ML12173A464

Comments by Wjr on Draft TIA for ASR at Seabrook

ML12173A464
Person / Time
Site:	Seabrook
Issue date:	06/04/2012
From:	Office of Information Services
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FOIA/PA-2012-0119
Download: ML12173A464 (21)

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Comments by WJR on Draft TIA for ASR at Seabrook By letter dated September 12, 2011 (Agencywide Documents Access nd a] i'ystem (ADAMS) Accession No. ML1116105300), the U.S. Nuclear Regulatory4 nlion~(N RC)

Region I Office requested technical assistance from the Office of ear r Regulation (NRR) to evaluate the potential consequence of alkali-silica reacti dation of a safety-related concrete structure at Seabrook Station. More b eon NRR review for adequacy of a NextEra prompt operability dete ina io D) s ciated open issues, NRC staff should be able to identify what c diti na formati is ne edin order to fully evaluate the impact of the degradation on the urr Ii in d design basis in the final operability determination for structures important t. As the primary case for review, NextEra evaluated the Seabrook Contro ild' .lectncal Tunnel and Penetration Room) in light of the recently discovered ded, niim. Other structures important-to-safety within the scope of the maintenance ru a Is en affected by the ASR problem.

Region I requested NRR assistance tcdss; ove concerns by providing answers to the five Task Interface Agreement (TI qi ion h are stated in Section 3.0 "Evaluation" of this response.

2.0 BACKGROUND

NextEra Energy (the li ee) a yz concrete core samples from the interior surface of exterior walls of th ont. uil as part of their assessment to support renewal of their license. In Ap 01 ertaken as a part of the core sample analysis reported a change in m te rti . analysis reported the presence of ASR-degradation in core samples t n ro ly wet walls below grade, with reductions reported in the concrete compres st gth modulus of elasticity from that expected. NextEra evaluated these tha ri determine the impact on the design basis of the Control Building. By thpar *e licensee performed an immediate and prompt operability determination (POD) con d eliminarily, that the Control Building (CB) was operable but with reduced st serves to design capacity.

NextEra ntinued to evaluate the extent of this condition for five other safety related concrete buildings. The other five buildings for which concrete core samples were taken were: Equipment Vault (housing ECCS equipment including that for Residual Heat Removal (RHR)], Radiological Controls Area (RCA) Walkway, Emergency Feedwater Building (EFW), Emergency Diesel Generator (EDG) Building, and the Containment Enclosure Building (CEB). As of June 30, 2011 there are two open prompt operability determinations, one for the Control Building and one for the other five buildings collectively. The licensee found additional evidence of ASR in four of the five other buildings and they that information in a separate immediate and prompt

operability determination using the same evaluation techniques as for the Control Building. This evaluation is also considered preliminary or open. Based on NRC internal discussions, it appears that the calculation methods and correlations that NextEra used in their prompt operability determination may not be fully appropriate in light of the ASR problem.

NextEra's planned actions are two-fold: 1) to follow their operability determination process; and,

2) to follow the guidance in NEI 95-10, "Industry Guideline for Implementing the Requirements of 10 CFR Part 54 - The License Renewal Rule," to develop an aging manage t program to support the license renewal application. Possible outcomes to the PODs ar er red ,

conditions (which may not be possible); 2) resolved conditions (use "as is"r2 e nge incorporated or Action Request (AR) disposition approved); or 3) curre t liL revised (e.g., 10 CFR 50.59 evaluation). The licensee has posted t e nte al website their operability determination process for reference (EN- 003- 05, No. 1 on Certrec Document Tab List).

NextEra's proposal related to license renewal was describ in a I r d Ap il 14, 2011, under the response to NRC request for additional info ti B.2. -* gencywide Documents Access and Management System (ADAM io . ML11108A131). This letter describes periodic reviews for operability a I loped to support the aging management review. At the time, the proposal i ude an lysis (termed "final" by NextEra) of the impact of ASR on the curren le ign asis, including the extent of the condition, to be completed by June 2 11 c t at r and as noted above, the control building POD was kept open; a new im e re completed for the other five building core sample results that were olved of conditions review. The subject NextEra letter also commits to an i ring luatio to be completed in March 2012. On June 29, 2011, the NRR visi 0Li wal issued another "Request for Additional Information" (ADAMS A.c s No 1 338) related to key aspects of NextEra's comprehensive plan for a i eA roblem for the Structures Monitoring Program including that for the F a and Containment ("Followup RAI B2.1.31-1, B2.1.31-4, and B2.1.. h o etothis letter dated August 11,2011, (ADAMS Accession M 22 30 es not reflect a comprehensive plan for determining operability i a buildings along with plans for the development of aging managem nt re pr M.

With re to rt u ements, Region I reviewed the NextEra current Structures Mon in**

• found a violation of the maintenance rule for the control building. The fi *bed in detail in NRC Inspection Report 05000443/2011002 (ADAMS Accession L 3 ). More details related to the newly discovered ASR issue were also do ted the NRC Inspection Report 05000443/2011007 (ADAMS Accession No. ML1 1"0432) as part of a license renewal inspection. The cover letter for the latter report notes ththe aging management review for the ASR issue is not complete and that there is a need for a continuing review in the Part 50 and 54 areas. The staff of Region I and NRR (Division of Engineering and Division of License Renewal) have been discussing actions since January 2011 to ensure that the Part 50 and 54 reviews are coordinated.

The documents listed below were made available for review on the licensee's "Certrec" internal website (Certrec Document Library Tab List). These documents reflect current NextEra view of operability for the Control Building and the associated tunnel and penetration room. The (VF NTER BRAINJDWN0 C MT)

"Certrec" system was set up in order to facilitate NRC staff access to NextEra's internal documents. The NRC staff was requested to inform Region I and NextEra if the document is to be printed, for review purposes, prior to doing so.

1. C-S-1-1 0159 CALC_000, Rev. 0, 'B' Electrical Tunnel Transverse Shear Evaluation Supplement to Calculation CD-20

2. C-S-1-10150 CALC 000, Rev. 0, Effects of Reduce Modulus of Elastici - 'B ctrical Tunnel Exterior Walls

3. CD-20-CALC, UE Control and Diesel Generator Building Design of below grade for Electrical Tunnel and the Control Building (Original Desi n C ti

4. Action Request (AR) 581434 Prompt Operability Determin crete Properties Below Grade in 'B' Electrical Tunnel Exterior Walls.

