ML15280A306
| ML15280A306 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 09/03/2014 |
| From: | FirstEnergy Nuclear Operating Co |
| To: | Advisory Committee on Reactor Safeguards |
| Shared Package | |
| ML15280A293 | List: |
| References | |
| L-15-310, TAC ME4640 C-CSS-099.20-063, Rev 1 | |
| Download: ML15280A306 (58) | |
Text
Attachment N:
Comment Resolution to Comments from 3"' Party Reviewers ool Calc. No:
C-CSS-099.20-063, Rev.
Sheet No:
4-efS
-i Sheet Rev:
000 7/i7JW FiiUEoeigv Nuclear Opel ntiiig Coinpnuy Davis Hesse Niirlear Power.Station S&L Project No 13077 029 T= Techiucal Coiuineut E= Editonal Comment Comment Resolution Form Site: Davis-Hesse Calculation title Slueld Building Design Calculation 1
2 3
Page, section paragraph Page 10 Attachment D Page 36 and Attachment E T
or E
T T
T Project: Tliird Party Review of Shield Building Design Calculation Calculation No.
C-CSS-099 20063 Comment As indicated on Page 10 of the Calculation, a 10% weight increase is applied to Bechtel's 3D model to account for architectural flutes and other non simcmill components Ii is stated that Tins is also consistent with Ref 8c" This j< sumption should be. justified.
Provide a more specific tefeience for this assumption.
Pet Attachment D. the Demand to Capacity Ratios (IX Rs) aie calculated based on moments only. Provide justification foi calculation of IX Ks based on moments only.
Pei page 36 of the Calculation Document and also the calculations in Attachment E. the reinforcement and concrete stresses are only calculated in legions of the Shield Building where maximum moment DCR occurs. Provide justification thai use of DCRs based on moments only is adequate for locating maximum stress locations.
Revision aud'or Date: 0 dated 5/16/2013 Resolution The 10% weight is back calculated by comparing the total weight of the FF. model 1 without shoulders) with the total weight specified in the original stick-mass model used for seismic analysis (with shoulders. Ref 8r)
Since the FF. model does not explicitly include the shoulders, this weight is added to the model Additional statements are piouded in the calculation to clarify For P-M interaction check. DCR could either be based on moment (with a given axial foice). or based on force (with a given moment), oi based on some sort of combination of moment and.<xi.il force For ultimate sttength design regardless of which type of DCR is used DC R
1 is sufficient to indicate that the demand is enveloped by the P-M diagram although this may not reflect the true margins For winking stress design the DCRs based on moment aie used because of the observed higji magnitude of thermal moment and the fact that such moments will induce stiess gradient cross the thickness which will result in higher stresses in the thin SB shell Acceptance or Disposition of Resolution Page 1 ofS
Attachment N: Comment Resolution to Comments from 3rd Party Reviewers Calc. No:
C-CSS-O99.2O-O63, Rev. QOO Sheet No:
2 Sheet Rev:
000 I
ii ii mi i v-N in ten i Opeialing Company DnvJs-Besse Nuclear Power Station S&L Project No 13077-029 Site: Davis-Besse C'nlculntion title: Slueld Building Design Calculation 4
5.
6 Page, section, paragraph Attachment E, page 103 Attachment I Attachment J Pages In il.i.
ii:'li
"*/
T or E
T T
T Proiect: Tlurd Party Review of Shield Huildnip, Design Calculation Calculation No.
C-CSS-099 20-063 Conunent The crack width formula it the bottom of this page is incorrect The coefficient ot'O 0000091 mint be changed to 0.000091 Accordingly, this correction will yield a maximum ctack width of 0 01286 m. which is laigei than the allowable crack width of 0 01 inch as indicated in the plants USAR The in-plane shear capacity evaluation is carried by assuming that the shear stftti "' concrete is equal to the total base shear divided by the SB wet ion's area, and thetefoie does not utilize-die FEM stress results. Provide justification for why I I.M lesults are not used The bortorn of construction opening is located at elevation z=S79' The lowest elevation where the sectional analysis is performed is at 2~5,84' The elevations between 579' and 584' are not investigated Although it is unlikely that these elevations ate oveiswcssed. they should be addressed in the calculations for the take of completeness Revision and/or Date: 0 dated 5/16.'2O13 Resolution The calculations liave been revised to exclude stresses due to thermal loads Note that per USAR 3.8.2.2.5, cracking due to thermal loads is taken care of by providing sufficient reinforcement SP-20 referenced for crack width calculations takes into account only the stresses due to mechanical loads Using only the mechanical loads j>er SP-20, the crack width calculated is 0.0086", which is less tlian o.o r The slueld building is expected to behave as a typical shear wall type of structure, enabling the in-plane shear to be resisted by the whole cross-section. However, only a portion of the circumference is assumed to resist the induced shear wluch is conservative.
More information is provide in Attachment 1 Attachment J is revised to be extended to EL579' Acceptance or Disposition of Resolution Papr2 of 5 itek a is p<<rt <<r tt><<i<<d u *&>- (bird furiy ki&mb Ac fnca 1 ntat&cs thai w c>~..,
Attachment N: Comment Resolution to Comments from 3fd Party Reviewers ool Calc. No:
C-CSS 099.20-063, Rev. D8CT Sheet No:
3 Sheet Rev:
000 Fir*tEneigy Nurlem OperatingCompany Da\\1s-Be<<e Nuclear Power Station S&I. Project No.
13077-029 Site: Davis Besse Calculation title: Shield Building Design Calculation 7.
- T 9.
Page, section.
paragraph Page 9, Section 7 4 Figuie 24. Page 48 of the calculation and Page 11 of Attachment}
Attachment A, pages 6.
- 7. 9 and 17 T
or h
T
]
T Project: Tlurd Party Review of Shield Buildma Destmt Calculation Calculation No C-CSS-099:
Comment Per plant USAK Section 3.E.2.2.4. the load combination with To only must be uicluded in die working stress analysis as one of the loading combinations, where To is the thermal load during operational conditions However
.llthough this combination is listed m section 7 4 of the Calculation, it is not addresses in the calculations.
Provide clarification as to why this combination is not addressed The term "Moment Capacity" on Figure 24, Page 48 of the calculation and also Page 11 of Attachment J should be changed to 'Moment" as it is not corresponding to the capacity of the section. Rather, it is corresponding to the section moments corresponding to different levels of strain in the rebars The text in these pages should be modified accordingly.
The mass weight applied at Node_ i =3 throughout ilie calculations in this altachement 0063 Revision and/or Date: 0 dated 5/1672013 Resolution To is included ui Ihe analysis. Please see Section 7.5 for each individual load combination used ui FEM. Note LC 502 is for To only Agree-see revised Agree, re-analysis is performed after correcting the mass.
Related sections are also Acceptance or Disposition of Resolution ti if
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Attachment N: Comment Resolution to Comments from 3rd Party Reviewers Calc. No:
C-CSS-099.20 063, Sheet No:
4ofS^0.
Sheet Rev:
1 h stFnei gv Nuclear Operating Company Davis-Bes'Nuclear Power Station SAL Project No 13077-029 oo\\
Site: Davis Besse Calculation title Shield Building Design Calculation to 11 12 13 Page, section, paragraph Page 9 Page 22 Page 53 Page*iv& v T
or E
E E
T E
Project Tlurd Parrs,' Review of Shield Building Design Calculation Calculation No.
C-CSS-099.20063 Comment must be corrected The coirect mast weight is 2791 kips Accoidingly. all the affected pages ill AII ii luiieni A should Ik-modified Sfdioa II H 3.3 1.2b referenced for working stress design should be changed lo section II H 3
3.1..V Section 3 8 2.3 3 referenced for strength reduction factors should be changed to section 38.23.4.
The maximum cracking width reported in Table 44 must be changed from 0.089 inch to 0 01286 inch (see comment 4).
Note that this exceeds the acceptance cutenon of 0.01 inch The calculation number is referring to rev 003 while the calculation is Rev 0.
Revision aud/or Date: 0 dated 5/16/2013 Resolution reused See Art. A for details.
Agree, the section number is revised Agree, the section number is revised Revised as appropriate See response to comment 4.
Agree the rev number is revised Acceptance or Disposition of Resolution Comments By: Sryrd A. Bassam Dnte Resolution By Page 4 of S Date flfmritfytft tofmalJyLl C fiJH.)
1 I
1 C
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>>I0 £ nfkn Mfnid
Attachment N:
Comment Resolution to Comments from 3'd Party Reviewers Calc. No:
C-CSS-099.20 063, Rev.pm' Sheet No:
Sheet Rev:
Iii slEnri gy Nucleni' Opri nliug Coinpnnv Dnus-Besst Nuclear Power Station SAL Project No.
13077-O29 Rexiewed Bv: Ja\\ad Musk'uunn Date PauSofS
Cortmtt*
FirstEnergy Nuclear Operating Company Davis-Besse Nuclear Power Station S&L Project No. 13077-029 Ca\\c N'o C-CZL-Site: Davis-Besse Calculation title: Shield Building Design Calculation 10.
11.
12.
13.
Page, section, paragraph Page 9 Page 22 Page 53 Pages iv & v T
or E
E E
T E
Project: Third Party Review of Shield Building Design Calculation Calculation No.
C-CSS-099.20-063 Comment Section II.H.3.3.1.2b referenced for working stress design should be changed to section II.H.3.3.1.2a.
Section 3.8.2.3.3 referenced for strength reduction factors should be changed to section 3.8.2.3.4.
The maximum cracking width reported in Table 44 must be changed from 0.089 inch to 0.01286 inch (see comment 4).
Note that this exceeds the acceptance criterion of 0.01 inch.
The calculation number is referring to rev. 003 while the calculation is Rev. 0.
Revision and/or Date: 0 dated 5/16/2013 Resolution Acceptance or Disposition of Resolution Comments By: Seyed A. Bassam Reviewed By: Javad Moslemian Date
(>ib]7o\\3> Resolution By Date Co rep Date:
Page 4 of4 This document contains information that is confidential and proprietary to Sargent & Lundy L.L.C. (S&L).
It was prepared by S&L for use by S&L, its clients, their contraclors, subcontractors, and bidders on projects where S&L provides engineering services and shall not otherwise be reproduced in whole or in part or released to any third party without the prior written consent of S&L.
Copyright Sargent & Lundy, LLC. 2010 all rights reserved
o.
PC-Action Required: No Due Date: N/A July 16, 2014 Mr. Jon Hook Design Engineering Manager FENOC Davis-Besse Nuclear Power Station 5501 North State Route 2 Oak Harbor, OH 43449
Subject:
Bechtel Job Number 25593 Letter/File No.:
25593-000-TCM-GEG-00014 Review Calculation C-CSS-099.20-063. "Shield Building Design Calculation". Rev. 1
References:
1.
Calculation C-CSS-099.20-063, Shield Building Design Calculation, Main Body,Rev.1 2.
Calculation C-CSS-099.20-063, Shield Building Design Calculation, Attachment A,Rev.1 3.
CR-2013-14097
Dear Mr. Hook:
Bechtel has reviewed Revision 1
of Calculation C-CSS-099.20-063 and the supporting documentation provided by FENOC. This information (Refs.1-3) indicates that all new cracks, as identified in the 8 core bores, are within the shoulder areas and that all cracks observed in the original inspection as well as the newly identified cracks remain within the previously observed crack width magnitudes (maximum 0.013 inches).
Based on the information provided and our limited review of that information, it is our opinion that this new observed cracking is within the bounds of the testing program carried out at the Purdue University and the University of Kansas related to rebar splice capacity and does not affect the conclusions reached as the result of that testing.
Furthermore, the new observed cracking also does not adversely affect the seismic loading distributions in the Shield Building, as documented in Attachment A of Calculation C-CSS-099.20-063. Therefore, the analyses and designs performed in Rev. 0 of the Design Basis Calculation remain valid for this newly observed cracking as documented in Ref.3.
Note that the "Full Apparent Cause Evaluation", as included as part of CR-2013-14097, is not within the scope of review performed by Bechtel.
BECHTEL POWER CORPORATION
^eHTz^oe usa
>>i (301) aaa^ooo
0-A-Umo of p-^ico.
4-PC-25593-000-TCM-GEG-00014 July 16, 2014 Page 2 of 2 If you have any questions or comments, please call me at 301-228-8087.
- Regards, Douglas Dismukes Project Engineer
Enclosure:
- 1) Comment List by Bechtel cc:
Bechtel C. Ravotta J. Munshi H. Liu W. Hickerson S. Routh FENOC J. Hook T. Henry R. Bair
P&
07/16/2014 Review Comments on Calculation C-CSS-099.20-063, Rev.l (Main Body and Att. A)
Main Comment:
1.
We suggest that the original contents/language of Rev.O calculation not be changed to reflect the outcome of ongoing monitoring.
Instead, such updates should be managed and dispositioned separately by either adding an "UPDATE" upfront in this calc or as a new addendum to the calc.
This way, monitoring effect can be captured in a clean manner that preserves the original calc.
With the current approach, we will accumulate language over time from periodic monitoring that will in time clutter the calc and confuse the reader.
Other Comments:
1.
A new map should be added, or the existing one updated, to show the new cracks or crack growth (For example, create a new map from Figure Al to include the 8 core bore locations).
2.
Main Body and Attachment A. We suggest you delete the following sentence as it is addressed separately (in RCA).
It does not add value to this calculation and is beyond our scope of review or confirmation:
"Through the investigation into this condition, it has been determined that moisture within the structure had migrated to the existing laminar cracks and that the subsequent freezing of this moisture caused the crack growth."
3.
In Attachment A of Calculation C-CSS-099.20-063
. Page 3, it is stated that"...the width of the cracks remains bounded by the previously identified maximum width of 0.013 inches." Note that 0.013" is merely an observation rather than a criterion.
It should not be used to bound crack widths for future observations because there is no technical basis to support it. Suggest deleting 0.013" and instead use something like "in line or within previously observed crack widths".
4.
Attachment A of Calculation C-CSS-099.20-063
, Page 12, describes the Shoulder ID's for un-cracked or cracked locations.
It should be understood that in the Rev.O calculation, the global effect of cracking was conservatively estimated based on careful evaluation of the crack map showing the distribution and extent of cracking at various locations. This calculation did not explicitly include the information about which shoulder, flute or area outside these regions was cracked or un-cracked into the model.
Rather an aggregate effect of such cracking was represented in the lumped mass stick model to represent the stiffness distribution at various Pagel
O.
A-O9? 50 levels.
Therefore, we believe specific details about which shoulder may or may not have shown more cracking is not relevant here and should be included in the updated crack map (see Comment #1).
The logic should be: review of the new crack map confirms that the estimated 70% and 20% crack area in different regions used in Att. A, Rev.O is still valid.
5.
Main Body, Section 2.0, Summary of Conclusion. The discussions should be expanded on why the new crack propagation does not violate the two limiting factors.
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Page 2
FirstEnerpv DESIGN VERIFICATION RECORD Page 1
of 1 NOP-CC-2001-01 Rev. 00 SECTION I:
TO BE COMPLETED BY DESIGN ORIGINATOR DOCUMENT(S)/ACTIVITY TO BE VERIFIED:
Shield Building Design Calculation, C-CSS-099.20-063 Rev 001 SAFETY RELATED
AUGMENTED QUALITY
NONSAFETY RELATED SUPPORTING/REFERENCE DOCUMENTS Refer to the body of the calculation DESIGN ORIGINATOR:
(Print and Sign Name)
"7 hem at,
- -iff\\f/
DATE SECTION II:
TO BE COMPLETED BY VERIFIER VERIFICATION METHOD (Check one)
[5j DESIGN REVIEW (Complete Design Review Checklist or Calculation Review Checklist)
ALTERNATE CALCULATION QUALIFICATION TESTING JUSTIFICATION FOR SUPERVISOR PERFORMING VERIFICATION:
APPROVAL:
(Print and Sign Name)
A DATE EXTENT OF VERIFICATION:
a COMMENTS, ERRORS OR DEFICIENCIES IDENTIFIED?
YES NO RESOLUTION: (For Alternate Calculation or Qualification Testing only)
RESOLVED BY:
(Print and Sign Name)
DATE VERIFIER:
(Print and Sign Name)
DAT APPROVED BY:
(Prift and Sign Name) fz DATE Ml
CALCULATION REVIEW CHECKLIST NOP-CC-2001-04 Rev. 05 QUESTION General 1
Does the stated objective/purpose clearly describe why the calculation is being performed?
2.
Are design input / output documents and references listed and clearly identified in the document index, includinq edition and addenda, where applicable?
3.
Were verbal inputs from third parties properly documented?
4.
Are design input parameters, such as physical and geometric characteristic and regulatory or code and standard requirements, accurately taken from the design input documents and correctly incorporated, includinq tolerances and units?
5.
Are the design inputs relevant, current, consistent with design/licensing bases and directly applicable to the purpose of the calculation, including appropriate tolerances and ranqes/modes of operation?
6 Are all design inputs retrievable?
If not, have they been added as attachments?
7.
Are preliminary or conceptual inputs clearly identified for later confirmation as open assumptions?
8.
Where applicable, were construction and operating considerations included as input information?
9 Were desiqn input / output documents properly updated to reference this calculation?
Assumptions 10.
Have the assumptions necessary to perform the analysis been clearly identified and adequately described?
11.
Are all assumptions for the calculation reasonable and consistent with design/licensing bases?
12.
Have all open assumptions needing later confirmation been clearly identified on the Calculation cover sheet, including when the open assumption needs to be closed?
13 Has an SAP Activity Initiation Form been created for open assumptions?
14 Have engineering judgments been clearly identified?
15 Are engineering judqments reasonable and adequately documented?
16.
Is suitable justification provided for all assumptions/engineering judgements (except those based upon recognized engineering practice, physical constants or elementary Method of Analysis 17 Is the method used appropriate considering the purpose and type of calculation?
18.
Is the method in accordance with applicable codes, standards, and design/licensing Identification of Computer Codes (Ref: NOP-SS-1001) 19.
Have the versions of the computer codes employed in the design analysis been certified for this application?
20 Are codes properly identified alonq with source (vendor, organization, etc.)?
21 Is the code applicable for the analysis being performed?
22.
Is the computer program(s) being used listed on the FENOC Usable Software List for the site?
NA y
</
/
/
Yes
/
V J
y No CALCULATION NO.
REV. c o I
ADDENDUM NO.
^lA UNIT D6oi
- sets
/iiYflCW, A
RESOLUTION
FirstEnercw CALCULATION REVIEW CHECKLIST NOP-CC-2001-04 Rev. 05 QUESTION 23.
Does the computer model, that has been created, adequately reflect actual (or to be modified) plant conditions (e.g., dimensional accuracy, type of model/code options used, time steps, etc.)?
24.
Did the computer output generate any ERROR or WARNING Messages that could invalidate the results?
25 Is the computer output reasonable when compared to inputs and what was expected?
Computations 26.
Are the equations used consistent with recognized engineering practice and design/licensing bases?
27.
Is there a reasonable justification provided for the uses of any equations not in common use?
28.
Were the mathematical operations performed properly and the results accurate?
29.
Have adjustment factors, uncertainties, empirical correlations, etc., used in the analysis been correctly applied?
30.
Is the result presented with proper units and tolerance?
31.
Has proper consideration been given to results that may be overly sensitive to very small changes in input?
Conclusions 32 Is the maqnitude of the result reasonable and expected when compared to inputs?
33 Is there a reasonable justification provided for deviations from the acceptance criteria?
34.
Are stated conclusions justifiable based on the calculation results?
35.
Are all pages sequentially numbered and marked with a valid calculation and revision number?
36.
Is all information legible and reproducible?
37.
Is the calculati back to the Or an presentation complete and understandable without any need to refer qinator for clarification or explanations?
38.
Is calculation format presented in a logical and orderly manner, in conformance with the standard calculation content of NOP-CC-3002 (Attachment 1)?
