NExTerao

ENERGY _

February 23, 2015

10 CFR 54

SBK-L-15024

Docket No. 50-443

U. S. Nuclear Regulatory Commission

Attn: Document Control Desk

Washington, DC 20555-0001

Seabrook Station

Response to Requests for Additional Information for the Review of the

Seabrook Station, License Renewal Application- SET 23 (TAC NO. ME4028)

Relating to the Alkali-Silica Reaction (ASR) Monitoring Program

References:

1. NextEra Energy Seabrook, LLC letter SBK-L-10077, "Seabrook Station Application for

Renewed Operating License," May 25, 2010. (Accession Number ML101590099)

2. NRC Letter, Requests For Additional Information for the Review of the Seabrook Station,

License Renewal Application- Set 23 (TAC NO. ME4028), November 25,2014 (Accession

Number ML 14301 A316)

In Reference 1, NextEra Energy Seabrook, LLC (NextEra) submitted an application for a

renewed facility operating license for Seabrook Station Unit 1 in accordance with the Code of

Federal Regulations, Title 10, Parts 50, 51, and 54.

Enclosure 1 contains NextEra responses to the information requested in Reference 2 for RAIs

B.2.1.31A-2(a) and B.2.1.31A-7. Within these responses, changes to LRA Appendix AUpdated UFSAR Supplement, and Appendix B - Aging Management Programs associated with

the Alkali-Silica Reaction Monitoring Program are provided. The changes are explained, and

where appropriate to facilitate understanding, portions of the LRA are repeated with the change

highlighted by strikethroughs for deleted text and bolded italics for inserted text. In some

instances the entire text of a section has been replaced or added. In these cases a note is included

in the introduction indicating the replacement of the entire text of the section.

As discussed with the staff in a teleconference on January 30, 2015; NextEra will require

additional time to fully provide the staff with requested information for the remaining RAIs,

which is dependent on ongoing ASR testing. NextEra anticipates providing a response to the

remaining RAIs no later than June 30, 2015.

NextEra Energy Seabrook, LLC, P.O. Box 300, Lafayette Road, Seabrook, NH 03874
U.S. Nuclear Regulatory Commission

SBK-L- 15024 /Page 2

This letter contains no new commitments.

If there are any questions or additional information is needed, please contact Mr. Edward J.

Carley, Engineering Supervisor - License Renewal, at (603) 773-7957.

If you have any questions regarding this correspondence, please contact Mr. Michael Ossing

Licensing Manager, at (603) 773-7512.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on February 23, 2015

erely'/ •

Ge-an Curtland

Site Vice President

NextEra Energy Seabrook, LLC

Enclosure 1 - Seabrook Station License Renewal Application, Response to Requests for

Additional Information - Set 23, RAIs Relating to the Alkali-Silica Reaction

(ASR) Monitoring Program for the Seabrook Station License Renewal

Application

cc: D. H. Dorman

J. G. Lamb

P. C. Cataldo

R. A. Plasse

L. M. James

NRC Region I Administrator

NRC Project Manager

NRC Senior Resident Inspector

NRC Project Manager, License Renewal

NRC Project Manager, License Renewal

Mr. Perry Plummer

Director Homeland Security and Emergency Management

New Hampshire Department of Safety

Division of Homeland Security and Emergency Management

Bureau of Emergency Management

33 Hazen Drive

Concord, NH 03305

Mr. John Giarrusso, Jr., Nuclear Preparedness Manager

The Commonwealth of Massachusetts

Emergency Management Agency

400 Worcester Road

Framingham, MA 0 1702-5399
Enclosure 1 to SBK-L- 15024

Seabrook Station License Renewal Application

Requests for Additional Information - Set 23

Response to RAIs Relating to the Alkali-Silica Reaction (ASR) Monitoring Program for the

Seabrook Station License Renewal Application
U.S. Nuclear Regulatory Commission

SBK-L-15024 /Page 2

B.2.1.31A-2(a)

Background

In its response to Request for Additional Information (RAI) B.2.1.3 1A-2, part 4, dated

May 15, 2014, regarding criteria by which the frequency of inspection may be changed, the

applicant stated that there are no plans to change the inspection frequency. However, the

applicant also stated that if the "ASR monitoring results" indicate a need to amend the

acceptance criteria or frequency of inspection, it will take such action under the "operating

experience" program element of the Alkali-Silica Reaction (ASR) Monitoring Program.

Issue

It is not clear if the "ASR monitoring results" will be used to increase the inspection interval to

greater than the 5-year interval specified in American Concrete Institute (ACI) 349.3R.

Changing the inspection frequency for either tier two or tier three structures beyond 5 years may

inhibit the applicant's ability to adequately monitor for expansion due to cracking from reaction

with aggregates.

