ML19330C315
| ML19330C315 | |
| Person / Time | |
|---|---|
| Site: | Millstone, Dresden, Palisades, Oyster Creek, Haddam Neck, Ginna, San Onofre, Yankee Rowe, La Crosse, Big Rock Point  |
| Issue date: | 06/23/1980 |
| From: | Rolonda Jackson Office of Nuclear Reactor Regulation |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| TASK-02-04, TASK-02-04.A, TASK-02-04.B, TASK-02-04.C, TASK-03-06, TASK-2-4, TASK-RR NUDOCS 8008080229 | |
| Download: ML19330C315 (37) | |
Text
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[,h m, j NUCLEAR REGULATORY COMMISSION WASHINGTON. O. C. 20555
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JW232 IHIS DOCUMENT CONTAINS MEMORANDUM FCR:
- 0. Crutchfield, Acting Chjef s
Systematic Evaluation Program 3 ranch THRU:
James P. Knight, Assistant Director for Ccmponents and Structures Engineering, OE N
FROM:
Rchert E. Jackson, Chief Geosciences Branen, CE
SUBJECT:
INITIAL REVIE'A AND RECOWENDATIONS FOR SITE SPECIFIC SPECTRA AT SEP SITES
'de have been working for the past two years with the SE? Branch and their consultants in order to provide preliminary reccmendatiens regarding site specific spectra to be used in the SEP for evaluation of the seismic design adequacy of the selected plants.
The Branch reccmmendations are attached, however, it should be noted that they are subject to the limitaticns described in the sections entitled
" Purpose and Sccee" and" Recommendations." These recctm:endations were prepared by Dr. Leon Reiter based primarily on documents submitted in the Site Specific Spectra drogr u.
'4e expect that our evaluation of items still forthccming in the Site Specific Spectra Progra may result in the following:
1.
It is likely that there will be further changes in the return periods associated with the recommended spectra for the various sites. These return periods will still be able to be described as "of the order of 10C0 or 10,000 years", which is the present descripticn of the spectra and the level implicitly accepted by NRC in recent licensing decisions.
2.
There will be no major change in the relatihe levels cf seismic hazard between sites.
3.
There will be little or no chacge in the "ceterministic" cc=carisons for the various site used to evaluate the acceptability of the spectra recc=enced in ne attached review.
4 There is a preliminary indicaticn that a recuction in spectra at inter-mediate and low frequencies may be called fcr at rock sites (Cresden, 3inna, Hacdam 'leck and Millstene). Probabilistic precictions of peak velocities at these sites may also be affected.
8008080229
JUN 2 31980 While it is difficult to predict tne outccme of an innovative program that is still.in progress it is our best estimate, based on the above, that this subsequent evaluation will not result in very large changes in spectra recomended for use in the evaluation of the SE?.
We recornmend that you utilize these spectra in your reanalysis of the SEP facilities. We further recom.end that a minimum spectra be established as discussed in the report. This reccmmendaticn is based en the innovative nature of the Site Specific Spectra Program and the need for continued review and maturation of the program. The site specific spectra provided are generally less than would result frem a literal application of Appendix A to 10 CFR and the current Standard Review Plan throughout the frequency range of interest for nuclear power plants.
Since follow up work and sensitivity studies are continuing, we will monitor progress and provide a final recc. endation in December 1980 upon completion m
and review of these elements of the program.
9 h
<E.4 A-$ &
Robert E.
en, Chief Geoscience4p anch Division 07 Engineering
Enclosure:
As stated cc: w/ enclosure R. Vollmer
- 0. Eisenhut G. Lainas H. Levin D. Allison G. Lear L. Heller J. Greeves F. Schauer G. Sagchi D. Bernreuter, LLL L. Wight, TERA G53 ?ersonnel wy
s.
Initial Review and Recommendations for Site Specific Spectra at SEP Sites-
' Purcost: lnd~ Scope This review presents initial recommendations for Site Specific Spectra to be used in the reevaluation of SEP plants.
It is based upon review of the following items.
(1) Draft Seismic Hazard Analysis: TERA - Lawrence Livermore Laboratory (LLL), 3 volumes, August 1979.
(2) Peer Review Coments to above reports, Individual coments by Dr. O. Nuttli, Dr. L. Sykes, Dr. D. Veneziano, Dr. A. An'g, (LLL Review Board); Fugro, URS Blume Assoc., Dr. A. Cornell, Mr. R. Holt, Comonwealth Edison (licensee sponsored reviews); Dr. L. Abramson (NRC, Applied Statistics Branch) Fall-Winter 1979.
(3) Response to Peer Review Site Specific Spectra Project (SSSP), TERA, May
- 1980.
(4) Draft Seismic Hazard Analysis: SSSP Sensitivity Results, TERA-LLL, May 1980.
(5) Attenuation Panel Feb.1980, and coments on the panel meeting by Dr. O. Mutt.li, Dr. M. Trifunac, Dr. R. McGuire, Dr. N. Donovan.
(6)
Letter Report evaluation of Attenuation Panel-by TERA, April 4, 1980.
(7) l Letter Reports on Ossippee Attenuation Model by TERA, May 22, May 29, 1980
'(8)
Interim Summary of assessment of conservatisms by TERA, May 30, 19S0.
_(9) Evaluation ot-Ossippee Attenuation Models and alternatives by LLL, May 23, 1980.
(10)_ Seismic _ Hazard Evaluation for SEP plants (Draft) N. M. Newmark (May 30,1980).
