ML20127F694

Forwards BNL Preliminary Review of Containment Response Analyses in Facility PRA & Request for Addl Info.Response Requested within 30 Days of Ltr Receipt.Meeting Planned to Discuss Responses

ML20127F694
Person / Time
Site:	Shoreham File:Long Island Lighting Company icon.png
Issue date:	05/08/1985
From:	Butler W Office of Nuclear Reactor Regulation
To:	Leonard J LONG ISLAND LIGHTING CO.
References
NUDOCS 8505200568
Download: ML20127F694 (47)

Text

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Docket No. 50-322 AY 0 8198$

Mr. John D. Leonard, Jr.

Vice . President - Nuclear Operations Long' Island Lighting Company Shoreham Nuclear Power Station P.O.. Box 618, North Country Road Wading River, New York 11792

SUBJECT:

PROBABILISTIC RISK ASSESSMENT (PRA) - SH0REHAM NUCLEAR' POWER STATION The NRC staff and its contractor, Brookhaven National Laboratory (BNL), have completed a preliminary review of the containment response analyses in the Shoreham PRA.- The results'of this review are included in Enclosure 1 to this' letter. In order to complete our review, we require answers to the comments-listed in Enclosure 2. We request that you provide us with responses to the coments in Enclosure 2 within 30 days of your receipt of this letter. Because we anticipate that some of the coments may require detailed response, we intend to schedule a meeting to discuss them. The staff's Project Manager for Shoreham, Mr. R. Caruso, will contact your staff to arrange the meeting.

Sincerely, JSI Walter R. Butler, Chief Licensing Branch No. 2 Division of Licensing

Enclosures:

As stated cc w/ enclosures:

G. Thomas R. Bernero R. W. Houston A. Thadani B. Sheron DISTRIBUTION Docketa F11 ems NRC PDR Local PDR NSIC LBf2 Reading- EHylton EBBordenick JPartlow RCaruso ACRS 16 BGrimes EJordan 1 i\

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n' Docket No.'50-322 08ld Mr. John D. Leonard, Jr.

Vice President - Nuclear Operations .

Long Island Lighting Company .

Shoreham Huclear Power Station P.O.~ Box 618, North Country Road

' Wading River, New York 11792

SUBJECT:

PROBABILISTIC RISK ASSESSMENT (PRA) - SHOREHAM NUCLEAR POWER' STATION The NRC staff and its contractor, Brookhaven National Laboratory (BNL), have completed a preliminary review of the containment response analyses in the Shoreham PRA.- The results of this review are included in Enclosure 1 to this letter. In order to complete our review, we require answers to the comments listed in Enclosure 2. We request that you provide us with responses to the comments in Enclosure 2 within 30 days of your receipt of this letter. Because we anticipate that some of the coments may

. require. detailed response, we intend to schedule a meeting to discuss them. The staff's Project Manager for Shoreham, Mr. R. Caruso, will contact your staff to arrange the meeting.

Sincerely,

/S/

Walter R. Butler, Chief Licensing Branch No. 2 Division of Licensing

Enclosures:

.As stated cc w/ enclosures:

G. Thomas R. Bernero R.'W. Houston A. Thadani B. Sheron -

DISTRIBUTION Docket File NRC PDR Local PDR NSIC LB#2 Reading EHylton BBordenick JPartlow x RCaruso ACRS 16 BGrimes EJordan h

DL: A2 DL:LB#2 N L RCa so WButler

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UNITED STATES f

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j N0' CLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555

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, Docket No. 50-322 Mr. John D. Leonard, Jr.

Vice President - Nuclear Operations Long Island Lighting Company Shoreham Nuclear Power Station P.O. Box 618, North Country Road Wading River, New York 11792

SUBJECT:

PROBABILISTIC RISK ASSESSMENT (PRA) - SHOREHAM NUCLEAR POWER STATION The NRC staff and its contractor, Brookhaven National Laboratory (BNL), have completed a preliminary review of the containment response analyses in the Shoreham PRA. The results of this review are included in Enclosure 1 to

'this letter. In order to complete our review, we require answers to the ccmments listed in Enclosure 2. We request that you provide us with responses to the coments in Enclosure 2 within 30 days of your receipt

'of this letter. Because we anticipate that some of the coments may require detailed response, we intend to schedule a meeting to discuss them. The staff's Project Manager for Shoreham, Mr. R. Caruso, will contact your staff to arrange the meeting.

Sincerely, Walter R. Butler, Chief Licensing Branch No. 2 Division of Licensing

Enclosures:

As stated' I cc w/ enclosures:

G. Thomas R. Bernero i R. W. Houston A. Thadani B. Shcron so w % ew<e.m.

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Mr. Joh'n D. Leonard, Jr' Shoreham Nuclear Power Station Long Island Lighting Company cc list (1) occ: Lawrence Brenner, Esq.*- Stephen B. Latham, Esq.

