era
ENERGYS&

SEABROOK

December 13, 2012

SBK-L-12257
Docket No. 50-443

Mr. William Dean, Administrator
U.S. Nuclear Regulatory Commission
Region I

2100 Renaissance Boulevard
Renaissance Park

King of Prussia, PA 19406

Seabrook Station
Response to Confirmatory Action Letter

References:
1. NRC letter to NextEra Energy Seabrook, CAL No. 1-2012-002,
Confirmatory Action Letter (CAL), Seabrook Station, Unit 1 —
Information Related to Concrete Degradation Issues, dated May 16, 2012.
(ML121254172)
2. NextEra Energy Seabrook Letter to NRC, SBK-L-12122, Response to
Confirmatory Action Letter, dated June 8, 2012. (ML12171A277)

Tn Reference 1, the NRC-issued Confirmatory Action Letter (CAL) No. 1-2012-002
which confirmed commitments NextEra Energy Seabrook, LLC (NextEra Energy
Seabrook) made regarding planned actions to address alkali silica reaction (ASR) in
certain structures at Seabrook Station, and required NextEra Energy Seabrook to notify
the NRC Region 1 Administrator if, for any reason, NextEra Energy Seabrook cannot
complete any of the actions or commitments within the specified schedule and to advise
the Administrator in writing of the modified schedule. In Reference 2, NextEra Energy
Seabrook submitted its integrated corrective action plan which provided details related to
some of the CAL required actions associated with the implications of ASR on structures
at Seabrook Station. NextEra Energy Seabrook has completed nine of the eleven CAL
actions within the committed dates.

The purpose of this letter is to notify the Administrator of revisions to two of the
remaining commitments, actions 7 and 11, related to planned actions in Reference 2.
These revisions are based on additional information discovered as part of NextEra Energy
Seabrook’s ongoing actions to assess the impact of ASR on structures at Seabrook
Station. These changes and the basis for the changes have been discussed with the NRC
Working Group on ASR during NRC inspection activities.

NextEra Energy Seabrook, LLC, P.O. Box 300, Lafayette Road, Seabrook, NH 03874


U.S. Nuclear Regulatory Commission
SBK-L-12257/Page 2

CAL action 7 states that NextEra will, “Complete long term aggregate expansion testing
(ASTM C 1293 Concrete Prism Test) by June 30, 2013.” This action along with CAL
action 6 was intended to evaluate the potential for additional ASR expansions to occur in
plant structures that exhibit ASR and to determine if the ASR reaction is self limiting at
some future date. Action 6 stated; “Complete short term aggregate expansion testing
(ASTM C 1260 Mortar Bar Expansion Test) by June 30, 2012.” This action has been
completed and the test results and conclusions have been discussed with and reviewed by
NRC staff. The Mortar Bar Expansion testing conducted by Simpsom, Gumpertz &
Heger (SG&H) for NextEra Energy Seabrook exceeded the expansion limits specified in
the ASTM C 1260 test method. The testing was conducted with coarse aggregates
removed from onsite plant structures that exhibited ASR expansion (i.e., reacted
aggregates) as well as similar coarse aggregates which did not have features of ASR
expansion (previously un-reacted aggregates). The test was extended several months
beyond the specified 14-day test period in order to gain additional insight into the future
reaction and expansion potential of the aggregates. The results of these tests showed that
there was minimal difference in the expansion rate of the reacted and un-reacted
aggregate samples and that the aggregates remained reactive even when the test was
extended several months. From this test data, NextEra Energy Seabrook and our
independent engineering consultants (SG&H) concluded that the coarse aggregates
contain sufficient reactive silica for the ASR reaction and expansion to continue long-
term under existing environmental conditions. Since the ASTM C€ 1260 Mortar Bar
Expansion test results demonstrated that the ASR reaction would continue long-term
without reaching a plateau or exhaustion of reactive silica, the results of the ASTM C
1293 Concrete Prism test, required by action 7, would not provide any useful expansion
rate data or additional insights. Additionally, NextEra Energy Seabrook will complete
the second, 6-month inspection campaign of Combined Crack Index (CCI) monitoring in
December 2012. The first campaign evaluated the CCI after six months and
demonstrated that the reaction rate is slow and there has been negligible change in
expansion. The additional planned CCI monitoring will provide a direct indication of any
progression of ASR that the ASTM test method cannot provide. Thus, NextEra Energy
Seabrook requests that the commitment to perform the ASTM C 1293 Concrete Prism
test be deleted.

CAL action 11 states that NextEra Energy Seabrook will, “Complete anchor test program
by December 31, 2012.” The concrete anchor testing program is currently in progress at
the Ferguson Structural Engineering Laboratory (FSEL) at the University of Texas at
Austin. The concrete test beams for the anchor testing have been fabricated and are
undergoing accelerated ASR aging. To be consistent with the approach taken with CAL
action 8, NextEra Energy Seabrook is requesting that the commitment be changed to
read, “Submit technical details of the anchor test program planned at the contracted
research and development facility by February 28, 2013.”

If you have any questions of a technical nature, please contact Mr. Richard Noble, ASR
Project Manager at (603) 773-7308.


U.S. Nuclear Regulatory Commission
SBK-L-12257/Page 3

Should you have any questions regarding this letter, please contact Mr. Michael O’ Keefe,
Licensing Manager at (603) 773-7745.

Sincerely,

NextEra Energy Seabrook, LLC

Kevin T. Walsh
Site Vice President

ce:
U.S. Nuclear Regulatory Commission
Attn: Document Control Desk
One White Flint North
11555 Rockville Pike
Rockville, MD 20852

J. G. Lamb, NRC Project Manager
NRC Senior Resident Inspector

Mr. Christopher M. Pope

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 01702-5399