~
-2 In addition to these documents there have been many discussions and telephone conversations with individuals at TERA, LLL, reviewers, attenuation panel members and Ors. Newmark and Hall.
Following is a list of other items and reviews which will be forthccming and could have an impact upon the results.
1.
Review of the Draft Seismic Hazard Analysis by the USGS.
2.
Additional Review and comments by Drs. Newmark and Hall.
3.
Review of 411 submissions by the licensees on their recommendations for site specific spectra (several have been reviewed).
4.
Comparison of SSSP resuits with other eastern U. S. hazard analyses.
5.
Feedback meeting with original expert group.
6.
Reconinendation from' TERA-LLL and possible reanalysis based upon utilization of input frem sensitivity results, attenuation panel and feedback meeting.
Recommendations it is recommended that the following spectra presented in the Sensitivity Results (May 1980) be used as site specific free field spectra.
Eastern U. S. (Yankee Rowe, Connecticut (ankee, Millstone, Ginna, Oyster Creek)
"1000 year" spectra' assuming no background and Ossippee Attenuation.
Central U. S. (Dresden, Palisades, Lacrosse, Big Rock Point)
1000 yr" spectra assuming no background and Gupta-Nuttii Ati.enuatien.
i
'These spectra account for gross site conditions (soil or rock) and do not take into account any specific conditions which may result in amplification (Lacrosse, Yankee Rowe, Palisades).
It is also recomended that a minimum be established for which no spectra be allowed to go below. It is suggested that this minimum be the median (50th percentile) representation of real spectra for a magnitude 5.3 earthquake.
This minimum exceeds the "1000" yr spe:tra'for Big Rock Point, Lacrosse and Palisades at frequencies greater than 2 to 3 Hz.
The rationale for these reccmendations are discussed below.
General Coments The SSSP was conceived as a multi-method approach for determining site specific spectra (Bernreuter,1979).
It encompassed probabilistic approaches at predicting i
peak acceleration, peak velocities and uniform hazard spectra for different return periods and a empirical approach wflich includes calculation of 50th and 84th percentile spectra frem ensembles of real data at different magni-tudes, site conditions and distance ranges. The probabilistic approach utilized is basically that suggested by Cornell (1968) which has been modified to formally incorporate " expert" judgements. This approach is explained in detail in the documents referenced above and in Part 1 of the Executive Summary by TERA Corp.
The difference between so called " deterministic" approaches (for example,
'that found in the Standard Review Plan") and probabilistic approaches are described below. -In the deterministic approach (Figure 1) local (fault) and regional
- Although this approach _is commonly called " deterministic" it is better described as "judgemental-empirical." A'true deterministic approach would involve using
- the. principles of physics _to calculate ground motion due to a rupturing f ault.
,.(tectonicprohince)sourceregionsarespecifiedgeometrically(Step 1).
The largest earthquake a.ssociated with each source is then defined frcm
~ historical seismicity and/or geological estimates, and it is assuced to occur at a location in each source' closest to the site in consideration (Step 2). The resultant ground motien (usually peak acceleration) at the site from each of these sources is then estimated utilizing magnitude-acceleration or intensity-acceleration relationships (Step 3). The largest of these is then considered the controlling ground motion and it determines the assumed earthquake loading at the site (Step 4).
In the current NRC practice this earthquake loading (Safe Shutdown Earthquake) usually is peak acceleration used to anchor the standardized Regulatory Guide 1.60 spectrum. This method dces not take into account the frequency of earthquake occurrence and allcws no description of uncertainty.
In the probabilistic approach described in Figure 2, earthquake sources are determined (Step 1) as'in the deterministic approach. Historical seismicity is then used to determine an earthquake recurrence model for each source (Step 2). This model is usually determined from a linear regression analysis relating earthquake size (magnitude er intensity) to frequency of These recurrence models are terminated at the largest earthquake occurrence.
expected frem each: source. Most probabilistic models assume that earthquake occurrence folicws a Poisson process or that these earthquakes occur randcmly withrespect'totimeandspacewithinagihensource. The ground motion (peak or spectral parameter) at the site from the different earthquakes at different distances is estimated using a set of magnitude (or intensity) - ground motion relationships that explicitly incorporate the dispersion of the data about such relationships (Step 3).
Finally, integrating the effect of different size earthcuakes from different locations in different scurces with the
recurrence information from Step 2, the probabilities that given levels ofgrouadmotionwillnotbe:exceededwithingiYentimeperiodsare calculated (Step 4).
The deterministic approach is strongly controlled by the choice of input parameters (source configuration, intensity-acceleration relationship, response spectra etc.). Sizeable changes in characterizationof safe shutdown earth-quakesforNuclearPowerPlantsinthepast5to10yearshaYeresultedfrom staff' adoption of the Regulatory Guide 1.60 spectrum and the Trifunac-Brady (1975) intensity-acceleration relationship. Probabilistic prediction can also be driven by the choice of input parameters.
In the eastern U. S. these input parameters or their statistical representation cannot in many cases be unambiguouslyderihedfromtheexistingdata. The innohative approach of the SSSP was to canYas expert opinion as to what-the choice of these input parameters were, what range they might be expected to assume and what credibility could be attached to them. Each experts input was treated separately, spectra were computed for each expert at each site than a trial synthesis was performed combining all the experts at each site based upon their own self-ranking. The input parameters covered four areas:
(1) the configuration of seismic source zones in the central and eastern U. S. (2) the largest earthquake expectedineachofthesezones(3)theearthquakeactihityrateandrecurrence statistics associated with each zone and (A) methods for predicting ground motion in the eastern and central U. S. from an earthquake of a giYen size at a
.given distance.