Administrative Judge John F. Shea,,III,'Esq.

Atomic Safety & Licensing Board- Twomey, Latham & Shea U. S. NRC Attorneys at Law .

Washington, DC 20555 P. O. Box'398 33 West Second Street Dr. George A. Ferguson Riverhead, New York 11901 Administrative Judge School of Engineering Atomic Safety & Licensing Howard University Board Panel

• 2300 6th Street, NW U. S. NRC Washington, DC 20059 Washington, DC 20555 Dr. Peter A. Morris

• Administrative Judge Atomic Safety & Licensing Appeal Atomic Safety & Licensing Board Board Pcnel*

U. S. NRC U. S. NRC-Washington,-DC 20555 Washington, DC 20555 Alan S. Rosenthal, Eso., Chairman

• Gary J. Edles, Eso.*

Atomic Safety & Licensing Appeal Board Atomic Safety & Licensing

.U. S. NRC Appeal Board Washington, DC 20555 U. S. NRC Washington, DC 20555 Howard L. Blau, Esq. ' Gerald C. Crotty, Esq.

217 Newbridge Road Ben Wiles, Esq.

Hicksville, New York 11801 Counsel to_the Governor Executive Chamber W. Taylor.Reveley III, Esq. State Capitol Hunton & Williams Albany, New York 12224 707 East Main Street P. O. Box 1535 Herbert H. Brown, Esq.

Richmond, Virginia 23212 Lawrence Coe Lanpher, Esq.

Karla J. Letsche, Esq.

Howard A. Wilber* Kirkpatrick, Lockhart, Hill, Atomic Safety & Licensing Appeal Board Christopher & Phillips U. S. NRC 1900 M Street, NW - 8th Floor

.Washington, DC 20555 Washington, DC 20036

-Eleanor L. Frucci, Esq. Leon Friedman, Esq.

Atomic Safety & Licensing Board Costigan, Hyman & Hyman U. S. NRC- 120 Mineola Boulevard Washington, DC 20555 Mineola, New York 11501 -

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, s ~SHOREHAM (1) ,

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. James B.10ougherty, Esq.. Mr. William _Steiger 3045 Porter' Street, NW- Acting Plant Manager _

Washington,1DC 20008~

-Shoreham Nuclear Power Station:

P. O., Box 628- ,

s Wading l River, New York--11792-

. Fabian'G. Palomino, Esq.- .

lSpecial Counsellto the Governor .

-Executive Chamber - State Capitol MHB Technical Associates Albany,New;. York 122241 .1723 Hamilton Avenue - Suite K-

' San-Jose,' California 95125 1- ' -Edward M. Barrett, Esq.

1 General Counsel Hon. Peter Cohalan

'l Long' Island Lighting Company 'Suffolk County Executive .

250 Old. County Road. County Executive / Legislative _ Bldg.

'Mi.neola,-New York _ 11501 Veteran's: Memorial Highway Hauppauge, Ne'w York 11788 LMrJBrianMcCaffrey:

Long Island _ Lighting Company ' Mr. Jay Dunkleberger.

Shoreham Nuclear Power Station New York-State Energy Office- ~

P. 0.MBox 618. ..

Agency Building;2-North Country Road .

Empire State Plaza

'Whding River, New= York 11792- Albany, New; York 12223 Marc W. Goldsmith Ms. Nora Bredes. .

Energy Research Group,.Inc. -Shoreham Opponents Coalition

.. -400-1 Totten Pond Road- 195 East Main Street. . .

_Smithtown, New York 11787

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Waltham, Massachusetts 02154 Chris Nolin. .

Martin'Bradley Asharei Esq. New York State Assembly.

> Suffolk County Attorney Energy Committee. .

626 Legislative Office Building

.;H. Lee:Dennison. Building .

LVeteran's Memorial = Highway: Albany, New York-~12248

> Hauppauge, New York _.11788

^

Ezra I. Bialik, Esq.

-Ken Robinson, Esq. .

Assistant Attorney General-

.New York State Department of Law.