Request

State whether the frequencies of inspection, established within the ASR Monitoring Program

(Tier 2 and 3), will be allowed to exceed the 5-year interval generally accepted for concrete

inspections per ACI 349.3R. If so, provide a justification for how inspection frequencies,

exceeding a 5-year interval, will ensure adequate aging-management of ASR-affected structures.

NextEra Energy Seabrook Response to RAI B.2.1.31A-2(a)

The ASR Monitoring Program augments the Structural Monitoring Program in which the

inspection frequencies were established based on the recommended guidelines contained in

chapter 6 of ACI 349.3R-96.

The frequencies of inspection of Tier 3 and Tier 2 areas currently specified in the ASR

Monitoring Program may change based on trending, however the inspection frequencies will not

exceed the 5-year frequency specified in the Structures Monitoring Program for Harsh

Environment Areas.

Inspection frequencies for Mild Environments are discussed below in response to RAI

B.2.1.31A-7

RAI B.2.1.31A-7

Background

LRA Section B.2.1.31 A, dated May 16, 2012, states under the "Monitoring and Trending"

program element that "newly discovered areas exhibiting visual signs of ASR are identified

during routinely performed Structural Monitoring Program inspections." LRA Section B.2.1.31

states that periodic visual inspections are performed at a frequency determined by the

characteristics of the environment in which the structure is found. LRA Section B.2.1.31 further
U.S. Nuclear Regulatory Commission

SBK-L-15024 /Page 3

states that for structures in a harsh environment, inspections are performed on a 5 year basis

whereas for structures in a mild environment, inspections are performed on a 10 year basis. The

applicant's response to RAI B.2.1.31-5, dated February 3, 2011, describes what is defined as a

harsh environment and lists the frequency of visual inspections for the structures within the

scope of license renewal, based on the structure category defined in ACI-349.3R.

Issue

ASR has been observed throughout the site in concrete structures exposed to various

environments. Considering that the ASR Monitoring Program augments the Structures

Monitoring Program and ASME Section XI, Subsection IWL Program, and that "newly

discovered" areas requiring monitoring for ASR progression will be identified during routine

inspections in accordance with these programs, the staff is concerned that the frequency of

inspection for structures in a mild environment, i.e., 10 years, may not identify "newly

discovered" areas in a manner that would provide for adequate monitoring and trending.

Request

The staff requests that the applicant:

1. State whether the ten-year inspection frequency is adequate for identifying new locations

affected by ASR in structures exposed to a mild environment, and if so, provide the basis

why the 10-year frequency will provide for adequate monitoring and trending, during the

period of extended operation.

2. If these structures in a mild environment will be monitored at a frequency other than that

originally described in the License Renewal Application (LRA), state the new inspection

frequency and provide the basis for its determination.

NextEra Energy Seabrook Response to RAI B.2.1.3 1A-7

1. Per the Structural Monitoring Program a Harsh Environment is defined as:

"...an area subjected to outside ambient conditions, high moisture, wet or humidity, very

high ambient temperatures or frequent large cycling of temperatures (including

freezing/thawing), frequent exposure to caustic materials, or extremely high radiation

levels. "

The Structural Monitoring Program defines and classifies a Mild Environment as an area that is

not a Harsh Environment.

Based on the definition above ASR is not expected to be discovered in concrete structures

exposed to a Mild Environment as a Mild Environment lacks the sufficient moisture needed to

produce an Alkali-Silica Reaction. Accordingly, the 10-year inspection frequency is appropriate
U.S. Nuclear Regulatory Commission

SBK-L-15024 /Page 4

for monitoring and trending other concrete degradation mechanisms for structures exposed to

Mild Environments such as those described in ACI 349.3R-96 and ACI 201.1R-92.

2. To date the progression of ASR degradation has not been detected in a concrete structure located

in a mild environment, therefore, the structures in a Mild Environment will continue to be

monitored on a 10 year frequency as originally described in the LRA.

Note: Inspection frequencies increase when a deficiency is found in an area for all Environments

(deficiencies include but are not limited to ASR).

Based on the above definition of what constitutes a Harsh Environment, LRA Section B.2.1.31

(Structures Monitoring Program), has been revised as follows:

The Seabrook Station Structures Monitoring Program includes periodic visual inspection of

structures and structural components for the detection of aging effects specific for that structure.

These inspections are completed by qualified individuals at a frequency determined by the

characteristics of the environment in which the structure is found. A structure found in a harsh

environment is defined as one that is in an area that is routine! subject to outside ambient

conditions, very high temperature, high moisture or humidity, frequent large cycling of

temperatures, frequent exposure to caustic materials, or extremely high radiation levels. For

structures in these harsh environments, the inspection is conducted on a five year basis (plus or

minus one year due to outage schedule and two inspections within ten years). Structures not

found in areas qualifying as a harsh environment are classified as being in a mild environment,

and are inspected on a ten year basis (plus or minus one year due to outage schedule and two

inspections within twenty years).