, Responseswerereceihedfrcm10ofthe14expertpolled.
(The questionnaires were lengthy and required several days to answer in a comprehensihe manner).
These responses were almost exclusihely directed at the-first three areas.
The significant lack of resporise in areas of ground motion made it recessary Additional forTERA-LLLtodehelopitsowngroundmotiondeterminationscheme.
approaches were presented in the sensitihity results and an additional special " Attenuation Panel" was convened to discuss this difficult problem.
Inadditiontothegroundmotionproblem,theextensihepeerrehiewconducted The most for the initial draft report identified other problem areas.
significant of these were related to the way each expert's zonation was treated and the assumed dispersion of the data. These subjects were also treated in the sensitihity studiu mentioned abohe.
Specific discussions on each of these problem areas follow.
Soecific Corrents Ground Motion Determination The problem is to quantitatively predict ground motion east of the Rockies when there is practically io strcng motion data recorded in this The existing data base (most Western U. S.) was recorded in areas region.
whereseismicwaheattenuationand,tosomeextent,seismicsourcesaredifferent.
Amethodmustbedehelopedtopredictthismotiontheoreticallyormakeuseof the historical (non-instrumental) felt reports frcm ;he eastern U. S. in The initial
~ conjunction with strong ground-motion data from the western U. S.
results (August 1979) utilized felt reports frcm the well-documented Southern Illinois Earthquake of 1968 and the assumption that ground motion associated with a gihen felt effect (site intensity) and epicentral distance will be the The sensitihity studies (May 1980) examined same in both east and west.
h l
.the affects of-assuming that the ground motion associated with a gi en fe t
~.
. effect and given earthquake size will be the same for. both east and west.
The studies accomplished _this result for three felt-effect predictions; the 1968 Southern Illinois Earthquake, the 1940 Ossippee New Hampshire earthquake, and' a modification of the Gupta-Nuttii (1976) relation based upon several central U. S. earthquakes. While the attenuation panel had mixed. feelings there seemed to be some preference for this latter assumption.
In conjunction' withthesensitihitystudies,theexisting_datasetwasalsomodifiedto prevent undue dependence upon a single earthquake and to eliminate strong motion records that were beliehed to represent only part of the actual shaking. In addition, studies of seheral other earthquake suggested a difference in attenuation of ground motion between the northeastern and central U. S.
At distances greater than 100 kilometers, the affects of shaking less attenuated in the central U. S. when compared with that in the appea northeast. As a result of these considerations, we recommend that the 1980 model based upon the Ossippee earthquake be used as a basis for determining grous motion in the northeastern U. S.; while the 1980 model based upon the Gupta-Nuttii relationship be used as a basis for determining ground motion in the central U. S.
The Ossippee attenuaticn was calculated seheral ways.
In the original SSSP Sensitivity Results (May 1980) an aherage distance was first computedforeachintensitylehelandthenaregressionwasperformedtreating distance as the independent parameter and site intensity as the dependent i
Asignificantdifferencewascbserhedwhentheaheragingwasemitted!
parameter.
and the regression performed directly on the data (TERA Letter Reports, May 22 and May 29,1980). It is not imediately clear which approach is more We appropriate. Conceptually it appears better to avoid the averaging step.
y f
. feel,-howeYer, that at'this time the origincl technique using the aYeragingstepshould-beused. The reasons for this are (LLL' Letter, May 23, 1980): -(1) This method is analagous to that used by Gupta and t!uttli (1976) to deriYe their attenuation relationship. (2) the second method would predict ground motion significantly less at most distances than that proposed by the theoretical model of fluttii (1979) while the original method falls much closer to his model.
The attenuation panel recommended greater use of such theoretical relationships for determining ground motion.
Initial calculations show that when these theoretical relationships are incorporated into SSSP methodology peak accelerations for return periods of 1000 years appear to be similar to the Gupta-tiuttli and original Ossippee attenuations.
While some small differences between central and northeastern attenuation can be expected we.lel that at this time, reliance upon results produced utilizing-a particular regression technique on one earthquake in the
- northeast which are significantly less than theoretical and empirical results for the. central U. S. is imprudent. Clearly,hoseYer,determinationofa proper attenuation relationship is an area that requires additicnal work.
Zaninc The initial treatment of experts input to configuration and credibility of seismic source zones allowed for the existence of a background zone consisting of m
, theunion(enehelope)ofalltheexpertszonesinaparticularregion.
The extent to which this background zone was used depended upon the experts generallehelofbelief(credibility)intheexistencecfthesezones. As a result, this leads to tying one expert's results to others and the allowance of specific numbers of the larger earthquakes normally associated with a seismic zone being allowed to occur anywhere within the background. Various reviewers criticized this approach and some alternatihes were suggested.
Thesensitihitystudiescomputedspectrabasedupontheoppositeextremei.e.
the assumption that each expert had 100f. belief in his zone and no backgrouM need exist. These two computations bound the problem.
For SEP sites, the latter assumption results in a reduction in estimated seismic hazard.
Ifasitewerelocatedinthemiddleofanactiheseismic zone such as New Madrid the assumption of no background wculd result in an increase in estimated seismic hazard.
There are many arguments. that may be made as to how this problem may be treated correctly.
