ML20315A082
| ML20315A082 | |
| Person / Time | |
|---|---|
| Issue date: | 11/06/2020 |
| From: | NRC/OCIO |
| To: | |
| Shared Package | |
| ML20315A080 | List: |
| References | |
| FOIA, NRC-2020-000234 | |
| Download: ML20315A082 (7) | |
Text
From: Ghosh, Amitava Sent: Thu, 23 Apr 2020 21 :22:27 +0000 To: Colaccino, Joseph Cc: Patel, Pravin
Subject:
Management Briefing DEX 4-23-20 Revised Clean Attachments: Management Briefing DEX 4-23-20 Revised .docx Hi Joe .
Here is a clean copy. Thanks a lot for everything.
Amit
LAR 20-001 1 Seismic GAP Between Annex Building and Nuclear Island, Vogtle 3
Background:
SNC submitted LAR 20-001 to revise the seismic gap in ITAAC (No. 819, 3.3.0013), Tier 2 and Tier 2* of the license and UFSAR. The proposed gap will be revised from 3" to 2 1/6" between the Annex Building and Nuclear Island (NI) in the North-South direction above-grade El 141 ' to El 154'. In a previous LAR, the seismic gap between these bui lding was reduced from 4" to 3".
Issues:
- A margin of 1/ 16" between a Cat I structure (NI) and a non-safety structure (Annex Building) in the North-South direction can reduce further due to continued settlement.
- There is no settlement data between these two structures in the North-South direction and the predicted settlement is significantly different that what has been observed in the licensee document.
Regulatory Bases:
10 CFR Part 50 Appendix A, GDC 2 "Design Bases for Protection Against Natural Phenomena" and GDC 4 "Environmental and Dynamic Effects Design Bases" SRP 3. 7.2 Section 1.8 "lnt,eraction of Seismic Cat 1 structure with Non-seismic Structures" 10 CFR Part 52 Appendix D, VIII "Processes for Changes and Departures" Safety Significance: The seismic gap between Cat 1 and Cat II (Annex Building) structure is small. Potential Safety significance occurs if the gap between Cat 1 and Cat II closes to zero because there is no analysis presented showing that a zero gap will not affect the structural integrity of the CAT I structure by the Licensee.
Staff Review Activities:
While reviewing the LAR, the ESEA staff noted that the margin is extremely small (only 1/ 16")
and decided to audit the SNC documents in the ERR. The staff had two clarification calls to further understand the data provided by SNC.
The staff used information in the ERR to develop their settlement curves (see graph) to characterize the trend in the settlement between the nuclear island and the annex building.
Based on these data, the staff concluded tha (b)(4)
(b)(4)
Therefore, the staff has another issue of using the predicted settlement to
......,..,..,...,..,.......,....,..,...,..,.,.,.,...,.,.a
- p during Safe Shutdown Earthquake (SSE).
Path Forward : SNC needs either (1) to provide a realistiically predicted settlement affecting the seismic gap in the North-South direction from the remaining loadings of the completed structures or (2) to address that the zero gap is acceptable based on an analysis demonstrating that a Cat II structure (Annex Building) will not affect the structural integrity of the Cat 1 Nuclear Island during an SSE.
References:
[1] Westinghouse Electric Company, LLC. 2019. E&DCR No. APP-1000-GEF-250, Rev. 0.
[2] P.C. Rizzo Associates, Inc. 2014. Settlement Re-Analysis of the AP1000 Buildings with Consideration to Construction Sequence Vogtle Units 3 and 4. APP-G9-GEF-005, Rev. 5.
(b)(3) 16 U.S.C §824o-1(d), (b)(4), (b)(7)(F)
(b)(4)
From: Ghosh, Amitava Sent: Thu, 23 Apr 2020 21 :10:22 +0000 To: Colaccino, Joseph Cc: Patel, Pravin
Subject:
Management Briefing DEX 4-23-20 Revised2 Attachments: Management Briefing DEX 4-23-20 Revised .docx Good evening Joe .
Here is my revised version. Please comment.
- Thanks, Amit
LAR 20-001, Seismic GAP Between Annex Building and Nuclear Island, Vogtle 3 lHues
Background:
SNC submitted LAR 20-001 to revise the seisrmc gap in ITAAC (No. 819, Commented (CJ1J: The Issue section should speary 3.3.0013), Tier 2 and Tier 2* of the license and UFSAR. The proposed gap will be revised from tile issues W:llh lhe current LAR review.
3' to 2 1/6" between the Annex Building and Nuclear Island (NI) in the North-South direction Commented [GA2R2J: Text addod as suggested.
above-grade El 141' to El 154'. In a previous LAR, the seismic gap between these building was reduced from 4* to 3".
- A margin of 1116" between a Cat I structure /Nil and a non-safety structure {Annex By11dingl in the North-South direction can reduce further due to continued setUemenL
_* _ There is no settlement data between these two structures in the North-South direction and the predicted settlement Is significantly different that what has been observed in the licensee document.
