ML20236R348
| ML20236R348 | |
| Person / Time | |
|---|---|
| Issue date: | 07/14/1998 |
| From: | Stewart Magruder NRC (Affiliation Not Assigned) |
| To: | Essig T NRC (Affiliation Not Assigned) |
| References | |
| PROJECT-689 NUDOCS 9807210396 | |
| Download: ML20236R348 (37) | |
Text
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p po%g\ UNITED STATES j
- NUCLEAR REGULATORY COMMISSION
$ WASHINGTON, D.C. 30e86-0001
\ ,# July 14,1998 MEMORANDUM TO: Thomas H. Essig, Acting Chief Generic issues and Environmental Projects Branch Division of Reactor Program Management Office of Nuclear Reactor Regulation FROM: Stewart L. Magruder, Project Manager M'dl Generic Issues and Environmental Projects Branch Division of Reactor Program Management Office of Nuclear Reactor Regulation
SUBJECT:
SUMMARY
OF JUNE 10,1998, MEETING WITH THE NUCLEAR ENERGY INSTITUTE (NEI) REGARDING REDUCED SEISMIC LOAD !
CRITERIA FOR TEMPORARY CONDITIONS (TC)
On June 10,1998, representatives of the Nuclear Energy Institute (NEI) met with representatives of the Nuclear Regulatory Commission (NRC) at the NRC's offices in Rockville, Maryland to discuss issues related to reduced seismic load criteria for TC.
A list of meeting attendees is provided in Attachment 1. A copy of the slides used by NEl representatives is provided in Attachment 2.
Mr. G. Holahan, Director, Division of System Safety and Analysis, NRR, opened the meeting by st:: ting that the primary objective of the meeting was for the NRC staff to understand the process by which NEl plans to pursue the subject issue. Mr. G. Lainas, Acting Director, Division of Engineering, NRR, stated that NEl should articulate what its programmatic goals are and what regulatory process NEl intends to use in achieving its goals.
After brief remarks by Messrs. J. Butler and B. Bradley of NEl about industry perspectives on the role of reduced seismic load criteria for TC and its relation with respect to other NEl/ industry initiatives, Messrs. D. Moore and A Amin made summary presentations of NEl's October 9,1997, submittal on the reduced seismic load criteria. During their
/
presentations, both Mr. G. Lainas and Mr. G. Holahan raised questions regarding the programmatic and technical aspects of the issue. Specifically, the staff asked which approach /
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among the available options (e.g., Notice of Enforcement Discretion, Technical Specification allowed outage time (AOT), Exemption of Regulation, License Amendment, Technical Specification Changes, Maintenance Rule, etc.) NEl plans to pursue. The staff also asked why g
l the issue of "non-uniform handling of temporary conditions" in plant operation was not listed as i l one of the risk important items previously proposed by NEl. NEl indicated that it has not had the time to thoroughly evaluate these questions and would examine them carefully and provide a response to the staW. The staff indicated that there are a few policy related issues (e.g., use of 1E-5/yr as an acceptable core damage frequency (CDF) increase criterion, conformance with NRC PRA policy statement) that need to be further examined prior to arriving at a staff position on the proposed criteria.
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T. Essig July 14, 1998 Several technical questions pertaining to the NEl proposed reduced seismic load criteria for temporary conditions were raised by the staff and discussed among the attendees. These questions included: the use of less than the minimum 0.1 g peak ground acceleration required by Appendix A of 10 CFR 100, the large uncertainty involved in the quantification of delta seismic CDF increase, and the large variability of available plant risk based data. NEl representatives and their consultants attempted to answer some of the questions. However, a consensus seemed to emerge that substantial work is needed to effectively address both the regulatory and technical questions raised and future interaction between the staff and NEl will be needed to resolve this issue.
The staff summarized the following observations and action items prior to adjouming the meeting:
The proposed NEl approach has merit.
Many questions, related to both regulatory and technical aspects of the issue, need to be further examined and resolved both by the staff and NEl.
NEl will examine its programmatic goals and identify a specific regulatory process by which it plans to pursue the goals.