39.
Have all changes in the documentation been initialed (or signed) and dated by the author of the chanqe and all required reviewers?
Design/Licensing 40 Have all calculation results stayed within existing desiqn/licensing basis parameters?
41.
If the response to Question 40 is NO, has Licensing been notified as appropriate? (i.e.
UFSAR or Tech Spec Chanqe Request has been initiated).
42.
Is the direction of trends reasonable?
43.
Has the calculation Preparer used all applicable design information/requirements provided?
44.
Did the calculation Preparer determine if the calculation was referenced in design basis documents and/or databases?
45 Did the Preparer determine if the calculation was used as a reference in the UFSAR?
46.
If the calculation is used as a reference in the UFSAR, is a change to the UFSAR required or an update to the UFSAR Validation Database, if applicable, required?
47 If the answer to Question 46 is YES, have the appropriate documents been initiated?
NA
/
y y
Yes y
y
/
/
i y
y y
- f s
y y
y y
y y
y y
y No CALCULATION NO.
c-ccc-oqqjg cg>j?
REV. OOI ADDENDUM NO. *J /A UNIT f>fi<3i COMMENTS RESOLUTION
CALCULATION REVIEW CHECKLIST NOP-CC-2001-04 Rev. 05 COMMENTS Page 3 Of 3 CALCULATION NO.
c-REV. oo l
ADDENDUM NO.
a/I A UNIT QUESTION NA Yes No RESOLUTION 48.
Has the applicability of 10CFR50.59 to this calculation been considered and documented?
Acceptable 49.
Does the calculation meet its purpose/objective?
50.
Is the calculation acceptable for use?
51.
What checking method was used to review the calculation?
Check all that apply.
spot check for math complete check for math comparison with tests check by alternate method comparison with previous calculation 52.
If the calculation was prepared by a vendor, does it comply with the technical and quality requirements described in the Procurement Documents?
Reference the Purchase Order number or other procurement document number in the Comments Section of this question.
53.
Have Professional Engineer (PE) certification requirements been addressed and documented where required by ASME Code (if applicable).
Review Summary:
Technical Review (Print and Sign Name)
Design Verification (Print andjtign Name) 5^
Date Date Owner's Acceptance Review (Required for calculations prepared by a vendor)
Reviewer (Print and Sign Name)
Approver (Print and Sign Name
\\
Date Date
FirstEnergy DESIGN INPUT RECORD Page 1
of 4 NOP-CC-2002-01 Rev. 03 Related Design Activity:
Shield Building Design calculation Revision:
0
BV1
BV2 DB U
PY Title of Design Activity Calculation C-CSS-099.20-063 Safety Class ASME Class Seismic Category IEEE Class Env. Zone Responsible Engineer Discipline DBMS Printed Name R.Dair
.Signature Date Contributing Engineer Contributing Engineer Reviewer DBMS T.Henry Vnl 13 Reviewer DBEA M.Nelson Engineering Supervisor (Required if DIR is revised and a revision to the Engineering Change package is not required)
J.Hook Design Input Considerations Design Inputs include, but are not limited to, the following, where applicable.
Design Input Source (ID, Revision/Version, Section, Design Input (Design Parameters, Limitations, Conditions)
NUCLEAR SAFETY CONSIDERATIONS Basic functions of each structure, system, and component affected.
Design Criteria Manual (DCM), Rev.
32 DCM Section M.J.I, Rev. 0 provides the basic functions of the Shield Building (SB).
Redundancy, diversity, and separation requirements of structures, systems, and components.
NA NA Failure effects requirements of structures, systems, and components, including a definition of those events and accidents which they must be designed to withstand and, when applicable, a single failure analysis of Class 1E systems.
DCM Section II.J.1 Rev. 0, II.H.3.3.1 Rev. 3 The referenced DCM sections describe the events and accidents that the SB is designed to withstand.
Other requirements to prevent undue risk to the health and safety of the public or environmental impact.
NA NA Regulatory Requirements (Reg. Guides, NUREG's, NRC Correspondence and commitments, specific NRC design criteria, general design criteria, etc.)
USAR Section 3.8.2.2, Rev. 29 USAR Section 3.8.2.2 describes the regulatory basis for the design of the SB. This includes the descriptions of Appendixes 3A, 3B, 3C,and 3D.
OPERATING CONSIDERATIONS Performance requirements, such as capacity, rating, system output.
NA NA
F/rstiEnengv Page 2 of 4 DESIGN INPUT RECORD NOP-CC-2002-01 Rev. 03 Related Design Activity:
Shield Building Design calculation Desi 7.
8 9.
10.
11.
Design Input Considerations n Inputs include, but are not limited to, the followinq, where applicable Design conditions, such as pressure, temperature, fluid chemistry, and voltage.
Interface requirements, including definition of the functional and physical interfaces involving structures, systems, and components.
Hydraulic requirements, such as pump net positive suction heads (NPSH), allowable pressure drops and allowable fluid velocities.
Operational requirements under various conditions (Operating Manual), such as plant startup, normal plant operation, plant shutdown, plant emergency operation, and system abnormal or emergency operation (e.g.,
flood conditions, earthquake, tornado, chemical sprays, electrical shorts, pipe whip, jet impingement, internally generated missiles, etc.).
Test requirements, including in-plant tests, code required tests, and the conditions under which they will be performed.
Design Input Source (ID, Revision/Version, Section, Page)
Calculation C-NSA-000.02-016, Rev. 00, Calculation C-NSA-000.02-005 Rev. 02 A05, and Calculation C-NSA-000.02-006 Rev.
1 A02 Drawing M-0120 Rev. 17 Drawing M-0123 Rev. 30 NA NA NA Revision:
0 Design Input (Design Parameters, Limitations, Conditions)
Calculation C-NSA-000.02-016 provides the maximum pressure and temperature for the main steam line rooms following a postulated steam line break.
Calculation C-NSA-000.02-005 provides the max pressure in the Annulus due to a main feedwater line break in the Aux Bldg.
Calculation C-NSA-000 02-006 provides the maximum temperature in the Annulus due to a steam generator blowdown line break in the Annulus.
Dwg. M-120 shows the relationship of the SB to the Aux.Bldg.
main steam line rooms 601
& 602.
Dwg M-123 shows the relationship of the SB, Annulus, and Aux Bldg mechanical penetration rooms 303 & 314.
NA NA NA STRESS/SEISMIC CONSIDERATIONS 12.
13.
Loads, such as seismic, wind, thermal, and dynamic and fatigue Mechanical/Structural requirements such as vibration,
- stress, shock, and reaction forces.
Calculation VS21/B001-001, Rev.
01 DCM Sections ID.2 Rev.
3, ID.3 Rev. 3 DCM Section II.G.2.4 Rev. 3 NA Calculation VS21 details the OBE & SSE applicable to the Shield Building, DCM Section I. D specifies the design basis winds, tornado wind, dP, and missile loads applicable to the SB.
DCM Section II.G.2.4 specifies the soil and hydrostatic pressure loads applicable to the SB.
NA
F/rstEhencjy Page 3 of 4 DESIGN INPUT RECORD NOP-CC-2002-01 Rev. 03 Related Design Activity:
Shield Building Design calculation Design Input Considerations Design Inputs include, but are not limited to, the following, where applicable 14.
Structural requirements, such as equipment foundations and pipe supports.
Design Input Source (ID, Revision/Version, Section, Page)
DCM Section II.G 5 Rev.
1
& H.3 Rev. 3 Revision:
0 Design Input (Design Parameters, Limitations, Conditions)
DCM Section II.G.5 describes the various loads applicable to the SB.
DCM Section II.H.3 describes the load combinations and allowable loads/stresses for this structure.
ENVIRONMENTAL CONSIDERATIONS 15.
Environmental conditions anticipated during storage, construction, and operations, such as pressure, temperature, humidity, corrosiveness, site evaluation, wind direction, nuclear radiation, electromagnetic interference and duration of exposure.
DCM Section II.D.7 Rev.
1 Calculation C-NSA-000.02-005, Rev. 02, Addendum A05 Calc. C-NSA-000.02-006, Rev.
1, A02 Calc. C-NSA-000.02-016, Rev. 0 This section of the DCM states a minimum air temperature of
-10F.
Calc. C-NSA-000.02-005 calculates the maximum annulus pressure due to main feedwater line breaks in the Auxiliary Building.
Calc C-NSA-000.02-006 calculates the maximum annulus temperature due to a steam generator blowdown line break in the Annulus.
Calc. C-NSA-000.02-016 calculates the maximum temperature and pressure in the main steam line rooms following a postulated steam line break.
CODES, STANDARDS, MATERIAL CONSIDERATIONS 16.
17.
18.
19.
20.
Material requirements, including such items as compatibility, electrical insulation properties, protective coating and corrosion and faiigue resistance.
Chemistry requirements, such as provisions for sampling and limitations on water chemistry.
Codes and/or standards appropriate for the design, including applicable code year/addenda.
Fire Protection or resistance requirements.
Materials, processes, parts and equipment suitable for application.
NA NA ACI 307-69, ACI 318-63 NA NA NA NA DCM Section II.H.2.5.1.5 describes Shield Building design codes NA NA
FirstEnergy Page 4 of 4 DESIGN INPUT RECORD NOP-CC-2002-01 Rev. 03 Related Design Activity:
Shield Building Design calculation Design Input Considerations Design Inputs include, but are not limited to, the following, where applicable Design Input Source (ID, Revision/Version, Section, Page)
Revision:
0 Design Input (Design Parameters, Limitations, Conditions)
SPECIAL HANDLING CONSIDERATIONS 21.
22 Transportability requirements, such as size and shipping weight, limitations, I.C.C. regulations.
Handling, storage, and shipping requirements.
NA NA NA NA PHYSICAL SAFETY, ACCESSIBILITY, LAYOUT CONSIDERATIONS 23.
24.
25.
26.
Layout arrangement requirements.
Access and administrative control requirements for plant security.
Accessibility, maintenance, repair, and inservice inspection requirements for plant, including the conditions under which these will be performed.
Safety requirements for preventing personnel injury, such items as radiation hazards, post accident vital access restricting the use of dangerous materials, escape provisions from enclosures, and grounding of electrical systems.
NA NA NA NA NA NA NA NA OTHER 27.
28.
29.
30.
31 Electrical requirements, such as source of power, voltage, raceway requirements, electiical insulation and motor requirements Instrumentation and control requirements, including indicating instruments, controls and alarms required for operations, testing and maintenance.
Other requirements, such as the type of instrument, installed spares, range of measurement, and location of indication should also be considered.
Personnel requirements and limitations, including the qualification and number of personnel available for plant operation, maintenance, testing, and inspection and permissible radiation exposures for specified areas and conditions.
Digital upgrade considerations and requirements including EMI/RFI considerations, software/firmware control, and compliance with EPRI guidelines.
Other:
NA NA NA NA NA NA NA NA NA NA NA
fi DESIGN INTERFACE
SUMMARY
NOP-CC-2004-09 TT Calculation No.
Rev. No 1
Page 1
of 7 C-CSS-099.20-063(r)
BV1 BV2 PY DB X
Chemistry - Environmental
[6]
1.2 2.1 5.3 6.3 6.11 General Impacts Misc Mechanical Interfaces Materials Plant Controls
- Human Factors Chemical / Environmental NOTE:
Ail fields marked with an asterisk are mandatory.
Chemistry - Plant Chemistry [28]
1.2 5.3 General Impacts Materials NOTE:
All fields marked with an asterisk are mandatory.
Design Eng - Elec / I&C, Misc Electrical [20]
1.2 General Impacts 2.1 Misc Mechanical Interfaces 3.1 Misc Electrical Interfaces 6.1 FIRE Protection / Safe Shutdown NOTE:
All fields marked with an asterisk are mandatory.
Design Eng - Elec / I&C, Misc I&C [51]
1.2 General Impacts 2.1 Misc Mechanical Interfaces 4.1 Misc I&C Interfaces 6.3 Plant Controls
- Human Factors NOTE:
All fields marked with an asterisk are mandatory.
Design Eng - Elec / I&C, Security Systems [81]
DIE ISSUED SMA 1.1 Mandatory DIEs, Program & Procedure Interfaces NOTE:
All fields marked with an asterisk are mandatory.
FirstEhergy DESIGN INTERFACE
SUMMARY
NOP-CC-2004-09 CT CT Calculation No.
Rev. No 1
Page 2 of 7 C-CSS-099.20-063^
BVl D BV2 py DB Design Eng
- Elec / I&C, Safe Shutdown [52]
1.1 Mandatory
- DIEs, Program & Procedure Interfaces 1.2 General Impacts 3.1 Misc Electrical Interfaces 6.1 FIRE Protection / Safe Shutdown NOTE: All fields marked with an asterisk are mandatory.
Design Eng - Engineering Analysis, Misc. [1]
1.2 General Impacts 2.1 Misc Mechanical Interfaces 6.2 Rx Containment Bldg & Drywell 6.7 IMSSS Design Basis 6.8 Internal Missile Hazards 6.9 Reactivity Ctrl, Accident, & Core Reload Analysis NOTE:
All fields marked with an asterisk are mandatory.
Design Eng
- Engineering Analysis, PSA [2]
DIE ISSUED SMA 6.5 PSA Probabilistic Safety Assessment NOTE:
All fields marked with an asterisk are mandatory.
Design Eng, Mech /
Structural
- Buildings & Struct [67]
DIE ISSUED SMA 1.2 General Impacts 6.2 Rx Containment Bldg & Drywell NOTE:
All fields marked with an asterisk are mandatory.
Design Eng, Mech / Structural - Misc. Mechanical [21]
1.2 General Impacts 2.1 Misc Mechanical Interfaces 5.3 Materials 6.2 Rx Containment Bldg & Drywell
FffstEherav DESIGN INTERFACE
SUMMARY
NOP-CC-2004-09 BV1 BV2 PY
Calculation No.
Rev. No 1
Page 3 of 7 C-CSS-099.20-063(})
DB X
6.3 Plant Controls
- Human Factors NOTE:
All fields marked with an asterisk are mandatory.
Design Eng, Mech
/
Structural
- Misc. Structural [60]
1.2 Genera] Impacts 2.1 Misc Mechanical Interfaces 5.1 Misc Structural Interfaces 5.2 Seismic Considerations 6.2 Rx Containment Bldg & Drywell NOTE:
All fields marked with an asterisk are mandatory.
Design Eng, Mech /
Structural
- Seismic [65]
3.1 Misc Electrical Interfaces 5.2 Seismic Considerations NOTE:
All fields marked with an asterisk are mandatory.
Emergency Response [9]
DIE ISSUED SMA 1.2 General Impacts NOTE:
All fields marked with an asterisk are mandatory.
Industrial Safety [18]
DIE ISSUED SMA 1.2 General Impacts NOTE:
All fields marked with an asterisk are mandatory.
Maintenance - Procedures
[40]
1 1
"Mandatory DIEs, Program & Procedure Interfaces NOTE:
All fields marked with an asterisk are mandatory.
Maintenance
- Support Programs [48]
DIE ISSUED SMA 1.2 General Impacts NOTE:
All fields marked with an asterisk are mandatory.
firstEherov DESIGN INTERFACE
SUMMARY
NOP-CC-2004-09 CT TT Calculation No.
Rev. No 1
Page 4 of 7 C-CSS-099.20-063l1>)
BV1 BV2 Maintenance - Work Planning [33]
DIE ISSUED SMA 1.1 "Mandatory DIEs, Program & Procedure Interfaces 1.2 General Impacts NOTE:
All fields marked with an asterisk are mandatory.
Operations - Unit 1 [5]
1.2 2.1 5.2 5 3 General Impacts Misc Mechanical Interfaces Seismic Considerations Plant Controls
- Human Factors I
I 6.9 Reactivity Ctrl, Accident, & Core Reload Analysis NOTE:
All fields marked with an asterisk are mandatory.
Operations Services
- Emergency Response Squad [53]
DIE ISSUED SMA 1.2 General Impacts NOTE:
All fields marked with an asterisk are mandatory.
Operations Services
- Fire Marshal
[54]
1.2 General Impacts 2.1 Misc Mechanical Interfaces 6.1 FIRE Protection / Safe Shutdown NOTE:
All fields marked with an asterisk are mandatory.
Operations Services
- Procedures [30]
- Mandatory
- DIEs, Program & Procedure Interfaces i
i 1.2 General Imparts NOTE:
All fields marked with an asterisk are mandatory.
Plant & Equip Reliability Eng
- Cyber Security [76]
DIE ISSUED SMA 1.2 General Impacts
FirstEherov DESIGN INTERFACE
SUMMARY
NOP-CC-2004-09 Calculation No.
Rev. No 1
Page 5
of 7 C-CSS-099.20-063(l)
BV1 BV2
PY u
DB D
£.3 Plant Controls
- Human Factors NOTE:
All fields marked with an asterisk are mandatory.
Plant & Equip Reliability Eng - Reactor Eng [24]
DIE ISSUED SMA 1.2 General Impacts 2.1 Misc Mechanical Interfaces 6.9 Reactivity Ctrl, Accident, & Core Reload Analysis NOTE:
All fields marked with an asterisk are mandatory.
Plant & Equip Reliability Eng [22]
1.1
'Mandatory DIEs, Program & Procedure Interfaces 1.2 General Impacts 2.1 Misc Mechanical Interfaces NOTE:
All fields marked with an asterisk are mandatory.
Plant & Equip Reliability Engr - E & IC [110]
DIE ISSUED SMA 1.2 General Impacts NOTE:
All fields marked with an asterisk are mandatory.
Project Management - Refueling Engineering [77]
DIE ISSUED SMA 6.10 Refueling Equipment & Rx Assembly NOTE:
All fields marked with an asterisk are mandatory.
Radiation Protection
[7]
DIE ISSUED SMA 5.3 6.6 General Impacts Materials Radiation Protection
- ALARA NOTE:
All fields marked with an asterisk are mandatory.
Site Protection
- Operations [42]
DIE ISSUED SMA 1.1 "Mandatory DIEs, Program & Procedure Interfaces
DESIGN INTERFACE
SUMMARY
NOP-CC-2004-09 Calculation No.
Rev. No 1
Page 6 of 7 C-CSS-099.20-063(l>)
BV1 BV2 PY D
1.2 General Impacts 6.6 Radiation Protection
- ALARA NOTE:
All fields marked with an asterisk are mandatory.
Tech Svcs Eng, Eng Programs - Appendix J [59]
DIE ISSUED SMA 3.1 Misc Electrical Interfaces 6.2 Rx Containment Bldg & Drywell NOTE:
All fields marked with an asterisk are mandatory.
Tech Svcs Eng, Eng Programs
- EQ [55]
DIE ISSUED SMA 1.2 General Impacts 3.1 Misc Electrical Interfaces NOTE:
All fields marked with an asterisk are mandatory.
Tech Svcs Eng, Eng Programs - FAC [80]
7.1 Misc Mechanical Interfaces NOTE:
All fields marked with an asterisk are mandatory.
Tech Svcs Eng, Eng Programs
- ISI [56]
1.2 General Impacts 2.1 Misc Mechanical Interfaces NOTE:
All fields marked with an asterisk are mandatory.
Tech Svcs Eng, Eng Programs - 1ST, NDE, Boric Acid [57]
1.2 General Impacts 2.1 Misc Mechanical Interfaces 5.3 Materials 6.5 PSA Probabilistic Safety Assessment NOTE:
All fields marked with an asterisk are mandatory.
Tech Svcs Eng, Eng Programs
- Maintenance Rule [58]
RrstEne/w DESIGN INTERFACE
SUMMARY
NOP-CC-2004-09 Calculation No.
Rev. No 1
Page 7 of 7 C-CSS-099.20-063(l)
[7]
6.4 Maintenance Rule 10CFR 50.65 NOTE:
All fields marked with an asterisk are mandatory.
