Information Notice 2011-13, Official Exhibit - NYS000329-00-BD01 - NRC Information Notice 2011-13, Control Rod Blade Cracking Resulting in Reduced Design Lifetime (Jun 29, 2011) (NRC in 2011-13)

Official Exhibit - NYS000329-00-BD01 - NRC Information Notice 2011-13, Control Rod Blade Cracking Resulting in Reduced Design Lifetime (Jun 29, 2011) (NRC in 2011-13)

ML12335A479
Person / Time
Site:	Indian Point
Issue date:	06/29/2011
From:	Laura Dudes, Mcginty T Office of New Reactors, Division of Policy and Rulemaking
To:
SECY RAS
References
RAS 21619, 50-247-LR, 50-286-LR, ASLBP 07-858-03-LR-BD01 IN-11-013
Download: ML12335A479 (4)

United States Nuclear Regulatory Commission Official Hearing Exhibit In the Matter of

Entergy Nuclear Operations, Inc. (Indian Point Nuclear Generating Units 2 and 3)

ASLBP #:07-858-03-LR-BD01 Docket #:05000247 l 05000286 Exhibit #:

Identified:

Admitted: Withdrawn:

Rejected: Stricken: Other: NYS000329-00-BD01

10/15/2012

10/15/2012 NYS000329 Submitted: December 22, 2011 c.,-VR REGU<..tr < 0 .. i ....

• • • • " UNITED STATES NUCLEAR REGULATORY

COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

OFFICE OF NEW REACTORS WASHINGTON, DC 20555-0001 June 29, 2011 NRC INFORMATION

NOTICE 2011-13: CONTROL ROD BLADE CRACKING RESULTING

IN REDUCED DESIGN LIFETIME

ADDRESSEES

All holders of an operating

license or construction

permit for a nuclear power pressurized-water

reactor or boiling-water

reactor (BWR) issued under Title 10 of the Code of Federal Regulations

(10 CFR) Part 50, "Domestic

Licensing

of Production

and Utilization

Facilities," except those who have permanently

ceased operations

and have certified

that fuel has been permanently

removed from the reactor vessel. All holders of and applicants

for a power reactor combined license, standard design certification, standard design approval under 10 CFR Part 52, "Licenses, Certifications, and Approvals

for Nuclear Power Plants."

PURPOSE

The U.S. Nuclear Regulatory

Commission (NRC) is issuing this information

notice (IN) to inform addressees

that GE Hitachi Nuclear Energy (GEH) has discovered

severe cracking in Marathon control rod blades (CRBs) near the end of their nuclear lifetime limits in an international

BWR/6. As a result of investigations

into the cracking, GEH has determined

that the design life of certain Marathon CRBs may be less than previously

stated and is revising the end-of-life

depletion

limits of these CRBs. The NRC expects that recipients

will review the information

for applicability

to their facilities

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

Suggestions

contained

in this IN are not NRC requirements;

therefore, no specific action or written response is required.

DESCRIPTION

OF CIRCUMSTANCES

In August 2010, GEH, as part of its surveillance

program to monitor Marathon CRB performance, visually inspected

four discharged

CRBs at an international

BWR/6 and found cracks on all four CRBs. The cracks were much more numerous and had more material distortion

than those observed in previous inspections

of Marathon CRBs. The cracks were also more severe in that they resulted in missing boron-carbide

capsule tube fragments

from two of the inspected

CRBs. (A lost parts analysis determined

that the missing fragments

caused no negative effect on plant performance.)

Additionally, these cracks occurred at locations

of lower reported local boron-10 depletion

than previously

documented.

GEH attributed

the cracking to irradiation-assisted

stress-corrosion

cracking that results when a material that is susceptible

to irradiation

is in an aggressive

environment

from oxidizing

BWR ML 111380019 OAGI0001190_00001 water and experiences

excessive

stress because of boron-carbide

swelling.

GEH determined

that a significant

contributor

to the extensive

cracking was a rapid thermal transient

that occurred when the automatic

depressurization

system actuated and injected cold water. GEH does not anticipate

the same severe extent of Marathon CRB cracking in other plants unless a similar or more extreme thermal transient

should occur. GEH further concluded

that the cracking phenomenon

is confined to D-Iattice

and S-Iattice

BWR plants; no inspections

to date have identified

cracks on C-Iattice

Marathon CRBs. GEH attributed

this to a difference

in the C-Iattice

design that better accommodates

boron-carbide

swelling.

Based on the results of the investigation, GEH determined

that the lifetimes

of Marathon CRBs in D-Iattice

and S-Iattice

plants may be less than previously

stated. Therefore, GEH recommended

a lifetime reduction.