The staff will provide a response to NEl's October 9,1997, letter addressing the subject matter.
Project No. 689 Attachments: As stated cc w/att: See next page l
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Distribution: Mtg. Summary w/ NEl Re Reduced Seismic Load Criteria Dated .luly_14,_199(L l Hard_ Copy Docket File {
PUBLIC PGEB R/F OGC j ACRS j SMagruder DJeng EMail SCollins/FMiraglia BSheron
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T. Essig -2 July 14, 1998 Severai technical questions pertaining to the NEl proposed reduced seismic load criteria for temporary conditions were raised by the staff and discussed among the attendtes. These questions included: the use of less than the minimum 0.1 g peak ground acceleration required by Appendix A of 10 CFR 100, the large uncertainty involved in the quantification of delta seismic CDF increase, and the large variability of available plant risk based data. NE!
representatives and their consultants attempted to answer some of the questions. However, a consensus seemed to emerge that substantial work is needed to effectively address both the regulatory and technical questions raised and future interaction between the staff and NEl will be needed to resolve this issue.
The staff summarized the following observations and action items prior to adjouming the meeting:
The proposed NEl approach has merit.
Many questions, related to both regulatory and technical aspects of the issue, need to be further examined and resolved both by the staff and NEl.
NEl will examine its programmatic goals and identify a specific regulatory process by which it plans to pursue the goals.
The staff will provide a response to NEl's October 9,1997, letter addressing the subject matter.
Project No. 689 Attachments: As stated cc w/att: See next page DISTRIBUTION: See attached page Document Name:g:\stm10610.98 A Y OFFICE PM:PGEB SC:PGEB[' D:bSdf~ DME NAME SMagruderTw^ FAkstulewicz GHolanank hinas DATE 7/ T/98 7/ f/98 7/])/98 [7/ /k /98 OFFICAL OFFICE COPY l
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NRC/ INDUSTRY MEETING ON REDUCED SEISMIC LOADS UNDER TEMPORARY CONDITIONS JUNE 10,1998 NAME ORGANIZATION j i
John Butler NEl Biff Bradley NEl H.T. Tang EPRI Doyle Adams Entergy Operations, Inc.
John Richards Duke Power Co.
Robert Kennedy Consultant David Olson Sargent & Lundy Moe Amin Sargent & Lundy Torrey Yee Southern California Edison Donald Moore Southern Company Services Altheia Wyche SERCH Licensing /Bechtel Bob Tedesco NUSIS-Consulting Robert Budnitz FRA Inc.
David Fischer NRC/NRR John Chen NRC/RES Nilesh Chokshi NRC/RES Stephen Dinsmore NRC/NRR Kamal Manoly NRC/NRR Roger Kenneally NRC/RES David Jeng NRC/NRR Robert Rothman NRC/NRR Goutam Bagchi NRC/NRR Jack Strosnider NRC/NRR Gus Lainas NRC/NRR Gary Holahan NRC/NRR Attachment 1 L_ ___
N'RC/ INDUSTRY MEETING ON REDUCED SEISMIC LOADS UNDER TEMPORARY CONDITIONS June 10,1998 m One White Flint North a Rockville, Maryland DRAFT AGENDA .
TIME TOPIC PRESENTER 2:00 Opening Remarks NRC 2:05 Introduction John Butler,NEI 2:IO Industry Perspectives on the Role ofReducedSeismic Loads in the BifTBradIcy,NEI i Larger Risk-InformedInitiative l 2:30 Summary ofOctober 9 Submittal on ReducedSeismic Loads Don Moore, SCS Moe Amin, S&L ;
3:00 Summary ofInitial NRC Review Comments Goutam Bagchi,NRC 1 3:30 Discussion All l 4:00 M ; urn i
f i
l l
. _ _ _ _ _ _ _ _ _ _ _ _ _ _ a
l STATEMENT OF PROBLEM
+ Temporary conditions not typically part of design basis
- TC's common part ofplant operation &
maintenance '
- Licensees need an accepted methodology to )
evaluate TC which adequately accounts for the {
l duration of the TC and ensures no undue risk to plant safety Statement of Problem Unneeded Conservatism Due to Lack of Specific Realistic Guidance:
- Can Result in Unnecessary Mod's
-Increases Worker Dose a e.g., when temporary shielding cannot be installed as needed to reduce dose rates
- Wastes Limited Time and Resources I l
SPECIFIC REQUIREMENTS Attributes of methodology to evaluate TC
- Use risk informed approaches (March '97 NRC mtg.)
