ML101600292

Summary of Meeting with NextEra Point Beach, Llc. Response to GL 2004-02

ML101600292
Person / Time
Site:	Point Beach
Issue date:	07/08/2010
From:	Justin Poole Plant Licensing Branch III
To:	Point Beach
beltz T, NRR/DORL/LPL3-1, 301-415-3049
Shared Package
ML101930305	List: ML101600292
References
GL-04-002, TAC MC4705, TAC MC4706
Download: ML101600292 (24)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 July 8, 2010 LICENSEE:

NextEra Energy Point Beach, LLC FACILITY:

Point Beach Nuclear Plant, Units 1 and 2

SUMMARY

OF MARCH 17,2010, MEETING WITH NEXTERA ENERGY POINT BEACH, LLC, REGARDING RESPONSE TO GENERIC LETTER 2004-02 (TAC NOS. MC4705 AND MC4706)

On March 17, 2010, a Category 1 public meeting was held between the U.S. Nuclear Regulatory Commission (NRC) and representatives of NextEra Energy Point Beach, LLC (NextEra, licensee), at NRC Headquarters, One White Flint North, 11555 Rockville Pike, Rockville, Maryland. The purpose of the meeting was to discuss NextEra's planned approach to address the NRC's request for additional information (RAI) dated March 3, 2010 (Agencywide Documents Access and Management System Accession No. ML100570321). The RAI pertains to information submitted by NextEra in response to Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized Water Reactors," for Point Beach Nuclear Plant, Units 1 and 2.

The licensee's draft response is attached as Enclosure 1. A list of attendees is attached as.

The following summarizes the outcome discussed for each of the proposed RAI responses:

RAI1 The licensee is re-evaluating their test protocol, which may affect debris assumed to reach the strainer, which could cause additional evaluation. The licensee intends to follow the safety evaluation (SE) for NEI 04-07 and the NRC's March 2008 review guidance with respect to this area.

The licensee should show the installed configuration is at least as robust as the Ontario Power Generation test that supported 5.45 D for CalSil. The licensee will clearly state that the zone of influence (lOI) for NUKON will be 17D (remove note and asterisk). The licensee will add that the lOI for inorganic zinc is 10D.

The licensee's response is acceptable as is.

RAI4 The licensee's response is acceptable as is.

- 2 The licensee's response is acceptable as is.

RAI6 The NRC staff has an action to provide feedback on what the staff has viewed as acceptable regarding fraction generated and eroded for CalSil within the ZOI. More justification is needed for the current numbers if the licensee chooses to stick with the current numbers. The licensee should clearly state that 15 percent applies to initially generated material. The licensee should justify any assumption that small and large pieces would transport to inactive locations.

The NRC staff has an action to verify that the 50 percent small debris transport assumption is acceptable.

This is an open item until the licensee decides on and communicates with the NRC staff regarding its path forward. Asbestos 100 percent fines would be acceptable, as would Alion NUKON erosion testing. The licensee should refocus its response on transporting, not testing.

This is an open item depending on the licensee's test plan decision. The NRC staff stated that a decision to not credit settlement would render this RAI moot.

RAI10 The licensee should state that they are not crediting debris trapped in eddies. The licensee needs to verify that this is their intent and add it to their response.

RAI11 The licensee's response is acceptable as is.

RAI12 This is an open item depending on the licensee's decision on retesting. The licensee will then determine which assumptions to credit and will justify those it does credit.

RAI13 The licensee's response is acceptable as is.

- 3 RAI14 This is an open item depending on the licensee's decision on path forward on testing. The NRC staff stated that a decision to not credit settlement would render this RAI moot.

RAI15 This is an open item depending on the licensee's decision on path forward on testing. The NRC staff stated that a decision to not credit settlement would render this RAI moot.

RAI16 If the licensee decides that it will no longer credit settlement, then the licensee needs to state that it will retest with a protocol that does not credit settlement and that is consistent with the March 2008 review guidance, otherwise, further discussion is needed.

RAI17 This is an open item depending on the licensee's decision on path forward on testing. The NRC staff stated that a decision to not credit settlement would render this RAI moot.

RAI18 The licensee will provide detail on how procedural controls will prevent structural issues, if structural criteria remain limiting.

RAI19 b) The licensee will provide additional details on how amounts of miscellaneous debris could reach the strainer, and how that affects sacrificial area assumptions.

c) This is an open item depending on the licensee's decision on path forward on testing. The NRC staff stated that a decision to not credit settlement would render this RAI moot.

d) This is an open item depending on the licensee's decision on path forward on testing. The NRC staff stated that a decision to not credit settlement would render this RAI moot.

RAI20 The licensee will send in calculations and sketches to clarify its answer.

RAI21 The licensee will respond similarly to RAI 1, but will include a statement that transport will be done per the SE on NEI 04-07.

RAI22 The licensee's response is acceptable as is.

- 4 RAI23 The licensee's response is acceptable as is.

RAI24 The licensee's response is acceptable as is.

Following the discussion on the specific RAI responses, the licensee discussed possible ways to avoid removal of fibrous insulation from the regenerative heat exchanger due to asbestos and high dose levels. The NRC staff stated that a limited-offset break may be a possible path forward but additional information would need to be provided for the staff to evaluate.