It seems clear that neither extreme is correct and some better way of accounting for credibility is warranted., TERA-LLL has argued that a true representation of credibility in such a complex problem may be very cumbersome cociputationally and prohibitively expensive.
It is our recorr.mendation that, barring such a computation spectra intermediate between these two assumptions De used at this time. As shown below the actual difference between spectra ccmputed using the two extreme assumptions is not large and any error in estimating the intermediate spectra willnothaheasignificanteffect.
l i
- 10 Dispersion of Data In The August 1979 report the dispersion assumed about the final ground motion prediction was assumed to be log normal with (=0.9 (base e).
In addition the distribution was truncated at 1 2a. This size of the dispersion was deter-mined combining dispersions normally encountered in determining site intensity from
. earthquake size (epicentral intensity) and in conherting this intensity to ground These indihidual dispersions can be considered as due to randomness found motion.
in nature. Several rehiewers argued however that treating these errors-as independent and disregarding their cross correlation is overly conservative and that it increases the total dispersion beyond that resulting from true randomness.
Where ground motion records due exist, e.g. Western U. S., the dispersion associated with ground motion from a given size of earthquake can usually be described with 7=0.5 to 0.7.
Data points do not normally extend out beycnd limits of 1 3 7.'These criticisms are considered valid and its recommended that the dispersion defined as r=0.7, truncated at 1 37 be accepted.
Extension of the truncation point beyond 37 will not have a significant effect upon the results.
~
Synthesis Curves Somealternatemethodsweresuggestedtosynthesizetheresultsoftheharious expert judgements. The SSSP utilizes a self-ranking system.
In the opinien of TERA Corporation, alternate methods would not have a significant effect upon the synthesizedcurhes.-Byinspectionitappearsthatthesynthesiscurvesreoresent
~
a median or_ somewhat higher than median representation of the individual spectra computed for each expert.
It is recommended that this synthesis be used to
' describe the hazard.
,s.
-U-Integration of Recommendations
'In the sensitivity stud'es, uniform ha:ard spectra are presented for all the ground motion models recomended above,i.e. Ossippee (1980 model) for north-eastern sites and Gupta-Nuttli (1980) for central U. 5. s'ites.
All spectra are computed assuming no background and C=0.9 + 20 truncation.
These spectra are approximately equal to the recorrended spectra of
. P.O.7 + 3r truncation with a ioning assumption intermediate between a back-ground and no background because:
- 1) The decrease in peak accelerations end peak velocities computed for_ representative individual experts from 30.9 -(; 20-) to. o 0.7 (+ 3r) is on the average about 7 to 107. for the Gupta-Huttii and Ossippee attenuhtions; (2) the increase in peak accelerations and peak velocities from no background to background is on the average about 15 to 20% for the August 1979 attenuation (the only comparison availau'le).
Although there is some preliminary indication of attenuation model dependence for the background-no background comparison these approximations are considered adequate given the precision of the spectra-and the size of the differences.
Adecuacy and Conservatism of the Recommended Soectra While the "1000 year" spectra are recommended it is not possible to state with any certainty that the true return period (inverse of annual risk of exceedence) is 1000 years. Generally these estimates are believed to be conservative for the following reasons.
12 -
1.- Strong motion data sets are in many ways biased toward high values.
?!on-triggered instruments or low-level records receive little attention.
This is also true at great distances and for longer periccs where noise may be contributing significantly to observed motion.
- 2. The' assumption that earthquakes occur _ randomly within a given seismic source zone is conservative for large zones of low to moderate level seismicity such as those around most SEP sites. While the sources of central and eastern U. S. earthouakes remain hidden,most seismologists conclude that damaging earthquakes will eventually be associated with specific faults.
- 3. The uniform spectra represent composite risk from different source zones which may effect different frequency ranges. Under certain situations, exceeding the spect.ra at different frequencies implies the simultaneous occurrence of earthquakes in more than one source zone,
- 4. The assumption that intensities from large earthquakes attenuate at the same rate as intensities from small earthquakes is conservative.
Some'non-conservative aspects of this and other studies are:
- 1. The strong-motion data set used mixes accelerograms recorded in the true free field with those recorded in the basements of buildings. Many engineers feel that the effect of large foundations in these buildings is to reduce high frequency motion.
- 2. The.probabilistic spectra represent the chance of being exceeded more than once in' a given return period. The probability of being exceeded twice or more, however, is small when compared to the probability of beino exceeded only once.
l p
a:
4
+
- Based upon-consideration of all of the aboYe and their estimated relatiYe weights,we consider the true return period associated with these spectra to be, longer than 1000 years. TERA in a recent reassessment of conservatism (Letter,May 30,1980) conclu' des that those spectra presented in the Sensitivity Resultsas"1000yearspectra"canbeconserhatiYelyrepresentedas5000to10,000 year loads. Additional work will better define what the return periods are.
At the present time however, we believe that there is no way of indicating what these true return periods are or establishing rigourously defined confidence limits.
In the past there has been implicit acceptance of design spectra that were assumed to have return periods of the order of 1000 or 10,000 years.
It is our judgement that these spectra f all with'in this description.
The most important qualli.y of these spectra is that, although no great confidence can be attached to the absoluce probabilities (i.e. return periods),the systematic incorporation of expert opinion and uncertainty and the wide ranging sensitivity tests indicate greater stability when estimating relative hazard probabilities at these levels of ground motion. This would apply to estimating the equivalen?