- Straight forward & practical
- Applicable to all nuclear power plants
- Use existing plant specific data
- Reasonable record keeping requirements
- Responsive to NRC issues from March '97 mtg.
and IN 97-71 EXAMPLES of TCs Lead blankets for temporary shielding scabiding & temporary structures
- Rigging
+
Temporary equipment storage
+ Tempc,rary snubber removal i
2 I u--_-_--_-_----------------------- - - - - - . I
'e a
e f
l BENEFITS !
=
Maintains adequate plant safety using risk-informed approach
+
Applicable to all plants (uniform approach)
Reduces plant O & M cost (minimizes plant modifications and analysis cfTorts for TCs)
+
Suppons ALARA objectives . Reduces Worker Exposure Reduces risk resulting from perfonning unnecessary modifications in an operating plar.t
+
Provides a systematic and controlled approach to assess seismic for TCs e
Sample Cost Savings Resulting from Reduced Seismic Loads Enabling the Installation of More Temporary Shielding system Uuskulded A a C Person mn Dollst Done Ame sholded Does shmided Dose Tame m savnes sevmps (unrum4ir) Rme far 120 ante for 340 Ans (A-a)*C LM(mramh) IM(arem&) omws)
Iso Condauer 500 313 186 500 63 5 E39,000 amtwo Shendown 100 63 37 POD 13 0 st30,000 Caoung Laep a shadown i00 e3 37 300 Ts s7s.000 Conhng Imop A TOTAL 810K / pomon- I.300 84 8 SM3,000 sum I foTAL s20K / paman- 1.300 M8 s1.646,000 sue TOTAL s 40K / punen- 1,300 M8 s3,372.000 sen I
3
)
INTRODUCTION l
i l
J GUIDELINES FOR REDUCED SEISMIC LOADS TO ASSESS (
TEMPORARY CONDITIONS (TCs)IN NPP '
'l
. Summarize main points in NEI Comments to NRC submitted 10/9/97. ,
1 i
. Provide additional data for examples solved using 10/9/97 methodology. j i
l I
6/10/98 NRC Meeting M. Amin i
i
INTRODUCTION EXAMPLES OF TEMPORARY CONDITIONS (TCs)
- Lead blankets for temporary shielding
- Rigging
- Temporary equipment storage
- Freeze plug
- Temporary snubber removal l
l 1
. I 6/10/98 NRC Meeting M. Amin
. .i
, INTRODUCTION w
EXPERT TASK FORCE (ETF)
Consists ofETF Consultants; EPRI, NEI, and S&L Project Managers; and seven nuclear utility representatives:
i
(
Consultants: Project Managers:
- 1. R. P. Kennedy 1. H. T. Tang (EPRI) 1
- 2. C. Allin Cornell 2. J. C. Butler (NEI)
- 3. R. J. Budnitz 3. D. E. Olson (S&L)
- 4. C. W. Rowley
- 5. M. Amin Utility Representatives:
Name Name of Utility Ron Janowiak Comed David Rencher TU Electric Rich Klimczak Pacific Gas and Electric Company Don Moore Southern Company Services, Inc.
Torrey Yee Southern California Edison Company Doyle Adams Entergy Operations,Inc.
- John Richards Duke Power Company I
l 6/10/98 l NRC Mec'ing M. Amin
INTRODUCTION -
PROBLEM DEFINITION FOR METHODOLOGY I Given
- 1. T = duration of next refueling cycle in which reduced seismic loads (RSL) are to be used for TCs.
2.t = expected duration of RSL usage within T.
- 3. ASCDFan = allowable for time-averaged increase in seismic core damage frequency.