The licensee and the staff then discussed the need for a follow-up call once the licensee had made their decision on settlement credit. This call would be to notify the NRC staff of the licensee's plan with regard to settlement credit, a proposed date for revised draft RAI responses, next steps for rationale to retain asbestos around the regenerative heat exchanger, and a timeline for further meetings.

No members of the public were in attendance. No Public Meeting Feedback forms were received.

Please direct any inquiries to me at 301-415-2048, or Justin.Poole@nrc.gov.

Justin C. Poole, Project Manager Plant Licensing Branch 111-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-266 and 50-301

Enclosures:

1. Licensee Draft RAI response

2. List of Attendees cc w/encls: Distribution via Listserv Draft RAI Responses

DRAFT RESPONSES TO GL 2004-02 RAls POINT BEACH NUCLEAR PLANT On January 4, 2010, an e-mail was received by NextEra that contained a draft Request for Additional Information on GL 2004-02 for Point Beach Nuclear Plant (PBNP). The draft was subsequently discussed during a teleconference on January 11 between representatives of the NRC and NextEra.

There are outstanding questions associated with the testing protoc to assess the settling behavior of debris in the vicinity of the containment sump straine Until more detailed assessments of the impacts can be com!J)let e issues fully evaluated, and firm schedules developed, NextEra cannot formally re$pond to stions that pertain to testing protocols. Accordingly, the draft response addr~~es the RA

",,,,tinn,,, that are not related to previously completed settling behavior of debris.

Attachment Page 1 of 16

NEXT ERA ENERGY POINT BEACH, LLC RESPONSES TO RAI QUESTIONS Question 1 Please provide an updated debris generation evaluation based on the insulation configuration determined to provide an acceptable overall head loss evaluation. The licensee should provide the information requested in the content guide for the debris generation area. For areas where the evaluation and assumptions are unchanged, the licensee may state that there are no changes from the original debris generation evaluation provided to staff for review.

NextEra Response NextEra is evaluating the recent NRC position that insuttJc:l d data is available to justify crediting settling during strainer testing. ShOUI~:rJ'~xtEra deter that retesting the strainer with a protocol acceptable to the NRC tha(gees not credit settliri equired, this RAI would be resolved.

Question 2 Please provide the zones ofinfluence al debris generation calculation. If the ZOls are not those specified by the etyf;valuation !j'~ on NEI Guidance Report 04-07, provide a justification for the ZOI used. Tf;I#, folio issues'sli/;rquld be addressed for any ZOls that use the Westinghouse testing or other;~~sting th qS [1ofl3~~n evaluated by the NRC

~ff NextEra Response The following table sum calculations most recently analyses:

rlz cllti d1;.1:1

~I~

Q~§ of influ~nye (lOis) used for the debris generation The sam~ ?:e>ls are expected to be used in future iTDebrls?llvpe lOI (LID)

Transco RMI R

Asbestos 17 ISil 5.45 lag.,

17 N

'~J; 17*

Miner ; 'Wool 17 Temp Mat wI wire mesh retainer 11.7 Qualified Concrete Coatings 4

Qualified Steel Coatings 10

• NextEra has committed to remove all Nukon and other fibrous insulation from major components and piping within the ZOI of postulated large diameter pipe breaks. At the current time, the only NRC accepted ZOI for NUKON on major components is 170. Design, procurement, and planning is proceeding to remove Nukon from within a 170 ZOI. However, if an applicable reduced ZOI is reviewed and endorsed by the NRC with sufficient time to reduce the scope of NUKON@ insulation replacement during the currently committed outages, NextEra may elect to reduce the replacement efforts in order to minimize ionizing radiation exposure to the personnel performing the removal and Page 2 of 16

replacement work. To date, insulation replacements involving -35% of the scoped work on a single unit have resulted in a combined exposure of over 20 Rem to personnel.

With the exceptions of the lOis for qualified coatings, each of the above lOis have been endorsed by the NRC in NEI 04-07, Volume II. The bases for the lOis used for qualified coatings on steel and concrete was provided in previous submittals, and rests on applicable results from "JOGAR" testing.

Question 3 The set (9 sub-parts) of issues listed below constitute a generic RAI hat is asked for licensees that credit 201 reductions based on Westinghouse testing conduc t Wyle Laboratories.

Some questions may not apply to all licensees as they are depe t on the type of insulations for which 201 reduction are being credited. If the licensee b~

at a particular question is not applicable to its use of the test results, this should be $ta..

short reasoning provided. The PWROG has committed to consider reso/K{f1rl some issues generically.

The success of this effort is not clear as of this time. TIj:estaff notes th licensee's July 31, 2009, supplemental response stated that itJ~;;'Supporting industrY s to substantially reduce the 201 for jacketed NUKON insulation a.~(l*that then-current effort uld eliminate NUKON to the extent necessary to ensure it doeslJ.c>t remaifi';v~4thin the 201 0 rge diameter, limiting pipe breaks.

NextEra Response As discussed in the response to Question..