Tech Svcs Eng, Eng Programs - Misc Programs [27]
1.2 General Impacts 2.1 Misc Mechanical Interfaces 5.1 Misc Structural Interfaces NOTE:
All fields marked with an asterisk are mandatory.
Training
- Services [46]
1.1 2.1
'Mandatory DIEs, Program & Procedure Interfaces Misc Mechanical Interfaces NOTE:
All fields marked with an asterisk are mandatory.
Training - Simulator [8]
DIE ISSUED SMA 1.1 Mandatory DIEs, Program & Procedure Interfaces 1.2 General Impacts
Plant Controls
- Human Factors NOTE:
All fields marked with an asterisk are mandatory.
COMMENTS Calculation C-CSS-099.20-063 is being prepared by Design Engineering Mechanical/Structural Unit. Therefore, no formal response to DIE 60 is required. The mandatory design interfaces {8, 22, 30, 33, 40, 42, 46, 52, 54, & 81) are not required for this passive change to the analysis of the Shield Building and these DIEs are waived.
DIE 1 Revision 1 is provided to address thg Final Review of DIE input from Revision 0 of the calculation, f tZ^V-Supervisor:
f^/vVw. ^ -J*
^'FuT^
'r^/ftf fyj.
jflCt Prepared By:
Henry, Thomas.
Date:
"'\\n\\ta <Y Reviewed By:
- Bair, Richard Date O
fifStEhggy DESIGN INTERFACE EVALUATION Page l of 2 NOP-CC-2004-07 Modification/ Document/Activity Calculation C-CSS-099.20-063 Shield Building Design Calculation Proposed Rev.
0 DIE No./Rev.
i/o SECTION 1
SUMMARY
OF CHANGE 8. POTENTIAL IMPACT To: Interfacing Organization Design Eng
- Engineering Analysis, Misc.
Point of Contact Blakely, Dennis Mail Stop A-DB-3105 Due Date 07/25/2013 From/Return To: (Responsible Engineer)
Bair, Richard Mail Stop A-DB-3105 Phone 419-321-6277 Description of Change/Areas of Concern Calculation C-CSS-099.20-063 documents the new design basis analysis of the Shield Building. The Shield Building interfaces with various areas of the Auxiliary Building that are subject to pressurization due to postulated High Energy Line Breaks (HELB). The applicable pressurization calculations and the associated HELB pressures are required to be evaluated in the new Shield Building analysis.
SECTION 2
- RESPONSE REFER TO NOP-CC-2004, SECTION 4.2.1 AND ATTACHMENT 1 FOR GUIDANCE.
DIRC Impacts)
- Evaluate impact identified by the following questions from the Design Interface Review Checklist Topic/Question No.
Question 1.2/2.0 1.2/2^
Note:
Does the change require doors, hatches, Plugs, shake / rattle space seals, fire seals, penetrations, and/or blowout panels being removed or blocked open during implementation ? Impacts to consider include:
Flooding or High Energy Line Break (HELB)
Other Impacts) - Evaluate impact from the following General and Subject Matter Expert level questions.
Describe the effect on the current licensing basis for the system
/ structure / component (SSC) involved.
Describe effect of proposed change on existing design basis.
Identify relevant design criteria and standards (including applicable revision/addenda).
Identify potential failure mechanisms and failure consequences Describe the impact on operational configuration, system interactions, and any other pertinent considerations. Identify required actions.
Identify appropriate installation requirements and acceptance criteria for testing identify any limitations such as open assumptions or engineering holds. Identify what is restrained and what is required to release the hold.
F the change will add, modify, or delete equipment, components, systems, or processes that result in the need for personnel to acquire additional skills and knowledge, THEN complete the Affected Documents section below.
Identify Training as the Document Type, assign an Action Code, and Responsible Organization.
FirstiEhagy Page 2 of 2 DESIGN INTERFACE EVALUATION NOP-CC-2004-07 Modification/Document/Activity Calculation C-CSS-099.20-063 Shield Building Design Calculation Proposed Rev.
0
DIE No./Rev.
COMMENTS/ADDITIONAL INPUT/INFORMATION (1)
Discussions with Design Civil indicate that high energy line break (HELB) loads need to be included in the calculation.
The Engineering Analysis Unit calculations that need to be reviewed for potential HELB pressure and temperature loads affecting the Shield Building (external and annulus-side) are as follows:
(a) C-NSA-000.02-005, R02, MAIN FEEDWATER LINE BREAKS AND CRACKS IN THE AUXILIARY BUILDING (b) C-NSA-000.02-006, R01, STEAM GENERATOR BLOWDOWN LINE BREAKS IN THE AUXILIARY BUILDING (c) C-NSA-000.02-007, R02, MAIN STEAM TO AFW PUMP TURBINE LINE BREAKS AND CRACKS IN THE AUXILIARY BUILDING (d) C-NSA-000.02-009, R02, AUXILIARY STEAM LINE BREAKS AND CRACKS IN THE AUXILIARY BUILDING (e) C-NSA-OOG.02-012, R01, AUXILIARY BUILDING HELB PRESSURE ANALYSIS USING GOTHIC 7.0 (>>> PRESSURE ONLY <<<)
(f) C-NSA-000.02-016, R00, 36 INCH MAIN STEAM LINE BREAK IN ROOMS 601 AND 602 The addendums of each calculation need to be reviewed, as appropriate.
USAR Table 3.6-11 (and any outstanding Change Notices) provides a convenient listing of peak HELB temperatures that can be used as a guide in identifying calculations that could potentially affect the Shield Building.
Engineering Analysis Unit calculations do not evaluate any jet impingement loads.
(2) Page 10, 'Temperature load" paragraph: A reference is needed for the LOCA temperature gradient.
(3) General:
Do negative pressure loads in the annulus other than tornado need to be condsidered?
(e.g., calculation 060.013)
AFFECTED DOCUMENTS List new and/or existing documents requiring issue/update as a result of this activity (e.g., drawings, procedures, databases, lesson plans, and vendor manuals).
It is presumed the latest revision/version of the document was used when identifying the impact.
Document Type Document I.D.
Unit Rev Version Document Owner/Responsible Organization Action Code*
Notification No.'
'Action Codes:
1
- Required for Operational Acceptance.
2 - Required for implementation. Requires an Engineering Hold per NOP-CC-2003.
3 - Required to be issued concurrent with the change package.
4 - Required for closeout of the activity.
5 - Later - can be completed when responsible organization deems appropriate. "Requires a SAP Notification number.
^f Sinterface Not Required (Provide Justification)
SECTION 3 -CONCLUSION The proposed activity is the release of engineering calculation, C-CSS-099.20-063, R00, "Shield Building Design Calculation."
This calculation documents a revised Shield Building design analysis that includes laminar cracking.
The proposed calculation does not have any output documents that affect any calculations that are the responsibility of the Engineering Analysis Unit Therefore, completion of a Design Interface Evaluation is not required.
See the "Comments/Additional Input/Information" section for comments concerning high energy line break inputs and other review comments.
fo Interface Provided (Indicate if Final Review required) lS Final Review Required Interface EvaluatorJPrint Name and£ig Nelson, Michael" Date lApproval" (Print Name, and Sign) 07/12/2013 lBlakely, Dennis Date D
Comments need to be resolved Interface Evaluator pate My comments/input have been properly incorporated and/or addressed.
Interface Evaluator
- Required for Engineering Organizations rvcu.se>
see 3CS i£$,
see
firstEnergy REGULATORY APPLICABILITY DETERMINATION NOP-LP-4003-01 Rev. 03 Page 1
of 3
No.
13-00918 Rev.
02 Initiating Activity No.
Calculation Calculation C-CSS-099.20-063 Rev.
Title:
Shield Building Design Calculation Brief description of activity (what is being changed and why):
A temporary construction opening was created in the Shield Building (SB) for the reactor vessel closure head replacement project in 2011. During concrete removal, laminar cracking was observed in the plane of the outer reinforcement layer in the areas around the temporary construction opening. Subsequent inspection discovered laminar cracking also existed in the plane of the outer reinforcement layer for most of the architectural flute areas, two main steam line penetration areas, and the top 20 feet (approximate) of the cylindrical shell. Detailed technical investigation of the SB, followed by consultations with industry experts, concluded that the laminar cracking does not lead to any adverse impact on the structural adequacy of the SB.
Confirmatory testing, using conservative test specimen configurations, determined the effects of laminar cracking on the strength of lap-splices for the outer circumferential reinforcement.
A new SB calculation, C-CSS-099.20-063, provides the new design evaluation of the SB, including the effects of the laminar cracking, for the cylindrical shell wall, dome, and spring line areas of the structure. The new calculation does not replace the existing design evaluations for the areas near the penetrations and permanent openings, and the foundation. For the areas not within the scope of the new calculation, the existing analysis and design methods, results, and conclusions described in USAR Section 3.8.2.2 remain valid.
Revisions of the existing SB calculations for the areas of the structure evaluated by the new calculation are not within the scope of this activity.
Considering the effects of SB laminar cracking involves changes to the existing USAR-described Section 3.7.2.1.1 seismic analysis and the Section 3.8.2.2.1 safety analyses, as well as addition of Appendix 3E for the detailed description of the changes. The changes include a revision to the described design strength of the outer circumferential reinforcement in the cylindrical shell (input parameter) and the described method of evaluation for structural analysis of the SB, with the analysis for the new SB design calculation performed using ANSYS.
Revision 1 Revision 1 addresses the record date and record number discrepancies of a reference used for Revision 0 of the No. 13-00918 Screen and Evaluation. The record number shown in Revision 0 is incomplete and the date shown is incorrect. The same discrepancies also pertain to a reference shown in approved USAR Change Notice No. 13-0070. The discrepancies were addressed for significance by Bechtel CR 23568-000-GCA-GAMG-00024 / FENOC CR-2013-19957.
RAD No. 14-00863 reviewed the RAD and 50.59 impacts of the discrepancies and Change Notice No 14-028 corrected the USAR reference. RAD No. 14-00863 concluded the "entire scope of the activity is exempt from the 10 CFR 50.59 process on the basis that it is limited in its entirety to administrative changes and changes evaluated under another program that included a 10 CFR 50.59 Screen." Therefore, Revision 1
of No. 13-00918 is limited to correcting the record date and number of the reference used for the Screen and Evaluation, and adding Change Notice No 14-028 to Section 3.2 of the RAD and to the "List of Documents Reviewed" section of the Screen.
Revision 2 Revision 2 of this RAD addresses Revision 01 of Calculation C-CSS-099.20-063. This calculation revision is required to document the evaluation of crack propagation areas adjacent to previously identified laminar cracks. USAR Change Notice 14-179 will revise the applicable USAR sections for this condition.
FwsfcEherxjy REGULATORY APPLICABILITY DETERMINATION NOP-LP-4003-01 Rev. 03 Page 2 of 3
No.
13-00918 Rev.
02 Initiating Activity No.
Calculation Calculation C-CSS-099.20-063 Rev.
01 BVPS 1 BVPS 2 DBNPS PNPP 1.
EXEMPTIONS Is the scope of the entire activity exempt from the 10CFR50.59 process because it is limited to:
1.1 Managerial or administrative changes D YES 0 NO 1.2 UFSAR changes (or equivalent information) excluded from the requirement to perform a 10CFR50.59 Screen and Evaluation by NEI 96-07 or NEI 98-03?
YES 0 NO 1.3 Maintenance activities and temporary alterations in support of maintenance planned for 90 days or less while at power D YES 0 NO 1.4 Chanqes evaluated under another program that included a 10CFR50.59 Screen DYES 0 NO 2.
OTHER REGULATIONS 2.1 Does the activity require a license amendment?
2.1.1 Operating License YES 0 NO 2.1.2 Technical Specifications YES 0 NO 2.1.3 Environmental Protection Plan (BVPS and PNPP only)
YES 0 NO 2.2 Is the activity or any portion of the activity governed by one or more of the following regulations:
2.2.1 Quality Assurance Program (10CFR50.54(a))
YES 0 NO 2.2.2 Security Plans (10CFR50.54(p))
DYES 0 NO 2.2.3 Emergency Plan (10CFR50.54(q))
YES 0 NO 2.2.4 1ST Program Plan (10CFR50.55(a)(f))
YES 0 NO 2.2.5 ISI Program Plan (10CFR50.55(a)(g))
YES 0 NO 2.2.6 Fire Protection Program (10CFR50.48)
YES 0 NO 2.2.7 Independent Spent Fuel Storage Facility (10CFR72.48)
YES 0 NO 2.2.8 Another regulation:
Standards For Protection Against Radiation (10 CFR 20 including ODCM)
YES 0 NO Specific Exemptions (10 CFR 50.12)
YES 0 NO ECCS Acceptance Criteria (10 CFR 50.46)
YES 0 NO Environmental Protection (DBNPS only)
YES 0 NO Other-list the regulation(s):
El YES 0 NO
firsf&rergy REGULATORY APPLICABILITY DETERMINATION NOP-LP-4003-01 Rev. 03 Page 3 of 3
No.
13-00918 Rev.
02 Initiating Activity No.
Calculation Calculation C-CSS-099.20-063 Rev.
01 BVPS 1 BVPS 2 0 DBNPS PNPP 3.
CONCLUSION 3.1 Does 10CFR50.59 apply?
0 YES NO 3.2 Does this activity require a change to the UFSAR?
Change Request No:
13-0070,14-028, 0 YES D NO 3.3 Summarize the bases for responses:
Include Keywords used to search documents.
- /V-/7^
<Sd.~>
Keywords:
concrete, missile, shield bldg, annulus, annulus vent, reinforcing, rad shielding, seismic cat I, rad safety, rad Prot, tornado, leak test, pressure test, emerg vent system, cont. purge system, cont. vessel, coating, crack, analytical technique, HELB 1.0 Exemptions
- The scope of the entire activity is not exempt from the 10CFR50.59 process on the basis that it is limited in its' entirety to managerial or administrative changes, USAR changes excluded from the requirement to perform a 10CFR50.59 Screen and Evaluation by NEI 96-07 or NEI 98-03, maintenance activities and temporary alterations in support of maintenance planned for 90 days or less while at power, or, changes evaluated under another program that included a 10CFR50.59 Screen.
2.0 Other Regulations 2.1.1 and 2.1.2 Operating License and Technical Specifications: The calculation provides a new design evaluation of the SB. No changes are required to the Operating License or Technical Specifications as a consequence of the evaluation.
2.2.1 Quality Assurance Program:
The calculation provides a new design evaluation of the SB. There is no adverse impact on the QA Plan.
2.2.2 Security Plan: The calculation provides a new design evaluation of the SB. The security plan is not affected.
2.2.3 Emergency Plan: The calculation provides a new design evaluation of the SB. The emergency plan is not affected.
2.2.4 1ST: The calculation provides a new design evaluation of the SB. The 1ST program is not affected.
2.2.5 ISI: The calculation provides a new design evaluation of the SB. The ISI program is not affected.
2.2.6 Fire Protection: The calculation provides a new design basis evaluation of the SB. The fire protection program is not affected.
2.2.7 Independent Spent Fuel Storage Facility:
The calculation provides a new design evaluation of the SB.
The ISFSI is not affected.
2.2.8 Another Regulation:
Standards for Protection Against Radiation (10 CFR Part 20 including the ODCM):
The calculation provides a new design evaluation of the SB. The calculation does not affect 10 CFR Part 20 doses or the Offsite Dose Calculation Manual (OOCM).
Specific Exemptions and ECCS Acceptance Criteria: The new calculation for the SB is not governed by any Specific Exemptions (10 CFR 50.12) or ECCS Acceptance Criteria (10 CFR 50.46).
3.0 Conclusion 3.1 10 CFR 50.59: 10 CFR 50.59 applies because the calculation is not exempt as documented in Section 1.0 above.
3.2 Change Notice: USAR Change No.13-070 & 14-028 provides the USAR changes, except for Section 3.6.
CR 2013-11990 addresses the necessary changes to USAR Section 3.6. USAR Change Notice 14-179 provides the USAR changes associated with the identification of the Shield Building crack propagation. No other licensing documents are affected.
Preparer (Print name)
Bair, Richard N Reviewer (Print name)
Reineck, Bradley T Database Updated
^
Signature S?
trf f<L<,
Signature
^_
Signature (^f fer Date
/
/
Date Date i
i A
FirstEherqy 10 NOP-LP-4003-02 Rev. 01 Initiating Activity No.
Calculation Calculation C-CSS-099.20-063 D BVPS 1 BVPS CFR 2
50.59 SCREEN 0 DBNPS Page 1
of 12 PNPP No.
Rev.
Rev.
13-00918 02 01 Title Shield Building Design Calculation Scope of activity being screened.
General A temporary construction opening was created in the Shield Building (SB) for the reactor vessel closure head replacement project in 2011. During concrete removal, laminar cracking was observed in the plane of the outer reinforcement layer in the areas around the temporary construction opening. Subsequent inspection discovered laminar cracking also existed in the plane of the outer reinforcement layer for most of the architectural flute areas, two main steam line penetration areas, and the top 20 feet (approximate) of the cylindrical shell. Detailed technical investigation of the SB, followed by consultations with industry experts, concluded that the laminar cracking does not lead to any adverse impact on the structural adequacy of the SB. Confirmatory testing, using conservative test specimen configurations, determined the effects of laminar cracking on the strength of lap-splices for the outer circumferential reinforcement.
A new SB calculation, C-CSS-099.20-063, provides the new design evaluation of the SB, including the effects of the laminar cracking, for the cylindrical shell wall, dome, and spring line areas of the structure. The new calculation does not replace the existing design evaluations for the areas near the penetrations and permanent openings, and the foundation. For the areas not within the scope of the new calculation, the existing analysis and design methods, results, and conclusions described in USAR Section 3.8.2.2 remain valid.
Because of the observed laminar cracking in the structure, it was necessary to develop a more accurate representation of the building for the given condition, using state-of-the-practice modeling tools. The SB is structurally analyzed in accordance with the membrane theory of thin shells The membrane theory of thin shells was used in the existing design analysis to analyze the cylindrical wall and dome of the SB in accordance with Articles I-2 and I-3 of the ASME Code,Section III, 1968. The existing analysis used closed form equations and was done by hand. The new design evaluation was performed using a three-dimensional finite element model and the ANSYS computer program, except for the operating and accident thermal loads. For thermal loads, both the existing and new analyses were done by hand and in accordance with ACI 307-69.
This calculation evaluates the Shield Building for all applicable design basis loads and loading combinations. In addition, this calculation documents the tests and analyses performed to evaluate the affect of the identified laminar cracks in this structure, Ref. Condition Report 2011-03346.
Revision 1
In accordance with revision 1
of RAD 13-00918, the scope of Revision 1
of the 50.59 Screen consists of correcting the record date and number of Reference No.
1.
Revision 2 Revision 2 addresses the propagation of the Shield Building cracks identified in 2013. These cracks have been investigated under Condition Report (CR) 2013-14097. See this CR for details of the investigation and causes.
Calculation C-CSS-099.20-063 has been revised to address the crack propagation condition.
New Analysis of Shield Building Design Strength Parameters USAR Subsection 3.8.2.2.6 describes the design strength parameters used for the original design of the SB for both the working stress design and ultimate strength design methods. For the ultimate strength design method, in accordance with ACI 318-63, a value of 4,000 psi was considered for the design compressive strength of concrete (fd) and a value of 60,000 psi was considered for the minimum yield strength of reinforcement (fy).
The allowable concrete and reinforcement stresses for the working stress design method were established, for applicable load combinations, in accordance with ACI 307-69, using these design strength values for concrete and reinforcement.
The laminar cracking, which lies in the plane of the outer reinforcement layer, potentially affects the bond between the concrete and the reinforcement and may reduce the design strength of the reinforcement,
F/rstEnerqy 10 NOP-LP-4003-02 Rev. 01 Initiating Activity No.
Calculation Calculation C-CSS-099.20-062
Rev.
Rev.
