 /96 Afe 2/ /96 d2/ /96 l* See previous concurrence

UFFI.IAL KtLUKU WrY'

IN 96-xx February xx, 1996 rods did not exhibit the expected number of recoils. The licensee retested all rods that stuck, as well as those rods that failed to recoil more than twice, and the results were similar to the previous testing.Some foreign reactors have also experienced

of slow and/or stuck RCCAs.This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact one of the technical

contacts listed below or the appropriate

Office of Nuclear Reactor Regulation

project manager.Dennis M. Crutchfield, Director Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical

contacts: Margaret Chatterton, NRR (301) 415-2889 Internet:

mscltnrc.gov

Stephen Koenick, NRR (301) 415-2841 Internet:

ssk2@nrc.gov

Attachment:

List of Recently Issued NRC Information

Notices nfnlfIMrFUT

MAWMF.C.*1IJTNT

ST CR SI(a JuuiVILAS, f IIV c ..%a,,% ..OFFICE PECB/DRPM

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lDATE 2/ /96 12/ /96 2/ /96--^*A IrJ^n 4^n OFF1161AL

KLLUKU url

IN 96-xx February xx, 1996 Some foreign reactors have also experienced

of slow and/or stuck RCCAs.This information

notice requires no specific action or written response.

If you have any questions

about the information

in this notice, please contact one of the technical

contacts listed below or the appropriate

Office of Nuclear Reactor Regulation

project manager.Dennis M. Crutchfield, Director Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical

contacts: Margaret Chatterton, NRR (301) 415-2889 Internet:

msclnrc.gov

Stephen Koenick, NRR (301) 415-2841 Internet:

ssk2@nrc.gov

Attachment:

List of Recently Issued NRC Information

Notices DOCUMENT NAME: G:\IN\IN ST CR.SSK OFFICE PECB/DRPM

I SPLB/DSSA

I ADM:PUB I SC:SPLB/DSSA

I lRIV/DRS I j NAME SKoenick*

MChatterton*

TECH ED* EWeiss*DATE 2/06/96 2/07/1/92/

96 2/07/96 2/ /96..I .OFFICE BC:SPLB/DSSA.1 c. ISC:PECB/DOPS

I IC/PECB:DOPS

I I D/DRPM I 1I_--- _ __*................................................

.....NAME I oneL Lz'^J/ 4d EGoodwin I AChaffee JDCrutchfield

DATE 2/ T/96 I 2/ /96 12/ /96 Z/ /96 See previous concurrence

OFFICIAL RECORD COPY

Dennis M. Crutchfi'YXd, Director Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical

contacts: Stephen Koenick, NRR (301) 415-2841/_ Internet:

ssk2@nrc.gov

Attachment:

List of Recently Issued NRC Information

Notices DOCUMENT NAME: G:\IN\IN-DAMP

OFFICE SPLB/DSSA

I SCSPLB/DSSA

I ADM:PUB I BC:SPLB/DSSA

I RIV/DRS I NAME MChatterton

EWeiss TECH ED kp6 RJones DATE 2/ /96 2/ /96 2///96 2/ /96 2/ /96 T - -- _- ar - - I- -. .. I OFFICE ELUB/URPMI4 suncpEu~DPS

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D/UKI'M I NAME SKoenick EGoodwin AChaffee DCrutchfield

DATE j2/ /96 2/ /96 2/ /96 2/ /96------- ------ -----WtI1LAPL KtLUKU LUFi