~~"e"!iiI Era i currently crediting use of reduced lOis based on WestiH.~house testi.. conq~w, aboratories. Should the NRC approve the use of aoc~A>lOI in the~vt~fel'aneduced lOI is applicable to currently installed insula' onfigun:ltions at P6rslP, NextEra may elect to reduce the replacement efforts ino r to minim~e ionizing:radiation exposure to the personnel performing the removal and repla'bement work.

Therefore, none subparts of Questi are currently applicable to PBNP.

Question 4>

For any ;kd~l;ed 20ls that rediteq that are less than the size specified in the SE on NEI 04-07, i3~

discuss w er the corresponding debris size distribution was assumed to have an increag.generatio fines and small pieces that is sufficient to account for the higher destructiOf1.j3re$sures t would exist within the smaller 20ls relative to the larger SE-approved 201s.

NextEra'Response As discussed in the response to Question 2 above, NextEra is currently not crediting use of reduced lOis based on Westinghouse testing conducted at Wyle Laboratories. Should the NRC approve the use of a reduced lOI in the future, and the reduced lOI is applicable to currently installed insulation configurations at PBNP, NextEra may elect to reduce the replacement efforts in order to minimize ionizing radiation exposure to the personnel performing the removal and replacement work.

Therefore, Question 4 is currently not applicable to PBNP.

Page 3 of 16

Question 5 The July 31, 2009, supplemental response states that 30% of mineral wool was assumed to be destroyed into fines due to exposure to the blowdown from a ruptured pipe, based on the similarity of this material to low-density fiberglass. Specifically, this comparison was based on relating mineral wool to Kaowool, which is actually a type of ceramic fiber. However, evidence exists that mineral wool can be more fragile than low-density fiberglass, as discussed in NEA/CSNI/R (95)11, "Knowledge Base for Emergency Core Cooling System Recirculation Reliability," and NUREG/CR-6224. In light of this evidence of the potential for increased fragility of mineral wool as compared to low-density fiberglass, please provide a basis for concluding that the mineral wool installed at Point Beach would generate a of fine debris equivalent to that of fiberglass.

NextEra Response The previous response was prepared and submitted pr to'PBNP cOh1~leting the debris generation and transport analyses that evaluated th figuration after~Il!lnating major fibrous debris sources in the potential LOCA ZOls, ce that time, the larg~lifljority of mineral wool has been (or will be) eliminated.

I t",

In the future, analyses of debris sources inside of coht~I~~~nf; will assume that 100% of the mineral wool that still resides in the ZQtJs;reduced to firfe$lJ;,

"{

if:

Question 6 fPrl The July 31, 2009, suppleme"a! response sta!es inrespb~~~to 2 that calcium silicate was conservatively assumed toJ!.e100~reducedtqp~rticulatesto bound erosion effects that may occur. The staff does n

'hderst is stat

'nt in light of the information presented on page 26 of the July 9, supp ntal res se. The table on page 26 appears to indicate that only about 35% 0 alciu was ed to be destroyed into fine particulate, whereas the majority w s (i.e., non-particulate), 85% of which were assumed to salt nt pool flo.

Ithough it appeared that the analytically transportedaebrts a

.5 along with some small pieces) may have been modeled using fifleparticulate for 10S"§.i;lesting, it did not appear to the staff that erosion effects could be conside~ed bounded, Sl 0 er~ib(l appeared to be assumed for the majority of the calcium silicate small pieces 0 (jebrisgenerated that was assumed to be settled in the containment poqb; Please cl the size distribution assumed for calcium silicate debris and provide justificatiefr r the a ed distribution.

NextEra Response The previous response to Question 2 was an error that resulted from misreading the previous debris generation analysis.

In future analyses, the fraction of CalSii that is reduced to fines will be 30% generated directly from the LOCA blowdown, with an additional 10% of the remaining 70% (7%) eroded into fines, for a total of 37%. This amount of fines will be used in any future testing (less that portion allocated to inactive sumps, subject to a limit of 15% consistent with previously established precedent).

Page 4 of 16

Question 7 The July 31, 2009, supplemental response did not adequately describe the assumptions made concerning the washdown mechanism of debris transport. Please describe any credit taken for retention of debris in upper containment (e.g., on gratings, structures, floors, etc.), such that, after the completion of the blowdown and washdown processes, the retained debris is assumed not to reach the containment sump pool. Please identify the types, sizes, and quantities of the debris assumed to be retained above the containment sump pool.

NextEra Response The small debris (defined as s 4" along its longest dimension) ar cted to be carried away from the break in all directions through any openings in robust.

surrounding the break location much like dust that is suspended in the air. The pr~ps ve will likely carry the small debris quite some distance from the break.

Though the small debris originating in the RCS loop compartments will throughout containment, it is also expected that adqrtion of it will be impe y physical obstructions within the loop compartment and iry1:Qtb,er locatio~~i Such obstr ns include the compartment walls, the steam generators, reacto~~olant PUrlPs, and various ing. In addition, the RCS loop compartments contain extenSi~~ bate work platforms. These grates overlie the RCS components and will catch small ris that is blasted up toward the refueling floor (EI. 66').