- 4. Specific = as listed in Don Moore's Vugraphs of today.
Requirements Determine Seismic load reduction factor,(k):
RSL = k x (Design-basis (DB) seismic load), 0 s (k) s 1.0 Notes
- 1. One value of(k) to be used through out (T) for all TCs, and usage duration to be tracked. If tracked total usage duration exceeds (t), (k) can not be used for the remainder of(T).
- 2. RSL to be used in all applicable DB load combinations and TCs to be evaluated using DB allowables.
6/10/98 NRC Meeting M. Amin
'l
~ INTRODUCTION a
CONTENTS OF BALANCE OF PRESENTATION
- Concepts
- Example Results l
- Concluding Rmarks i
1 6/10/98 NRC Meeting M. Amin
CONCEPTS ,
w u. -
T _
"4 E
w
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m LEGEND GI = SUCCESS PATH I e*
- G2 = SUCCESS PATH 2 G1
EACH AFFECTING ONE PATH ONLY G2 O O O O O ONE OR MORE TC.
AFFFATING bOTH STRATEGY l PATHS O
RF = REFUELING OLTTAGE T = DURATION OF GI REFUELING CYCLE G2 O O O O O STRATEGY 2 G1 g,
STRATEGY 3 Figure 2-x Three Separate Strategies for Applying Reduction Factor (k) on Temporary Conditions (TCs) 6/10/98 NRC Meeting M. Amin
. CONCEPTS l
I h
- , T _
w B
REAL TIME N == == == k
! b o.L Q
b s.L 2,k a @
5d 1,k Ii,k; i =0,1,2, = i'I' DISTINCT DURATION WITHIN T, FOR APPLYING L TL=[J,k D
Figure 2-y Trucking Application Times of(k) on TCs I
i 6/10/98 NRC Meeting M. Amin l
l i
CONCEPTS .
k T _
t _
T-R 5
= - - -
SCDIMD SCDF
~
.. , TIME E 4 g S'~
w e SCDF = seismic core damage frequency.
SCDF3 = base SCDF = SCDF when TCs are absent.
SCDF(k) = SCDF when (k) is applied on TCs and TCs are considered as permanent.
SCDF (k, = time-averaged SCDF over T, when total TC duration is t/T) (t).
SCDF(k, t/F) = (t/T) x SCDF(k) + ((T-t)/T) x SCDFu Figure 2-Z Time- Averaged Seismic Core Damage Frequency when (k) is used ca TCs and Total TC duration is (t) 6/10/98 NRC Meeting M. Amin
CONCEPTS i
i TIME-AVERAGED INCREASE IN SEISMIC CORE DAMAGE FREQUENCY, ASDF(k, t/T), AND DETERMINATION OF k
. ASDF(k, t/T) = SCDF(k, t/T) - SCDFb
=
=(t/T)x ASCDF(k)
. ASCDF(k) = increase in seismic core damage frequency when (k) is applied on TCs and TCs are considered as permanent.
. For given values of(t), (T), and ASCDFan; (k) is determined as the solution of equation ASDF(k, t/f) = ASCDFan 6/10/98 NRC Meeting M. Amin
CONCEPTS- 4 STEPS FOR CALCULATION OF SCDF6 AND SCDF(k)
- 1. Construct seismic core damage (SCD) fault trees e Base case (TCs are absent) for SCDF8 calculation *
- Case when TCs are considered with (k) applied and TCs considered as permanent, for SCDF(k) calculation *
- 2. Quantify SCD fragility function
= Quantify probability of basic events of the fault trees *
- Solve fault trees
- 3. Convolve SCD fragility function with mean hazard curves to compute SCDFs and SCDF(k) e Conservative mean hazard curve of LLNL(1993) or EPRI for eastern sites and available mean hazard curve for western sites
- identifies a step that requires special input for this methodology; the steps not so marked are standard PRA steps.
6/10/98 NRC Meeting M. Amin
, CONCEPTS i
~
, ,i CD p{ int l
CD = Core damage RI = Random failure in i i Path I, I = 1 and 2.