On April 27, 2011, NRR Division of Engineering provids ort b rforming an initial review of NextEra's basis for acceptability of the reduction mr u ticity in light of concrete core testing which supported 10 CFR 50.59 scre pro with ut prior NRC staff review and approval. This evaluation and its related de du nt accept the reduced parameters of compressive strength and m asti for the Control Building and the Containment Enclosure Building as apo I o ' r the operability determination (Certrec Document Library Tab List, E osur nd Control Bldg MSP - Design Change Package Description No. EC-27207, v. P0 , o rete Modulus of Elasticity Evaluation). The staff questioned the adequacy o i g ion.

The licensee is also plannin a nt use review for the maintenance rule violation noted above. Corrective action e ensive walkdown of all structures important-to safety with suspected n rdance with a revised structures monitoring program procedure t ets th atest ACI standard in the area (ACI 349.3R-02). This has been comple a I ing, containment enclosure building, and the containment.

Completion t e s s for the other buildings is tentatively December 2011. Further, the license s a root cause evaluation of the ASR issue which should be complet ti fo oration into the planned March 2012 Engineering Evaluation as noted a L~ s- od To thin the limitations of their testing and analysis, NextEra determined that none of the seismi tagory I structures tested have been found to be outside their design basis and were, therefor , operable with extent of conditions questions needing be addressed. The Seabrook design and licensing basis to which the licensee made these determinations was documented in UFSAR Section 3.8. NextEra is willing to address the additional questions from the NRC staff; but, it is uncertain if those questions will be addressed in the final operability determination tentatively scheduled for September 30, 2011. It also remains uncertain what NextEra's comprehensive plan is based on review of their August 11, 2011, response to NRC letter of June 29, 2011.

D 'ION OFFIAA (USE

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In light of the newly discovered ASR issue, it appears that NextEra technical personnel are developing new insights for what key aspects must be addressed in the final operability determination for any building with evidence of ASR. NextEra is considering NRC staff questions to date and has hired consultants in this area. These consultants also will be developing a new model for the Containment Enclosure Building load analysis.

[It should be noted that NextEra'sschedule indicatedin the above paragraphha anged and the prompt operability determinationswere revised in mid October 2011 fo B eeic Tunnel (AR 581434, Revision 001) and Containment EnclosureBuilding, Vaults, EFW Pump House, and Diesel GeneratorFuel Oil Tank Roo R evision 001).]

Recommended Actions by Region I In order for Region I to independently determine operabili f the c ro uilding or any other important-to-safety structure affected by the ASR probt&; as rimary case, we need a review for adequacy of the control building prom t r ation and any related open issues as identified by NextEra. This info o ou ap lied to the final operability determination for the control building and any i o nt-to-safety structures. The important-to-safety structures affected by the* l* wi in the scope of the maintenance rule and are also consiste of license renewal. More specifically we need to independently develop a pre nsi et of issues to be applied to any final operability determination as a rt f ove I o he licensee's process and any new insights gained from NextEra' t i s ar Accordingly, Region I reque R luate the adequacy of NextEra's control building prompt operability dete its ted open issues with particular focus, but not limited to, the below list ke c i s The licensee has provided a set of documents as noted on the "Ce ite re en bove, but the NRR review should not be limited to those documen egi I tate ensuring that additional documents, as needed, are available on th b. ,a cessary, by an onsite inspection. NRR's determination should enable the o i t there is reasonable assurance of continued operability given the concrete tio ied due to ASR for the control building once the final operability determi NextEra for this or any other important structure affected by the ASR D u of this review, Region I requests that NRR specifically identify any concerns with a umptions, methodologies, or calculations, etc., along with the regulatory or other basis o ch concern; and, notify Region I immediately if NRR finds that any of the reviewed documen for the control building do not provide reasonable assurance of continued operability of that bu ding. As a minimum, the response to this TIA should include an independently developed comprehensive set of issues to be addressed in the final operability determination for the Control Building in order for us to further assess the licensee's process and their new insights gained for all important-to-safety structures with evidence of ASR.

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3.0 EVALUATION Question 1:

Working with Region I staff in an inspection forum, NRR staff should identify a ?mprehensive list of issues that need to be addressed in the final operability determination for he Control Building, given the current view of operability by NextEra as reflected in the pr t operability determination.

[Discussion by Region 1: NRC staff identified questions as listed in the NR Accession No. MLIII 78A338) dated June 29, 2011. The questions rd t cts of NextEra's comprehensive plan for assessing the ASR problem for the S t Monitoring Program,including that for the Fuel Handling Building and Conta RAI B2.1.31-1, B2.1.31-4, and B2.1.28-3)]. If the issues are initially consi c re e, please give considerationto the below additionalviews produced by th i I staff. If those issues are not consideredcomprehensive, then identity th additi I s to be included with considerationto those listed below along with reg r othe asis for the concern. An example would be the need for Poisson ratio alcu n pies because there are assumed numbers in the UFSAR or the nee f ss age tests because of applicable ACI standardrequires it in the currentlicen i

Response

The NRR staff notes that reference ContrB i in TIA 2011-13 refers to the "B" Electrical Tunnel, which s be he trol ilding foundation, extending between EL -20 ft and EL +21 ft 6 in, thert alave been reported to be affected by ASR. It is noted that the ControlhB ding re ve grade and its foundation have not been reported to be affected by ASR. r o ill hereafter use the designation of "B" Electrical Tunnel rathe than Co IBu SR affected structure that is the subject of the TIA.

The Electri IT Is Category 1 reinforced concrete structures designed to house the Train A nd in afe ated cable/cable-tray systems in train independent structures.

The struct t he ty-related systems, equipment and components located inside the Ele

• T ne st all postulated external environmental conditions.

Th unne tructure is designed to withstand all credible conditions of loading, d in o loads, severe environmental loads, extreme environmental loads, and ab oads. he loads included ground water hydrostatic pressure, OBE and SSE loads.

The ical Tunnels are situated one on top of the other.

There are no defined Technical Specification functions associated with the Electrical Tunnel. It stands to reason that the electrical transmission cables housed within the structure are necessary for operation, safe shutdown, or permit continued decay heat removal. The structural integrity of the structure that houses them is an important function during all modes of operation.

A program to address the diagnosis, prognosis, appraisal and aging management of important-to-safety concrete structures subject to alkali-silica reaction (ASR) d radation should, in E NA - FIF L O AL INS & ME

general, consist of the following elements: (i) Condition assessment (extent and characterization); (ii) Root Cause; (iii) Testing to estimate "expansion to date" and "the current expansion rate"; (iv) Testing to estimate "potential for further expansion"; (v) Interim and long term structural appraisal; (vi) Monitoring and aging management; (vii) Mitigative and remedial measures and (ix) Potential for further deterioration due to other mechanisms. In response to the TIA question, the NRR staff provides the following observations and guidance.