Environmental-Protection Bu'reau 2 World Trade Center - Room 4615 New York State Department of Law New York, New York 10047 2 World Trade-Center New-York, New York 10047 t

Resident-Inspector- Thomas E. Murley ,

.Shoreham NPS, U. S. NRC U.S. NRC, Region I i nx Post _ Office Box B 631 Park Avenue L -Rocky Point, New York _ 11778 King of-Prussia, Pennsylvania 19406 L

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. ** j' ' ENCLOSURE 1 t' ,

BROOKHAVEN NATIONAL LABORATORY MEMORANDUM DATE: September 27,- 1984

.To:

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W. T. r t ,'

rnoM: - K R. Te' ins and S. Y.- eh-

SUBJECT:

Preliminary Review of the Containment Response Analyses in the Shoreham PRA INTRODUCTION We havec . onducted a preliminary review of the containment 1 response analy-A parallel ef-

. ses contained in _ the Shoreham Probabilistic Risk Assessment.

fort sponsored by RRAB/ DST /NRC is under way at BNL to review the event tree development and quantification. . This " front' end" evaluation is a much more extensive review than the present review and it has provided many valuable in-sights. We have concentrated 'our review on comparisons ~ to Limerick since BNL '

has gained extensive experience in the previous review,2,3 and the plants are . very similar. Our review has thus concentrated on areas where there are analytical differences ..between the two PRAs - or containment design differ-ences. The degraded core frequencies for the four accident classes are shown

..in Fig. 1. The definitions used in the Shoreham classification scheme.are in-

- cluded as Attachment 1. The dominant differences between these two estimated frequencies is iin the Class IV ATWS .with Shoreham being two orders of magni-tude higher than Limerick. Clasli II loss of containment heat removal is also

. estimated to be higher in Shoreham than Limerick. In order to keep this com-parison in perspective,'a comparison of the results for all the available BWR PRAs is show in Fig. 2. Note that the Limerick' PRA gives sub_stantially lower However, methodological core melt- frequencies' than any of the other PRAs.

differences make direct comparison between the -_various PRAs difficult. The Limerick PRA used the basic approach and techniques- of the Reactor Safety i Study (WASH-1400)" but accounted for plant- specific design differences between Limerick (BWR4 with a Mark-II containment) and the WASH-1400 plant (BWR4 with a Mark-I containment). The Shoreham PRA methodology is compared to WASH-1400 in Table 1.

The high . frequency of ATWS events in .Shoreham is of particular concern

- because of the potential for severe releases. Much of the difference in ATWS frequency can be attributed to the lack of an automatic poison'in.iection sys-tem and to di.fferences in the AOS inhibit logic. In other respects the scram .

systems used in Shoreham and Limerick are quite similar.

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J W. T. Prdt September 27, 1984 Having nited that the ATWS core melt frequency in Shoreham is relatively high, it is . interesting to note that the calculated radiological impact is

.only. moderate as indicated in Table 2. This is basically because of the large.

decontamination. factors (DFs) . calculated for Shoreham. Because of the differ-ent classification schemes used in the PRAs,'it is difficult to make direct comparisons of the DFs. However, in order to get some perspective on the'high DFs- claimed for Shoreham, the release fractions for a typical ATWS sequence are compared in Table 3 for the three plants. Both WASH-1400 and the Limerick

- PRA calculated severe releases for these rapid sequences, but Shoreham calcu-lates releases two orders of magnitude lower. We noted .above that the Lim-erick PRA used WASH-1400 methods so that one would expect the source tenns predicted in the two studies to be similar for compatible failure modes. How-ever, from an inspection of Table 1- (Item F), .it is clear that the Shoreham '

PRA used more recent methods to determine the radionuclide source . terms and most of the reduction is apparently due to higher pool DFs. . It will be im-portant' to verify that these reduction factors can be achie'ved under all se-quence conditions and failure modes.

DISCUSSION Of the five Shoreham plant accident classes, the final set of risk con-tributing accident sequences are chosen based on the ranking of importance of

. the product of the end state probability and source reduction factors. Four-teen risk contributing release categories and two non-risk contributing cate-gories are defined. Three of these sixteen categories are Class IV accident sequences.. . They are SNP-10 (CgRgTt -y), SNP-11 (CgRgT -y), and SNP-12 i (CgRgT 4.. Note that SNP-12 consists of

- both y;-y'; andCyhRgT 1

-y") aswhere scenarios described the y"in Table assumes the wetwell failure. be-scenario low the waterline at the basemat. The DFs were calculated for the fourteen categories as shown in Table 5. Among the fourteen categories, three are Class 1V accident sequences. However, the y" sequence was not included in this table. The pool scrubbing DFs for the various accident ' sequences are summarized in Table 6 with the implication that the DF for y" sequence are at

, least as much as the values in this table. The high suppression pool DFs of the Shoreham plant are based on the assumption that the pool is intact, and o all fission ' products go through the pool [with the exception -of Class IV L (CgRgT i -y) sequence in which 10% pool bypass is assumed] before entering the - ,

l containment. In order to evaluate its high DF claims, the containment struc-L tural design of Shoreham and Limerick were examined and compared. The follow-ing preliminary assessment c.an be made.