Path 1 Failure Path 2 Failure SIP = Seismic failure in og- og- permanent elements in Path I, I = 1 and 2.
R1 S1P R2 ,
S2P Figure 2-1 Core Damage Fault Tree Used for Calculation of SCDF6 for Strategies I and 2 6/10/98 NRC Meeting M. Amin 1
l 4
CONCEPTS -
f.
o l
CD CD = Core damage
-f y a. l RI = Random failure in Path I, I = I and 2.
i i SIP = Seismic failure Pamt Fanure Path 2 FaHure elements in Path I, I
= I and 2.
"b- "b~
SIT = Seismic failure in temporary j elements in Path I, I l
= I,2 R1 51 S2 s (R2 "O "O S1P S2T S2P
, Figure 2-2 Core Damage Fault Tree Used for Calculation of SCDF (k) for Strategy 1 6/10/98 NRC Meeting M. Amin
',l, .
CONCEPTS co
- [_ b _ ** I CD = Core damage
- e. m . , . RI = Random failure in Path I,I = I and 2.
.(-} .()-
SIP = Seismic failure in permanent elements in Path I, I = I and 2.
y S2T = Seismic failure in temporary
,,, , , elements in Path 2 "O
(- .
Figure 2-3 Core Damage Fault Tree Used for Calculation of SCDF (k) for Strategy 2 l
6/10/98 NRC Meeting M. Amin
CONCEPTS
= a
"[_M " I
- a. Fw SCDFs si se s
- b. Fw SCDF(k)
CD = Core damage
. SP = Seismic failure of permanent elements ST = Seismic failure in temporary elements i Figure 2-4 Core Damage Fault Trees Used for Calculation of SCDFb andSCDF (k) for Strategy 3 l
I 6/10/98 NRC Meeting M. Amin
- f. CONCEPTS QUANTIFICATION OF BASIC EVENT PROBABILITIES OF FAULT TREES
- 1. Probability ofrandem failure in a safe shutdown path:
- PR = 0.01, unless a site-specific value is available.
- 2. Combined logaritlunic standard deviation for fragility description of safe shutdown path without TCs and when TCs are considered permanent with (k) applied e pc = 0.40
- 3. High confidence low probability of failure of a safe shutdown path when the peak and valley and spectral shape variabilities are considered at 84%
probability ofnon-exceedance
. HCLPFu = minimum ofHCLPFu values applicable to the elements of the path.
6/10/98 f NRC Meeting i M. Amin l 4
CONCEPTS [,
QUANTIFICATION OF BASIC EVENT PROBABILITIES OF FAULT TREES (Cont'd)
- 4. Median capacity of a safe shutdown path when TCs are not present
- Amp = (HCLPFs41.2) / .
x exp(2.3pc)
- 5. Median capacity of a temporarv element added to the path to consider presence of TCs with the reduction factor (k) applied
. Amt = k x Amp 6/10/98 NRC Meeting M. Amin
l
- 0 *
', EXAMPLE RESULTS F4ure 3-1 Hazard Curve for Examples 10 E41 u__ .__-__ .. . _ _ _
_.= _
__. m
' #*2 -~ -
x-1N& -
% .1/
.- s
.: x x x ,
NN - se2 x
,... wgm
, == __
',_ + E P1
'N N g +f P2 2,u. __-.-
\'N
\ _
. . _ . .. ~
_ , m .
5
^
. . [d !
100E 06 - I
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_y_. .__
L?;;;;=:==7- \
$we -_ _ _.- _ _. _ ..
___\ _ .
6 iam I
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Figure 3-x Comparison of Mean Hazard Curve for Examples EP1, EP2, and WP 6/10/98 NRC Meeting M. Amin
EXAMPLE RESULTS -
O Table 3-2 Values of HCLPFs4 Capacity of Safe Shutdown Path with No TC Effect Included.
Example HCLPFs4 (g unit)
EPl 0.30 EP2 0.30 WP 2.24 3 Table 3-1 Design / Evaluation Magnitude of Reference Acceleration for the Three Examples Reference Acceleration Example Type Magnitude (g unit)
EPl PGA 0.2 EP2 PGA 0.2 WP Spectral 1.94 PGA = Peak horizontal ground acceleration.