13-00918 02 01 especially where the reinforcement is lap-spliced in the cracked areas. Therefore, confirmatory testing was performed at Purdue University and University of Kansas to investigate the effect of laminar cracking on the structural behavior {Reference 1).
The laminar cracking observed in the SB is an unusual situation where the crack exists in the plane of the outer reinforcement layer. Although there is a significant amount of test data on reinforcement bond development which forms the basis of the current ACI318 Code requirements, the effect of such laminar cracking on the bond transfer capacity of the reinforcement has not been evaluated. In order to understand and evaluate the bond transfer capacity of reinforcement with a crack in the plane of the rebar, a detailed test plan was developed to determine the bond transfer mechanism and capacity of reinforcement with a simulated crack in the plane of the reinforcement. The confirmatory tests were carried out using the same procedure, means, and methods as are typically used for testing of reinforcement and bond transfer capacity that forms the basis of the ACI Code provisions. The tests were performed at well renowned laboratory facilities under the guidance of well-known subject matter experts. These tests are considered routine development and bond tests and are considered 'confirmatory" in the sense that they follow the same process and procedures that are typically used for development and bond of reinforcement and are intended to confirm the effect of one of the aspects (cracking) on behavior and capacity.
The commentary to ACI 318-63 (Reference 9) includes References 6-8 as supporting documentation for the description of the basis for the ACI 318-63 Code provisions related to bond and tension splices. References 6-8 describe the test methods and procedures used to establish the bond transfer capacity of reinforcement. Based on a thorough review of References 6-8, it is concluded that the methods and procedures used to perform the confirmatory tests are consistent with those described in the references and comply with the ACI 318-63 Code provisions. Therefore, the confirmatory tests carried out are deemed to be acceptable from the Code perspective, as are the development and bond tests that form the basis for the ACI Code provisions. The level of quality associated with the testing is acceptable for the test data to be used as design input to a safety-related calculation.
Test Programs The SB is reinforced by No. 11 rebar In the circumferential direction and by No. 8,10, and 11 rebar in the meridional direction. For the No. 11 circumferential rebar, a lap-splice length of 79 inches is present between elevations 569.0 feet and 780.0 feet and a lap-splice length of 120 inches is present above elevation 780.0 feet.
In the vertical direction, the No. 11 rebar are spliced using lap-splices with a length of 79 inches. The meridional reinforcement is well confined by the outer circumferential reinforcement and the additional concrete cover, especially in the architectural flute shoulder areas, and is less critical to the effects of laminar cracking compared to the circumferential reinforcement. Therefore, the test program consisted of two sets, one corresponding to the testing for the 79-inch lap-splice length and the other corresponding to the testing for the 120-inch lap-splice length. The tests were independently performed at Purdue University and University of Kansas to ensure reliability of results and redundancy.
The Purdue University and University of Kansas test programs had twelve (12) and six (6) straight beam specimens, respectively, with equal number of specimen with 79-Inch and 120-inch lap-splice lengths. The reinforcement layout in the test specimens for both test programs was such that the lap-splices were located adjacent to each other compared to the generally staggered layout of lap-splices in the SB. This provides a conservative test specimen configuration, since for staggered layout, as onB lap-splice reaches its ultimate capacity, the adjacent continuous reinforcement continues to resist the applied load and provides a larger overall capacity compared to the ultimate capacity of the lap-splice. The curvature of the SB also provides additional confinement to the lap-splices due to the presence of stress normal to the plane between the reinforcement and concrete, while the straight test specimens do not consider this beneficial effect.
Additionally, the compressive strength of concrete in the test specimens conservatively represented lower bound values compared to the concrete compressive strength for the as-built condition of the SB.
Conservatively, the confirmatory testing also used a rebar spacing (and thus, the lap-splice spacing) of 6 inches, while a majority of the outer circumferential reinforcement in the as-built SB has a spacing of 9 to 12 inches.
The test specimens for both test programs were simply supported beams of rectangular sections loaded with a four-point flexural test setup, with loads applied at two points. For the University of Kansas test program, a coldjoint was created in the plane of reinforcement in the splice region for some test specimens to simulate the laminar cracking. The loading was applied continually in a static manner till failure for some test specimens. For
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13-00918 02 01 other test specimens, after initial loading, the test specimens were unloaded and subsequently reloaded in a state manner to failure; the initial loading caused cracking in the test specimen to simulate the presence of laminar cracks. The development of initial cracking in the test specimen, representing the laminar cracking in the SB, was verified; it was also verified that the width of initial cracks in the test specimen exceeded the crack widths observed in the SB. The load-deflection behavior, crack development, and reinforcement stresses were observed to identify the effect of laminar cracking on the behavior of the test specimens (Reference 1).
Flexural Test Results For the Purdue University test program, all test specimens showed similar behavior and the presence of laminar cracking, initiated by loading the specimen followed by unloading, had no effect on the strength of the specimen and the lapped splices in the reinforcement. The minimum and maximum tensile strength of the reinforcement in the flexural test specimens were 69,000 psi and 80,000 psi, respectively, with a computed average strength of 74,833 psi. The smaller tensile strength values were observed In the specimens with the lap-splice length of 79 inches, and the minimum tensile strength from all tests exceeded the minimum yield strength value of 60,000 psi.
Additionally, yielding of reinforcement was observed for all the test specimens in the Purdue test program.
For the test program at University of Kansas, the reinforcement attained a minimum tensile strength of 67,000 psi for the test specimens with lap-splice length of 120 Inches. For the flexural test specimens with lap-splice length of 79 Inches, except for one test specimen that did not achieve the minimum yield strength of the reinforcement, the tensile strength from the other two test specimen exceeded the minimum yield strength of the reinforcement The minimum and maximum tensile strength of the reinforcement for all flexural test specimens at University of Kansas test program were 57,000 psi and 70,000 psi, respectively, with an average of 66,167 psi.
New Design Strength In the Purdue University and University of Kansas test programs, which involved a total of eighteen (18) test specimens, only one specimen with a lap-splice length of 79 inches failed prior to reaching the minimum yield strength of the reinforcement. However, as described above in the description of the test programs, both programs used conservative conditions compared to that in the SB. Therefore, although one test specimen did not achieve the minimum yield strength of the reinforcement, the outer circumferential reinforcement in SB with the laminar cracking is expected to achieve its minimum yield strength.
Although the test programs identified potential impact only on the outer circumferential reinforcement with a lapsplice length of 79 inches located between elevations 569.0 feet and 780.0 feet (Reference 1), the new design evaluation of the SB conservatively considers a limiting design strength of 55,000 psi, taken to be lower than the minimum tensile strength observed in both test programs, for the outer circumferential reinforcement in the entire cylindrical shell instead of using the minimum yield strength of 60,000 psi. The new design evaluation uses the specified minimum yield strength of 60,000 psi for all other reinforcement. A value of 4000 psi is used for the compressive strength of concrete (fd), consistent with USAR Subsection 3.8.2.2.6.
The new design strength values are in accordance with ACI318-63. ACI318-63 defines the minimum yield strength of reinforcement as the minimum value determined in tension according to applicable ASTM specifications; this corresponds to the testing of Individual rebar in tension tests. The reinforcement design strength is limited to 60,000 psi for vertical rebar, outer hoop rebar in the dome, and inner horizontal hoops in the new design evaluation, while it is conservatively limited to only 55,000 psi for outer hoop bars in the cylindrical shell. Note that 55,000 psi is not being defined as the minimum yield strength of reinforcement, but is being used as its limiting design strength in the evaluation. For the reasons mentioned earlier, the considered design strength for the outer circumferential reinforcement represents a lower-bound strength limit The confirmatory tests were performed using the same process and procedures that are typically used for such tests to form the basis for ACI Code equations. It Is noted that the ACI 318-63 Code specified value of 60,000 psi is meant to provide a limiting strength for design. The actual yield strength is generally higher and is not used In the design. In that sense, the 55,000 psi limit provides a similar but an even lower limit for design. The lower bound strength of 55,000 psi actually only applies to spliced circumferential rebar in the cracked regions.
Analysis and Design Procedure The existing SB design was performed in accordance with ACI 307-69 and checked by the ultimate strength method in accordance with ACI318-63 (USAR Section 3.8.2.2.3). In accordance with USAR Section 3.8.2.2.3, the load combinations specified in ACI 307-69 provided the design basis of the building; additionally, the ultimate
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13-00918 02 01 strength design load combinations specified in ACI 318-63, with the load factors provided in USAR Appendix 3A, were used to check the SB design. The design of the SB ensured an elastic behavior of steel reinforcement is maintained during a Maximum Possible Earthquake, controlling cracking of concrete and impairment of leaktight integrity (USAR Section 3.8.2.2.2).
Consistent with the USAR, the new design evaluation of the SB is performed for both the working stress design and ultimate strength design methods. The loads and load combinations from USAR Subsection 3.8.2.2.4, and the design strength values from USAR Subsection 3.8.2.2.6, supplemented by the design strength of 55,000 psi for the outer circumferential reinforcement in the cylindrical shell, were used. This ensures that the design of the SB meets the design basis codes and methods, and the requirements of General Design Criteria 2 and 4 of Appendix A to 10CFR50, as described in USAR Sections 3D.1.2 and 3D.1.4 of Appendix 3D.
Seismic Loads for Shield Building with Laminar Cracking For the original analysis and design of the SB, USAR Section 3.7.2 describes the methodology for performing the seismic analysis. Specifically, USAR Subsections 3.7.2.1 and 3.7.2.2 establish the method and criteria, respectively, for performing the seismic analysis. A frequency analysis established the dominant frequencies of vibration of the structure in all directions and then seismic demands, such as structural accelerations and the floor response spectra, were computed for both the maximum probable earthquake and the maximum possible earthquake. The SB was analyzed using a fixed-base lumped mass stick model, wherein the structure was mathematically idealized as lumped masses at floor levels and the beam elements between the mass points represented the equivalent stiffness of the structure. The contribution from the architectural flute shoulder areas was considered to determine the equivalent stiffness properties of the beam elements.
For the new design evaluation, to investigate the influence of the laminar cracking on the seismic demands of the SB, confirmatory analyses were performed using the mathematical modeling approach described in USAR Subsection 3.7.2.1.1. The analyses were performed using lumped mass stick models developed using ANSYS, which is a quality controlled, validated, and verified computer program. One model represented the SB without the effects of laminar cracking (benchmark model) and the other represented the SB with the effects of laminar cracking. The stiffness and mass properties in the lumped mass stick model without the effects of cracking matched the properties used in the original seismic analysis in Section 3.7.2, while for the model with cracking, the stiffness properties were calculated by neglecting the contribution of the concrete located outside the cracked surface in the SB shell. The distribution of laminar cracking used for the calculation of reduced stiffness properties is based on the Impulse Response (IR) scanning maps per Reference 2. Frequency analysis was performed in, ANSYS to determine the dominant frequencies and mode shapes.
The dominant frequencies and the mode shapes for the lumped mass stick models without and with the effects of laminar cracking were compared. These results were also compared to the dominant frequencies of the SB based on the original design basis analysis, including the seismic analysis methods, described in USAR Section 3.7.2. The structural frequencies for the lumped mass stick model without the effects of laminar cracking closely matched the frequencies based on the original design basis analysis, validating the modeling approach. The two SB ANSYS lumped mass stick models - with and without the effects of laminar cracking -
showed a very close agreement for the dominant frequencies. This shows that the seismic response of the SB, including the structural accelerations and the floor response spectra, for both maximum probable and maximum possible earthquakes is not impacted by the change in stiffness properties due to laminar cracking.
The new design basis evaluation, therefore, used the seismic loads based on the analyses described in Section 3.7.2.
The location and extent of laminar cracking, considered in the two SB cracked models, was evaluated for the potential effect of the identified crack propagation areas. The first SB model considering laminar cracks was based on the conservative assumption that all sixteen (16) of the SB shoulders contained laminar cracks (i.e.
100% laminar cracks in all shoulders). The second SB model that considered laminar cracks was based orl Reference 8 with varying degrees of cracking within four vertically oriented regions of the SB.
These models have been reviewed in Rev. 01 of Calculation C-CSS-099.20-063 for the additional areas of the crack propagation. As identified above and in Reference 18, the areas of crack propagation are contained in the SB shoulders. These additional crack areas are enveloped by the first SB model described above. The locations of the crack propagation were compared against second SB cracking model. This comparison determined that there is sufficient margin in this model to envelop the additional cracking. Also, the frequencies for the first SB cracked model controlled (greater delta to the uncracked SB frequencies) than the second SB cracked model, which provides an additional degree of margin. Therefore, the calculation revision concluded that the new (2~
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13-00918 02 01 Shield Building analysis would continue to use the seismic loads based on the analyses described in Section 3.7.2 of Ref. 1.
Analytical Techniques For the original design of the SB, the membrane theory of thin shells was used to analyze the cylindrical wall, spring line and dome of the SB in accordance with Articles 1-2 and 1-3 of the ASME Code,Section III, 1968. At places where changes in geometry or loading exist, an analogy of a beam on elastic foundations was made in conformance with Article I-7 of the ASME Code. The seismic demands were calculated by performing seismic analysis using a cantilevered lumped mass stick model of the SB. For thermal loads, the cracking effect of reinforced concrete was considered, as suggested by ACI 307-69. ACI Publication SP-20, "Causes, Mechanism and Control of Cracking in Concrete" was used to determine the maximum width of cracks at the surface and compare the result to the allowable width permitted by the ACI Standard Building Code (ACI318-63). (USAR Subsection 3.8.2.2.5)
For the new design evaluation, the SB was also analyzed using the membrane theory of thin shells. A combination of finite element analysis and classical analytical techniques were used to determine the structural response of the SB to the design bases loads.
The new structural analysis of the SB was performed using a three-dimensional finite element model in ANSYS.
ANSYS shell element type SHELL181 was used to model the cylindrical shell wall, dome, and spring line of the SB. SHELL181 is a three-dimensional 4-noded shell element with six degrees of freedom at each node and is suitable for modeling thin to moderately-thick shell structures such as the SB. The element resultants comprise of membrane forces and bending moments, in-plane shear forces and twisting moments, and out-of-plane shear forces. The resistance to the controlling load combinations is provided primarily by in-plane shear with very little out-of-plane bending. Since the laminar cracking does not reduce the thickness of the shell and is located in the plane of outer reinforcement, the load carrying capacity by membrane action, in-plane shear, out-of-plane shear, and out-of-plane bending is not impacted and uncracked section properties are considered in the analysis. The finite element model uses a sufficiently refined mesh size that is appropriate to accurately capture the structural response of the SB for the applicable loads and load combinations.
The supporting foundation, penetrations, and permanent openings were not included in the new finite element model. The SB is founded on a rigid mat, as described in USAR Subsection 3.8.2.2.5, and the original analyses in USAR Subsections ZJ.2.2 and 3.8.2.2 were performed using a fixed base condition. The laminar cracking is not present around the permanent openings and penetrations, except for the main steam line penetrations 39 and 40. The main reinforcement in the cylindrical shell is not lap-spliced in the areas around the main steam line penetrations 39 and 40. As described in USAR Subsections 3.8.2.2.2 and 3.8.2.2.5, adequate reinforcement is provided around the openings and penetrations, including the diagonal rebar at each corner, as applicable. The reinforcement maintains continuity in the cracked area around these penetrations and is well anchored to the shell outside of the cracked area, thus providing an adequate force transfer mechanism. The laminar cracking potentially affects the design strength of the 79 inch lap-splices on the outer circumferential reinforcement, but the design strength of the reinforcement provided to strengthen the main steam line penetrations 39 and 40, including the diagonal rebar at each corner, are not impacted. Therefore, there is no adverse effect on the structural integrity of the areas around the main steam line penetrations 39 and 40 due to the laminar cracking.
The analytical methods and results described in USAR Subsection 3.8.2.2 for the evaluation of the stress concentration effects at the permanent openings and major penetrations are still applicable. As described earlier, the stiffness of the structure and the load carrying capacity of the SB by membrane action, in-plane shear, out-of-plane shear, and out-of-plane bending are not impacted by laminar cracking. Therefore, the response of the piping and electrical penetrations at their interface with the SB will not be adversely impacted by the laminar cracking.
All applicable design bases loads from USAR Subsection 3.8.2.2.4, except the operating and accident thermal loads, including dead and live loads, wind and tornado loads, maximum probable and maximum possible earthquake loads, lateral earth pressures, and operating and accident pressures were imposed on the finite element model and the analysis was performed using a fixed base condition. As described in the previous section, the dynamic behavior of the SB with laminar cracking closely matches the dynamic behavior of the SB without laminar cracking. Therefore, the seismic loads from USAR Section 3.7.2 were used without any modification. The seismic accelerations at various elevations of the lumped mass stick model were applied to the finite element model of the SB. The loads Imposed on the SB due to Main Feedwater and Steam Generator
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13-00918 02 01 Blowdown line breaks in the Annulus and the Main Steam line break in the Auxiliary Building were also considered In the analysis. The thermal loads associated with these high energy line breaks are Insignificant compared to the accident thermal loads caused by the design basis Loss of Coolant Accident and were ignored.
The Main Steam line break results in a bounding pressure loading on the SB compared to the Main Feedwater and Steam Generator Blowdown line breaks; thus, the Main Steam line break pressure loading was imposed on the finite element model.
For the operating and accident thermal loads, manual computations were performed In accordance with ACI 307-69. These computations accounted for the reduction of bending moments imposed on the SB cross-sections due to cracking caused by thermal loads. The results from these Independent load cases were combined to determine the shell element resultants for the load combinations described in USAR Subsection 3.8.2.2.4 for both working stress design and ultimate strength design methods. The load factors provided in USAR Appendix 3A were used for ultimate strength design load combinations. The independent load cases Ho and HA, which are described in USAR Subsection 3.8.2.3.4 and represent the reactions on the structure due to thermal expansion of pipes under operating and accident conditions, respectively, are generally not applicable for the analysis and design of the SB, since the high energy pipe systems such as Main Steam and Main Feedwater are isolated from the SB. This consideration is supported by Table 11.0.1-2 of Reference 10.
The effect of temporary construction openings created during the original construction, 2002 reactor pressure vessel head replacement project, 2011 reactor vessel closure head replacement project, and 2014 steam generator replacement project were considered in the new evaluation by performing a separate sectional analysis. This analysis provided the redistribution of stresses caused by self weight of the SB considering the sequence of creation and restoration of the temporary construction openings.
Design Methodology As described in USAR Subsection 3.8.2.2.3, the existing SB design was performed in accordance with ACI 307-69 and checked by the ultimate strength method in accordance with AC! 318-63. The new evaluation of the SB design was performed and checked in accordance with the same Code, using the strength reduction factors provided in USAR Subsection 3.8.2.3.4. The design strength values used in the new evaluation were those given in the "New Design Strength" section above.
Except for the outer circumferential reinforcement along the entire height of the cylindrical shell, where a conservative design tensile strength of 55,000 psi was used, the ultimate strength design method used a value of 60,000 psi for all other reinforcement. Accordingly, the allowable stresses for the working stress design method for the outer circumferential reinforcement in the cylindrical shell were also conservatively reduced proportionally. The new values for each load combination listed In USAR Subsection 3.8.2.2.4 are as follows:
- a. To fs = 22.1 ksi
- b. DL + To f, = 22.1 ksi c.DL + W fs= 13.8 ksi
- d. DL + E fs= 16.6 ksi e.DL + To + E fs = 30.0 ksi
- f. DL + To + W fs = 30.0 ksi (Note: Notations above are from USAR Subsection 3.8.2.3.4).
The allowable stresses for concrete and all other reinforcement were taken from USAR Subsection 3.8.2.2.6.