Additionally, a portion of the small debris will. be diStrit:)l,jted to ions that are not exposed to spray wash-down (e.g. inter

'~ite elevatiqp floo~stieneafh tQ~ efueling floor and above the sump, piping, structural ~;~

\\~~

~ing, ab the sump and at intermediate elevations of containment) as the ini. 'I;blowdown:;pressure t propagates throughout the containment and pressurizes all compa nts.

for implltTtentation at P im.:I~~lte,y. Containment spray is secured when the utes for alalle break LOCA). NextEra has submitted an tive Source Term (AST) methodology. If AST is approved

\\;.~;spr:';'ff!;;;Y be continued for a period of -4 hours post-event to provide ~tl~'inUed iodine scr ing frQfI};.the containment atmosphere. Thereafter, it would be secured in ord;~r to provide a'tional flow margin to support flushing boron concentrations from the core. Theref,we, the expo~,~re of retained smalls to containment spray is limited.

':4}~

ifj To account for the

. Ig~~psition on obstructions sequestering of deposition in unsprayed locations and inactive

'/50% of the total small debris generated are removed from further participation, while the r ining 50% are assumed to eventually reach the sump and be available during recirculation. The erosion fraction is applied to 100% of the small and large debris (if any), regardless whether they are held up, and all of the eroded fines are assumed to transport to the sump.

Other than the fraction of small debris that is assumed to be held up on internal structures described above, all of the debris generated by an analyzed break will be assumed to reach the sump.

Page 5 of 16

Question 8 The July 31,2009, supplemental response included some discussion of the erosion of frangible debris (e.g., fiber, calcium silicate, asbestos). However, based on the staff's review of the information provided on pages 13 and 14, it appeared that, while erosion due to exposure to a blowdown jet had been considered, erosion due to exposure of settled debris to water flows in the containment sump pool over the sump mission time had not been adequately considered.

Please describe how erosion of frangible debris settled in the containment pool resulting from pool flows was addressed in the analysis and provide a justification for assumptions that deviate from the SE on NEI 04-07. If erosion testing was performed to support the assumptions being made, please also provide the following information:

a. Please describe the test facility used and demonstrate the fty of the flow conditions (velocity and turbulence), chemical conditions, and debri

. I present in the erosion tests to the analogous conditions applicable to the plan Itt

b. Please provide justification for any erosion tests co c ed at a mitit~ium tumbling velocity if debris settling was credited in the test flume for ties in excess o~:t~t~ value.

c. Please identify the duration of the erosion tes how the results wer~"i~trapolated to the sump mission time.

NextEra Response NextEra is evaluating the recent NRC ooncl!r'Sion that insufficje justify crediting settling during strainer te~tipg.$ho\\oJ!igNext

,etermine that retesting the strainer with a protocol acceptable to the N~;~ WhiC~Qqiiinot c it settling is required, this RAI would be resolved.

"" "'iii Question 9 Please describe otcJ;bris tH"l~ettles in the test flume is accounted for in the sump performance e e JLl"t~llfi009, supplemental response indicates that a significant pen f s large piec'es'of debris were analytically assumed to transport to the strainer!. or Ie, ne case for which results were reported in the supplemental response,llpproximatel p of1a.riJe pieces of Temp-Mat were analytically assumed to reach the strainers, as were 30%

rgef>jeces of Nukon and 34% of small pieces offiberglass.

These ana"ir;al assumption ducedthe quantity of settled small and large pieces of frangible debris that we(~analytically med to erode in the containment pool. However, for the strainer head toss,testing co ted by Performance Contracting, Inc. (PC!), the NRC staff considers it likely thlf!t:~ si9.q*

nt fraction of large and small debris pieces that were analytically considered transportal:#~1:l.

ally settled in the test flume rather than transporting to the test strainer. The head 10sS'testing did not model the erosion of this debris that was analytically assumed to have transported. The licensee's consideration of debris erosion, therefore, appears to be non-conservative, because neither the analysis nor the head loss testing accounted for the erosion of debris that settled during the head loss testing. Please estimate the quantity of eroded fines from small and large pieces of frangible debris (e.g., fiber, calcium silicate, and asbestos) that would result, had erosion of the debris settled in the head loss test flume been accounted for, andjustify the neglect of this material in the head loss testing program. If this eroded debris is not accounted for in a prototypical or conservative manner, then please provide a basis for the conservatism of the analytical debris erosion results given that the analysis may significantly underestimate the total quantity of settled debris (when debris that settled in the test flume is considered).

Page 6 of 16

NextEra Response NextEra is evaluating the recent NRC conclusion that insufficient testing and data is available to justify crediting settling during strainer testing. Should NextEra determine that retesting the strainer with a protocol acceptable to the NRC which does not credit settling is required, this RAI would be resolved.

Question 10 The July 31, 2009, supplemental response states on page 14 that amline and vector plots were used to identify isolated eddies that had velocities higher tha incipient tumbling velocity but did not contribute to debris transport from the zone.

e identify the types and quantities of debris assumed to be trapped in eddies of this rovide the basis for considering debris assumed to be present in these areas to recirculation to not transport to the strainers...