~
levels of probabilities of exceedence at different sites and smail relative differences in probabilities of exceedence at the same site. Thus,while we are not sure that the "1000 year spectra" really represent 1000, 5000 or 10,000 year
~ return periods at all the sites we have greater confidence that they represent approx-imately equivalent levels of hazard whatever the true return period is. This is based inlargepartupontherelatiUeconsistencyofeffectsassociatedwiththesensi-tivity tests (SSSP Sensitihity Resul s, May 1980) anc the synthsizing of wide ranges of expert judgement with respect to each region.
, Comparison of Spectra with " Deterministic" Procedures In order to further evaluate the adequacy and rea5cnableness of the recommended design spectra several comparisons with non-probabilistic technic.ues were pe rfomed.
Comoarison with soectra determined usinc the tectonic crovince accroach (Accendix M.
In this approach (Figure 1) the largest historical earthquake that has occurred in the host province is assumed to occur near the plant while' the largest historical earthquakes in adjacent provinces are assumed to occur in these provinces at locations closest to the site.
The ground motion at the site from these earthquakes is estimated and this determines the seismic input to design. Tectonic province boundaries and earthquake sizes were estimated based upon recent licensing decisions.
The configuration of the New Madrid Zone was also used assuming the more recent suggest1ons of Nuttli and Hermann (1978).
The assumptions for each site are listed in Table 1.
Earthquake size is also given in terms ef' magnitude (m ) and these are based upon recent individual determinations b
of the magnitudes from intensity data and the general relationship proposed by Nuttli and Herrmann (1978).
Utilizing these events, a series of theoretical and empirical equations were used to predict the peak accelerations and velocities at each site.
In order to deal.with differences in these equations, selected results representing the most appropriate theoretical and empirical relationships were averaged to arrive at final estimates of peak acceleration and velocity.
Table 2 shows the con-trolling _(largest) peaks estimated at each site.
These are compared with the peak accelerations and velocities associated with the recommended unifom hazard (probabilistic) spectra.
4 The unifom hazard peak accelerations reach or exceed the deterministic peak accelerations at all sites except Palisades, Lacrosse and Big Rock Point.
This is a reflection of the fact that these 3 sites lie in areas of low
~ seismicity and estimated seismic hazard in the central stable region.
The uniform hazard peak velocities exceed the deterministic peak velocities except at Dresden where it is less. This is a reflecticn of the fact that probabilistic techniques take into account larger than historical earthquakes.
Sensitivity studies show that these have the largest effect upca peak velocities. This is reflected in the deterministic procedure for Dresden where the proximity of the New Madrid zone has a significant impact.
In general it can be-said that the 1000 year uniform hazard peaks bracket the deterministic peaks. Differences between the two sets of values result from the ability of the uniform hazard approach to overcome the artificial constraints often posed by the " tectonic province approach. Thus, while the tectonic province approach would require Big Rock Point and Haddam Neck to utilize similar seismic input for design purposes, the probabilistic methodology takes into account the real difference in seismicity and perceived earthquake hazard at these sites.
The deterministic peak accelerations and velocities are converted to response spectra using the amplification factors suggested by Newmark and Hall in MUREG CR-0098. Figs. 3 thru 11 compare the recommended unifonn hazard spectra with 50th and 84th percentile deterministic spectra.
In the central U.S. the recom-mended spectra generally fall below or at the 50th percentile. In the eastern United States the uniform hazard spectra are approximately
. equihalent to the 84th percentile deterministic spectra. While the deterministic peaks. are generally lower than the predicted peaks, use of the 84th percentile amplification factors usually more than compensate for the differences. Again the uniform hazard spectra more adequately reflect perceived relatihe hazard. The " tectonic province" approach can be made to achieve h
h
-conservatism in this case by utilizing conser ati e amplification factors.
Figures 12 and 13 show the uniform spectra compared to Reg. Guide 1.60 spectra anchored at 0.1 and 0.2g.
FollowingsuggestedStandardRehiewPlan procedures for new plants that is utilizing the trend of the means of Trifunac and Brady (1975) to anchor the Reg. Guide 1.50 spectra, would result in design spectra anchored at between 0.12 and 0.20g. The specific acceleration used would depend in large part upon the applicants submittal and the rehiewer's conserhatism.
For the central V. S. the recommended spectra are mostly below the Reg. Guide spectrum anchored at 0.lg while for eastern U. S. the recomended spectra are at orabohetheReg.Guidespectrumanchoredat0.1g. The aherage recomended spectrum would be roughly equihalent to the Reg. Guide 1.50 Spectrum anchored
~
at a peak acceleration of about 0.1.
The observation that the average peak 9
acceleration associated with the recommended spectra (Table 2) is about 0.15g illustratestheoftendiscussedconserhatismoftheReg.Guidespectrum.
It was conservatihely derihed from earthquakes of different sizes recorded at different distances and different site conditions.
Comoarison with Real Soectra A more applicable comparison can be found in Figures 14 and 15. Here the recomended spectra are compared to the 50th and S4th Percentile lehels of ensemblesofresconsespectraderihedfromstrongmotionrecordsrecorded
~
at nearby distances (usually 27 km or less) from earthquakes of magnitude t.
-'t
. 5.3 1 0.5 in,the western U. S. and Italy. At these distances differences
.in regional attenuation are not pronounced. At periods less than 0.3-0.5 seconds
~the recommended spectra f all in between the 50th and 84th percentile except for Palisades, LaCrossse and Big Rock Point which -are slightly below the 50th Percentile. Differences again can be related to real differences in earth quake hazard.