The new design evaluation of the SB was performed using the shell element results from the finite element analysis previously described. For the working stress design method, the shell element forces and moments were used to compute the service level stresses in the concrete and reinforcement. Similarly, for the ultimate strength design method, the combined effect of shell element membrane forces and bending moments, out-of-plane shear forces, and in-plane shear forces were compared against the ultimate section capacities determined in accordance with ACI 318-63. The calculation of section capacities considered the reduced design strength of the outer circumferential reinforcement in the cylindrical shell of the SB. The check for in-plane shear was performed on a global basis using the cumulative forces at the entire cross-section of the shell at a particular elevation, while all other design checks were performed for each shell element in the finite element model.
For the new evaluation, the lateral earth pressure loads on the SB were re-created using the same methods and input soil data described in USAR Subsections 3.8.1.4.4,2.5.1.8, and 3.4.2.1, and Section 2C.6.3 of Appendix 2C.
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13-00918 02 01 For the new design evaluation, the effect of tornado loads, including the tornado missiles, was accounted for by conservatively ignoring the concrete cover on the outer face of SB shell. The load combinations with tornado load effects were considered in the design check of the SB using the ultimate strength design method. The tornado missile penetration depths listed in USAR Table 3.3-2, calculated using the methods described in USAR Section 3.5.8, are less than half of the conservatively reduced shell thickness. These results meet the USAR Section 3.5.2 criteria for minimum thickness to prevent concrete spalling and generation of secondary missiles.
Serviceability and Durability Considerations As described in USAR Subsection 3.8.2.2.2, the control of cracking and impairment of leaktight integrity, due to concrete shrinkage and temperature gradients, is achieved by placing adequate reinforcement in the concrete walls, dome, and foundation, and by ensuring elastic behavior of the steel reinforcement is maintained during a Maximum Possible Earthquake. USAR Subsection 3.8.2.2.5 further specifies that cracking due to thermal loads is controlled by providing large amount of reinforcement and limiting the maximum surface crack width calculated using the provisions in ACI Publication SP-20 to less than the allowable of 0.010 inch per ACI 318-63 and USAR Subsection 3.8.2.2.5. The allowable crack width per ACI 318-63 is intended to limit the potential moisture infiltration paths that may lead to reinforcement corrosion. Corrosion protection for the reinforcement is provided by providing a sufficient concrete cover.
Consistent with Subsection 3.8.2.2.5, the new design evaluation of the SB evaluated the surface cracking consideration using the guidelines provided in ACI Publication SP-20. The maximum crack width at the surface due to mechanical loads Is 0.0086 inch, which meets the crack control guidelines provided in ACI 318-63.
For the SB with the extent of cracking shown in Reference 2, the crack width of most observed laminar cracks was less than 0.010 inch, with a maximum width of 0.013 inch for one of the cracks. No unusual levels of carbonation, moisture infiltration, or reinforcement corrosion activity were identified, and the observed laminar cracks were originally considered 'passive'. However, CR 2013-14097 identified that there were several areas of crack propagation adjacent to previously documented laminar cracks. Procedure EN-DP-01511 (Reference 5) specifies periodic inspections of the Shield Building to monitor and identify any change in the laminar/propagation cracks. The crack widths of shrinkage cracks at the surface are very small and will not provide a path for any significant moisture infiltration to the cracks. The concrete cover to the reinforcement is maintained and the architectural flute shoulder areas will continue to provide adequate confinement to the circumferential and meridional reinforcement, since the flute shoulder areas are tied to the cylindrical shell by additional anchor reinforcement. The reinforcement has neither degraded nor lost its corrosion protection.
Additionally, the exterior surfaces of SB above grade were coated to provide additional protection from moisture.
Based on these considerations, the SB with the configuration of laminar cracking depicted in Reference 2 will maintain its serviceability and long-term durability under the operating conditions.
Design Evaluation Results The structural design of the SB using the working stress design method was performed in accordance with ACI 307-69. For the most critical element, the ratio of maximum stress in the reinforcement to the corresponding allowable stress is 0.88. Similarly, the ratio of maximum stress in concrete to the corresponding allowable stress is 0.81. This ensures that the SB meets the structural acceptance requirements specified in ACI 307-69.
The design check of the SB using the ultimate strength design method was performed in accordance with ACI 318-63. For the most critical element, the demand to capacity ratio for combined interaction of membrane forces and bending moments is 0.76, while the maximum demand to capacity ratio for the effect of out-of-plane shear forces is 0.37. The maximum total in-plane shear demand at the base of SB was also significantly lower than the global in-plane shear strength, calculated in accordance with ACI 318-63 using the concrete shear capacity and the contribution from the shear reinforcement. The ratio of shear reinforcement required to resist the maximum total in-plane shear to the provided shear reinforcement is 0.67. These results demonstrate that the stresses and strains for the SB are within the ACI 318-63 limits and that the structure meets the strength requirements specified in ACI 318-63.
The evaluation for out-of-plane shear and in-plane shear were also performed in accordance with the working stress design method in ACI 318-63, to supplement the ACI 307-69 requirements, and the demand to capacity ratios for both checks are governed by the ultimate strength design method.
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13-00918 02 01 The SB with the extent of laminar cracking documented in Reference 2 behaves within the elastic range and is capable of withstanding the design basis loads and load combinations described in USAR Subsection 3.8.2.2.
The compliance of the SB design to the applicable provisions of ACI 307-69 and ACI 318-63 is documented in Reference 3. The design evaluation demonstrates that the SB maintains its structural integrity, meets the requirements of the design codes, and can perform its intended design functions.
References
- 1. Bechtel Report 25593-000-G83-GEG-00016, "Effect of Laminar Cracks on Splice Capacity of No. 11 Bars based on Testing Conducted at Purdue University and University of Kansas for Davis-Besse Shield Building," July 18, 2012
- 2. First Energy Report 25593-000-GQT-GEG-00001, "Impulse-Response Test Data," July 24, 2012
- 3. FENOC Calculation C-CSS-099.20-063, Rev. 001, "Shield Building Design Calculation"
- 4. FENOC Condition Report CR-2011-03346, "Fractured Concrete Found at 17M Shield Building Construction Opening," through February 21, 2012
- 5. EN-DP-01511, Rev. 001, "Design Guidelines for Maintenance Rule Evaluation of Structures"
- 6. Ferguson, P.M., and Thompson, J.N., "Development Length of High Strength Reinforcing Bars in Bond, "ACI Journal, Proceedings V. 59, No. 7, July 1962, pp. 887-922
- 7. Ferguson, P.M., and Matloob, F.N., "Effect of Bar Cut-off on Bond and Shear Strength of Reinforced Concrete Beams," ACI Journal, Proceedings V. 56, No. 1, July 1959, pp. 5-24
- 8. Watstein, D., and Mathey, R.G., "Investigation of Bond in Beam and Pull-out Specimens with High Yield Strength Deformed Bars," ACI Journal, Proceedings V. 57, No. 9, March 1961, pp. 1071-1090
- 9. Commentary on Building Code Requirements for Reinforced Concrete (ACI 318-63), ACI Publication SP-10
- 10. Davis-Besse Nuclear Power Station Unit 1
Design Criteria Manual, Rev. 32
- 11. FENOC Condition Report 2013-14097, "Shield Building Laminar Crack Propagation" List the UFSAR-described design functions potentially affected by the activity.
Shield Building As described in USAR Sections 1.2.10.2 and 3.8.2, the SB functions as one of the containment structures. The SB provides its functions as a safety-related, Seismic Category I structure (USAR Subsection 3.2.1.1). The SB provides:
- biological shielding,
- controlled release of the annulus space atmosphere under accident conditions, and
- environmental protection, including missile protection, of the containment vessel.
The SB encloses the steel containment vessel (CV).
An annular space exists between the SB and CV. During normal operation, the SB provides shielding from radiation originating at the reactor vessel and the primary coolant loop components.
In the event of an accident, the shielding reduces the station and off-site intensities emitted directly from the released fission products to acceptable levels.
The SB serves as a ventilation boundary for the station Emergency Ventilation System (EVS) to control releases from the Annulus space, penetration rooms and Emergency Core Cooling System (ECCS) rooms under accident conditions. The SB also serves as a boundary for the Containment Purge System (CPS) for normal operation.
Emergency Ventilation Systems The station Emergency Ventilation System (EVS) functions as a Seismic Category I system to maintain a negative pressure in the SB Annulus space, and connected spaces, following a Loss-of-Coolant Accident (LOCA). Operation of the system minimizes the release of unfiltered radioactive particles from the containment vessel to the environment.
Containment Purge System The Containment Purge System functions as a Seismic Class II system to maintain a slight negative pressure in the SB Annulus space during normal operations (USAR Sections 1.2.8.3.3 and 3.2.1.1).
10CFR 50.59 screening questions.
Check the correct response.
1.
Does the proposed activity involve a change to an SSC that adversely affects an kJ YES NO UFSAR-described design function?
2.
Does the proposed activity involve a change to a procedure that adversely affects how
] YES
@ NO UFSAR-described SSC design functions are performed or controlled?
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Does the proposed activity involve revising or replacing an UFSAR-described
@ YES NO evaluation methodology used in establishing the design bases or in the safety analyses?
4.
Does the proposed activity involve a test or experiment not described in the UFSAR, YES 0 NO where an SSC is utilized or controlled in a manner that is outside the reference bounds of the design for that SSC or is inconsistent with analyses or descriptions in the UFSAR?
List the documents reviewed where relevant information was found, including section numbers and key words searched:
UFSAR Sections:
1.2.10.2, 2.5.1.8, 3.2, 3.3.2, 3.4.2.1, 3.5.2, 3.5.5, 3.5.8, Change Request No:
13-070,14-028, &
1 3.6, 3.7.2, 3.8.1.4.4, 3.8.1.1.6, 3.8.2, 3.11.2, 6.2.3.1, 10.2.5.4, 12.1.1.3, 12.1.2, 12.2.2.1, 12.3.2.1; Tables 3.2-1, 3.3-2, 3.6-11, 3.7-1, 12.1-1, 15.4.6-2
- Appendix 2C, Appendix 3A, Appendix 3D, Technical Specifications
3.6.1,3.7.12,3.7.13,5.5.3 Other regulatory documents:
-NRC Regulatory Guides:
o1.26 Rev.
3, Quality Group Classifications and Standards for Water-, Steam-, and Radioactive Waste-Containing Components of Nuclear Power Plants o1.29 Rev. 2, Seismic Design Classification Keywords:
"concrete", "missile", "shield building", "annular space",
"annulus", "annulus ventilation", "reinforcing", "radiation shielding", "seismic category I", "radiological safety",
"radiation protection", "tornado", "leak test", "pressure test", "emergency ventilation system", "containment purge system", "containment vessel", "coating", crack",
"analytical technique"
, "HELB"
@ At least one question is answered YES.
Perform a 10CFR50.59 Evaluation.
All questions are answered NO.
A 10CFR50.59 Evaluation is not required.
Justify the determination:
LDoes the proposed activity involve a change to an SSC that adversely affects an UFSAR-described design function? YES As described in USAR Sections 1.2.10.2 and 3.8.2, the SB functions as one of the containment structures.
The SB provides its functions as a safety-related, Seismic Category I structure (USAR Subsection 3.2.1.1).
The SB provides:
-Biological shielding,
-Controlled release of the annulus space atmosphere under accident conditions, and
-Environmental protection, including missile protection, of the containment vessel.
The station Emergency Ventilation System (EVS) functions as a Seismic Category I system to maintain a negative pressure in the SB Annulus space, and connected spaces, following a Loss-of-Coolant Accident (LOCA). Operation of the system minimizes the release of unfiltered radioactive particles from the containment vessel to the environment.
The Containment Purge System functions as a Seismic Class II system to maintain a slight negative pressure in the SB Annulus space during normal operations.
The new SB calculation, C-CSS-099.20-063, provides the new design evaluation of the SB, including the effects of the laminar cracking, for the cylindrical shell wall, dome, and spring line areas of the structure.
Also, Revision 1 of Calculation C-CSS-099.20-063 documents the evaluation of the crack propagation at a number of previously identified laminar cracks in the Shield Building shoulder areas, Ref. CR 2013-14097.
This revision concludes that the identified crack propagation does not adversely affect the existing revision 0 analysis because 1) the analysis considers a limiting design strength of 55, 000 psi for all of the outer circumferential reinforcing steel and 2) the locations of the crack propagation are limited to areas that are enveloped by areas of the structure previously considered to be cracked in the existing analyses.
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13-00918 02 01 As per the existing design, the new calculation evaluated the SB in accordance with ACI 307-69 and checked the design by the ultimate strength method in accordance with ACI 318-63. The load combinations specified in ACI 307-69 and ACI 318-63 were used, with the ultimate strength design performed using the strength reduction factors provided in USAR Subsection 3.8.2.3.4. All applicable design bases loads were imposed on the analyzed structure, including (but not limited to) dead and live loads, wind and tornado loads, maximum probable and maximum possible earthquake loads, operating and accident thermal loads, and lateral earth pressures.
The existing analytical results for evaluation of the stress concentration effects at the permanent openings and major penetrations are still applicable since cracking is not present in these areas, except for the main steam line penetrations 39 and 40. The main reinforcement in the cylindrical shell is not lap-spliced in the areas around the main steam line penetrations 39 and 40. As described in USAR Subsections 3.8.2.2.2 and 3.8.2.2.5, adequate reinforcement is provided around the openings and penetrations, including the diagonal rebar at each corner, as applicable. The reinforcement maintains continuity in the cracked area around these penetrations and is well anchored to the shell outside of the cracked area, thus providing an adequate force transfer mechanism. The laminar cracking potentially affects the design strength of the 79 inch lap-splices on the outer circumferential reinforcement, but the design strength of the reinforcement provided to strengthen the main steam line penetrations 39 and 40, including the diagonal rebar at each corner, are not impacted. Therefore, there is no adverse effect on the structural integrity of the areas around the main steam line penetrations 39 and 40 due to the laminar cracking. The analytical methods and results described in USAR Subsection 3.8.2.2 for the evaluation of the stress concentration effects at the permanent openings and major penetrations are still applicable.
No unusual levels of carbonation, moisture infiltration, or reinforcement corrosion activity were identified during inspections, and the observed laminar cracks were considered 'passive',
i.e., the cracks are not expected to grow (References 4 and 5). However, as noted above, it has been identified that crack propagation has occurred at a number of previously identified laminar crack locations, Ref. CR 2013-14097. The crack widths of shrinkage cracks at the surface are very small and will not provide a path for any significant moisture infiltration to the laminar cracks. The concrete cover to the reinforcement is maintained and the architectural flute shoulder areas will continue to provide adequate confinement to the circumferential and meridional reinforcement, since the flute shoulder areas are tied to the cylindrical shell by additional anchor reinforcement. The reinforcement has neither degraded nor lost its corrosion protection. Additionally, the exterior surfaces of SB above grade were coated to provide additional protection from moisture. Based on these considerations, the SB will maintain its serviceability and long-term durability under the operating conditions.
The effect of temporary construction openings created during the original construction, 2002 reactor pressure vessel head replacement project, 2011 reactor vessel closure head replacement project, and planned 2014 steam generator replacement project are considered in the new evaluation by performing a separate sectional analysis. This analysis provides the redistribution of stresses caused by self weight of the SB considering the sequence of creation and restoration of the temporary construction openings.
With the exception of design tensile strength of the outer circumferential reinforcement in the shell, the original design basis, including conformance to the design codes, of the SB described in USAR are maintained. However, as discussed above, based upon the results and conclusions from confirmatory testing (Reference 1), the new design evaluation of the Shield Building now will conservatively consider a limiting design strength value of 55,000 psi for the outer circumferential reinforcement, instead of the ACI 318-63 Code specified minimum yield strength value of 60,000 psi. For the reasons mentioned earlier, the considered design strength represents a lower-bound strength limit. This is considered as an adverse effect The thickness of concrete is not affected by the calculation; therefore, the biological shielding function of the SB is not affected. The "controlled release" ventilation boundary function of the SB is not affected, because the design ensures an elastic behavior of steel reinforcement is maintained during a Maximum Possible Earthquake, controlling cracking of concrete and impairment of leaktight integrity. Thus, the CVS and Containment Purge System functions are not affected. As noted above, the cracks in the Shield Building have propagated in a number of shoulder areas of this structure. Calculation C-CSS-099.20-063 has been revised to evaluate the affect of this propagation on the serviceability of the SB. The calculation has concluded that the existing areas of laminar and propagation cracks will not affect the serviceability
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PNPP 13-00918 02 01 of the SB. The new evaluation demonstrated conformance to the requirements associated with maintaining the SB environmental protection function. The new design evaluation demonstrated that the SB maintains its structural integrity, meets the requirements of the design codes, and can perform its intended design functions, as a safety-related, Seismic Category I structure.
Thus, the proposed activity, specifically the alteration of the design strength value to 55,000 psi for some of the rebar, adversely affects a USAR-described function of an SSC. Additionally, USAR Change Notice 14-179 will revise the USAR description of the laminar cracks and the associated evaluation to include the crack propagation condition identified in CR 2013-14097. Therefore, the proposed activity does involve a change to an SSC that adversely affects an USAR-described design function.
2.Does the proposed activity involve a change to a procedure that adversely affects how UFSAR-described SSC design functions are performed or controlled?
NO The new SB calculation, C-CSS-099.20-063, does not affect procedures pertaining to the operation or control of any SSC. The new design evaluation demonstrated that the SB maintains its structural integrity, meets the requirements of the design codes, and can perform its intended design functions, as a safety-related, Seismic Category I structure.
Therefore, the proposed activity does not involve a change to a procedure that adversely affects how USAR-described SSC design functions are performed or controlled.
3.Does the proposed activity involve revising or replacing an UFSAR-described evaluation methodology used in establishing the design bases or in the safety analyses?
YES Both the existing and new design evaluations for the SB were performed in accordance with ACI 307-69 and checked by the ultimate strength method in accordance with ACI 318-63. Load combinations specified in ACI 307-69 provided the design basis of the building; additionally, the ultimate strength design load combinations specified in ACI 318-63, with the load factors provided in USAR Appendix 3A, were used to check the SB design. The membrane theory of thin shells was used in the design to analyze the cylindrical wall and dome of the SB in accordance with Articles I-2 and I-3 of the ASME Code,Section III, 1968. At places where changes in geometry or loading exist, an analogy of a beam on elastic foundations was made in conformance with Article I-7 of the Code. For seismic load, a cantilevered beam of lumped masses was modeled to determine seismic forces. For thermal load, the cracking effect of reinforced concrete was considered, as suggested by ACI 307-69. ACI Publication SP-20, "Causes, Mechanism and Control of Cracking in Concrete" was used to determine the maximum width of cracks at the surface and compare the result to the allowable width permitted by the ACI Standard Building Code and the USAR. For the new evaluation, the lateral earth pressure loads on the SB were re-created using the same methods described in the USAR.
The existing seismic evaluation of the SB used a fixed-base lumped mass stick model, wherein the structure was mathematically idealized as lumped masses at floor levels and the beam elements between the mass points represented the equivalent stiffness of the structure. A frequency analysis established the dominant frequencies of vibration of the structure in all directions and then seismic demands, such as structural accelerations and the floor response spectra were computed for both the maximum probable earthquake and the maximum possible earthquake. The contribution from the architectural flute areas was considered to determine the equivalent stiffness properties of the beam elements. For the new design evaluation, to investigate the influence of the cracking (laminar and propagation) on the seismic demands of the SB, confirmatory analyses were performed using the mathematical modeling approach described in the USAR Section 3.7.2. Although seismic analyses were not re-performed, dominant frequencies of the SB with the effects of cracking were compared using lumped mass stick model approach with the dominant frequencies of the SB without the effects of cracking. The affect of the crack propagation areas on the existing models that considered the effects of the previously identified laminar cracks was evaluated. The existing laminar crack models were found to have sufficient conservatism to envelop the areas of crack propagation. The effects of cracking (laminar and propagation) were shown to be insignificant, thus eliminating the need to perform seismic analysis.