1. The diaphragm floor at elevation 62'8" of the Shoreham plant was not an-chored to the containment wall as in the Limerick design. The Shoreham containment wall displacement will expand outwardly under pressure as i shown in Fig. 3. Based on this free standing diaphragm floot design, the I. PRA suggests that the most likely leakage paths will occur at the junc-

[ tion of the diaphragm floor and less likely at the basemat. Under this l

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y v- W.-T. Pratt September 27, 1984 failure condition, the suppression ' pool. integrity and high scrubbing ef-ficiency will probably be maintained. However when gross containment failure occurs, as will be the case in many Class IV accidents, the base-mat-co'ntainment wall juncture was judged by Stone and Webster as the most probable location to fail (Appendix. M of Ref. 'l). Under such failure conditions (generally defined as the y" scenario), the suppression pool water will be blown out into the surrounding chambers.

2.- The' suppression pool of both plants is surrounded by chambers; while the' Limerick surrounding chamber is partitioned, the Shoreham surrounding chamber is a continuous annular-like space. Both surrounding chambers have drains. Limerick's PRA assumes drainage of the suppression pool in y" sequence. Likewise, it is reasonable to assume that the Shoreham sup-pression pool will also be drained under such failure conditions (y" se-quence). If such is the case, the DF of Class IV y" sequence should be evaluated explicity. At present, the Shoreham PRA doe' s not include the y" scenario in any of the sixteen release calculations. Instead they are

" binned".with the y' sequences where the pool remains intact.'

3. After the bottom hea'd failure, the Shoreham PRA predicts that 90% of the core debris will flow to the suppression Dool via the four downcomers un-derneath 'the vessel in the CRD room. The remaining 10% of the core de-bris will attack the concrete floor of the CRD room. Because of the lim-ited amount of molten corium, the core-concrete interaction does not gen-

~erate a substantial amount of gases to threaten the containment integrity.

The estimate of 90% of the core debris flowing into the pool is probably a very good estimate if the molten core debris can be treated as non-vis-cous incompressible fluid (as modeled in Appendix L of Ref.1), since the remaining molten core on the concrete floor cannot be more than 1/2" deep before it spills over the downcomer's neck and flows into the pool. How-ever, there is a wide range of possible debris conditions at the time of vessel failure." Generally the high temperature molten debris (~4300F) is taken to be the limiting case. For Shoreham, however, the low temper-ature solid debris (~2700F) may be the worst case since very little de-bris would flow through the downcomers. Thus the effect of more than 10%

,of molten core remaining on the concrete . floor should be addressed.

i The revised geometry (see Fig. 4) of the downcomer vent pipes is intended to maximize corium flow into the pool but this also increases the poten-tial for steam spikes and oxidation release.

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'1. The revised reactor pedestal geometry is not described adequately in the schematic (Fig. 4). , Verify that the vent pipes and manways remain un-blocked in the revised pedestal geometry.

2. Provide the estimate of the fraction of molten corium which is expected to spread out of the pedestal area through the open manways and vent pipes.

3.' Verify that the downcomer vent pipes only protrude 1/2" above the dia-phragm floor of the drywell as indicated in Fig. 4 4 Section 3.6 of the PRA takes credit for ~ containment leakage which _will prevent gross containment failure for 2 pressurization rates except the very rapid pressurization associated with large breaks. However, the structural analysis by Stone and Webster (Appendix M) did not identify ,

any significant source of leakage. The expected leakage source and the #

leakage rate as a function of pressure should be provided.

5. The . basis'for the partitioning - between release category 10 and 11 (no pool bypass vs. partial pool bypass) should be provided. The phenomeno-logical basis for the estimate of ~ only 10% bypass should be provided.

. Preliminary results from IDCORE indicate that for some RWR. sequences the vessel will fail with only 20% of the core molten. Presumably 80% of the melt release would bypass the SRV's and be released into the drywell.

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6. The basis fo'r the binning into release categories is poorly described and '

the' transfer from Tables H.4-8 etc. (Attachment 2) into the 16 release categories is inscrutable. A table listing the specific sequences which

.are binned into each category.should be provided.

7. The lack of R5 sequences in the release categories makes it apparent that these releases have been binned " downward" into the lesser release cate-gory Rg. The basis for this " downward" binning and any other sequences that are moved to less severe categories should be provided.

8. Table H.4-25 appears to be incomplete in that it does not include se-i quences D6 and 08. The completed table should be provided.