(a) During the period 9/26/2011 thru 9/28/2011, NRR staff participated, on h Region 1 inspectors, in an inspection with regard to the ASR issue at Seabro tatio ur the inspection, the NRR staff reviewed the licensee's prompt operabili *n (POD) for the B Electrical Tunnel (AR 581434, Revision 000). This ha that the structure is operable since it is fully qualified, meeting a ui n. Although there was no immediate safety concern identified, the sta llowing broad comments with regard to the POD. Similar comments I AR 01664399, Revision 000, which is the POD for other ASR-affe 1 structures.

" It is based on the assumption that the eat (emp I based on sound concrete) in the ACI 318 code for concr essive strength (f c) and shear strength, tensile strength, bon o lus lastic etc. remains unaffected by ASR.

• Effect of ASR (reduced concrete e s o e design qualification of anchorages of supports for s r d nents (e.g. cable-trays carrying SR cables, etc) attached to AS affe ed te was not addressed quantitatively.

• Effect of ASR on shear p ity o t wa as not addressed quantitively.

• Effect of ASR on na freq global response of the tunnel wall under seismic load and co ati as not addressed quantitatively.

Based on t11 fe revised its prompt operability determinations in mid October 20 1 he r Tunnel (AR 581434, Revision 001) and Containment Enclosure din uipment Vaults, EFW Pump House, and Diesel Generator FI Oil R m 1664399, Revision 001). The determination was revised fr "A C Id be considered Operable since it is fully qualified, meeting As-Bu it to " d SSC should be considered Operable but degraded, and wF Qu tion. ntinued Operability is based on the provisions of RIS 2005-e's conclusion also stated that full qualification will be attained when the to nd analysis plans developed to address the ASR issues are completed and the I ocu e=nts*.

tesolution is incorporated into the UFSAR and/or other applicable design Comment [wjrl]"Add a statement here that I NRC review found the ODs acceptable. There is a need for the agency to take a stand on ed on the technical guidance in Section 6.2 of the NRC Inspection Manual: Part operability based on 'best available" info. Then 9900 - Operability Determinations & Functionality Assessments for Resolution of the rest will follow regarding the need to Degraded or Nonconforming Conditions Adverse to Quality or Safety (Reference 17), an 1 continue to review operability as new I information is obtained.

SSC that is determined to be operable but degraded or nonconforming is considered to be in compliance with its TS LCO, and the operability determination is the basis for continued operation. The basis for continued operation should be frequently and regularly reviewed until corrective actions are successfully completed. Using information F N N~kNO

from the ongoing detailed investigations of the ASR issue by the licensee, the PODs should be re-assessed based on the results of the licensee's testing and detailed engineering evaluation scheduled to be completed in March 2012.

(b) Although several documents in the form of contractor/consultant recommendations were made available, the licensee has not yet made available to the NRC its firm Action Plan to address the ASR issue at Seabrook. Also, licensee plans have bee ganging. In order to make an objective assessment of the licensee's ongoing actiondress nthe ASR issue, the licensee should finalize and make available, in the i ia tu or available for NRC review a firm and comprehensive Action Plan (no contractor/consultant recommendations) for the effects of ASR Se gory 1 concrete structures at Seabrook in support of the interim an Ion esign basis evaluations of affected structure and aging management should be an Appendix B quality document. This action plan shoul u h natic strategy for the root cause, diagnosis, prognosis, structural ai man gement and potential mitigation of the ASR-degradation issue o ncre r ures at the station.

(c) The issues and questions raised in the li tion NRC RAI Follow-up B.2.1.31-1 (Reference 18, ADAMS Acce o. 11 38) dated June 29, 2011, are considered comprehensive. All the i o ly for addressing the ASR issue during the remaining period of c + ear op ating license, under 10 CFR Part 50. In addition, further d 0 d be given to the issues in Items (d) thru (i) below in the response t A ues land the responses to TIA Questions 2 to 5.

(d) Since the ASR-degrad n of n p -safety concrete structures at Seabrook is a significant condition ad qU *ty, the licensee should address the root cause and corrective action ri n XVI "Corrective Action" of 10 CFR 50 Appendix B.

(e) Groundwat a es tha ave been collected and tested as part of the license renewal pro ct d ne t t gro ind water environment at Seabrook Station is aggressive due o t Ion els'greater than 500 mg/L (EC 145305). Areas impacted by gro a rently designated as harsh environment. Further, the ASR-affected B I ails showed ground water in-leakage, and efflorescence and I h It the inside. Since ASR interacts with other deterioration processes nc er applicable degradation mechanisms for concrete and reinforcing aIpotent for further deterioration of ASR in combination with other degradation ch *s should be addressed.

(* N C staff understands that the licensee has been taking and testing core samples from the interior of the ASR-affected structures. The licensee should address the degradation effects through the wall-thickness and especially on the exterior of the affected structures in contact with the soil and ground water, which may likely be more severe if the source of moisture is water infiltration from the outside.

PAEC=ALS= L

(g) The licensee should address the effect of ASR on the bond between concrete and reinforcement in the affected structures.

(h) Since the effects of ASR on the design basis appraisal and aging management actions are dependent on the severity of ASR (measured as expansion-to-date and other considerations), the licensee should determine severity in a reliable manner by more than one method. The licensee should consider conducting stiffness dage tests of cores in the laboratory in addition to in-situ surface crack mapping to tJ"ne the severity.

(i) If the ASR-degradation of an affected important-to-safety stru e at is determined to be severe to very severe, the licensee should co r sulting experts for appropriate nonlinear finite element modeling of ASR d structural appraisal of the affected structure. Comment [wjr2]: I would add requirement (j)

- In the Action Plan, provide a commitment and schedule to obtain core samples from all Question 2: Category I concrete structures to confirm the presence or absence of ASR degradation.'

Because the original design basis assumes no AS*p the design life of the structure, what, if any, are the specific original n ssu ions affected by the presence of ASR that are not clearly evident in the UFSAR tI" j v fDiscussion by Region 1: Forexample s .I 1l*ethods such as the relationship between compressive strength and m of I ity to shearcapacity and shearforce are used in the seismic analysis. The a med r io ships may not be valid with ASR present in the structure.]

Response

(a) The design of the ategory I Structures affected by ASR, including the "B" Electrical T e ra) in Seabrook Station UFSAR (Reference 14), Section 3.8.4 "Other S i* a t ,ctures." UFSAR Section 3.8.4.4.a states that reinforced coycret si fC ry 1 structures was in accordance with the strength design prc e 318-71 code (Reference 22), except as indicated in Subsection 3 .5. F ction 3.8.4 contains physical descriptions, codes, loads and load iiigp and analysis procedures, structural acceptance criteria (e.g.,

~Ao lestr S s)/ quality control, and testing requirements of Seismic Category 1 Sexclusi e of the containment structure and its internals. The basic load ma ons considered in the design of each seismic Category 1 structures are given U AR Table 3.8-16. Detailed design criteria are documented in NextEra system cri ti n document No. SD-66 "Structural Design Criteria."