Spectral = Average of 5% damped ground spectral acceleration over the frequency band from 3 to 8.5 Hz.
6/10/98 NRC Meeting M. Amin
EXAMPLE RESULTS Table R1 Values of Seismic Load Reduction Factors kl, k2, and k3 for EP2 (ASCDF n = IE-5) t/T kl k2 k3 0.1 0.26 0 0.32 0.2 0.38 0 0.46 0.3 0.47 0 0.56 0.4 0.54 0 0.63 0.5 0.59 0 0.69 0.6 0.64 0.05 0.74 0.7 0.68 0.09 0.78 0.8 0.72 0.I 1 0.82 0.9 0.76 0.I3 0.85 1.0 0.79 0.15 0.88 6/10/98 NRC Meeting M. Amin
____-________-_-____-__a
EXAMPLE RESULTS
- l Table R2 Values of Seismic Load Reduction Factors kl, k2, and k3 for EP2 (ASCDF.n = 5E-6) t/T kl k2 k3 0.1 0.38 0 0.46 0.2 0.54 0 0.63 0.3 0.64 0.05 0.74 0.4 0.72 0.I 1 0.82 0.5 0.79 0.15 0.88 0.6 0.87 0.22 0.94 0.7 0.90 0.34 0.99 0.8 0.95 0.44 1.00 0.9 1.00 0.52 1.00 1.0 1.00 0.58 1.00 6/10/98 NRC Meeting M. Amin
~
1 EXAMPLE RESULTS Table R3 Values of Seismic Load Reduction Factors kl, k2, and k3 for Three Examples at Specified (t/T) (ASCDF.n = IE-5)
(t/T) = 0.3 Reduction Factor Example kl k2 k3 EPl 0.32 0 0.40 EP2 0.47 0 0.56 WP 0.58 0.20 0.79 (t/T) = 0.5 Reduction Factor Example kl k2 k3 EPl 0.40 0 0.50 EP2 0.59 0 0.69 WP 0.64 0.28 0.87 6/10/98 NRC Meeting M. Amia
EXAMPLE RESULTS Table R4 Values of Seismic Load Reduction Factors kl, k2, and k3 for Three Examples at Specified (t/T) (ASCDF.u = SE-6)
(t/T) = 0.3 Reduction Factor Example ' kl k2 k3 EPl 0.44 0 0.54 EP2 0.64 0.05 0.74 WP 0.66 0.31 0.90 (t/T) = 0.5 Reduction Factor Example kl k2 k3 EPl 0.54 0.05 0.65 EP2 0.79 0.15 0.88 WP 0.72 0.41 0.99 6/10/98 NRC Meeting M. Amin
- q
, EXAMPLE REsULTs Table R5 Values of Reduction Factor k2 at (t/F) = 1.0 Reduction Factor k2 Exampie ASCDF.n = SE-6 ASCDF.n = IE-5 EPl 0.14 0.05 EP2 ,
0.58 0.15 WP 0.55 0.41 i i
NOTE:
If Strategy 2 with this value of k2 is used, since (t/T) = 1.0, no tracking of (k2) application times is necessary.
1 I
6/10/98 NRC Meeting M. Amin
EXAMPLE RESULTS -
Table R6 Sensitivity of Reduction Factors at (t/r) = 0.30 to Changes in Combined Variability Factor, pe, (EP2, HCLPFs4 =
0.30g, ASCDF n = IE-5)
S, Type of k 0.45 0.40 0.35 kl 0.43 0.47 0.51 k2 0 0 0 k3 0.53 0.56 0.59 6/10/98 NRC Meeting M. Amin
EXAMPLE RESULTS l
l I
'1 Table R7 Sensitivity of Reduction Factors at (t/r) = 0.30 to Variation )
in HCLPFs4 (EP2, c = 0.40, ASCDF u = 1E-5)
]
i i
HCLPFs4 Type of k 0.30g 0.20g j kl 0.47 0.65 k2 0 0 k3 0.56 0.74 l
1 1
6/10/9P NRC Meeting M. Amin
CONCLUDING REMARKS -
}
CONCLUDING REMARKS l
- 1. The developed reduced seismic load (RSL) methodology has following attributes:
- Uses the intent of draft risk-informed regulatory documents
. It is practical e Uses existing plant-specific seismic hazard and fragility data e It is applicable to all NPPs
. It has record keeping requirements
- 2. The duration of one refueling cycle (T) is reasonable period for planning of TCs. For risk averaging purposes, (T) is neither too shoit nor too long.