9. The source escape fractions used for end state screening (Table 3.6-10) appears to be quite arbitrary yet it greatly influences the importance ranking. In particular: the use of Z as the surrogate for melt release w ignores the fact that there are noble gases in the melt release which

, will not be scrubbed at all; the use of a large scrubbing factor (500)

'for Cg transients is inappropriate since most of the melt release will be released directly to a failed containment; the reduction factor of 0.01 for i" failures is indefensible since the event tree precludes everything but large ruptures where the pool will be blown out into the reactor 4

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W. T. Pratt September 27, 1984

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building at high pressures. Taken in conjunction with the scrubbing fac-tor of .002 the reduction factor of 0.01-implies double scrubbing with a decontamination factor of 50000 for an event in which the final level of

, water in th'e suppression pool is highly uncertain.

Table 3.6-10 should be replaced by a table with defensible reduction fac-

- tors. As a minimum the table should include a separate category for Cu transients, which recognizes the defined sequence of events (containment.

failure before core melt). In addition, a detailed . justification for each reduction factor should be provided along with the numerical results of the ranking process.

10. Sheet 1 of Figure H.4.2 has been reduced so that it is illegible. A full-size legible copy should be provided.

RECOMMENDATIONS In addition to the above information, we feel that there are several areas which are inportant, enough to warrant independent verification. The ba-sis for our concern and the proposed resolution- for each item is outlined below:

1. Core debris disposition: The partitioning of 907. of the core debris into the wetwell is highly speculative and assumes that debris will be nearly inviscid. In fact the molten core may be very viscous. and may be solid-ified by quenching in the lower head of the vessel or on the drywell floor.

We propose to run a Class I accident -sequence (e.g. TQUV) with 50% of the debris retained on the drywell floor in order to examine the potential for early release of fission products for this class of events.

-2. The Shoreham PRA presents no quantitative analysis to preclude failure of the wetwell below the waterline. In fact, Appendix M indicates that the most likely failure location is at the bottom of the wetwell. A failure in this region would force the pool into the annular region of the reac-

' tor building Surrounding the primary containment. If the reactor build-

'ing does not fail and the drains are not on, the pool may still tend to mitigate releases from the containment as they are bubbled through the failure location into the reactor building.

We propose to use SPARC to address the DFs for the y" configuration as-suming the pool is retained in the annular area surrounding the contain-ment. We will also assess the significance of the assumption of no pool DF for this sequence (as assumed in the Limerick PRA). The partitioning

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between y" and non-y" scenarios will be based on the applicant $s response to questions 1 and 2 and the structural analysis of Appendix M. The 0

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W. T. Pratt - 6- Ssptember 27, 1984 partitioning between scrubbing and no scrubbing for the y" scenario will be based upon our assessment of the possible pool configurations after a large rupture at the basemat at high containment pressure.

- 3. The ' release ' fractions for Shoreham are several orders of magnitude lower than both WASH-1400 and Limerick. Most of this difference can be attri-buted to high pool DFs based on limited experimental data as cited in Ap-pendix N.

We pr opose to use SPARC to assess the potential for lower decontamination factors for a range of conditions. The calculations will emphasize va-porization release to a saturated pool since our previous experience in-dicates the potential for lower DFs under these conditions.

4 The issue of the energetics associated with steam explo.sions remains un-resolved, but the issue is being addressed by the NRC as. part of the Con-tainment Loads Working Group (CLWG) effort. We propos'e to review the preliminary results of the CLWG effort to ensure that the NRC position is consistent with the low probability of containment failure (4x10-4) or the low l probability of an oxidation release given containment failure (6x10-3) that is cited in Appendix L of the Shoreham PRA.

REFERENCES

1. Science Applications, Inc., Probabilistic Risk Assessment, Shoreham Nuclear Power Station, SAI-372-83-PA-01, June 1983.

2. H. Ludewig, J.W. Yang, and W.T. Pratt, " Containment Failure Mode and Fis-sion Product Release Analysis for the Limerick Generating Station: Base Case Assessment," BNL Informal Report, BNL-NUREG-33835, April 1984.

3. I. A. Papazoglou, et al., "A Review of the Limerick Generating Station Probabilistic Risk Assessment," Brookhaven National Laboratory, NUREG/

CR-3028, February 1983.

4. " Reactor Safety Study--An Assessment of Accident Risks in U.S. Commercial Nuclear Power Plants," WASH-1400, NUREG-75/014

5. K.R. Perkins, G. A. Greene, and W.T. Pratt, " Appendix D-Standard Problem 4 (BWR Mark I)," Appendix D of the Containment Loads Working Group Standard Problem Results, to be published.