-There can be some concern however in that the recommended spectra may fall below some minimum level 'of ground motion from a nearby magnitude 5.3 (In-tensity VII). While Intensity VIII or larger earthquakes have been restricted in historical time in the central and eastern U.S. to five or six locations, Intensity VII earthquakes have occurred in sufficient
- numbers and at sufficient locations such that we believe that they could occur anywhere in the U.S. at varying' levels of certainty.
It is prudent therefore
~ to establish such a minimum level although a direct uniform hazard assessment would more accurately reflect relative earthquake hazard.
It is recommended that this minimum be set at the 50th percentile of. the plotted real spectra.
While the 84th percentile has been used in deterministic techniques it is not suggested that it be used as a. minimum since it is more a reflection of the dispersion of data resulting from the magnitude and distance range needed to gather an adequate number.of records for statistical treatment.
As indicated above use of the 50th Percentile would have a small effect upon
~
Lacrosse, Palisades' and '31g Rock' Point.
Conclusions Baseduponrehiewoftheindicateddocumentsandtheccmparisonwith" deterministic" procedures mentioned abohe, we beliehe that the site-specific uniform hazard responsespectrasuggestedrepresentanadequateleheloffreefieldground motionforuseinthereehaluationoftheSEPplants. Theharyinglehels.ofthese
~
spectra more accurately reflect true hariations in real seismic hazard than those I
derived utilizing the " deterministic" tectonic province approach. We also believethatitisprudenttoestablishsememinimumlehelbelowwhichnospectra be allowed to fall.
It is recommended that this be the 50th percentile of real data from a nearby magnitude 5.3 earthquake as shown in the ccmparatihe plots.
Utilization of this minimum would hahe a small effect upon Palisades, Lacrosse and Big Rock Point. Tnese spectra do not take into account specific site amplification factors that may be present at Lacrosse, Falisades or Yankee Rowe nor do they' reflect consideration of additional studies still ongoing in the SSSP program. Those spectra presented were computed for 5% damping.
4
Table 1 Controlling Earthquakes used in the Tectonic Province Approach Local Earthquake (Host Province)
Site (Average Epicentral Distance 10-15 km)
Distant Earthquakes (other than Host Provinces Yankee Rowe mb 5.3 (Intensity VII) mb6.0 (Intensity VIII) from White Mt. zone (80 km)
Haddam Neck mb 5.3 (Intensity VII) mb 6.0 (Intensity VIII) from White Mt. Zone (130 km)
Millstone mb5.3 (Intensity VII) mb 6.0 (Intensity VIII) from White Mt. Zone (140 km)
Oyster Creek mb 5.3 (Intensity VII) mb 6.0 (Intensity VIII) from White Mt. Zone (375 km) mb 5.8 (Intensity VIII) from.
Southern Valley and Ridge (550 kg Ginna mb5.3 (Intensity VII-VIII) mb 5.75 (Intensity VIII)(from55km Clarenden-Linden rault Dresden mb 5.3 (Intensity VII-VIII) mb 7.5 (Intensity XI-XII)from New Madrid Zone (280 km)
- mb6.7 (Intensity X) from Wabash Zone (200 km)
Palisades mb5.3 (Intensity VII-VIII) mb7.5 (Intensity XI-XII) from New Madrid Zone (315 km)
- mb6.7 (Intensity X) from Wabash Zone (300 km)
Lacrosse' mb5.3 (Intensity VII-VIII) mb7.5 (Intensity XI-XII from New Madrid Zone (600 km)
- mb6.7 (Intensity X) from Wabash-Icne (530 km)
Big Rock Pt.
mb5.3 (Intensity VII-VIII) mb7.5 (Intensity XI-XII) from New Madrid Zone (760 km)
- mb6.7 (Intensity X) from Wabash Zone (650 km)
" Controlling event based upon Nuttli and Herrmann (1973) interpretation of Mississippi Emoayment Seismic Zoning.
[.
Table 2 Comparison of Predicted Peak Accelerations ~and Velocities Based upon Probabilistic*
and Deterministic ** Techniques 2
Site Peak Acceleration (cm/sec )
Peak Velocity (cm/sec)
Probabilistic Deterministic Probabilistic Deterministic 1.
Yankee Rowe 195 123 22 11 2.
Hadden Neck 202 123 20 9
3..
Millstone 184 123 18 9
4.
Oyster Creek 161 123 18 9
5.
Ginna 169 132 17 10 6.
Dresden 124 132 16 20 7.
Palisades 102 132 15 12 8.
Lacrosse 91 132-14 9
9.
Big Rock Point 81 132 11 9
- Probabilistic valuee are those associated with TERA-LLL's synthesis for the 1000 yr-return period. Attenuation model used for sites 1-5 was 1980 Ossippee for sites 5-9 1980 Gupta-Nuttli. While explicit values assumed no background and a dispersion of 7=0.9 + 2::r This is estimated to be equivalent to intermediate background and a dispersion of GO.7, + 3 7
- Deterministic values were computed using Table 1 and averages of results from the following suites of predictive equations.
Local Events - all sites, suite (a)
Distant Events - northeastern sites (1,2,3,4), Suite (b),
central sites (6,7,3,9) Suite (c) intennediate site (5) Suite (a).
The suites of equations are:
a.
Herrmann -(personal ccmunication,1980), TERA-LLL Aug,1979, TERA-LLL 1980 Ossippee, TERA-LLL 1980 Gupta-Nuttli.
b.
Herrmann (personal communication, 1980)', TERA-LLL 1980 Ossippee c.