NextEra Response NextEra is evaluating the recent NRC conclusion t uffj,olent"testing and available to justify crediting settling during strainer testing. Sho ii;r!8 determine that retesting the strainer with a protocol acceptable to t~;rl~~C which d t credit settling is required, this RAI would be resolved.i"k Question 11 Based upon the informatigil;~1ffJVict@~i.en page::~p;\\~fthe Jul

, 2009, supplemental response, it appeared to the staff tffaf*higher d~"'ris transRJllJ fractions were calculated for large pieces of Nukon and Temp-Mat+d bris than fI all piec~s of these debris types. This result is unexpected, since smsl ces of is typicall more transportable. Please provide the basis for the calculated tra for small cJ, bris pieces being lower than that of large debris pieces fti$r an The apparen of'assuming that all large pieces fell directly to the sump, while small d oughout the containment. Since a portion of the small debris is retained abov

, the fraction that reaches the sump is less than 100% of the small debris gener ever, 100% of all fines generated are assumed to reach the sump.

With the replacement 0 NUKON and Temp-Mat (the only fibrous sources that result in "large" debris) in the various analyzed ZOls, the results of future analyses will not reflect any large debris pieces.

Page 7 of 16

Question 12 A number of assumptions were made in the transport analysis that are not consistent with, or are not included in, the baseline guidance approved in the SE on NEI 04-07 and for which insufficient justification was provided, including the following...

NextEra Response NextEra is evaluating the recent NRC conclusion that insufficient testing and data is available to justify crediting settling during strainer testing. Should NextEra determine that retesting the strainer with a protocol acceptable to the NRC which does not credo ettling is required, this RAI would be resolved.

Question 13 Please provide the basis for concluding that debris blocRage will not interceptors (including the submerged perforated se area and 4-in extent that would result in starvation of flow to the p strainers.

The question of potential 01 blockage is being eli ed enti~~ly by the rernovafof two of the Dis. The two Dis being removed are an impedimen

~ft~II~nt outage execution because they block access to significant parts of the C inment 10w~J1iI:~I;Ewation and must be physically removed and re-installed each outage.

are not cre~iill~d for holding back debris. In the future, all of the Dis, as well as other mo I IC at no Idn~;;f serve any purpose that can be credited in the sump screen performance ~lJalys testing+~~~9., the re-routed cavity drain line away from the strainers) rna e remov Please refer the annotgJecfdrawingQfUnit 1 0 next page that shows the Dis being removed.

Page 8 of 16

Page 9 of 16

Question 14 Sufficient information was not provided in the July 31,2009, supplemental response to provide assurance that the flow conditions simulated in the strainer head loss test flume are prototypical or conservative with respect to the plant conditions. Therefore, please provide plots of velocity and turbulence contours in the containment pool for the bounding computational fluid dynamics cases with respect to these two parameters that include the entire pool and which are based on the computational fluid dynamics model used in the debris transport analysis. Please also provide close-up plots of the velocity and turbulence contours in the region of the strainer and its immediate surroundings from the computational fluid dynamics el, showing the flow streams that were used to determine the flume velocities and tur:

ce levels for head loss testing. Please identify the bounding break scenario that was... ~

derive the flow parameters (e.g., velocity and turbulence) that were simulatfidin head loss test and identify which of the strainers is modeled in the test. Please identiFxihe v

. and turbulence values used for the strainer qualification testing and provide th(jpasis for co filing that they are prototypical or conservative with respect to the plantgpnrJition.

NextEra Response

~e~tEra is.~valuati~g the r~cent N.RC con~;lusion thclifl~ffi~le~t testin~ and data is ~vailable to Justifycrediting settling durinq strainer

.g. Should ~~.

ra determine that retesting the strainer with a protocol acceptable to thC!!,,which doe settling is required, this RAI would be resolved.

Question 15 s that debris was added to the test flume Due to tt.

port modes not modeled by the head loss

, and pOQlf(II), a fraction of the debris could be within itiatiQf1 ofi!ecirculation. As a result of adding all the NextEra is evalu the re/\\ ii NRC conclusion that insufficient testing and data is available to justify crediting sett t~n9"strainer testing. Should NextEra determine that retesting the strainer with a protoc ptable to the NRC which does not credit settling is required, this RAI would be resolved.

Question 16 Please provide a photograph or diagram of the ramp used to introduce debris slurries into the head loss test flume and provide further information that demonstrates that the simulated entry of debris into the test flume via the ramp was prototypical or conservative with respect to the plant condition.

Page 10 of 16

NextEra Response NextEra is evaluating the recent NRC conclusion that insufficient testing and data is available to justify crediting settling during strainer testing. Should NextEra determine that retesting the strainer with a protocol acceptable to the NRC which does not credit settling is required, this RAI would be resolved.

Question 17 In response to Question 6 in the July 31, 2009, supplemental response, the licensee indicated that water streams splashing down into the containment pool are 10 ed significantly further than 2 inches from strainer surfaces. However, it was not clear t t extent streams of water splashing down into the containment pool would exist within th of distances modeled in the head loss test flume used for the strainer qualification t ughly 20 ft). Please discuss any sources of drainage that enter the containmen i:.

I the range of distances modeled in the head loss test flume. Please identify w ;httu3r the dra dispersed form (e.g., droplets) or a concentrated tor.