UFSAR Section 3.8.4.5.d states that no special allowance has been made for variation of material properties over the life of the structure, beyond that which is taken into account in establishing allowable stresses, strains, capacity reduction factors, concrete protection of reinforcing, and crack control as outlined in the referenced ACI and AISC codes. Additional corrosion protection is provided to concrete structures by means of YA -OFAIC

ýO LU N ENARACM E T

waterproofing for parts of the structure below grade and by painting, coating or installing of liners for structural concrete tanks (such as the spent fuel pool).

(b) The presence of ASR generally show a reduction in the mechanical prope/ties of concrete (relative to their 28-day values and measured on unrestrained cre or cylinder specimens) such as compressive strength (f'.), tensile strength (ft), sheai strength (vj),

bond strength, elastic modulus (Ej), and potentially an increase in the P on's ratio (v).

However, the change in these properties due to the presence f A oi at difrent rates than the compressive strength in the same concrete. There at ip between the compressive strength and other mechanical properes t shear, bond, elastic modulus) of concrete used in design which e empirically (based on tests of non-degraded concrete) in the e as a function of the square root of the compressive strength of concreto t remain valid for structures affected by ASR degradation, dependin ev the degradation.

It should be noted that, in general, all relationships* e cod that are expressed as a function of /f'. depend chiefly on th concre n le strength rather than compressive strength (Reference 34). in It has been established in literature that u e t nsile strength of concrete more rapidly than it reduces compres iv*v ce 30). Thus far, the licensee has established by testing o e[ co of R-affected concrete from the B Electrical Tunnel that the meallq I asticity was outside the range calculated and expected using AI rel ship.

The relationships that m ot0r in v for ASR-affected concrete, depending on the severity, are located i fol in s of ACI 318-71:

(i) Relationsh .3 CI 318-71 to calculate modulus of elasticity of concrete, (ii) ip hap telatio 1 of ACI 318-71 for design for shear and torsion that are xpre a a f 4/f',. As an example, the equations to calculate nominal pe i I ear carried by concrete, v., in Section 11.4 of ACI 318-71. Also, f AR 81434, Revision snC( 1.

(i al ed to estimate tensile strength of concrete, ft, for design of n s d embedments. Typically, it is estimated as ft = 4'/f'c. See Section of 81434, Revision 1.

(, R on ips in Chapter 12 of ACI 318-71 that are used for the calculation of rein ment development length, Id,which is design for bond between reinforcement and concrete.

(c) T e NRR staff notes that the licensee's Prompt Operability Determination (AR 581434, Revision 001) for the B Electrical Tunnel (AR 581434, Revision 1) is based on the fundamental assumption that the empirical relationships (based on non-degraded concrete) in the ACI 318 code discussed in (b) above are not affected and remain valid for the ASR-degraded concrete. Therefore, the licensee must address the validity of this assumption for the ASR-degraded structure and its impact on the design basis evaluation in the final resolution of the ope ability determination.

ED ISIO L- Cl 0 Y ITO G& M

(d) The presence of ASR in the affected concrete structure results in the reduction or change in the mechanical properties (namely, elastic modulus, poisson ratio, compressive strength and tensile strength) typically used in analysis/design of concrete structures. Therefore, the structural analysis (global and local) and design evaluation of the ASR-affected structure under design basis loads and load combinations should be based on actual measured material properties and how these propertie ere affected by ASR expansion rather than assumed or standard properties or relati% S.

Consistent with the guidance in Section 5.3 "Conditions requ:ring eS tio f ACI 349.3R, this requirement is also reflected in Section 5.3 in Atta 0 implementing procedure EDS 36180, Revision 1, for the struct Im ogram at Seabrook. The licensee should also establish whether or not th lu of the mechanical properties of the ASR-affected concrete ar e normal range of values generally observed for concrete.

Question 3:

What is the appropriate ACI standard to be used f g te core sampling assessing in-situ ASR degradation for the contro"in t ns, numbers, frequency of sampling in the future, etc)?

[Discussionby Region 1: While this is a .ee d on staff questioning, we need to know the regulatoryor other basis use of e r of two applicablestandards or other more appropriatestandard.One s is A used by NextEra for correlationto penetration resistanceprobe da dd'* t C/ 214 (version 1965 is referenced in the UFSAR section 3.8.2.4). tItsh b h d hat a laterrevision of ACI 214 (ACI-214.R-

03) provides for additi nal sam rd to ach ve a 95% confidence level. The ACI 228 appearsto be met b s less sampling. These standardswere developed for generaldesign an nstruc ncrete structuresfor non-nuclearapplications.

Technical researcha need in rder to determine their relevance for nuclearapplication in which the stru es reinforced with rebar.]

Response

The app i plan for core sampling of degraded concrete depends on the obj cope f th investigation, the type of testing, and the role of the specific testing Sres t edegradation being addressed. In general, the purpose of an investigation for alI ea on (ASR) degradation of important-to-safety concrete structures at Seabrook is to ga e sary information and data to determine the cause and fully characterize, evaluate and ma e the effect of ASR (diagnosis, prognosis and appraisal) on the design basis of the affected structure, both in the short term and long term. The diversity of mix characteristics as well as the range of damage and environment must be reflected in the sampling so that the sample is representative of the variability consistent with the objectives of the investigation and testing. Appropriate statistical methods should be used, where possible, for reliable evaluation of variations and interpretation of test results. The following guidance is provided with regard to standards that can be used for sampling determinations.

R ER ISIO

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' RA OR G M

(a) The basic standard that provides guidance on statistically-based (probabilistic) sampling plan of hardened concrete in existing construction is ASTM C823 "Standard Practice for Examination and Sampling of Hardened Concrete in Constructions." This standard references among others: (a) ASTM Practice E 105 for recommendations on characteristics and minimum standards for developing a probability sampling plan in relation to the objectives of study, and practical constraints; (b) ASTM Practice E 122 for recommendations on sample size for samples to be subjected to tests yiel g a numerical value, based on the degree of confidence desired to be placed on the resultd (c) Test Method ASTM including C 42 preparing, obtaining, andprocedures for sampling testing ores for securing drilled fromsamples concreteof e eJ A strength, splitting tensile strength and flexural strength determinai so oncrete.