As previously noted, the SB is structurally analyzed in accordance with the membrane theory of thin shells. The membrane theory of thin shells was used in the existing design analysis to analyze the cylindrical wall and dome of the SB in accordance with Articles I-2 and I-3 of the ASME Code, Section
- III, 1968. The existing analysis used closed form equations and was done by hand. The new design
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13-00918 02 01 evaluation was performed using a three-dimensional finite element model and the ANSYS computer program, except for the operating and accident thermal loads. For thermal loads, both the existing and new analyses were done by hand and in accordance with ACI 307-69. Because of the use of finite element modeling, instead of closed form equations in the ASME Code Articles, the use of ANSYS will be treated as a methodology change, and thus be subjected to further review in a 10 CFR 50.59 Evaluation.
Therefore, except for the use of ANSYS, the proposed activity does not involve revising or replacing an USAR-described evaluation methodology used in establishing the design bases or in the safety analyses.
The use of ANSYS will be reviewed in the 10 CFR 50.59 Evaluation.
4.Does the proposed activity involve a test or experiment not described in the UFSAR, where an SSC is utilized or controlled in a manner that is outside the reference bounds of the design for that SSC or is inconsistent with analyses or descriptions in the UFSAR?
NO The proposed activity does not involve a test or experiment not described in the UFSAR, where the SSC is utilized or controlled in a manner that is outside the reference bounds of the design for that SSC or is inconsistent with the analyses or description in the UFSAR. This activity does not involve altering any plant parameters or environmental conditions such that any SSC is operated beyond the USAR-described reference bounds or is inconsistent with the USAR-described analyses or descriptions.
Preparer (Print name)
Bair, Richard N Reviewer (Print name)
Reineck, Bradley T Signature /"^
i*
/^^_
Signature Date
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7fii/i4 Date Database updated JjJ Date
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13-00918 02 01 Title Shield Building Design Calculation 1.0 Executive Summary to be submitted to the NRC:
1.1 Activity
Description:
A new calculation, C-CSS-099.20-063 (Reference 2), provides the new design evaluation of the Shield Building (SB),
including the effects of the laminar cracking, for the cylindrical shell wall, dome, and spring line areas of the building.
The calculation includes the results of lab testing performed to determine the effect of laminar cracking on the structural behavior and strength of the structure. The calculation includes a change in methodology.
Revision 1
In accordance with Revision 1 of RAD No. 13-00918, the scope of Revision 1 of the 50.59 Evaluation consists of correcting the record date and number of Reference No.
11.
Revision 2 Revision 2 of this 50.59 Evaluation documents the review of Calculation C-CSS-099.20-063, Revision 01. This calculation revision evaluates the effect of the crack propagation identified during the periodic inspection of the existing laminar cracks, Ref. 18. The areas of crack propagation are limited to portions of the Shield Building shoulders (i.e. no crack propagation was identified in the shell of the SB wall).
1.2 Summary of Evaluation:
The activity does not meet any of the criteria in paragraph (c)(2) of 10 CFR 50.59 for obtaining a license amendment. All activities "screened out" except for the potential adverse effects of laminar cracking and change in methodology.
The SB with the extent of cracking (laminar and crack propagation) documented in FENOC references 9 and 18 behaves within the elastic range and is capable of withstanding the design basis loads and load combinations described in USAR Subsection 3.8.2.2. The compliance of the SB design to the applicable provisions of ACI 307-69 and 318-63 is documented in the new design evaluation. The design evaluation demonstrates that the SB maintains its structural integrity, meets the requirements of the design codes, and can perform its intended design functions.
The methodology used for the new evaluation of the Shield Building involves use of the ANSYS computer code. Existing methods are described in USAR Subsection 3.8.2.2. The use of ANSYS for this application was concluded a methodology change for the 10 CFR 50.59 Screen. However, its use does not involve a departure from the method of evaluation described in the USAR, because the planned use of ANSYS is considered "approved by the NRC for the intended application". The NRC has approved the use of ANSYS for the type of analysis planned for the evaluation of the Shield Building, and FENOC satisfies the applicable terms, conditions, and limitations for its use.
1.3 Is a License Amendment Required prior to implementation of the change?
Yes 0 No
No.
13-00918 Rev.
02 firstEhergy 10 CFR 50.59 EVALUATION NOP-LP-4003-03 Rev. 02 Initiating Activity No.
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Bair, Richard N Reviewer (Print name)
Reineck, Bradley T xl Yes GST No Additional review required?
Manager (Print name)
Jon G. Hook Onsite Review Meeting Number Director, Site Operations (Print name)
Signature/^
Program Owner C
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13-00918 02 01 2.0 Detailed
Description:
The NRC issued a Confirmatory Action Letter (CAL) to document the FENOC actions required to demonstrate long-term confidence in the SB integrity (Reference 5). These actions included providing the NRC with the results of the root cause evaluation and corrective actions for the SB cracking. In the root cause evaluation report (Reference 6),
FENOC determined that the root causes for the SB laminar cracking were attributed to: the environmental factors associated with the 1978 blizzard, the lack of an exterior moisture barrier and the structural design elements of the SB.
The design specification for the construction of the SB did not specify application of an exterior sealant for moisture.
The root cause preventive action was to apply an exterior sealant system. The NRC evaluated the corrective actions identified by FENOC in the root cause report to determine whether they were sufficient to prevent recurrence, and to ensure the continued capability of the SB to perform its design safety functions (biological shielding, controlled release of annulus atmosphere under accident condition, and environmental protection of the containment vessel). Based upon this review, the NRC concluded that the corrective actions and preventative actions, if adequately implemented, would prevent recurrence of the laminar cracking in the SB (Reference 7). A new calculation, C-CSS-099.20-063, provides the new design evaluation of the SB, including the effects of the laminar cracking, for the cylindrical shell wall, dome, and spring line areas of the structure. The new calculation does not replace the existing design calculations for the areas of the building near the penetrations and permanent openings, and the foundation. For the areas not within the scope of the new calculation, the existing analysis and design methods, results, and conclusions described in USAR Section 3.8.2.2 remain valid.
In accordance with Revision 1 of RAD No. 13-00918, the scope of Revision 1 of the 50.59 Evaluation consists of correcting the record date and number of Reference No. 11.
Revision 2 of this 50.59 Evaluation documents the review of Calculation C-CSS-099.20-063, Revision 01. This calculation revision evaluates the effect of the crack propagation identified during the periodic inspection of the existing laminar cracks, Ref. 18. The areas of crack propagation are limited to portions of the Shield Building shoulders (i e no crack propagation was identified in the shell of the SB wall). During shield building monitoring inspections performed in August of 2013, using equipment with enhanced optics, FENOC discovered laminar cracking that had not previously been identified in the bore being observed. Subsequently, FENOC expanded the inspection to include the entire population of bores, 80 in total for signs of cracking. A total of 91 inspections were performed on the 80 bores over the next several days. Out of the 80 bores inspected, "new" cracking was identified in 8.
As a result of the identified cracking, FENOC again contracted Pll to perform a comprehensive technical cause assessment (RCA-2) to identify the cause(s) of the unexpected crack propagation. This investigation focused on the time period from September 2011 to September 2013 which corresponds to the propagating crack conditions.
It also considered the continuing validity of RCA-1 as the cause of the initial laminar cracking.
Laboratory testing and various analytical models were used; including thermal and structural analyses which helped determine the cause of the laminar crack propagation to be due to Ice-Wedging. Ice-Wedging requires the three following conditions to occur: 1) a pre-existing crack, 2) water present in the crack with localized saturation, and 3) an Ice-Wedge cycle that contained a freezing condition.
Contributing to the Ice-Wedging cause is application of the coating to the shield building. While application of the coating has effectively prevented water from entering the shield building, its application has also prevented a finite amount of moisture from leaving the structure. Until this moisture dissipates it provides the water accumulation mechanism required for Ice-Wedging. The amount of free water will diminish over time due to absorption and disbursement.
The shield building crack propagation has been well researched as a result of the analysis performed under RCA-2.
The crack growth rate has been determined, and can be predicted as a result of this analysis. Testing performed both Purdue University and the University of Kansas shows that there are no adverse effects of the laminar crack on the capacity of the rebar and that the design basis calculation has design margin.
Therefore, appropriate corrective actions which are being implemented are focused on the on-going monitoring of the shield building.
3.0 Analysis
Same as the existing SB calculations, the new calculation evaluated the SB in accordance with ACI 307-69 and
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13-00918 02 01 checked the design by the ultimate strength method in accordance with ACI 318-63. The load combinations specified in ACI 307-69 for the working stress design method and ACI 318-63 for the ultimate strength design method were used. All applicable design bases loads and load combinations were imposed on the analyzed structure, including dead and live loads, wind and tornado loads, maximum probable and maximum possible earthquake loads, lateral earth pressures, and operating and accident loads including high energy line break effects. The analysis for thermal loads was performed by manual calculations. Except as clarified for computer code ANSYS, below, the new calculation does not use methods that revise or replace USAR-described evaluation methodology.
Both the existing analysis and the new analysis use the membrane theory of thin shells. As described in the 10 CFR 50.59 Screen (No. 13-00918), the new analysis of the SB was performed by Bechtel Power Corporation, using a three-dimensional finite element (FE) model in ANSYS, which is a quality controlled computer program verified and validated for use in nuclear safety-related applications in accordance with the project procedures. The existing analysis used closed-form equations in accordance with Articles I-2 and 1-3 of the ASME Code,Section III, 1968. Thus, the use of ANSYS is treated as a methodology change and evaluated under 10 CFR 50.59(c)(2)(viii) in this 50.59 evaluation.
As concluded in the 50.59 Screen, the proposed activity, specifically the alteration of the design strength value to 55,000 psi for some of the rebar, adversely affects a USAR-described function of an SSC. Therefore, the effects of the laminar cracking screened-in for the design strength change.
New Analysis of Shield Building Design Strength Parameters USAR Subsection 3.8.2.2.6 describes the design strength parameters used for the original design of the SB for both the working stress design and ultimate strength design methods. For the ultimate strength design method, in accordance with ACI 318-63, a value of 4,000 psi was considered for the design compressive strength of concrete (fc1) and a value of 60,000 psi was considered for the minimum yield strength of reinforcement (fy). The allowable concrete and reinforcement stresses for the working stress design method were established, for applicable load combinations, in accordance with ACI 307-69, using these design strength values for concrete and reinforcement.
The laminar cracking, which lies in the plane of the outer reinforcement layer, potentially affects the bond between the concrete and the reinforcement and may reduce the design strength of the reinforcement, especially where the reinforcement is lap-spliced in the cracked areas. Therefore, confirmatory testing was performed at Purdue University and University of Kansas to investigate the effect of laminar cracking on the structural behavior (Reference 11).
The laminar cracking observed in the SB is an unusual situation where the crack exists in the plane of the outer reinforcement layer. Although there is a significant amount of test data on reinforcement bond development which forms the basis of the current ACI 318 Code requirements, the effect of such laminar cracking on the bond transfer capacity of the reinforcement has not been evaluated. In order to understand and evaluate the bond transfer capacity of reinforcement with a crack in the plane of the rebar, a detailed test plan was developed to determine the bond transfer mechanism and capacity of reinforcement with a simulated crack in the plane of the reinforcement. The confirmatory tests were carried out using the same procedure, means, and methods as are typically used for testing of reinforcement and bond transfer capacity that forms the basis of the ACI Code provisions. The tests were performed at well renowned laboratory facilities under the guidance of well-known subject matter experts. These tests are considered routine development and bond tests and are considered "confirmatory" in the sense that they follow the same process and procedures that are typically used for development and bond of reinforcement and are intended to confirm the effect of one of the aspects (cracking) on behavior and capacity.
The commentary to ACI 318-63 (Reference 16) includes References 13-15 as supporting documentation for the description of the basis for the ACI 318-63 Code provisions related to bond and tension splices. References 13-15 describe the test methods and procedures used to establish the bond transfer capacity of reinforcement. Based on a thorough review of References 13-15, it is concluded that the methods and procedures used to perform the confirmatory tests are consistent with the references and comply with the ACI 318-63 Code provisions. Therefore, the confirmatory tests carried out are deemed to be acceptable from the Code perspective, as are the development and bond tests that form the basis for the ACI Code provisions. The level of quality associated with the testing is acceptable for the test data to be used as design input to a safety-related calculation.
Test Programs
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13-00918 02 01 The SB is reinforced by No. 11 rebar in the circumferential direction and by No. 8, 10, and 11 rebar in the meridional direction. For the No. 11 circumferential rebar, a lap-splice length of 79 inches is present between elevations 569.0 feet and 780.0 feet and a lap-splice length of 120 inches is present above elevation 780.0 feet.
In the vertical direction, the No. 11 rebar are spliced using lap-splices with a length of 79 inches. The meridional reinforcement is well confined by the outer circumferential reinforcement and the additional concrete cover, especially in the architectural flute shoulder areas, and is less critical to the effects of laminar cracking compared to the circumferential reinforcement.
Therefore, the test program consisted of two sets, one corresponding to the testing for the 79-inch lap-splice length and the other corresponding to the testing for the 120-inch lap-splice length. The tests were independently performed at Purdue University and University of Kansas to ensure reliability of results and redundancy.
The Purdue University and University of Kansas test programs had twelve (12) and six (6) straight beam specimens, respectively, with equal number of specimen with 79-inch and 120-inch lap-splice lengths. The reinforcement layout in the test specimens for both test programs was such that the lap-splices were located adjacent to each other compared to the generally staggered layout of lap-splices in the SB. This provides a conservative test specimen configuration, since for staggered layout, as one lap-splice reaches its ultimate capacity, the adjacent continuous reinforcement continues to resist the applied load and provides a larger overall capacity compared to the ultimate capacity of the lap-splice. The curvature of the SB also provides additional confinement to the lap-splices due to the presence of stress normal to the plane between the reinforcement and concrete, while the straight test specimens do not consider this beneficial effect. Additionally, the compressive strength of concrete in the test specimens conservatively represented lower bound values compared to the concrete compressive strength for the as-built condition of the SB.
Conservatively, the confirmatory testing also used a rebar spacing (and thus, the lap-splice spacing) of 6 inches, while a majority of the outer circumferential reinforcement in the as-built SB has a spacing between 9 to 12 inches.
The test specimens for both test programs were simply supported beams of rectangular sections loaded with a four-point flexural test setup, with loads applied at two points. For the University of Kansas test program, a cold-joint was created in the plane of reinforcement in the splice region for some test specimens to simulate the laminar cracking.
The loading was applied continually in a static manner till failure for some test specimens. For other test specimens, after initial loading, the test specimens were unloaded and subsequently reloaded in a static manner to failure; the initial loading caused cracking in the test specimen to simulate the presence of laminar cracks. The development of initial cracking in the test specimen, representing the laminar cracking in the SB, was verified; it was also verified that the width of initial cracks in the test specimen exceeded the crack widths observed in the SB. The load-deflection behavior, crack development, and reinforcement stresses were observed to identify the effect of laminar cracking on the behavior of the test specimens (Reference 11).
Flexural Test Results For the Purdue University test program, all test specimens showed similar behavior and the presence of laminar cracking, initiated by loading the specimen followed by unloading, had no effect on the strength of the specimen and the lapped splices in the reinforcement. The minimum and maximum tensile strength of the reinforcement in the flexural test specimens were 69,000 psi and 80,000 psi, respectively, with a computed average strength of 74,833 psi.
The smaller tensile strength values were observed in the specimens with the lap-splice length of 79 inches, and the minimum tensile strength from all tests exceeded the minimum yield strength value of 60,000 psi. Additionally, yielding of reinforcement was observed for all the test specimens in the Purdue test program.
For the test program at University of Kansas, the reinforcement attained a minimum tensile strength of 67,000 psi for the test specimens with lap-splice length of 120 inches. For the flexural test specimens with lap-splice length of 79 inches, except for one test specimen that did not achieve the minimum yield strength of the reinforcement, the tensile strength from the other two test specimen exceeded the minimum yield strength of the reinforcement. The minimum and maximum tensile strength of the reinforcement for all flexural test specimens at University of Kansas test program were 57,000 psi and 70,000 psi, respectively, with an average of 66,167 psi.
New Design Strength In the Purdue University and University of Kansas test programs, which involved a total of eighteen (18) test specimens, only one specimen with a lap-splice length of 79 inches failed prior to reaching the minimum yield strength of the reinforcement. However, as described above in the description of the test programs, both programs used conservative conditions compared to that in the SB. Therefore, although one test specimen did not achieve the minimum yield strength of the reinforcement, the outer circumferential reinforcement in SB with the laminar cracking is expected to achieve its minimum yield strength.
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13-00918 02 01 Although the test programs identified potential impact only on the outer circumferential reinforcement with a lap-splice length of 79 inches located between elevations 569.0 feet and 780.0 feet (Reference 11), the new design evaluation of the SB conservatively considers a limiting design strength of 55,000 psi, taken to be lower than the minimum tensile strength observed in both test programs, for the outer circumferential reinforcement in the entire cylindrical shell instead of using the minimum yield strength of 60,000 psi. The new design evaluation uses the specified minimum yield strength of 60,000 psi for all other reinforcement.
A value of 4000 psi is used for the compressive strength of concrete (fc1), consistent with USAR Subsection 3.8.2.2.6.
The new design strength values are in accordance with ACI 318-63. ACI 318-63 defines the minimum yield strength of reinforcement as the minimum value determined in tension according to applicable ASTM specifications; this corresponds to the testing of individual rebar in tension tests. The reinforcement design strength is limited to 60,000 psi for vertical rebar, outer hoop rebar in the dome, and inner horizontal hoops in the new design evaluation, while it is conservatively limited to only 55,000 psi for outer hoop bars in the cylindrical shell. Note that 55,000 psi is not being defined as the minimum yield strength of reinforcement, but is being used as its limiting design strength in the evaluation. For the reasons mentioned earlier, the considered design strength for the outer circumferential reinforcement represents a lower-bound strength limit. The confirmatory tests were performed using the same process and procedures that are typically used for such tests to form the basis for ACI Code equations.
It is noted that the ACI 318-63 Code specified value of 60,000 psi is meant to provide a limiting strength for design.
The actual yield strength is generally higher and is not used in the design.
In that sense, the 55,000 psi limit provides a similar but an even lower limit for design. The lower bound strength of 55,000 psi actually only applies to spliced circumferential rebar in the cracked regions.
Analysis and Design Procedure The existing SB design was performed in accordance with ACI 307-69 and checked by the ultimate strength method in accordance with ACI 318-63 (USAR Section 3.8.2.2.3). In accordance with USAR Section 3.8.2.2.3, the load combinations specified in ACI 307-69 provided the design basis of the building; additionally, the ultimate strength design load combinations specified in ACI 318-63, with the load factors provided in USAR Appendix 3A, were used to check the SB design. The design of the SB ensured an elastic behavior of steel reinforcement is maintained during a Maximum Possible Earthquake, controlling cracking of concrete and impairment of leaktight integrity (USAR Section 3.8.2.2.2).
Consistent with the USAR, the new design evaluation of the SB is performed for both the working stress design and ultimate strength design methods. The loads and load combinations from USAR Subsection 3.8.2.2.4, and the design strength values from USAR Subsection 3.8.2.2.6, supplemented by the design strength of 55,000 psi for the outer circumferential reinforcement in the cylindrical shell, were used. This ensures that the design of the SB meets the design basis codes and methods, and the requirements of General Design Criteria 2 and 4 of Appendix A to 10CFR50, as described in USAR Sections 3D.1.2 and 3D.1.4 of Appendix 3D.