.q., streams of surfaces). Please discuss how these sources of age are modeled in create a prototypical level of turbulence in the t

e.

would occur in a running off of flume to NextEra Response s.:.~.ii; NextEra is evaluating the recent NRC co~pILJ~~Qthat insu'~i~nt testing and data is available to justify crediting settling during strainer testing. S d NextEl'"~ determine that retesting the strainer with a protocol acceptable to the NR.C th Qot creditsettling is required, this RAI would be resolved.

Question 18 The licensee stated tha~;t1:J~ head I

'v\\f0uld be li'!Ji~ed to less than 10ft by one of three methods. These are (1) bin, (

qUiring flow reduction, or (3) re-testing. The licensee didnitPfi int.

n such tha

. staff has assurance that adequate provisions have been'A~(fJt() a i" e th 1(#10 ft limit on head loss is not exceeded. Please provide informa~~lJdemonstrating;lf}atmea~l-Jres have been taken to ensure that the limit is not exceeded.

.'i%\\.

NextEra Resrlonse The response previ ed is no longer applicable because previously completed testing is no longer acceptab completion of testing determined to acceptable to the NRC, if it is determined that a reduc in screen differential pressure is required at cooler sump temperatures, then the preferred means would be reducing core injection flow. This would be accomplished consistent with submittals made pursuant to the Alternative Source Term (AST) licensing action. The license amendment request is currently being reviewed by the Commission.

If AST is not approved, or not approved by the time that GSI-191 is resolved, the next preferable option is suspension of sump cool down.

Preliminary reviews have determined that the core decay heat remains substantially greater than heat losses to ambient through the containment shell throughout the 30 day post-LOCA period, and all cooling flows to the containment (e.g., service water to the component cooling Page 11 of 16

heat exchangers and to the containment fan coolers) can be throttled or secured as necessary to limit containment heat removal over the long term.

These actions can be completed from accessible locations outside of the affected units containment, using safety related components and controls, and are reasonably achievable within the long period of time available.

Maintaining the sump (and potentially the containment atmosphere) temperatures slightly above 100°F for the 30-day duration will not challenge the environmentally qualified equipment in the containment.

If reduction in strainer differential pressure at reduced temperatu ecessary, further details of how this will be performed will be provided in the final subrnl n response to GL 2004-02.

Question 19

',w; RAI 4 requested that the licensee provide head loss orlexing testing In general, the information provided in the licens sponse is acceptab owever, the additional information led the staff to question s eas of t/;;~testing. Th 'i,~tlng was conducted at Alden Laboratory and allowed debt.

ing. < Somte issues, listedbelow, that have been identified by previous staff review of test!

. lows near-field settling are applicable to the Point Beach testing r>:~

'I.;.

NextEra Response NextEra is evaluating the reclItNB-C conclU' rfl~mp:!~nt testing and data is available to justify crediting settling durimg4~trai~~r testing d NexfEra determine that retesting the strainer with a protocol ~~peptable t,~ee NR ch does not credit settling is required, this RAI would be resolved.

w,'

Question 20 Zr,h:Q.*:'>he lie~psee provided clean strainer head loss (CSHL) and total head loss valuesifor multiple

. pE(ratar~s. The information supplied for this RAI is acceptable.

However; during review of ~h~ vendo{head loss calculation the staff questioned the methodolog.yy:sed to calcula e total strainer head loss. The question is with respect to the CSHL porlion~~)the overall h loss. In Table 7 of the PCI calculation attached to the RAI responses (TDt..6flJ)7-06), th al debris laden head loss (TDLHL) is calculated by adding the debris head loss, th~plen~

ad loss, and the Alden Research Laboratory CSHL. According to the calculation definitioJ'!,l;fhe TDLHL is the total corrected clean strainer head loss (TCCSHL) added to th~f&en test results debris laden head loss (A-DLHL). For example, the table 7 value for the TDLHL at 212 of is listed at 3.474 ft. If TDLHL is calculated using the TCCSHL added to the A-DLHL the value is 3.626. Please provide an explanation for the methodology used to calculate the TDLHL and verify that all components of head loss are included in the calculation.

NextEra affirms that the methodology used by the vendor in the calculation previously provided is correct, and it is subject for continued use regardless of changes in test protocol. The document provided is potentially confusing because of ambiguity in the terms used. The following explanation is evident from a careful reading of the full text of the calculation.

Page 12 of 16

In Table 7 of the calculation, the starting point is TCCSHL ("total corrected clean strainer head loss"). This is the total head loss for a clean strainer, as well as the connecting piping, elbows, etc., corrected to a temperature of 212°F. This is a calculated number obtained from a generic regression formula, and may not accurately reflect minor differences between the actual clean strainer design and the generic design.

To account for this, PCI then subtracted out the calculated clean strainer head loss, CSHL

("Clean Strainer Head Loss"; second column of Table 7) to obtain the "Plenum Head Loss" as shown in the third column of Table 7.

The Plenum Head Loss representing the head loss in the connecte iping and fittings is then added to the as-measured clean strainer head loss from the test a prototypical full scale strainer module identical to those that have been installed at P (CSHL, 4th column of Table 7) and the Actual Debris Loaded Head Loss ("A-DLH mn of Table 7) to obtain the Total Debris Loaded Head Loss ("TDLHL", 6th column ofrffable F.~oth the CSHS and the A-D LHL were previously corrected to 212°F.