Pursuant to 10 CFR 50.65 (Maintenance Rule), the licensee i the Structures Monitoring Program at Seabrook in accordance with sta I cedure, EDS 36180, Revision 1, "Structures Monitoring Program." r b is for ASTM C823 is that the licensee's procedure EDS 36180 for the St u i g Program at Seabrook Station references ACI 349.3R "Evalua istin u ar Safety-Related Concrete Structures" for evaluation criteria for c E .5.3 - "Invasive testing" of ACI 349.3R-02 states in part that "... Fu rtWO. -n on material sampling and petrographic analysis is contained in ASTM 3 d C 856. Similarly to NDE, the number of samples or tests taken and r the ained results are also important."

Also, Chapter 5 of ACI 349.3R stat e a luations in which the primary goal is to determine material prgpertie re ri pies r testing, the provisions of ASTM C 42 and C 823 should be followld defin mber and location of sampling points."

ACI reports including of Existing Nuclear Safety-Related Concrete Structures," ACI 214., )Ja'hing Cores and Interpreting Compressive Strength Results," A ilevlethods to Estimate Concrete Strength," ACI 437R "Streytgth Ea rg qoncrete Buildings" all reference ASTM C823 as the underlyin sta-3 re ith/egard to retrieving samples for testing and test samples'* ermsin stif g concrete structure to be subjected to invasive testing methods.

(b) ACI . Methods to Estimate Concrete Strength" provides guidance, incl nt use of methods to estimate the in-place strength of concrete in e xsber; penetration resistance, pullout, break-off number, ultrasonic pulse eb berenetration based on in-place non-destructive test methods such as urity etc. In this Report, the principal application of in-place tests is to mat the compressive strength of the concrete. These nondestructive tests do not dir y easure the compressive strength of the concrete in a structure. Instead, they measure me other property that can be correlated to compressive strength and the general approach is to correlate results of in-place tests performed at selected locations with strength obtained by testing of corresponding cores. ACI 228.1 R presents procedures for developing the relationship to estimate compressive strength from in-place tests, factors to consider in sampling and planning in-place tests and statistical techniques to interpret test results.

LB IN OMCO T)liýýN

As part of the initial (preliminary) condition assessment (Reference EC 145305) of the B Electrical Tunnel structure for ASR, the licensee performed penetration resistance tests (PRT) and concrete core testing for estimating the in-situ compressive strength for the purpose of establishing if the in-situ compressive strength complies with strength used in original design. The cores were also used for petrographic examination for the prsence of ASR degradation. ACI 228.1 R is an acceptable standard to use for guidance oncre ~C-0nNWImt [wijr3]: Be more cautious In sampling to establish the correlation between the PRT penetration measur en (or endorsing this standard: (I)the correlations do not account for ASR degradation and potential measurement from other in-place testing methods) and compressive strn I is also nonuniform variations in material properties; appropriate standard for implementing, including sampling, non-destre in- ng and (ii) NextEra gave up on this method since methods described therein. ACI 228.1R is also referenced in ACI 349. ong the PRT - core data did NOT correlate.

the implementing documents referenced in the licensee standard,1d1 180, Revision 1, "Structures Monitoring Program" at Seabrook Station.

(c) ACI 214.4R-03 "Guide for Obtaining Cores and Interpret 0o e tren h Results" includes guidance and methods for determining an in- t pecified concrete design compressive strength to assess the structur I pacity n sting structure based on testing of cores. The guide presents r s for o mm and testing the cores, including determining sample size, an n ults with a statistical basis that is consistent with the ACI 318 criteria.

If testing of cores are performed to a in-place design strength of the concrete for use in design evaluati n rmination should be made based on statistical evaluation of strength t suets c ist nt with concrete quality provisions in Section 4.2 and 4.3 of ACI 31 -7 hich i f-record for Other Category 1 Structures at Seabrook Sta , in ing t B Electrical Tunnel. Therefore, if the purpose of core testing is to dete a ace design compressive strength, f'c, (different from that used ing inal r e in the design evaluation of the ASR-affected structure, then AC s a riate guidance to use. The regulatory basis is that the st tistical bas' the guidance is consistent with the statistical basis of the concr te quai l ation acceptance provisions in Sections 4.2.2 and 4.3.1 thru 4.3.3 Iso r these sections) of ACI 318-71, which is the construction code-o -re the egory I Structures" at Seabrook Station, including the B Electri . A ted in Section 8.4 of ACI 214.4R-03, the confidence level used to esti t eq specified strength should be 95% for important-to-safety structures lin core testing that may be used to determine other types of in-place strength as 4 ar strength which is a function of tensile strength) of the degraded concrete for ign evluation should have a similar statistical basis, as much as possible. The licensee Sdoument the technical basis for adequacy of sampling used for tests used to determine n-place material properties of ASR-degraded concrete for use in analysis and design for the design basis evaluation of the degraded structure.

It should be noted that the statistical basis for concrete quality evaluation in the ACI 318 Code used for establishing the required average strength to assure attainment of the specified design compressive strength level, f'c, used in structural design stage, is based on ACI 214R. ACI 214R "Evaluation of Strength Test Results of Concrete" provides

(\PIREpE1lSlO4OF51,1(4L US QNLY/

N~rRCRM~kCO ýEN

guidelines and procedures for the statistical evaluation of concrete strength tests applicable to the compressive-strength test results required by ACI 301, ACI 318, and other similar specifications and codes. However, the focus of ACI 214R is with regard to molded cylinder strength tests of concrete sampled from the truck discharge or batch during original construction pours to verify compliance to the construction specifications, and not on existing structures. However, the statistical concepts therein could applied to the analysis of other concrete test results and similar concepts are applied in ACI 214R fo valuating core strength results.

(d) Although the licensee has made available documents that are contra recommendations, the licensee has not yet made available a firm document (of Appendix B quality) that it is being implemented for tp Vt nsively I

addressing the ASR issue in the short-term and the long-te should make available such a Test Plan (not contractor/consultant re e ti the immediate future. Core sampling or other methods of testing wo e o stimate the severity, expansion-to-date, potential for future expan n, on i tr nds, reinforcement assessment, etc., for the design evaluation and ai n e t of ASR issue. It is recognized that obtaining large numbers of ra m.i rict compliance with sound statistical procedures may not be always p phy 11 Conng may have to be limited to a controlled number of samples to inimize any mental effects on remaining structural performances. It is important tO t noue co rete representative of Comment

-wjr4]: Can we better define this?

difference (variability) in materials ,tr' su as changes in cement, For the ET, we now have a wall with (12 + 20=)

32 cores removed. When does it become a aggregates, and alternate mix pro ions.. ng environmental conditions including -problem?

loading, weathering, exposure iisture, dge influence the behavior of the concrete and should be considered ,ves tion. The licensee should consult ACI 349.3R and specialized literature AS u o in References 30 and 31, or other expert sources on the issue for g in mpling for specialized tests. Also, it should be emphasized that thh ou ake the most effective use of removed core samples to obtain the max. m da a Id enable proper characterization of the concrete. For all testing, t 'n sho proide the technical basis and justification of the adequacy of their sa Pl*n s nt with the objective of the testing in regard to addressing the im. act o*t S gr on the design evaluation of the affected structure. This tec ni s ould documented in the test plan and/or the engineering evaluation tha s i n/data from the testing.

u Di pe rm adequate laboratory tests for core sampling, including appropriate para er obtained along with laboratory test conditions?