The recommended

Marathon CRB lifetime reduction

imposes a 60-percent

local boron-10 depletion

lifetime limit, or 54-percent

for D-Iattice "V4 segment and 55-percent

for S-Iattice "V4 segment lifetime limit. GEH recommends

that all plants containing

D-Iattice

and S-Iattice

Marathon CRBs remove the blades from service before they exceed the revised lifetime limits. For any Marathon CRB that exceeds the revised lifetime limit while in use, GEH advises that reactor operation

can continue, but the licensee should monitor reactor coolant boron and tritium concentrations

in accordance

with normal plant procedures.

If no significant

increase is observed in these concentrations, GEH recommends

that reactor operation

can continue until the end of the cycle before removing the CRBs from service. GEH recommends

that licensees

contact GEH if they detect a significant

increase in boron or tritium concentration

or both. The U.S. plants that may contain D-Iattice

and S-Iattice

Marathon CRBs and that; therefore, are potentially

affected are Browns Ferry-1, -2 and -3, Cooper, Clinton, Dresden-2 and -3, Duane Arnold, Grand Gulf, Fitzpatrick, Hatch-1 and -2, Monticello, Nine Mile Point-1, Oyster Creek, Peach Bottom-2 and -3, Perry, Pilgrim, River Bend, Quad Cities-1 and -2, and Vermont Yankee.

DISCUSSION

GEH's Marathon CRBs consist of a series of absorber tubes, each containing

capsules filled with boron carbide (a neutron absorber), welded together to form the control rod blades. Absorber tube cracks allow water to enter both the outer absorber tube and the boron-carbide

capsules, whereupon

boron carbide may leach into the reactor coolant, which could result in reduced control rod worth. Licensees

must maintain control rods in an operable condition

as required by plant technical

specifications.

Technical

specification

requirements

for reactivity

anomalies

give a limit for the difference

between predicted

versus measured core reactivity

during power operation

to ensure that a reactivity

anomaly, such as change in control rod worth, does not result in a loss of shutdown margin or exceeding

specified

acceptable

fuel design limits. In addition, GEH advised plant operators

to continue monitoring

for reactor coolant boron and tritium concentrations

in accordance

with normal plant procedures

to detect CRB cracking and to follow the GEH Marathon CRB surveillance

program, particularly

for D-Iattice

and S-Iattice

plants. OAGI0001190

00002

CONTACT

This I N requires no specific action or written response.

Please direct any questions

about this matter to the technical

contacts listed below or to the appropriate

Office of Nuclear Reactor Regulation (NRR) project manager. IRA by CRegan fori Timothy J. McGinty, Director Division of Policy and Rulemaking

Office of Nuclear Reactor Regulation

Technical

Contacts:

Shih-Liang

Wu, NRR 301-415-3284 IRA by JTappert fori Laura A. Dudes, Director Division of Construction

Inspection

and Operational

Programs Office of New Reactors Arthur Kevin Heller, NRR 301-415-8379 E-mail: Shih-Liang.Wu@nrc.gov

E-mail: Kevin.Heller@nrc.gov

Note: NRC generic communications

may be found on the NRC public Web site, htt(2:1lwww.nrc.gov, under NRC Library. OAGI0001190

00003

CONTACT

This I N requires no specific action or written response.

Please direct any questions

about this matter to the technical

contacts listed below or to the appropriate

Office of Nuclear Reactor Regulation (NRR) project manager. IRA by CRegan fori Timothy J. McGinty, Director Division of Policy and Rulemaking

Office of Nuclear Reactor Regulation

Technical

Contacts:

Shih-Liang

Wu, NRR 301-415-3284 IRA by JTappert fori Laura A. Dudes, Director Division of Construction

Inspection

and Operational

Programs Office of New Reactors Arthur Kevin Heller, NRR 301-415-8379 E-mail: Shih-Liang.Wu@nrc.gov

E-mail: Kevin.Heller@nrc.gov

Note: NRC generic communications

may be found on the NRC public Web site, htt(2:1lwww.nrc.gov, under NRC Library. ADAMS Accession

No.: ML111380019 TAC ME5743 OFFICE SNPB:NRR Tech Editor BC:SNPB:NRR

D:DSS BC:SRSB:NRO

NAME AHelier JDougherty

AMendiola

SBahadur JDonoghue

DATE 6/15/2011

5/25/11 e-mail 6/16/2011 6/17/2011

6/14/2011 OFFICE LAPGCB:NRR

PM:PGCB:NRR

BC:PGCB:NRR

D:DCIP:NRO

D:DPR:NRR

NAME CHawes DBeaulieu

SRosenberg

LDudes (JTappert

for) TMcGinty (CRegan for) OFFICE 6/22/11 6/22/2011

06/22/11 06/27/11 06/29/11 OFFICIAL RECORD COpy OAGI0001190

00004