Beaulatpry Bases;I j Commented JCJ3J: Move reg basis end safety s,gn*flcance .above staff review while maintaining same lo CFR Part so Appendix A GPC 2 *pesian Bases tor Protection Aaarost Natural order Pbenomena* and GPC 4 Environmental and Dynamic Effects Design Bases* ~ mented [~ A4R4J: Text moved.
SRP 3 Z 2 Section I 8 "Interaction of Seismic Cat 1 structure with Non-seismic Structures*
W CFR Part s~p,eru11x D VIII
- eroce.sses.Jpr Chang~~adures*
Safety Sfanmcance,; The seismic gap between cat 1ang cat II {Annex Bulld1Qgl structure 1s Commented (CJSJ: See above.
small P.otenllaLSafelY_spcao.ce..o~urs illll!UIBP betweeo..Cawnd. .CaULctoseUo..lero Commented JGA6R6J: ToXI moved.
because there is no analysis presented showing that a zero gap will not affect the structural loteari!Y oi the CAI I structum lly tbe Licensee St aff Review Activities, While reviewing the LAR, the ESEA staff noted that the margin is extremely small (only 1/16.)
~nd decided to audit the SNC documents in the ERR. The staff had two clarification calls-tM Commented JCJ7]: Include in the issue section the lhA lflff :()Ul(I M 1 <111*-.rn in h, '""' ¥'" r , l ,t 11 1, rth r u ,t, r 11, d nr t<,i a 11gn1ricance or this sman margin.
provided by_fili~ Commented [GABRBJ: TeXI added as suggested.
.I.l:lu!.!l.ff used 1Q!Qrmnt1QDJ.!l..lb_e .EBR IQ develop their settlement CUIY.f"'i I~~
ch:Ui!LIE rize UJ,, lrelli!.iil..l!J,! sellli,n,ent betwc 1 ~ r ~ " J " t~ <1,nn~K bul Q.r)!l B;ised on the<;e d.-ita 1Ad4i1100; Iii; 1he staff "'~ conclud* *d thallthltlll (b)(4) rc;,;mented JCJ9J: I think a more expanded reference l_tc>__tllls nonconlormance report Is necessary.
l ~ommented (GA10R10): Added references on Page
!(b)(4) ITherefore, the staff has another issue of using the predicted settlement to assess the seismic gap during Safe Shutdown Earthquake (SSE) CommMtod (CJ11 J: This Issue Is nor discussed Regu1atocy Ba....
l above in lhe issue seclion Commentod (GA12R12J: Text added In Iha Issue
~g CJ=R Perl i Q /lppeRe1M A, C.0C
- 0e&1gR lil11&1111 fGI' Prel11&&1eR Ag111R&I lalwFal l section Commenttd (CJUJ: Move reg basis and aafety
~~QA&IM&Re* 9Fl9 ,;oc 4 ..,A1Jlifi8Af¥l0Alal an~ Q~*AOMia liff.eo&& (;)ooigR ~060&" s,gn1ricance abov'e staff review while maintaining same order SAP 3.7..a So61ioA I.B "lnt&J:aot1OR of Soi&ff:118 Cot 1 s1rwotul'8 **11th Mos:, s01&m1c 5:tfws&ures*
i afetyiJgAifioanoa* ha &aio~io 9ap bet:esoon Cat 1 and Crat 11(AnnoK iwlld1ng) Glrw&lura hi [ Commented [CJ14): See above,
~Q~ , J;l1;1t&Rli11I iielely lligRilioeooe QQQWFI ii 11:18 gap be~<<HR Cel 1 IIRd C11I II &1118811 lo -
bOGOW69 tRere 16 RQ anoly&i& PFeGOAt9" &hoeeqng that 9 a&F8 gap ***1II nat 9#9&l Iha &lFW&tw~,
iAlegrn,i ef 1h11 CAT ~~AJ&lwfe by Iha LIGIIR&H Path Forward: SNC needs either (1) to provide a realistically predicted settlement affecting the CommMttd (CJ15): This is not a sufficient path seismic gap in the North-South direction from the remaining loadings of the completed forward What I want to see Is what SNC needs to do to provide lnformat,on lhat jushfles having a gap on 2 structures or (2) to address that the zero gap is acceptable based on an analysis demonstrating 1/16 lneh. We have not described lhat.
that a Cat II structure (Annex Building) will not affect the structural integrity of the Cat 1 Nuclear Island during an SSE.
Commenttd (GA16R16[: Text modified to address the
References:
path forward .
[1] Westinghouse Electric Company. LLC. 2019. E&DCR No. APP-1000-GEF-250. Rev. 0.
[2] P.C. Rizzo Associates. Inc, 2014. Settlement Re-Analysis or tho AP1 000 Bu1ld1ngs w,th Consideration to Construction Sequence Voqtle Units 3 and 4. APP-G9-GEF-005. Rev. 5.
(b)(3) 16 US C §824o-1(d), (b)(4), (b)(?)(F)
(b)(4)