[Discussion by Region 1: Also, during the course of this review, please identify the need for any in situ testing of control building conditions including appropriateparametersto be obtained such as temperature and humidity along with test conditions for now and in the future. Also, provide guidance on where and how much rebarshould be exposed in orderto assess the effect on rebarfrom the ASR issue.

6 FOyTENUBRA 1iRTORM1NG &C9MM

No tensile strength testing is being performed on the concrete core samples and this question was raisedin the RAI in terms of how shear capacityis being determined. However, the Region I staff believe that the specific parameterof tensile strength of concrete may not be sufficiently accurate and therefore relevantin a constrainedstructure. As the pressure load from the ASR gel increases,that load may be transferredto the rebar.Available research in this areaappears to be conflicting. The UFSAR for containmentassume concrete in reinforced systems provide no tensile strength.

A core sample with ASR does not representthe forces containedin the st re b s this test, in particular,elastic rebound is not considered.Forsplit tensile te pls, the frictional influences in the test itself are not accommodated. The *r'ona further exacerbatedby the standardlaboratorypractice of placingplywood on s faces of the tensile specimen to stop it from rolling off the test stand, thus res e ansion of the sample.]

Response

(a) The licensee has not made available to the I Ian th it is implementing to address the ASR issue at Seabrook. I rto e an objective assessment of the testing, the licensee should finalize nd b in the immed ate future, for NRC review a firm and comprehensive T I tr ctorconsultant recommendations) for testing concrete for the effec t k n support of the interim and long-term design basis evaluations fe d cture an ing management of the issue.

This should be an Appendi B aIi d m t. This an should provide the different types of testing beinglpe e t be erformed, the purpose of each test and how the results would be in t e ing evaluation of the structure and aging management of the d n.

(b) As discuss d i e ues 2, since the presence of ASR in the affected concrete st, u s Its e reduction or change in the mechanical properties (namely, tic m isson ratio, compressive strength and tensile strength) typically nal esign of concrete structures, the structural analysis (global d esi ation of the ASR-affected structure under design basis loads oa s should be based using actual measured mechanical material e hed by testing of concrete in the affected structure.

c) of t Electrical Tunnel are so designed that shear forces are carried entirely the cre~' with no shear reinforcement. Review of drawings 9763-F-1 11342, -

1 343 and - 11345 and Calculations CD-20 (original design calculation) and C-S-I-59, Rev. 0, for the Electrical Tunnel Walls show that there is a vertical and horizontal lay of reinforcement on each face (inside and outside). There are no shear reinf rcement ties or anchored stirrups through the thickness tying the two layers (this is a Class 3 reinforcement detail per Chapter 8 of Reference 30, and provides the least concrete confinement of the three details). Further Calculation CD-20, Appendix A (original design calculation) and C-S-1-10159 (for operability determination) that evaluated the wall for tranverse shear used higher concrete strength of 5458 psi(based on 28-day cylinder tests) and 4790 psi (based on core testing), respectively, in lieu of the RE CISI L-OFFI US LY B3 ST

_. RI C=0OMNT)

design compressive strength of 3000 psi, to qualify the wall for shear. As discussed previously, the tensile strength, bond strength and the shear strength of concrete could also be reduced by ASR-degradation. Tensile strength affects shear capacity of concrete and also its ability to support the loads of the attached embedments and anchorages supporting safety-related components. Therefore, it is critical that the licensee establish the actual shear capacity of the affected concrete for the design evaluation. The licensee should perform appropriate testing to establish data for evalu t* the shear strength and bond strength of the affected-concrete and for evaluating pac t of anchorages and embedments for important-to-safety component i a concrete. The licensee should provide technical justification for e of the testing and evaluation methods they choose to use.

(d) The coarse aggregates used in Seabrook concrete is cru s ne aggregate (Reference 11). In its response to license renewal Rk a10 1-1 (Reference 20), the licensee indicated that alkali reactivity testsA egates would be performed per ASTM C 1260 "Mortar Bar Expansio T sf - o uration testing (16 Commnent [wir]: Delete "conducted" days), ASTM C 1293 "Concrete Prism" - long dt estin 1-2 uration years), screening and other test S-ort tests. In this regard, the staff notes that th is known to provide both false positives n ives (Reference 32), and expert opinion seems to indicate that this test m identify ASR reactivity in granite aggregates. The licensee sh ider d evaluate the potential limitations of C 1260 test, especially in deteAo r in ranite aggregates, in selecting the short duration test method. ap ing a rt duration test (14 to 16 days) such as the ASTM C 1567 "Standard st thod f rmining the Potential Alkali-Silica Reactivity of Combinatio C ntiti terials and Aggregate (Accelerated Mortar-Bar Method)" e 0 temate test option.

(e) In the appraisal for degradation, it is important to measure the expansion to d in or ate the severity of the current degradation. The staff understand a Iicn is conducting in-situ surface crack mapping to arrive at a Cracking T ' hould also consider performing the Stiffness Damage T t(R n 1), h is an important laboratory mechanical core test for structural as e to ss internal damage due to ASR, and (ii)to assess the expansion le re e It is of particular value in evaluating the condition of structural ointernal damage occurs through the thickness or depth, but visible ishs sed by heavy reinforcement.

S xpansion and rate are a function of humidity and temperature conditions to ich he concrete is exposed. It is important to measure these conditions on the ASR cted concrete. The actual temperature and humidity conditions seen in the field may need to be simulated in expansion tests to assess current and future expansion potential.

The licensee should plan for "in-situ" monitoring of actual structure conditions such as temperature and relative humidity/moisture conditions, in addition to crack mapping.

Oý ý LU NL TERN RANTRMI C ENl

Question 5:

Is the current NextEra structural monitoring program sufficient to discover or predict additional ASR damage to structures prior to the damage negatively impacting the design basis of the structure?

[Discussion by Region 1: To date three building assessments have been com Ied: control building, the containment, and the containment enclosure building. These as s ts were initiated as a consequence of discoveries made preparing for a renewed Ii ap- tij.