KRP:sm/tr cc: R. A. Bari G. A. Greene D. Ilberg H. Ludewig K. Shiu J. W.-Yang R. Youngblood W. S. Yu

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0.1 Table 1 Major C'hanges in the Shoreham PRA Compared' to the WASH-1400 Methodology

a. New sequence : initiators are defined and accident sequence models developed, including time phase event trees. .

b. The definition of generic accident release categories in WASH-1400 required lumping accident sequences with major differences in potential consequences . and containment interactions into the same category for consequence evaluation. For the Shoreham evaluation, realistic and refined release categories are defined so that each ' unique sequence type could be evaluated separately . assuring greater detail in defining 'the

- spectrum of radionuclide releases.

c. Smoothing of. probabilities among release categories was '

used in WASH-1400 to account for possible miscategori-zation of sequences and other uncertainties. This artifice is eliminated in the Shoreham evaluation because of the better definition of accident sequence release categories for consequence evaluation.

d. Accident - sequences are totally reevaluated using the latest BWR thermal hydraulic calculations for. trans- -

1ents, LOCAs and ATWS.

e. . Component failure rate data and common mode failures are reevaluated based upon the latest data from operating nuclear plants.

f. The radionuclide source term, release mechanisms, and removal mechanisms have been completely reevaluated .to incorporate the latest experimental data and analytical methods in the characterization of source terms.

g. The conservative estimates of the probability of - the steam explosion lea ~ ding directly to containment failure was reassessed. The steam explosion phenomenon leading -

, directly to a containment failure and substantial oxi-dation release is realistically evaluated considering tne specific Shoreham design. The probability of this ,

event is reduced.

h. The . conservative assumption that all potential core' damage. sequences lead to a major release was reassessed. Detailed containment event trees were developed to appropriately characterize the accident sequences which could lead ,to a radionuclide release.

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TABLE 3 Comparison of Release Fractions for ATWS Sequences -

i Iodine or Cesium Tellurium Shoreham .

1 Release WASH-1400 Limerick Shoreham WASH-1400 Limerick Shoreham Category ,

11. .1 1 .07 .73 2 1.6x10-4 .3 .1 . 62 2.5x10-2 s

I Based on comparable BWR relea'se assuming elemental iodine.

2 Depending on failure mode.

O I -

=

l 4

~' " "

^* **+v'p**'" * ** * * ""

=

r- - - - ~-

Tabla 4 .

DESCRIPTION OF Tile RELEASE CATEGORIES IDENTIFIED FOR Tile Sil0REllAM PRA (Slie:t I cf 4) .

W DOHlNAsif ACC10 fist til -

et t ( A5( pS00R(55804 pAlti CArtumr W84 W8l'IIM '

5t$stf([ CONISitulloit SA1,15 felt IN-ptANI ANAtt115 D(51CsA10A

- - * ~

Ihis release category is representative of Class I accident sequences Less of Off-site power taltlater, failure Cg8,T g-5 5kt1 3 to recover Olvision i er il electric power, lavolvlag a transient event leadlag to core meltdown where the coa. (erly failure la sainment f alls te Iselste er f alls by everpressure early la the accl. failure of high pressure lajectlen systems. ,

f ailure of A05. failure to isolate la the the crywell dcat seqvcace leeJing to h leslage type eclease from the drywell.

drywell.

f St#5-2 Ihis release category is representative of Class I accident seevences as flood whlch partially drales suppresslea CSTgg.3 lavolvlag a transicat event where the coatalancat falls to tselsts or pool. failure of high and to.s pressure Ia.

f alls by overpeessure early. leadlag to a leakage type release from jectica systems. failure to isolate la the (erly f ailure la the wet ctI. wet = ell. the Wet = ell i

1rJ5.) This release category levelves a core meltdown for a Class I accl. toss of condenser vacuum, failure of high Cg e,T, - y dent seenweace la which the comtalament falls la the long terg lead

• pressure lajectica systems, failure of AD5 lag to a ledese path free the drywell. the long time to centstament the contalament is Intact durlag the sig. Late fallure f allmes Is e pected to reduce the stil.orme fisslea products la coa- alficant fission product release perleds. la the Drywll

. talsweet substaattelly prior to release.

.e.