If the TCCSHL was added to the as-measured C§.Jr!.iy without first sUbtractlh t the calculated CSHL, the clean strainer head losses would hav~been erron sly double c d, with the resulting predicted head loss erroneously high by*'I.i1935 ft (

ches).

ill Bin This same calculation will be revised tQ.t!?n!?ct the result$.cffpending future testing, but the methodology will not be affected.*

Question 21 f~:n.*"

,,::.tll:>,?--

,'..* --\\>')

rationaifllicinsporl caleulations had not been completed BecauS'~ithe testing credited near-field settling, the size the testi4g are critical to the test result. Please verify

.tJ.tion usedi~... the head loss testing bound those eiinal igniconfiguration has been determined. In amoun

'ent fibrous debris assumed to reach the the amount assumed in the design basis. This discrepancy of insulation from the plant. Please state how this issue NextEra Response NextEra is evaluati t NRC conclusion that insufficient testing and data is available to justify crediting settlin strainer testing. Should NextEra determine that retesting the strainer with a protocol a eptable to the NRC which does not credit settling is required, this RAI would be resolved.

Question 22 In response to RAI 25, the licensee provided the calculated deaeration for both hot and cold conditions. However, the licensee did not provide information regarding how any required correction to net positive suction head required (NPSHRJ would affect the margin available for the emergency core cooling pumps..Please provide information that describes how NPSH margin is affected by the NPSH R correction described in Regulatory Guide 1.82, Revision 3, Appendix A.

Page 13 of 16

NextEra Response The NPSH available (NPSH A) to the RHR pumps has historically been calculated by crediting only atmospheric pressure (14.7 psig) inside of the containment, regardless of calculated containment conditions. This has been performed consistent with Item 1.3.1.1 of Regulatory Guide 1.82, Water Sources for Long-Term Recirculation Cooling Following a Loss-of-Coolant Accident, Revision 3, Appendix A.

When in an alignment to support simultaneous core outlet plenum and cold leg injection for boric acid concentration concerns, RHR flow must be throttled to pr nt NPSH R from exceeding NPSH A using the above approach. This is before con tion of the deleterious effect of entrained vapor voids on NPSH R, the NPSHA just me design NPSHR of the RHR pumps.

With the previously submitted calculated entrained voi~4~action of these conditions, the NPSH R should be increased by 30%.*nder the above assumptions, there is inadequate NPSHA to ensure proper operation q[the RHR pumps.

-;::~

It has been suggested that accounting for the cOfl'tpression ofl~e voids due to increased elevation head as sump water descends to the pump'~~cti,~.s*may be sufficient to counter the adverse effect of the voids on NPSH R.

l7Ii~wever, compression effects alone is inadequate to recover the 30% increase in NPSH R.

A1J Theoretically, the elevation head increase tions oflhe RHR suction piping would be sufficient to drive all of th~ enti3ined ga ol~tibn~., However, the rate of this diffusion controlled proceis,higftl~epen e size oftile entrained voids, and it would be difficult to conclusiv ernonstrste that all ined voids would be re-dissolved during the brief transit time to th p suctions,

~'nt The table below illustrates that the minimum NPSH A in the containment using this modeling of available pressure head is always well in excess of NPSHR, even when voiding effects are considered. The table does not credit the additional pressure caused by compression of the containment gasses from the injection of RWST water. It assumes an initial (pre-accident) containment pressure of 12.7 psia (2 psig vacuum) and a pre-accident containment temperature of 120°F (both are Technical Specification limits that minimize the pre-accident gas inventory in the containment). The nominal NPSH R is 15 ft at the maximum design flow rate of 2200 gpm, and the minimum level of the sump pool is approximately 28 feet above the RHR pump suctions.

Page 14 of 16

Sump Temp Cont.

Air Partial Press.

(psia)

Cont.

Total Pressure (psla)

Total Pressure Head (ft)

Screen Head Losses (ft)*

Approx.

Piping Head Losses (ft)

NPSHA (ft)

Void Fraction Corrected NPSHR (ft) 212 14.7 29.4 70.8 3.5 7.3 52.6 0.06%

15.5 192 14.3 24.1 57.5 3.9 7.3 50.9 0.07%

15.5 172 13.8 20.2 48.0 4.4 7.2 49.2 0.09%

15.7 152 13.4 17.3 40.8 5.1 7.2 47.3 0.13%

16.0 132 13.0 15.4 36.0 5.9 7.1 4

0.17%

16.3 112 12.5 13.9 32.4 7.1 7.1 0.25%

16.9 92 12.1 12.8 29.8 8.6 7.1

,v,i 0.37%

17.8 72 11.6 12.0 27.8 10.9 7.0k.');

3 0.64%

19.8

'7

~~">~

"These values of screen head loss are from previous tests, and yvoy!phave to be revi reflect any re-test result s with a different methodology.

A review of the above table shows that NPSHA witJ>~lways ex NPSHR by al~Jge margin.

The margin provides assurance that the minimal eff~.s"of inrnent leakage over time will not invalidate the conclusion that will remain adlg for the 30-day mission time of the ECCS systems.