These discoveries should be reflected in enhancements to the programs re f the Maintenance Rule. The Region requests NRR assistance in evaluatin ec ptability of NextEra's programs to maintain the integrity of the safety rela stru s

Response

The response is based on review of the [current] version o e Ii e' mp menting document for its structures monitoring program that w av e to the NRC staff, which is the NextEra Energy Structural Engineering StanIT* cedure EDS 36180, Revision 01, "Structural Monitoring Program," wine d of 3/15/2011. This document states that the procedure provid'u ebn uct of the structural condition monitoring program pursuant to 10 CFR 50 e ai t nce Rule, to provide reasonable assurance that those structures are ca f luir intended functions. This document references Regulatory Guide 1.160, nitoying t e iveness of Maintenance at Nuclear Power Plants." of the licensee' pie ti ument for the Structural Monitoring Program (EDS 36180, Revision 1) inco a p am for condition assessment of concrete subject to groundwater intrusio c tes: "Aprogram to monitor the presence of ASR and the rate of change of crte h I properties will be conducted at intervals of no more than five years. d a e similar to that outlined in EC 250348. The areas chosen shall be based vi us and potential ASR areas identified during Structural Monito ' g Pr dow The ASR assessment program shall be documented inthe Structur I r ro h Form 2 (Structural Deficiency Report - Initial Discovery),

Form 3 uct I cy Report - Engineering Staff Review) and Form 4 (Structural Deficien wup Inspection)." Attachment 2 of the procedure identifies gro t rusio areas.

T t det ination made in the Prompt Operability Determination (POD) for the Ele I Tunnel (AR 581434, Revision 001) is: "Affected SSC should be considered Comment [wjr'6]: Reword - see suggested rewrite.

Opera t degraded, and below Full Qualification. Continued Operability is based on the provisions f RIS 2005-20." For this determination, based on the guidance in regulatory Position Comment [wjr7T: For this determination, based on the guidance in regulatory Position C1.5 in RG 1.160 for monitoring structures under the Maintenance Rule, the ASR-affected C1.5 in RG I 160 for monitoring structures structure being degraded that it may not meet its design basis would be required to monitored in under the Maintenance Rule, the ASR-affected structure, being degraded such that it may not accordance with Paragraph (a)(1) of 10 CFR 50.65 (against performance criteria or goals) as meet its design basis, would be required to be opposed to paragraph (a)(2) condition monitoringl. The structure would continue to be monitored in accordance with Paragraph (a)(1) monitored in accordance with Paragraph (a)(1) until the degradation and its cause have been of 10 CFR 50.65 (against performance criteria or goals) as opposed to paragraph (a)(2) corrected. Further, for structures monitored in accordance W4*h Paragraph (a)(1), additional condition monitoring.

P ECAI FF1 LS' O EN f0 ALVNSVM& E

degradation-specific condition monitoring and increased frequency of assessments would be required until the licensee's corrective actions are complete and the licensee is assured that the structure can fulfill its intended functions and will not degrade to the point that it cannot fulfill its design basis.

EDS 36180, Revision 01, only refers to ACI 349.3R for evaluation criteria for concrete. The evaluation guidelines in ACI 349.3R focus on commonly occurring conditions arare not meant to be all-inclusive. While ACI 349.3R is a good reference for evaluation of corm degradations of concrete, it does not provide specific or detailed guidance valung f*

ASR. The document needs to incorporate specialist literature or specialize io at provides guidance specifically for the long-term ASR issue.

It is recognized that the licensee has a detailed investigation and luation in progress for addressing the ASR issue at Seabrook both in t a ng term, including prediction of the potential for future degradation. f the bove discussion, the licensee's current structural monitoring program shoul enha the following respects for the ASR degradation-specific condition rno in o to be sufficient to discover or predict additional ASR damage to strum ge negatively impacting the design basis of the structure.

(a) The scope, procedure, personnel qu s an results of e 2011 detailed ASR walk-downs and extent of condt i* vw m incorporated into the program as ASR-specific baseline informatn for use )mparison during future monitoring and testing. ý (b) The program should ha orate the applicable results of the ongoing testing and the detail e in evaluation of the ASR issue at Seabrook, currently scheduled to be t nsee in March 2012. The program should be updated, as ap riater management related to ASR in the affected structures based on thr n eng aluati results during the remaining duration of its ope tin rse (c) The h -ou-le further enhanced, as applicable, based on the results of the lo te I/or evaluation that would be in progress beyond March 2012.

gra ould be updated to include degradation-specific guidelines for inspection a 'toring required to detect ASR degradation for structures not affected so far.

ep am should also be updated to include ASR degradation-specific guidelines and q eri for inspection and monitoring of ASR-affected structures including increased uen y assessments for condition monitoring of areas identified to be affected by A R.

(e) The staff recommends that the licensee update the references for evaluation criteria and examination guideline for concrete in Sections 4.1 and 5.0 of Attachment 1 (Structures Monitoring Program Inspection Guidance) to EDS 36180 from ACI 349.3R-96 and ACI 201.1 R-02 to the latest versions, which currently are ACI 349.3R-02 and ACI 201.1 R-08.

In Section 4.1 "General Examination Guidelines for Concrete," the licensee should IEDR IS B L-O1 IA G& ON ifV RALBR~ui ORIA G& MOENN

specify specific examination guidelines for ASR, based on their operating experience with the issue.

4.0 REGULATORY REQUIREMENTS The regulatory requirements pursuant to 10 CFR Part 50 and guidance ap licable to addressing the ASR-degradation of concrete in Other Seismic Category tructures at Seabrook, which includes the B Electrical Tunnel, can be found in the folr ng regulations and regulatory documents.

(a) 10 CFR 50.65, Maintenance Rule, as it relates to monitori the and condition of structures, systems, or components (SSCs) in a s dcient to provide reasonable assurance that these SSCs are ai heir intended functions. When the performance or condition of n t tablished goals, appropriate corrective action shall be tak, (b) 10 CFR Part 50, Appendix B, as it relates t e ality a ra ce criteria for nuclear power plants.

(c) Criterion XVI "Corrective Action" of 1I dix B as it relates to implementing a corrective acti n lr o as re that significant conditions adverse to quality, such as f 2-Jfu , deficiencies, deviations, defective material and equipment, an n-con ance are promptly identified, cause addressed, and correct .

(d) 10 CFR Part 50, ndi Design Citerion (GDC) 1 as it relates to structures, systes m ents being designed, fabricated, erected, and tested to quan c ensurate with the importance of the safety function to be perfo (e1 art 5 A, GDC 2, as it relates to the design of the safety-related str e Withstand the most severe natural phenomena such as wind, oo a earthquakes and the appropriate combination of all loads.