- 3. Example calculations show that the (k) values are relatively insensitive to reasonable changes in (pc), indicating the reasonability of using a generic (pc).
- 4. Example calculations show that the (k) values are relatively sensitive to the HCLPFs4 value used in the calculation, indicating the need to use realistic plant-specific values in the calculations. -
1
- 5. Example calculations show that with ASCDF.n about IE-5, reasonable reduction factors ofinterest to plant O&M are obtained to address the seismic load case for TCs.
6/10/98 NRC Meeting M. Amin
m.
. CONCLUDING REMARKS CONCLUDING REMARKS (Cont'd)
- 6. Using ASCDFan of about lE-5 is reasonable for following reasons:
- The SCDF of current designs is in the range from lE-6 to 2E-4 with the average of about IE-5. Therefore, using ASCDFan of about lE-5 is consistent with current DB seismic loads for permanent modifications.
- a Using ASCDFano f about IE-5 will not significantly impact the aim of keeping the CDF near the NRC safety goal of IE-4.
- 7. Although ALERF is not quantitatively addressed, the intent ofhaving ALERF requirement is met by requiring that elements needed to assure containment isolation be treated same as safe shutdown path elements within the three strategies investigated for (k) calculation and tracking (k) usage duration. This is a reasonable way of coping with the ALERF requirement because existing Level 2 PRAs show that seismic LERF is dominated by contaimnent isolation bypass failures or major NSSS suppon failures. And TCs do not significantly influence seismic capacity of major supports. This approach of treating containment isolation is similar to the approach required in seismic IPEEE.
- 8. The 0.lg SSE PGA requirement in 10 CFR Pan 100 Appendix A and in 10CFR Part 100 Subpart B are intended for deign of permanent components.
l In the discussions related to this requirement, TCs were never discussed. A _ A l low calculated RSL (i.e., values of(k) near zero) shouldfregarded as a valid indicator for not requiring rigorous seismic analysis. As a step in the satisfaction of defense in depth, proper engineering considerations _should be p(p i developed to address low lateral seismic inertia for various TCgwhich ;
l low values ofRSL are calculated. Imposin 0.10g SSE PGA on TCs apphes -
I permanent design requirements on TCs with ut a technical basis. 1 A
6/10/98 NRC Meeting M. Amin i
Nuclear Energy Institute Project No. 689 cc: Mr. Ralph Beedle Ms. Lynnette Hendricks, Director Senior Vice President Plant Support and Chief Nuclear Officer Nuclear Energy Institute Nuclear Energy institute Suite 400 Suite 400 1776 i Street, NW 1776 i Street, NW Washington, DC 20006-3708 Washington, DC 20006-3708 Mr. Alex Marion, Director Programs Nuclear Energy institute Suite 400 1776 i Street, NW Washington, DC 20006-3708 Mr. David Modeen, Director Engineering Nuclear Energy Institute Suite 400 1776 l Street, NW Washington, DC 20006-3708 Mr. Anthony Pietrangelo, Director Licensing Nuclear Energy institute Suite 400 1776 l Street, NW Washington, DC 20006-3708 Mr. Nicholas J. Liparulo, Manager Nuclear Safety and Regulatory Activities Nuclear and Advanced Technology Division Westinghouse Electric Corporation P.O. Box 355 Pittsburgh, Pennsylvania 15230
. Mr. Jim Davis, Director Operations Nuclear Energy Institute Suite 400 1776 i Street, NW
, Washington, DC 20006-3708 l