Seismic Loads for Shield Building with Laminar Cracking For the original analysis and design of the SB, USAR Section 3.7.2 describes the methodology for performing the seismic analysis. Specifically, USAR Subsections 3.7.2.1 and 3.7.2.2 establish the method and criteria, respectively, for performing the seismic analysis. A frequency analysis established the dominant frequencies of vibration of the structure in all directions and then seismic demands, such as structural accelerations and the floor response spectra, were computed for both the maximum probable earthquake and the maximum possible earthquake. The SB was analyzed using a fixed-base lumped mass stick model, wherein the structure was mathematically idealized as lumped masses at floor levels and the beam elements between the mass points represented the equivalent stiffness of the structure. The contribution from the architectural flute shoulder areas was considered to determine the equivalent stiffness properties of the beam elements.
For the new design evaluation, to investigate the influence of the laminar cracking on the seismic demands of the SB, confirmatory analyses were performed using the mathematical modeling approach described in USAR Subsection 3.7.2.1.1. The analyses were performed using lumped mass stick models developed using ANSYS, which is a quality controlled, validated, and verified computer program. One model represented the SB without the effects of laminar cracking (benchmark model) and the other two models represented the SB with the effects of laminar cracking in
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13-00918 02 01 varying locations. The stiffness and mass properties in the lumped mass stick model without the effects of cracking matched the properties used in the original seismic analysis in Section 3.7.2. For the models with cracking, the stiffness properties were calculated by neglecting the contribution of the concrete located outside the cracked surface in the SB shell. The distribution of laminar cracking used for the calculation of reduced stiffness properties is based on the information contained in References 8. Frequency analysis was performed in ANSYS to determine the dominant frequencies and mode shapes.
The dominant frequencies and the mode shapes for the lumped mass stick models without and with the effects of laminar cracking were compared. These results were also compared to the dominant frequencies of the SB based on the original design basis analysis, including the seismic analysis methods, described in USAR Section 3.7.2. The structural frequencies for the lumped mass stick model without the effects of laminar cracking closely matched the frequencies based on the original design basis analysis, validating the modeling approach. The two SB ANSYS lumped mass stick models with varying crack locations showed a very close agreement for the dominant frequencies.
This shows that the seismic response of the SB, including the structural accelerations and the floor response spectra, for both maximum probable and maximum possible earthquakes is not adversely impacted by the change in stiffness properties due to the cracking. The new design basis evaluation, therefore, used the seismic loads based on the analyses described in Section 3.7.2.
The location and extent of laminar cracking, considered in the two SB cracked models, was evaluated for the potential effect of the identified crack propagation areas. The first SB model that considers laminar cracks was based on the conservative assumption that all sixteen (16) of the SB shoulders contained laminar cracks (i.e. 100% laminar cracks in all shoulders). The second SB model that considered laminar cracks was based on Reference 8 with varying degrees of cracking within four vertically oriented regions of the SB.
These models have been reviewed in Rev. 02 of Calculation C-CSS-099.20-063 for the additional areas of the crack propagation. As identified above and in Reference 18, the areas of crack propagation are contained in the SB shoulders. These additional crack areas are enveloped by the first SB model described above. The locations of the crack propagation were compared against second SB cracking model. This comparison determined that there is sufficient margin in this model to envelop the additional cracking. Also, the frequencies for the first SB cracked model controlled (greater delta to the uncracked SB frequencies) than the second SB cracked model, which provides an additional degree of margin. Therefore, the calculation revision concluded that the new Shield Building analysis would continue to use the seismic loads based on the analyses described in Section 3.7.2 of Ref.
1.
Analytical Techniques For the original design of the SB, the membrane theory of thin shells was used to analyze the cylindrical wall, spring line and dome of the SB in accordance with Articles I-2 and I-3 of the ASME Code,Section III, 1968. At places where changes in geometry or loading exist, an analogy of a beam on elastic foundations was made in conformance with Article I-7 of the ASME Code. The seismic demands were calculated by performing seismic analysis using a cantilevered lumped mass stick model of the SB. For thermal loads, the cracking effect of reinforced concrete was considered, as suggested by ACI 307-69. ACI Publication SP-20, "Causes, Mechanism and Control of Cracking in Concrete" was used to determine the maximum width of cracks at the surface and compare the result to the allowable width permitted by the ACI Standard Building Code (ACI 318-63). (USAR Subsection 3.8.2.2.5)
For the new design evaluation, the SB was also analyzed using the membrane theory of thin shells. A combination of finite element analysis and classical analytical techniques were used to determine the structural response of the SB to the design bases loads.
The new structural analysis of the SB was performed using a three-dimensional finite element model in ANSYS.
ANSYS shell element type SHELL181 was used to model the cylindrical shell wall, dome, and spring line of the SB.
SHELL181 is a three-dimensional 4-noded shell element with six degrees of freedom at each node and is suitable for modeling thin to moderately-thick shell structures such as the SB. The element resultants comprise of membrane forces and bending moments, in-plane shear forces and twisting moments, and out-of-plane shear forces. The resistance to the controlling load combinations is provided primarily by in-plane shear with very little out-of-plane bending. Since the cracking does not reduce the thickness of the shell and is located in the plane of outer reinforcement, the load carrying capacity by membrane action, in-plane shear, out-of-plane shear, and out-of-plane bending is not impacted and uncracked section properties are considered in the analysis. The finite element model uses a sufficiently refined mesh size that is appropriate to accurately capture the structural response of the SB for the applicable loads and load combinations.
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13-00918 02 01 The supporting foundation, penetrations, and permanent openings were not included in the new finite element model.
The SB is founded on a rigid mat, as described in USAR Subsection 3.8.2.2.5, and the original analyses in USAR Subsections 3.7.2.2 and 3.8.2.2 were performed using a fixed base condition. The laminar cracking is not present around the permanent openings and penetrations, except for the main steam line penetrations 39 and 40. The main reinforcement in the cylindrical shell is not lap-spliced in the areas around the main steam line penetrations 39 and 40.
As described in USAR Subsections 3.8.2.2.2 and 3.8.2.2.5, adequate reinforcement is provided around the openings and penetrations, including the diagonal rebar at each corner, as applicable. The reinforcement maintains continuity in the cracked area around these penetrations and is well anchored to the shell outside of the cracked area, thus providing an adequate force transfer mechanism. The laminar cracking potentially affects the design strength of the 79 inch lap-splices on the outer circumferential reinforcement, but the design strength of the reinforcement provided to strengthen the main steam line penetrations 39 and 40, including the diagonal rebar at each corner, are not impacted.
Therefore, there is no adverse effect on the structural integrity of the areas around the main steam line penetrations 39 and 40 due to the laminar cracking. The analytical methods and results described in USAR Subsection 3.8.2.2 for the evaluation of the stress concentration effects at the permanent openings and major penetrations are still applicable.
As described earlier, the stiffness of the structure and thus the load carrying capacity of the SB by membrane action, in-plane shear, out-of-plane shear, and out-of-plane bending are not impacted by laminar cracking. Therefore, the response of the piping and electrical penetrations at their interface with the SB will not be adversely impacted by the laminar cracking.
All applicable design bases loads from USAR Subsection 3.8.2.2.4, except the operating and accident thermal loads, including dead and live loads, wind and tornado loads, maximum probable and maximum possible earthquake loads, lateral earth pressures, and operating and accident pressures were imposed on the finite element model and the analysis was performed using a fixed base condition. As described in the previous section, the dynamic behavior of the SB with laminar cracking closely matches the dynamic behavior of the SB without laminar cracking. Therefore, the seismic loads from USAR Section 3.7.2 were used without any modification. The seismic accelerations at various elevations of the lumped mass stick model were applied to the finite element model of the SB. The loads imposed on the SB due to Main Feedwater and Steam Generator Blowdown line breaks in the Annulus and the Main Steam line break in the Auxiliary Building were also considered in the analysis. The thermal loads associated with these high energy line breaks are insignificant compared to the accident thermal loads caused by the design basis Loss of Coolant Accident and were ignored. The Main Steam line break results in a bounding pressure loading on the SB compared to the Main Feedwater and Steam Generator Blowdown line breaks; thus, the Main Steam line break pressure loading was imposed on the finite element model.
For the operating and accident thermal loads, manual computations were performed in accordance with ACI 307-69.
These computations accounted for the reduction of bending moments imposed on the SB cross-sections due to cracking caused by thermal loads. The results from these independent load cases were combined to determine the shell element resultants for the load combinations described in USAR Subsection 3.8.2.2.4 for both working stress design and ultimate strength design methods. The load factors provided in USAR Appendix 3A were used for ultimate strength design load combinations. The independent load cases Ho and HA, which are described in USAR Subsection 3.8.2.3.4 and represent the reactions on the structure due to thermal expansion of pipes under operating and accident conditions, respectively, are generally not applicable for the analysis and design of the SB, since the high energy pipe systems such as Main Steam and Main Feedwater are isolated from the SB. This consideration is supported by Table II.G.1-2 of Reference 17.
The effect of temporary construction openings created during the original construction, 2002 reactor pressure vessel head replacement project, 2011 reactor vessel closure head replacement project, and 2014 steam generator replacement project were considered in the new evaluation by performing a separate sectional analysis. This analysis provided the redistribution of stresses caused by self weight of the SB considering the sequence of creation and restoration of the temporary construction openings.
Design Methodology As described in USAR Subsection 3.8.2.2.3, the existing SB design was performed in accordance with ACI 307-69 and checked by the ultimate strength method in accordance with ACI 318-63. The new evaluation of the SB design was performed and checked in accordance with the same Code, using the strength reduction factors provided in USAR Subsection 3.8.2.3.4. The design strength values used in the new evaluation were those given in the "New Design Strength" section above.
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13-00918 02 01 Except for the outer circumferential reinforcement along the entire height of the cylindrical shell, where a conservative design tensile strength of 55,000 psi was used, the ultimate strength design method used a value of 60,000 psi for all other reinforcement. Accordingly, the allowable stresses for the working stress design method for the outer circumferential reinforcement in the cylindrical shell were also conservatively reduced proportionally to the ratio of the new design strength and the design yield strength of the reinforcement. The new values for each load combination listed in USAR Subsection 3.8.2.2.4 are as follows:
- a. To fs = 22.1 ksi
- b. DL + To fs = 22.1 ksi
- c. DL + W fs = 13.8 ksi
- d. DL+E fs = 16.6 ksi
- e. DL + To + E fs = 30.0 ksi
- f. DL + To + W fs = 30.0 ksi (Note: Notations above are from USAR Subsection 3.8.2.3.4).
The allowable stresses for concrete and all other reinforcement were taken from USAR Subsection 3.8.2.2.6.
The new design evaluation of the SB was performed using the shell element results from the finite element analysis previously described. For the working stress design method, the shell element forces and moments were used to compute the service level stresses in the concrete and reinforcement. Similarly, for the ultimate strength design method, the combined effect of shell element membrane forces and bending moments, out-of-plane shear forces, and in-plane shear forces were compared against the ultimate section capacities determined in accordance with ACI 318-
- 63. The calculation of section capacities considered the reduced design strength of the outer circumferential reinforcement in the cylindrical shell of the SB. The check for in-plane shear was performed on a global basis using the cumulative forces at the entire cross-section of the shell at a particular elevation, while all other design checks were performed for each shell element in the finite element model.
For the new evaluation, the lateral earth pressure loads on the SB were re-created using the same methods and input soil data described in USAR Subsections 3.8.1.4.4, 2.5.1.8, and 3.4.2.1, and Section 2C.6.3 of Appendix 2C.
For the new design evaluation, the effect of tornado loads, including the tornado missiles, was accounted for by conservatively ignoring the concrete cover on the outer face of SB shell. The load combinations with tornado load effects were considered in the design check of the SB using the ultimate strength design method. The tornado missile penetration depths listed in USAR Table 3.3-2, calculated using the methods described in USAR Section 3.5.8, are less than half of the conservatively reduced shell thickness. These results meet the USAR Section 3.5.2 criteria for minimum thickness to prevent concrete spalling and generation of secondary missiles.
Serviceability and Durability Considerations As described in USAR Subsection 3.8.2.2.2, the control of cracking and impairment of leaktight integrity, due to concrete shrinkage and temperature gradients, is achieved by placing adequate reinforcement in the concrete walls, dome, and foundation, and by ensuring elastic behavior of the steel reinforcement is maintained during a Maximum Possible Earthquake. USAR Subsection 3.8.2.2.5 further specifies that cracking due to thermal loads is controlled by providing large amount of reinforcement and limiting the maximum surface crack width calculated using the provisions in ACI Publication SP-20 to less than the allowable of 0.010 inch per ACI 318-63 and USAR Subsection 3.8.2.2.5. The allowable crack width per ACI 318-63 is intended to limit the potential moisture infiltration paths that may lead to reinforcement corrosion. Corrosion protection for the reinforcement is provided by providing a sufficient concrete cover.
Consistent with Subsection 3.8.2.2.5, the new design evaluation of the SB evaluated the surface cracking consideration using the guidelines provided in ACI Publication SP-20. The maximum crack width at the surface due to mechanical loads is 0.0086 inch, which meets the crack control guidelines provided in ACI 318-63.
For the SB with the extent of cracking shown in References 8 & 18, the crack width of most observed laminar cracks was less than 0.010 inch, with a maximum width of 0.013 inch for one of the cracks and all of the propagation cracks were found to be less than 0.010 inches in width. No unusual levels of carbonation, moisture infiltration, or reinforcement corrosion activity were identified. Procedure EN-DP-01511 (Reference 10) specifies periodic inspections of the Shield Building to monitor the laminar/propagation cracks. The crack widths of shrinkage cracks at the surface
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13-00918 02 01 are very small and will not provide a path for any significant moisture infiltration to the laminar cracks. The concrete cover to the reinforcement is maintained and the architectural flute shoulder areas will continue to provide adequate confinement to the circumferential and meridional reinforcement, since the flute shoulder areas are tied to the cylindrical shell by additional anchor reinforcement. The reinforcement has neither degraded nor lost its corrosion protection. Additionally, the exterior surfaces of SB above grade were coated to provide additional protection from moisture.
Based on these considerations, the SB with the configuration of laminar cracking and crack propagation depicted in References 8 & 18 will maintain its serviceability and long-term durability under the operating conditions.
Design Evaluation Results The structural design of the SB using the working stress design method was performed in accordance with ACI 307-
- 69. For the most critical element, the ratio of maximum stress in the reinforcement to the corresponding allowable stress is 0.88. Similarly, the ratio of maximum stress in concrete to the corresponding allowable stress is 0.81. This ensures that the SB meets the structural acceptance requirements specified in ACI 307-69.
The design check of the SB using the ultimate strength design method was performed in accordance with ACI 318-63.
For the most critical element, the demand to capacity ratio for combined interaction of membrane forces and bending moments is 0.76, while the maximum demand to capacity ratio for the effect of out-of-plane shear forces is 0.37. The maximum total in-plane shear demand at the base of SB was also significantly lower than the global in-plane shear strength, calculated in accordance with ACI 318-63 using the concrete shear capacity and the contribution from the shear reinforcement. The ratio of shear reinforcement required to resist the maximum total in-plane shear to the provided shear reinforcement is 0.67. These results demonstrate that the stresses and strains for the SB are within the ACI 318-63 limits and that the structure meets the strength requirements specified in ACI 318-63.
The evaluation for out-of-plane shear and in-plane shear were also performed in accordance with the working stress design method in ACI 318-63, to supplement the ACI 307-69 requirements, and the demand to capacity ratios for both checks are governed by the ultimate strength design method.
The SB with the extent of laminar cracking and crack propagation documented in References 8 & 18 behaves within the elastic range and is capable of withstanding the design basis loads and load combinations described in USAR Subsection 3.8.2.2. The compliance of the SB design to the applicable provisions of ACI 307-69 and ACI 318-63 is documented in Reference 2. The design evaluation demonstrates that the SB maintains its structural integrity, meets the requirements of the design codes, and can perform its intended design functions.
4.0 10 CFR 50.59 (c)(2) Criteria Questions 4.1 Does the proposed activity result in more than a minimal increase in the frequency of occurrence of q Yes 0 No an accident previously evaluated in the UFSAR?
The USAR was reviewed to identify the accidents/transients previously evaluated that are potentially affected by the new evaluation. USAR Tables 15.2-1, 15.3-1, and 15.4-1 provide the listings of the Class 1, Class 2, and Class 3 accidents by anticipated frequency and radiological consequences.
In the event of an accident, the SB reduces the station and off-site intensities emitted directly from the released fission products to acceptable levels. The SB serves as a ventilation boundary for the station Emergency Ventilation System (EVS) to control releases from the Annulus space, penetration rooms and Emergency Core Cooling System (ECCS) rooms under accident conditions.
The SB was not previously analyzed as an accident initiator. The SB functions to mitigate accidents. Consequently, the presence of SB laminar cracking does not represent more than a minimal increase in the frequency of occurrence of an accident previously evaluated in the USAR.
4.2 Does the proposed activity result in more than a minimal increase in the likelihood of occurrence of
[J Yes 0 No a malfunction of an SSC important to safety previously evaluated in the UFSAR?
The SB provides for 1) biological shielding, 2) controlled release of the annulus atmosphere under accident conditions, and 3) environmental protection of the containment vessel.
The SB is a Seismic Category I, safety-related structure. No malfunctions of the SB were
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13-00918 02 01 previously evaluated in the USAR. Post-accident, the EVS establishes a negative pressure in the SB annulus space and connected spaces. Leakage of fission products from the Containment Vessel to the SB annulus are exhausted by the EVS through HEPA and charcoal filters to the station vent (USAR Subsection 6.2.3). A malfunction (failure) of an active component in either of the redundant trains of the EVS is postulated (USAR Subsection 6.2.3).
If the cracking were through-wall, that condition could result in a malfunction of the EVS's ability to draw a negative pressure in the annulus in the event of the postulated EVS failure. However, the inspections identified laminar cracks and adjacent areas of crack propagation (References 8 & 18) and small, shrinkage cracks at the surface.
No unusual levels of carbonation, moisture infiltration, or reinforcement corrosion activity were identified during inspections. Procedure EN-DP-01511 (Reference 10) specifies periodic inspections of the Shield Building to monitor the laminar/propagation cracks.
A new SB calculation, C-CSS-099.20-063, provides the new design evaluation of the SB, including the effects of the laminar cracking, for the cylindrical shell wall, dome, and spring line areas of the structure. Because of the observed laminar cracking in the structure, it was necessary to develop a more accurate representation of the building for the given condition, using state-of-the-practice modeling tools. The evaluation included the results of confirmatory testing. (The review for acceptability of the new tool as a methodology change is provided in the response to question 4.8.)
The SB with the extent of laminar cracking and crack propagation documented in References 8 &
18 behaves within the elastic range and is capable of withstanding the design basis loads and load combinations described in USAR Subsection 3.8.2.2. The effects of the observed laminar cracking have been evaluated against the two structural design codes, ACI 307-69 and ACI 318-63, identified in Subsection 3.8.2.2.3 of the USAR. As documented in Reference 2, the SB design conforms to the applicable provisions of the ACI 307-69 and ACI 318-63 Codes. The design evaluation demonstrates that the SB maintains its structural integrity, meets the requirements of the design codes, and can perform its intended design functions.
Therefore, when the guidance from NEI 96-07, Revision 1, section 4.3.2, is applied, it is concluded that this activity does not result in more than a minimal increase in the likelihood of malfunction of an SSC important to safety. Specifically, that guidance states, in part:
Although this criterion allows minimal increases, licensees must still meet applicable regulatory requirements and other acceptance criteria to which they are committed (such as contained in regulatory guides and nationally recognized industry consensus standards, e.g., the ASME B&PV Code and IEEE standards).
Thus, the new design evaluation demonstrates that the presence of laminar cracks in the SB does not result in more than a minimal increase in the likelihood of occurrence of a malfunction of an SSC important to safety previously evaluated in the USAR.
4.3 Does the proposed activity result in more than a minimal increase in the consequences of an accident previously evaluated in the UFSAR?