1 0, endix A GDC 4, as it relates to safety-related structures being pr y protected against dynamic effects, including the effects of missiles, pi hipping, and discharging fluids, that may result from equipment failures and from vents and conditions outside the nuclear power unit.

NUREG-0800, Standard Review Plan, Section 3.8.4 - Other Seismic Category 1 tructures (h) Regulatory Guide 1.160, Revision 2 (March 1997), Monitoring the Effectiveness of Maintenance at Nuclear Power Plants JO'ED WA I ON INTOFýFIC AIN US CO L EN

5.0 CONCLUSION

Based on its review of TIA 2011-013 request, available documents, literature, information obtained at the NRC inspection during the period 9/26/11 - 9/30/11, and within the limitations of information available, the EMCB staff has provided reasonable technical guidance in this TIA response with regard to the issues related to the ASR degradation of concrete at Seabrook raised by Region 1 in the five questions in the TIA request. Specific technical gq ance to the issues is provided in the responses to the questions. In order to enable staff to e a fuy objective assessment, the licensee should make available to the NRC in t f its firm Action Plan and Test Plan (which should be Appendix B quality tech uI 5) that it is implementing to comprehensively address the ASR-degradati i ant-to-safety concrete structures at Seabrook Station.

6.0 REFERENCES

Note: References 1 thru 4-2 13 iare licensee documents ma availa o licensee's Certrec Comment [wJrS]: EDS 36180 was also a website. ISeabrook doc provided for staff review (Certrec).

1. Calculation C-S-1-10159, Rev. 0, 'B' Ele un Transverse Shear Evaluation Supplement to Calculation CD-20

2. Calculation C-S-1-10150, Rev. 0 Modulus of Elasticity -'B' Electrical Tunnel Exterior Walls

3. Calculation CD-20-CALC ol a Diesel enerator Building Design of Material and Walls below grad El el and the Control Building (Original Design

4. Drawings for C oBu crete (Electrical tunnel) 9763-F-1 11342, 9763-F-111343 and -111

5. Ac on ue R) 34, Revision 000, Prompt Operability Determination Reduced Co ie elow Grade in 'B' Electrical Tunnel Exterior Walls.

6. n t ) 581434, Revision 001, Prompt Operability Determination Reduced r r st Below Grade in'B' Electrical Tunnel Exterior Walls 145 5, Condition Assessment of Control Building Concrete

8. 574120 Preliminary Test Results of Control Building Concrete

9. AR 81434 Test Results from Control Building Concrete Modulus Testing (Results of petrographicanalysis of 4 of the 12 CB cores identified the presence of moderate to severe ASR in the concrete)

10. EC250348, Revision 002, Condition Assessment of Building Concrete (F TE RAIN9+ MING MMENT)

11. AR 01625775, Revision 000, Petrographic Analysis of Concrete Cores from Seabrook Station

12. System Description No. SD-66, Revision 2, System Description for Structural Design Criteria for Public Service Company of New Hampshire, Seabrook Station, Unit Nos. 1 and 2, 3/02/84.

13. Structural Engineering Standard Technical Procedure 36180, Revisio '0tructural Monitoring Program," NextEra Engineering Department Standard, 1 1

14. Seabrook UFSAR, Revision 12, Section 3.8.4, Other Seismic 0eg res

15. NUREG-0800, Standard Review Plan, Section 3.8.4 - ot ory 1 Structures

16. Regulatory Guide 1.160, Revision 2 (March 1997), onit in h ife iveness of Maintenance at Nuclear Power Plants

17. RIS 2005-20, Revision 1 dated April 16, a e 1I"NRC Inspection Manual, Part 9900: Technical Guidance, Operabi a d Functionality Assessments for Resolution of Degr on ormi Conditions Adverse to Quality or Safety."

18. Letter dated 6-29-2011 o Ri ard PI SNRC, to Mr. Paul Freeman, NextEra Energy Seabrook, LLC ue or Ad i nal Information for the Review of Seabrook Station License Rene p *ti lci Ily Followup to RAI B2.1.31-1 on pages 2-

3) (ML11178A3380)

19. NextEra E erg tter - 54to USNRC dated 8-11-2011, Docket No. 50-443, Seabrook 'o po to Request for Additional Information - NextEra Energy Seabroo nseole Application Request for Additional Information - Set 15

("ons Follow-up to RAI B.2.1.31-1 on pages 5-8)

20. rn er SBK-L-1 1063 to USNRC dated 4-14-2011, Docket No. 50-443, r i Response to Request for Additional Information - NextEra Energy ok e Renewal Application Request for Additional Information - Set 13 Ily ponses to Follow-up to RAI B.2.1.31-1 and -2 on pages 4-7) 111 A1 0)

21. Era Energy Letter SBK-L-10204 to USNRC dated 12-17-2010, Docket No. 50-443, eabrook Station Response to Request for Additional Information - NextEra Energy eabrook License Renewal Application Aging Management Programs (Specifically sponses to RAI B.2.1.31-1, -2 and -3 on pages 36-39) (ML1035405340)

22. ACI 318-71, Building Code Requirements for Reinforced Concrete (with Commentary)

23. ACI 349.3R-02, Evaluation of Existing Nuclear Safety-Related Concrete Structures i

24. ASTM C 823/C 823M - 07, Standard Practice for Examination and Sampling of Hardened Concrete in Constructions.

25. ACI 228.1R-03, In-Place Methods to Estimate Concrete Strength

26. ACI 214R-02, Evaluation of Strength Test Results of Concrete

27. ACI 214.4R-03, Guide for Obtaining Cores and Interpreting Compr *ve t Results

28. ACI 228.2R-98 (Reapproved 2004), Nondestructive Test Metho r I ation of Concrete in Structures

29. ACI 437R-03, Strength Evaluation of Existing Buildi

30. Structural effects of alkali-silica reaction - Tec *a idan n t appraisal of existing structures, The Institution of Struct don, UK, July 1992 and Addendum, April 2010

31. Report on the Diagnosis, Prognosis, atio f lkali-Silica Reaction (ASR) in Transportation Structures, US D of o ation, Federal Highway Administration, January2010

32. PCA R&D SN2892b, Ev ion Ikali ilica Reaction (ASR) Mortar Bar Testing (ASTM C 1260 and AS 1 urability Subcommittee - Concrete Technolog Y, Portland Cement Asso 00

33. Popovics, S., gth d Properties of Concrete - A Quantitative Approach, John Wiley Inc., 8.

34. Nilson, in esign of Concrete Structures, Eleventh Edition, McGraw-

35. a .ulay, Reinforced Concrete Structures, John Wiley & Sons, 1975.

( RED I OýNA - FICI EQ0 ýL FOR RNAL INS M T