5fti 4 Ihis release category levelygg g (g(g al[J,n,g (0p 4 CIllt l Hgl, tell Of toadseter vacuum. fallere of higy ggg144 7 deal legwace la willth the tentalement falls la the leag term lead. Pittlute lejettien systees, failure of mule lag to a leslage path frise the wetwell. the laag time to coatalament the coatalement is latact during the sig. C8ig g g +1" failure is espected to reJuce the altleorae fisslea products la coa, afficant fission product release periods, tale failure talancat sulataallally prior to release. le the Wal= ell e

. i a

i~

Tabla 1 - - -

DESCRIPTioti 0F Tile RELEASE CATEGORIES IDENTIFIED FOR Tile S110REllAM PRA (Sheat 2 of 4) 8filAlf 00HillANT A(Citfht (if '

(Altamity . W8AL H5Calil1018 5tquthCE Cohleicullest- ts0Ca(1580s talie Still FOR IN-PLANI A3ALV515 8t51CaA104

- ~ . _. ..

r thri 5 this category tavelwes Clssa If (*ss of condeaser watuun. f alleres of ed.

coat.i-at isiis .ve to iess e,a.uldent ua, .sequences cat ,e.e,ai la dich the ca,abiili, nicic. .ad ecit f.iiure .f . iant intu. CA*Ti.?

• felle cd ha care mettde=a. the centalament f ailure is assu.ed esen fallavlag contalancat failure; the fall.Je la te occur la the de t*PP'ession peel is effective la relatelag the e,pell cuatala.=at would.es rellse sad the fisslaareduced, sigalticantly products alsbarse la ta= fission presucts releasse fram the s core reglen In. vessel. '

1 1hr5-6 This category levelves Class Il accident sequences la i.htch the toss of coaJenser vacuua; f ailures of SM.

coatalm eat f alls due le less of decay heat removal capability aCIC5C. and Preg failure of coelaat lajec. cat 2 4 I . )'

felle e4 by care aclade==. the contslancat failure is assumed C,ni -7, 4

team fellevias costalament failures the gg to suur la the weswell and the finslen products althorse in sopprestlen poel is ef fectlee la regalatag contale-ient would not be significantly reduced, the fission products released from the I*U" 8" core region la. vessel, the Orwell

j s

s thP5-f thl release category is representative of a Class lit accident e LKA. failure of vapor suppressle". C8T3 4 g -7 sequence la i.hich the costalament falls early la the accident I*'lf

'*' '"'P' essure failure of contalament, se.svence due se taade suate pressure supprestles capability. the farly failure fisslea preJ =ts released from the core regles are discharged la the Oryi. ell directly to the drywll steesphere and are met significantly

• attemusted prior to lesbaye from the depell. This category laclwJes tarere LOC 4 aaJ htV failure accident seguiraces, Alch shalltage tentalmeent latogrily early la ll.e netluence.

5h,5.. this ,eiease ca e,.,, la.. .es . cians iii suident se-e in ~ '- *

• A . <> a - ' h h -d ' ~ ~ i- cl ,i. >

valth the toalainment f alls le the leag gene leading le a leslage "fC, *",, ,','"f '

I Il g ,ie g,,, ,e path fries the dryuull, lhe long time to contala= cal failure 16

• g'** I 8 g g*

espetted to srduce the altborne redlemutilde malerfel leventory 0" the OrF*eII

la tantale==st prior to its leakage le the entifemment.

Ii i  ! .

1-4

Tabi c'1 ,

DESCRIPTION Of Tile RELEASE CATEGORIES IDENTIFIED FOR Tile Sil0REllAM PRA (Shest 3 cf 4)- -

"" #EU (II M Nf8AL 0(5(RIPfl04 1100thCC C0hlettull04 pe0ce(1510m palel Ca 4 y

• SAill f04 In ptANT ANAtV115 0(11CsA10R this release catesery levelves a Class lit accident sequence in feedlue toCA. failure of high and low pressure C3 e,f, . 7 '

ShP5 9 I"Ill** systres, the contalement is latact i.hich the comtalmae=t falls la the long tesa leadlag to e leanage g),4'4

• T, path from the wetwell. Ihe long tlee te contalement f ailure is durlag the redleauCIlJe release perled free

• e.pected le acJuce the alsborne radteauclide material leventory the fuel. g ,,g gg,,,

la coatalawat prior to its leasage to the emetremment. la the Wet ell i

i i

$nts.10 This release category is representative of traastent events Mit Closure ATUS. f ailure of StC. falle'e v C,t,T, . 7 lavolulag Class 1. Class ll, and Class IV accident sequences where of all lajectlea systems felleulag contain.

the suppresslam peel 16 partially typassed and the contalaasat 10 et the fisslea products I y g,gg lategrity is test early in the accidcat sequence. osat released f ailure from "$e'fuelleGessef'in~(reas. g,,,#e Dry ell perled directly to the drywell bypasslag the suppresslea peel.

shis release gategory levelves a Class If accident seevence la 8458V Closure AIW5. f ailure of $tC. f ailure ggy441 9 Shr$-88 of all lajecties systems felle lag contain.