The thickness of concrete is not affected by the proposed activity; therefore, the biological shielding function of the SB is not affected. The "controlled release" ventilation boundary function of the SB is not affected, because the design ensures an elastic behavior of steel reinforcement is maintained during a Maximum Possible Earthquake, controlling cracking of concrete and impairment of leaktight integrity. As demonstrated in the response to 4.2 above, the SB remains in compliance with all pre-existing, UFSAR-described ACI codes. Therefore, all assumptions utilized within USAR-described dose analyses remain valid and bounding. No unusual levels of carbonation, moisture infiltration, or reinforcement corrosion activity were identified during inspections The observed laminar cracks were considered 'passive', however Reference 18 documents that some SB shoulder areas have experienced crack propagation. These areas of crack propagation are located adjacent to the plane of the outer circumferential reinforcing steel (i e these cracks do not extend to the exterior face of this structure). Therefore, these identified cracks do not adversely affect the serviceability of the SB (References 9 and 10). The D Yes No
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13-00918 02 01 reinforcement has neither degraded nor lost its corrosion protection. Additionally, the exterior surfaces of SB above grade were coated to provide additional protection from moisture.
Consequently, the presence of laminar cracks in the SB will not result in more than a minimal increase in the consequences of an accident previously evaluated in the USAR.
4.4 Does the proposed activity result in more than a minimal increase in the consequences of a rj yes 0 No malfunction of an SSC important to safety previously evaluated in the UFSAR?
No malfunctions of the SB were previously evaluated in the USAR. Post-accident, the EVS establishes a negative pressure in the SB annulus space and connected spaces. Leakage of fission products from the Containment Vessel to the SB annulus are exhausted by the EVS through HEPA and charcoal filters to the station vent. A malfunction (failure) of an active component in either of the redundant trains of the EVS is postulated (USAR Subsection 6.2.3). As demonstrated in the response to 4.2 above, the SB remains in compliance with all pre-existing, UFSAR-described ACI codes. Therefore, all assumptions utilized within USAR-described dose analyses remain valid and bounding. The new design evaluation demonstrates that the SB maintains its structural integrity, meets the requirements of the design codes, and can perform its intended design functions. The observed laminar cracks were considered 'passive', however Reference 18 documents that some SB shoulder areas have experienced crack propagation. These areas of crack propagation are located adjacent to the plane of the outer circumferential reinforcing steel (i.e. these cracks do not extend to the exterior face of this structure). Therefore, these identified cracks do not adversely affect the serviceability of the SB (References 9 and 10). The reinforcement has neither degraded nor lost its corrosion protection. Additionally, the exterior surfaces of SB above grade were coated to provide additional protection from moisture. Thus, the consequences of an EVS malfunction are not affected. Consequently, the presence of laminar cracks in the SB will not result in more than a minimal increase in the consequences of a malfunction of an SSC important to safety previously evaluated in the USAR.
4.5 Does the proposed activity create a possibility for an accident of a different type than any previously
[j yes g n0 evaluated in the UFSAR?
The SB was not previously analyzed in the USAR as an accident initiator. The new design evaluation addresses the structural integrity of the structure for all applicable design basis load combinations considering the presence of the laminar cracks. The new design evaluation demonstrates that the SB maintains its structural integrity, meets the requirements of the design codes, and can perform its intended design functions. The observed laminar cracks were considered 'passive', however Reference 18 documents that some SB shoulder areas have experienced crack propagation. These areas of crack propagation are located adjacent to the plane of the outer circumferential reinforcing steel (i.e. these cracks do not extend to the exterior face of this structure). Therefore, these identified cracks do not adversely affect the serviceability of the SB (References 9 and 10). The reinforcement has neither degraded nor lost its corrosion protection. Additionally, the exterior surfaces of SB above grade were coated to provide additional protection from moisture. Because the SB will continue to function in accordance with its original design, there are no new interactions, interfaces or effects that could create a new accident type that is not presently described in the USAR. For the same reason, there are no credible non-USAR-described accidents that the SB could initiate. Consequently, the presence of laminar cracks in the SB does not create the possibility of an accident of a different type than any previously evaluated in the USAR.
4.6 Does the proposed activity create a possibility for a malfunction of an SSC important to safety with a rj yes
@ No different result than any previously evaluated in UFSAR?
Post-accident, the EVS establishes a negative pressure in the SB annulus space and connected spaces. Leakage of fission products from the Containment Vessel to the SB annulus are exhausted by the EVS through HEPA and charcoal filters to the station vent. No malfunctions of the SB were previously evaluated in the USAR. A malfunction (failure) of an active component in either of the redundant trains of the EVS is postulated in the USAR. The new design evaluation addresses the structural integrity of the SB for all applicable design basis load combinations considering the presence of the laminar cracks. The design evaluation demonstrates that the SB maintains its structural integrity, meets the requirements of the design codes, and can perform its intended design functions. No unusual levels of carbonation, moisture infiltration, or reinforcement
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13-00918 02 01 corrosion activity were identified during inspections. The observed laminar cracks were considered
'passive', however Reference 18 documents that some SB shoulder areas have experienced crack propagation. These areas of crack propagation are located adjacent to the plane of the outer circumferential reinforcing steel (i.e. these cracks do not extend to the exterior face of this structure). Therefore, these identified cracks do not adversely affect the serviceability of the SB (References 9 and 10). The reinforcement has neither degraded nor lost its corrosion protection.
Additionally, the exterior surfaces of SB above grade were coated to provide additional protection from moisture. Thus, no new interactions, interfaces or effects are created by the cracking that could create a malfunction with a different result. Consequently, the presence of laminar cracks in the SB does not create the possibility for a malfunction of an SSC important to safety with a different result than any previously evaluated in the USAR.
4.7 Does the proposed activity result in a design basis limit for a fission product barrier as described in the UFSAR being exceeded or altered?
The Containment Vessel (CV) is a fission product barrier and the SB is not such a barrier (Reference 12). The design basis limits for the CV are the (a) internal design pressures of 36 psig and (b) internal design pressure 0.67 psig below external pressure (USAR Subsection 3.8.2.1.3).
The new design evaluation addresses the structural integrity of the SB structure for all applicable design basis load combinations considering the presence of the laminar cracks. The new design evaluation demonstrates that the SB maintains its structural integrity, meets the requirements of the design codes, and can perform its intended design functions. The observed laminar cracks were considered 'passive', however Reference 18 documents that some SB shoulder areas have experienced crack propagation. These areas of crack propagation are located adjacent to the plane of the outer circumferential reinforcing steel (i.e. these cracks do not extend to the exterior face of this structure). Therefore, these identified cracks do not adversely affect the serviceability of the SB (References 9 and 10). The reinforcement has neither degraded nor lost its corrosion protection. Additionally, the exterior surfaces of SB above grade were coated to provide additional protection from moisture. Thus, the laminar cracks have no direct or indirect effect on the CV as a fission product barrier and do not exceed or alter its design basis limits. Consequently, the presence of laminar cracks in the SB does not result in a design basis limit for a fission product barrier as described in the USAR being exceeded or altered.
4.8 Does the proposed activity result in a departure from a method of evaluation described in the UFSAR used in establishing the design bases or in the safety analyses?
Analytical evaluation of the SB was performed using the computer code ANSYS. The evaluation was performed for all applicable load conditions and load combinations described in the USAR Subsection 3.8.2.2.4.
ANSYS is a general purpose finite element (FE) analysis computer program having wide application in the nuclear power industry. ANSYS has been used for the analysis of containment structures in design control documents (DCD) submitted for certification of new reactor designs, such as the U.S. EPR and AP1000. A pertinent application of ANSYS was its use for the analysis of the U.S. EPR Reactor Shield Building design as a reinforced-concrete structure with an annular space. The AP1000 Shield Building design also includes a pertinent application of ANSYS, but the U.S. EPR Reactor Shield Building design was selected for the detailed review because it more closely matches the Davis-Besse SB design.
Applicable sections of the U.S. EPR DCD, Tier 2, Chapter 3 (Reference 3: Sections 3.7 and 3.8, and Appendix 3E) were reviewed to determine the extent of ANSYS use for the evaluation of the Shield Building. The U.S. EPR Reactor Shield Building (RSB) is a Seismic Category I structure and is part of the Nuclear Island Common Basemat Structure. The U.S. EPR RSB has geometrical and functional attributes similar to the Davis-Besse SB. The RSB was analyzed using a three-dimensional finite element model with shell elements in ANSYS. The finite element analysis results from the ANSYS model were used to design the structure. The RSB is a heavily reinforced concrete structure comprised of a cylindrical wall and dome roof. The RSB is approximately 186 feet in diameter by 230 feet high, which completely encloses the Reactor Containment Building Yes No Yes No
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hurricanes, tornados, aircraft hazards, and explosion pressure waves). The RSB serves as an additional preventative barrier to the release of radiation or contamination in the event of accident conditions.
In Chapter 3, Section 3.8.4.4, of the NRC safety evaluation report (SER) with open items related to certification of the U.S. EPR standard design (Reference 4), the NRC states on page 3-213 that
"...staff reviewed the design and analysis procedures used for the other Seismic Category I
structures to ensure that they meet the relevant requirements in 10 CFR 50.55a; 10 CFR Part 50, Appendix B; and GDC 1, GDC 2, GDC 4, and GDC 5, and are in accordance with SRP Acceptance Criteria 3.8.4.II.4. The staff also reviewed the FSAR to establish that the design is essentially complete, as required by 10 CFR 52.47(c). With the exceptions described below, the staff finds that the design and analysis procedures meet the regulatory requirements and regulatory guidance cited above."
The exceptions noted in the SER relate to the (a) analysis and design methodology for the spent fuel racks and (b) the identification, analysis, and design of critical sections for certified design. None of the noted exceptions correspond to the analysis methodology using ANSYS.
In fact, the U.S. EPR SER with open items states the following on Page 3-217 regarding the finite element modeling and analysis:
In FSAR Tier 2, Section 3.8.4, Revision 0, and Appendix 3E, the applicant described the FE models used for the structural analysis and design of other Seismic Category I structures, utilizing the ANSYS computer code. However, the staff could not determine the acceptability of these FE models without additional descriptive information.
In particular, the staff was concerned that without a sufficiently refined FE discretization of the structures, the member forces, strains, and stresses determined from the computer analysis may not be sufficiently accurate, which could ultimately lead to an non-conservative design. The same issue was also raised in the review of FSAR Tier 2, Section 3.8.3. Therefore, in RAI 155, Question 03.08.03-16, the staff requested that the applicant provide additional information on the FE models pertaining to mesh size and triangular shell elements used in the analysis of other Seismic Category I structures. The staff considers RAI 155, Question 03.08.03-16 resolved. The resolution of this RAI is discussed in Section 3.8.3.4 of the SER, under "Design and Analysis Procedures."
The loading conditions considered for the evaluation of the Davis-Besse SB, as documented in calculation C-CSS-099.20-063, are similar to the loading conditions considered for the analysis of the U.S. EPR Reactor Shield Building. The Davis-Besse SB analysis has been performed using a three-dimensional finite element model, similar to the three-dimensional finite element model used for U.S. EPR Reactor Shield Building. The U.S. EPR DCD Tier 2 and the associated NRC SER with open items do not identify any specific limitations and/or constraints for the analysis and design of the U.S. EPR Reactor Shield Building using ANSYS for the applicable loading conditions.
As noted above, the open items are not related to the use of the ANSYS for the analysis and design of the U.S. EPR Reactor Shield Building.
Since the U.S. EPR Reactor Shield Building has a similar geometric configuration and is subjected to similar loading conditions, the U.S. EPR Reactor Shield Building three-dimensional finite element model uses the same basic methodology as the Davis-Besse SB three-dimensional finite element model. Therefore, it is concluded that the methodology used for the Davis-Besse SB ANSYS analysis conforms to the methodology used for the analysis of U.S. EPR Reactor Shield Building using ANSYS, as documented in the U.S. EPR DCD Tier 2 (Reference 4: Section 3.8.4.4.2 and Figures 3.8-86 to 3.8-88). The analysis of the Davis-Besse SB has been performed accounting for all applicable restraints and limitations of the ANSYS computer code, as addressed in the following paragraph.
Prior to performing the evaluation of the Davis-Besse SB using ANSYS, the constraints and limitations of the program, such as element type, mesh size, loading conditions (in context of applicability for the specific element types), and other factors were adequately researched. For the applicable loading conditions and expected behavior, suitable element types were chosen with an understanding of the constraints and limitations of their use, as documented in the program
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13-00918 02 01 manuals, and with due consideration of section design. For the areas of the building analyzed using ANSYS, the program was used 'en toto' (i.e., adopted in totality), and the program was applied consistent with the applicable terms, conditions and limitations of its use.
Additionally, the new analysis has been benchmarked against the existing SB analysis for representative loading condition. The benchmark analysis conclusion is documented in Section 7.3 of calculation C-CSS-099.20-063. The benchmarking provides assurance that the ANSYS analysis results are within expectations and are reasonable based on the analysis methodology used.
The Shield Building structures for both Davis-Besse and U.S. EPR are axisymmetric thin shell structures, with a cylindrical wall capped by a dome. For typical Shield Building structures for nuclear power plants, the geometric attributes are such that their structural response is well behaved and the analysis results from the computer software conform to the theoretical solutions for typical loading conditions. To address the concerns raised by the NRC in the U.S. EPR FSAR RAI 155, Question 03.08.03-16, the Davis-Besse SB analysis used guidelines consistent with the response provided by AREVA to the subject RAI. The Davis-Besse SB finite element model used a sufficiently refined mesh size to be able to accurately represent the structural response of the structure for applicable loading conditions. The triangular shape shell elements were only used at the apex of the SB dome, which represents a non-critical location, and the results from these triangular shape elements were carefully reviewed and used for the design evaluation. The analysis results for the new evaluation of the SB were used after thorough review to ensure that the results were within expectations and were reasonable for the applicable set of geometric attributes and loading conditions. Therefore, it is appropriate to consider the use of ANSYS for the U.S. EPR Shield Building analysis as an acceptable "intended application" to demonstrate the acceptance of use of ANSYS for analyzing the Davis-Besse SB.
The new evaluation of the Davis-Besse SB was performed using ANSYS Version 13.0. The U.S.
EPR DCD does not identify the ANSYS versions used for the analysis of the Seismic Category I
structures. Newer program versions were issued and used over the duration of the design certification process. Newer versions of ANSYS are usually issued to include implementation of new element types, which improve upon and incorporate better idealizations/formulations compared to the existing set of element types to provide results that match better with the theoretical solutions. For example, the new design evaluation for the Davis-Besse SB uses SHELL181 element type, which is suitable for modeling thin to moderately thick shell structures, and generally produces better results compared to previous series of shell elements (SHELL43 &
SHELL63). Because the Davis-Besse SB is an axisymmetric thin shell structure, the structural responses are well behaved and the use of different versions of ANSYS (element type selection being one of the considerations) will not produce results and conclusions that are significantly different from one another. Thus, no margin is gained by using ANSYS Version 13.0 for the new design evaluation, compared to versions that may have been used for the analyses documented in U.S. EPR FSAR.
As noted above, the various versions of ANSYS "will not produce results and conclusions that are significantly different from one another." This statement has been validated by reviewing the results and conclusions provided in the ANSYS 13.0 Verification Manual for selected set of problems, which consider the applicable controlling parameters for the SB analysis, and comparing the same with the results and conclusions presented in the Verification Manuals for previous versions.
It is noted that the validation process used in the ANSYS Verification Manuals usually involves comparison of the finite element results with theoretical/closed-form solutions.
The application of ANSYS is consistent with the licensing basis of the plant and does not supersede a methodology addressed by the regulations. There are no plant-specific commitments to the methods of NUREG-0800 for analysis of the SB. The Plant Technical Specifications and the Technical Specifications Bases do not address the structural analysis methods for the building.
Use of hardware and software by Bechtel is controlled by procedures meeting the requirements of the Bechtel Nuclear Quality Assurance Manual (NQAM).
These requirements include training and
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Thus, the use of ANSYS for the new design evaluation of the Davis-Besse Shield Building is considered "approved by the NRC for the intended application." Therefore, the proposed activity does not result in a departure from a method of evaluation described in the USAR used in establishing the design bases or in the safety analyses.
5.0 List any open items or assumptions described in this Evaluation.
CR No.
None 6.0 References and Materials Reviewed:
1.USAR Revision 29 o§2.5.1.8 - Summary of Static and Dynamic Soil and Bedrock Properties o§3.4.2 - Static Loading o§3.5.2 - Missile Identification and Characterization o§3.5.8 -Analytical Technique, on Penetrations o§3.7.2 - Seismic System Analysis o§3.8.1.4.4 - Lateral Earth Pressure Loads o§3.8.2.2 - Shield Building o§3.8.2.3 - Containment Vessel Internal -Structures o§6.2.3 - Features Provided to Shield Vital Equipment Inside and Outside the Containment Vessel o§15.0 -Accident Analysis o§15.4.6 -Major Rupture of Pipes Containing Reactor Coolant Up To and Including Double-Ended Rupture of the Largest Pipe in the Reactor Coolant System (Loss-of Coolant Accident) oAppendix 3A - Descriptions of Load Factors for Shield Building and Containment Vessel Internal Structure Design oAppendix 3D - Conformance with the NRC General Design Criteria, Safety Guides, and Information Guides 2 Calculation C-CSS-099.20-063, Rev.001, "Shield Building Design Calculation" 3.U.S. EPR DCD Tier 2, Revision 3, "AREVA Application Public, Rev 3 - Chapter 03" [NRC ADAMS Accession #
ML12079A174]
4 U S EPR Safety Evaluations with Open Items for Chapter 3, Design of Structures, Components, Equipment, and Systems, "Chapter 03, Group III, EPR DC P2 SER Group III," dated 12/15/11 [NRC ADAMS Accession #
ML092860252]
5.NRC Confirmatory Action Letter (CAL No. 3-11-001), dated 12/2/11 6.FENOC Letter to USNRC, "Submittal of Revision 1 of Shield Building Root Cause Evaluation," dated 5/16/12 [NRC ADAMS Accession # ML12142A398]
7.NRC Inspection Report 05000346/2012009, "Inspection to Evaluate the Root Cause Evaluation and Corrective Actions for Cracking in the Reinforced Concrete Shield Building of the Containment System," dated 6/21/12 [NRC ADAMS Accession #ML12173A023]
8 First Energy Report 25593-000-GQT-GEG-00001, "Impulse-Response Test Data," 7/24/12 9.FENOC Condition Report CR-2011-03346, "Fractured Concrete Found at 17M Shield Building Construction Opening," through February 21, 2012 10 EN-DP-01511 Rev 002, "Design Guidelines for Maintenance Rule Evaluation of Structures 11 Bechtel Report 25593-000-G83-GEG-00016-000, "Effect of Laminar Cracks on Splice Capacity of No. 11 Bars based on Testing Conducted at Purdue University and University of Kansas for Davis-Besse Shield Building," July 30, 2012 12 Davis-Besse Emergency Plan Implementing Procedure, RA-EP-01500, Revision 15, "Emergency Classification" 13.Ferguson, P.M., and Thompson, J.N., "Development Length of High Strength Reinforcing Bars in Bond," ACI Journal, Proceedings V. 59, No. 7, July 1962, pp. 887-922 14.Ferguson, P.M., and Matloob, F.N., "Effect of Bar Cut-off on Bond and Shear Strength of Reinforced Concrete Beams," ACl'Journal, Proceedings V. 56, No. 1, July 1959, pp. 5-24 15 Watstein D
and Mathey, R.G., "Investigation of Bond in Beam and Pull-out Specimens with High Yield Strength Deformed Bars," ACI Journal, Proceedings V. 57, No. 9, March 1961, pp. 1071-1090 16.Commentary on Building Code Requirements for Reinforced Concrete (ACI 318-63), ACI Publication SP-10 17 Davis-Besse Nuclear Power Station Unit 1 Design Criteria Manual, Rev.37
- 18. FENOC Condition Report CR-2013-14097, "Shield Building Laminar Crack Propagation"