Herrmann (personal ccmunication,1980),' TERA-LLL Aug. 1979, TERA-LLL 1980 Gupta-Nuttli.
FA1.T (Lkw $mece)
, SITE FIXED OlSTANCE R
. ~~-
l FIXED MAGNITUDE M anab SCRACE STEF 2 "8
SELECT SOURCES GOVERNING EARTHGUAKE h
nu ucun:Cu ACCELSADCN
,.(*
FIXED PEAK ACCELERATION r.'
.carA l.-
I I
cisTanCs STEP s
- 3 LOACING AT ATTENUATION THE SITE FIGURE i DETERMINISTIC APPROACH TO LOAO!NG AT Te E SITE TEiA CCRFCRAT'CN Oec.8,1978
o N>
FAULT h Sesce)
' '. SITE LOC O' No. CF
=
EARTHQUAxES
>M F,
e l
8 F 2 AREA SOLACE MACNITUCE u STEP 1 STEP 2 SOURCES RECURRENCE j
8.3"&
b L#JCER TANTY N ATTENUATICN
. MACNiTUC4 M p(Ax g
ACm FMATICN
.l'**
.. 4..
. m,..
cATA*
=
a
=
ctSTANCE o
ACCEERATCN STEP a 8T*? 3 PROBABILITY OF ATTENUATION NON-EXCEEDENCE WITHIN A TIME PERIOD i FIGURE 2 CURRENT APPROACH TO HAZARD MAPPING FCR PEAK VALUES 7:RA CCRcCRAiiCN Dec. 3,1978
-\\
E g>4 M 100 0
- /
-/
/
a b
5
\\
\\
5 D
Y
-- n
\\s u
Q C
o-
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-- so y, 2
s(
x y' 10 0 5
w
'O
//
c
'f j
e g
-J
/
p f
l.c d
'/
/
5
.<o o
,s
.y 0.1,
0.01 0.1 1.0 10.0 PCRICO-SEC.
24". - Deterministic saectra using 34". amolificaticn f acter frem NURE3 CR - 0098.
5C". - Ceteninistic spectra using sa", acclification f ac:cr frca NUREG CR - CC98.
Y - Rec:a-ended crobabilistic scectra.:
Figure 3
~.
H A Q0 AM, NE, X ( :#. ),.
C b
-p*
/
-/
/
a E l00 0 g
- g
- j
.g t:
4 2- - 347
,g ic,
y l
2, A
/y N
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'0,
.o1 f
./
4 p-
/
4
.3
-q
//
y
//
e
'C ! j I
'/
g N
<o
/
',s
~
,/
-g
- f.
f.
I 0s 0.01 0.1 1.0 10.0 PERICO-SEC.
84% - Deterministic scectra using 31% molification factor from NUREG CR - 0098.
5C% ' Deterministic spestra using 50% molification f act:r fr:m EREG CR - C098.
H - Recermencea probacilistic spectra.,
Figure 4
MILLST0tlE (5%)
1000.0 o>
g, 100.0
~
2U
]
p g
M
'i 4
S,
- w, y
h
/
30,0
// /
'/
g
/
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t 0
~
. /
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Nu
/t
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Y
'i y
.0
//
/
/
i f
N N:
~. /.,
- /
p
-?
g 0.1 0.01 0.1 1.0 0.0 PERICC-SEC.
34% - Ceterministic scectra using 34% implification factor frca NUR5G CR - 0098.
50% - Deterministic spectra using EC% amplificacion factor frca NUREG CR - 0093.
M - Reccreended prccacilistic spectra.:
Figure 5
=.
f OY, STER, C.3EE,K,(5%).
1000.0 --
.c#
e*p
- 49
.h" 100.0
~
2 u
D n
4 S
_ -64 ",
~ %gs in
~
d
/
10.0
~
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g S
/
5 o
. /c t
.'0 e
7 s
/
. $g d
/
o-
=
1.C if L
f
~
.<o
~
g
-/
. e.
o-0.l 0.01 0.I 1.0 10.0 PERICO.SEC.
84% - Determiniscic scectra using 34". amplification factor frem NUREG CR - 0098.
50". - Jeterministic scactra using 501 amplification f actor frca N'JREG CR - C098.
0 - Recent. ended precabilistic speccras Figure 6
. h... !. r... _.
QIfif14 (E%),,,,
3 b
d
- p' g a 100.0,
'/
/
-'/
s C
+
D S
- r 4
___._NG gs 8
o-a ses 10 0 i
N N
%E w
./o
,,l 0
e y
i
/
p
+4 3
F u
l.C f
/N N
N
.<og
- g-g 0.1 0.01 0.1 1.0 10.0 PERIOO-SEC. 347.
Deterministic s:ectra using 84f. arolification f actor from tiUREG CR - C098.
507. - Ceterministic saectra using 50f. amolification factor from tiUREG CR - 0098.
G - Recem ended ;;rc' abilistic s:ectra.,
c 1
Figure 7 n.
t
.. - ~ -
ORESDEN, ( 5f.),,,
1000.0 g
0) e.
\\
100.0, N
i 8
,r
~
//~ ~O 2
.g@%
//
8
/
a
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h!
g 10.0 B
to
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y
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//
j
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o g
//,!
-f l/
I.C f
i
/
N E
.<o g
~,o
'O 0.1 0.01 0.1 1.0 10.0 PERICC.SEC.
Saf. - Ceter?,inistic spectra using 34'.' seclification fac:cr from NUREG CR - C098.