Question 23 i'!!)))

'iii RAI 21 requested additiona tion dern~i~tr~tfng thal1fhe maximum aluminum concentration in the contai p will beTe$$' than 20 parts per million (ppm). The July 31, 2009, respons closure ble 1 s d 12 different calculations of aluminum concentrations, som~""

hich are credible MAe they combine accident scenarios that are not possible. The respOf'l$e identi cas

.5 aSiht; limiting credible case. However, the aluminum conce ion f6r,case2: is 3,,Jw.hTch contradicts the licensee's statement that the concentratlQ

~,Iess t'1~h 20 ppm. Please address the discrepancy.

{if' NextEra R~~ponse

"(

smitted a co of the complete analysis. This analysis was provided per NRC not revised, cQ~rected or abridged to enhance readability.

'&'fii:'

The question stems

'flciency in the presentation of data that was identified by NextEra when reviewing the v repared document, but did not require correction because sufficient information was include n the document for it to be acceptable.

Note 4 of the owner's review comments ("Design Review Comment Form") on Page 5 of the enclosure states:

"When using table 6-1, care should be taken to not use the concentrations listed.

These concentrations were derived using the maximum sump volume to establish the total mass, but then divided the mass of chemical precipitants by the mass in the minimum sump volume (this approach is noted at the bottom of the page). This produces an erroneous and excessively high chemical concentration. If chemical Page 15 of 16

concentrations are desired, then they must be calculated from the chemical masses listed in the table and then divided by the mass of the maximum sump level. Both can be obtained from within the calculation." [The bold emphasis exists in original document and was not added by this response]

For the limiting case (case 2.5), the table lists a total mass of aluminum of 19.97 kg, and a maximum sump volume of 43317 fe. Converting to a correct concentration:

[Ppt] =20 kg x 2.2 Ib/Kg / (43317 fe x 62 Ib/ft3 for H20 ) ~ 16.4 ppm Therefore, the previous statement that the concentration would be I.

than 20 ppm was correct.

Note that because additional testing will be necessary, and he dominant sources (fiberglass and mineral wool) of the limiting reagent in form>

re

. ts (the aluminum ion) has been substantially reduced, NextEra may elect to"Ji~ise the prev completed chemical analysis to obtain a new, reduced chemical source te'r~ prior to perform of the next test.

Question 24 The response to RAI 22 in the July 31, 2009, sUbmittal,l s a table that provides a measure ofprecipitate as a function of sump vo/yme.but did not his back to the sump pH. Please clarify how the mass of precipitate formecJ Varif;)$ as a fun of sump volume and pH.

NextEra Response The previous RAI respon§i'irMicate.IJhat ses were rJEiirformed using a single, conservative, bounding.. valtle of pH.;i;I~herefor

. not possible to provide a response illustrating how the vofuQ'le of precip varies a~:'ifl function of sump pH.

<~:,:~::"

During a subsequent telep IceWAth tI ~NRC the intent of this question was clarified. It wasdetsr. ed t ormationsh d be provided that illustrates the range of sump pH tH,~trriay be cted e sump and how the single value used was both conserviil.five and boundlr

'sX;;

The analysil~Q,{~ViOUSIY prov

.d assurft~d a maximum sump pH of 9.5 for the entire 30 day post-accident Ctl..llfltion. Since;iiil;high pH favors the dissolution of aluminum (the limiting reagent), and ndI(+/-redit was tci~~n for the solubility of precipitant species of interest as a function of pH, this is conserVat.jye~rq~jded that the pH cannot credibly exceed 9.5.

The analysis of post-a;~id~nt sump pH concluded that the maximum sump pH that could be attained would be 9.4, without including the acidic effects of core inventory release and / or radiolysis of cable insulation materials.

In contrast, the same analysis concluded that the minimum sump pH would be as low as 7.65, with an additional reduction of 0.23 pH units due to the effects of released core inventory (Hyrdoionic acid, CsOH, etc.) and radiolysis of cable insulation materials.

Therefore, the assumption of a constant pH of 9.5 conservatively bounds the full range of possible sump pH.

Page 16 of 16 List of Attendees

LIST OF ATTENDEES FOR MEETING WITH POINT BEACH NUCLEAR PLANT REGARDING GL 2004-02/GSI-191 FOR UNITS 1 AND 2 Name Title Organization Justin Poole Project Manager NRRJDORL/LPL3-1 Steve Smith Rx Systems Engineer NRRJDSS/SSIB Mike Scott Branch Chief NRRJDSS/SSIB Brian Dunn

• Director NextEra Jim Costedio

• Licensing Manager NextEra Fritzie Flentje

• Licensing Supervisor NextEra Tom Kendall*

Engineer NextEra

• Per Teleconference

P ML1019 M

ti N'

ML100570454 eelno otice ML101600292 Mrs ee mq umma ry OFFICE DORLlLPL3-1/PM DORLlLPL3-1/LA NRR/SSIB/BC DORLlLPL3-1/PM DORLlLPL3-1/BC NAME JPoole BTuily MScott TBeitz RPascarelli /TBeltz for DATE 06/21/10 06/21/10 06/23/10 07/08/10 07/08/10