50f. - Ceterministic scectra using 5Cf. amolification factor fecm NUREG CR - C093.
0 - Reccerended probabilistic spectra.'
Figure 8
e.
PAISA053,(~%),,
b
[
4
. g 100,0,
- 15 v
"'4D.o
/
~
c o
g 9
M y
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o
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/
y
, '/
I0.0
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m
,/
/,
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/,,/',
T+4 w
I
\\
q.
l.C s
.<oe g
4
~
j C-
%~
/
0.1 0.01 0.1 1.0 10.0 PERICC-SEC.
34% - Deterministic spectra using 34% amplificaticn factor frca itUREG CR - 0098.
5C*.' - Ceterministic spectra using 5c% amolification factor fr:m tiUREG CR - 0093.
P - Recorrended probabilistic spectra.
Figure 9 t.
'I ' '
1000.0 4
g..
100.0 8
N N
D 37 f
- __y, N
f,10.0
'//
/-
/
w
./o
/
=
i g
'/
[
E
.}\\g
/
J i/,
'g I*O W
q f
1
/
~
.<o
~
~
o
~
.g 0.1
...i.
0.01 0.1 1.0 10.0 PERIOO-SEC.
34% - Deterministic scectra using 34% anplification factor frca.tGREG CR - C098.
50% - Ceterministic scectra using 5C% relification f actor from '4UREG CR - 0098.
L - Recommended probacilistic scectra.,
Figure 10 3
4
i 31G SCCK, P0, INT (5,%),,
1000.0 a
- i.
^
? %
9 100.0,
2 U
D 0
a s
'i 9
g.
9 y
7
& - - en.,
D 10.0
.Y
~
/ /
/
N h
./o w
i
=
l' j
~
~
//
4 s
8 d
. o-
=
l Y
/
1.c t
i
/
N N ~
D
.<n h*
.p 0.1 0.01 0.I 1.0 10.0 PF.RICO-SEC.
34". - Deterministic s:ectra using 34". amplification f act:r from :iUREG CR - C093.
50". - Deterministic scectra using 50". acclificaticn f actor frem !'UREG CR - C098.
3 - Recom ended crocabilistic s;:ectra.
Figure 11
~.
- E.U.S. Recomended Probabilistic Spectra and Regulatory Guide 1.50 Spectra 3
~
4 g.
100.0, s
- E v
t O1 j
~
-[
y
'i
- fd.~ 2.r
_,+
~f
.'.'IY$
/
/
/
l '"i.
fr N
E
~'o w
ne y
g 4
h b
o-s z
./
I.C A
[,[
E
,s
-7 0.1 0.01 0.I 1.0 10.0 PERICC-SEC.
Y - Yankee Rcwe 0 - Oyster Creek H - Haccam 1eck G-Ginna M-Millstene l
0.1 - R.G.1.50 anchored at 0.ig 0.2-R.G. 1.50 anchored at 0.2g Figure 12 L
.... ~. -...
C.U.S. Reccamended Probabilistic Spectra and Regulatory Guide 1.60 Spectra
,i-gg,g
!42'
-(g.4 100.0 r
4;i,;.
..c.,
/g_p
's r
. f f,' ff
-$~
~
b
/.. S N /
/
l0.0,
. g/,/
a s
,. ' 5' /
- e
_0
'b
,/
,/
$c.
r 4:
Ci
, / '<
o-
~
i.c.
w E
q
,o
/
4 z
fl,-
/
4 0.1 0.01 0.1 1.0 10.0 PERICO-SEC.
0 - Oresden P - ?alisades L - Lacrosse 3 - Big Rock Point 0.1 - R.G. 1.50 inchored at 0.la 0.2 - R.3.1.50 antnered at 0.2i Figure 13
4, Recommended Probabilistic Spectra at Rock Sites and Recorded Spectra at Rock Sites i
i i '
gg,g
/
-9
/
100.0
/
C
/,,
- t '*[%
o 0
g
,D 9 /
b p
h
, <.~ 5 qs%
/
q.
a 7
N
/
/
10.0 f
b
.f,f I
5
?
/
% 1+%
{
i
./0
}4 O
=
l I
.# y,Y d
j'/
. Q-z j
1.C
'/ j, EO
.C9 i,
.,$/'
4 j
I O
~.
0.1 J.
...i 0.01 0.1 1.0 10.0 PERICC-SEC.
0-Dresden H - Haddam tjeck G-Ginna M-Millstone 34% - 34% spectra from nearby Mag. 5.3
.5 event.
50%-5C% spectra fr:m nearby Mag. 5.3 - 75 eve't Figure 14
. e Recerm: ended Probabilistic Spectra at Soil Sites and Recorded Spectra at Soil Sites 1000.0 h
e g
100.0 8
N N
Eg$
?
1:
i D
c n
- r s
4 e
9 8
-a o.
a 10 0
.{:
f f
{
5
/
\\r.
- q0 Ifl 5.
e'>>
h/, 1' e
/
6
. O' c;
/
i
,l N"
(0 t
f,p'p
/
+*
x
/,
~ q
/
0.1 0.01 0.1 1.0 10.0 PERICO-SEC.
y - Yan'Kee Rowe 0 - Oyster Creek P - ?alisades L - Lacrosse 3 - Big Rock ?oint 34% - Sa'.' spectra frca nearby Mag. 5.3
.5 event 50% - 50% specora from nearby Mac. 5.3
.5 event L
Figure 15
- -. =
-..