=hich the centstament falls by a failure to scrae and remove ecat failure, the tissten products released decay heat, followed by core meltdown. the costalament failure I'on the feel la-vessel see totally trees, f arly f ailure 16 assumed te occur la the drywell and thollssion g~raducts are In the Orywell perted to the coa,talmne at through the sup.

.NI llHHj{diglicausted - --

prior to its leatage te llie~ehi.lr

- -~..e pressfem peel.

goa .ag, 4 g' Mlv Closure AIW5. fallure of itC. failure C,R fe g .1' thrl-li This, release category levelves e Class IV astideot leaguence la of all lajectlen systens felleulag tealain* 1*

which the contalement falls by a failure to scrw and remove meat failure, the filsten products released CeI441 desar heat, felleved by core smeltdeva. the costelament fallere free the fuss la nsigt pig totall treat. g,,,,g,gg,,,

is answed to occur le the weluell and the fisslea products are potted le the, tentalamen} ,[hgeogn, he- _sup. " l'8 8**Iy llynllitantly allthueled lerfor le lit leslage le liie environment, pilllie4*gies[,-

- .ius.mw

w -- - - - - - - - -

Tahls 4 DESCRIPTION OF Tile RELEASE CATEGORIES IDENTIFIED FOR Tile Sil0REllAM PRA (Slitst 4 of 4) o 00HINAh! ACCID (hi (II Sit (A5( G(N(sal. 0(1(187I1018 SiqutNCE CONIAltvil0N P90CA(1580N PAIN gagg w y

• 0(11CMf04 SA$ll f04 IN.PtAh[ ANAlvill

! laterfacIng (OCA, the suppresslee poel is C8T ihe$ 13 Ihis release categer is represensative of Class V accident partially ef fective la alligattag releases. i4I A

' sequences which lave ve core meltJema felleulag a toCA out.

slJe contalament. Ihe SRVs are actuated la order to alligste the release of fisslua products to the environs, eat by providlag an alternative path late the costelement l0.e. suppresslea pool)durlagthein-vesselreleaseperloJ.

This release catevery is representative of Class V accident laterfaclag LOCA. faltere of 1AVs. t,3 T4g 0 Shr5-14 seguence =hich lavelve core peltde-a folleulag a 10CA out-stJe costelament. Ihe 1Avs are assumed not to be opened,

• saJ the finsten products seleased f ree the fuel totally 6yyant the contalement.

t ShPS-IS This release category is representative of the terstaated core seltdu.a accident seguences la i.hich the centalement resalas latect toss of condenser vacuum, failure of high pressure lajectlen systems. f allure of A05, CBf 354 -(

anJ the release of radleauctlJes to the envireament would f.e very contalament lategrity is malataleed.

small, sad deterstaed t,y Is414ge to ti.e 'reacter building.

T lble release category is representative of the terminated core CRI larl-16 eeltdo-a accident sequences la i.htch the costelament reestas latect tels of condeassr pressure vacuum,f ailure lajectlen systems, failureofof hf(le 154 -(

anJ the relefse of radleauclides to the asylrormeet s.eeld be very sealalraset lelegrity le palatsised, ledils sad deteemined by leataje le the reacter building. Further.

wre, the seleases uuuld be Illiered by the stener filter systeet.

eN_

Table i SHOREHAM StJMMARY OF DEGRADED {0RE ACCIDENT ANA1.YSIS CASES CCNTAIN thf PRfrARY $UPPtt35fCN POOL

$&d FAILett . St1 TEM CICOMTAMINATION ggg3 M (C)

CE31**$..A CC3!;NAi;2(a) CIPCSITIOM(b) FAC OR$

Say vtwTs C3 ,Tg.s CI.W T sm 100 a.c Ct.w T 220(e 20 co n.c .

Cg n,Tg ,. a CtTg 4 g .7 07.W T $00 100 N.C C;2,T, - 7 ' CP.w T 800 100 M.:

CtT2 4 g .7 CP.W T 6C0 100 -

M.:

C2T2 4 g . 7' CP.W ,

T 600 100 N.C CtTg 4 g .7 CF.W L . 100

• M.C C2Tg4g.7 CP.W L . 100 N,C Cn,T,.7' 3

P.w t . ico - n.:

C,i,732 7 CP W T(.) sm 1:0 n.:

C 24gT s.7 . CP.W 7 600 100 M.:

Ctt agg 7 :P.W T 600 100 M.c CaTggg.A SP L(f) 2000 100 N.C.A SP L - 100 M.C.2, C8I54l.3 i

(a) CI Containment Isolation Fatture CP - Cantaterent Overtressure failure 04 - Containment tresca is in the Crywell (7)

• hd . Cantainment tresca is to tre isetwell (7'1 (3) . T . Transient event wits oricary system Intact ano en effective retentism of 805.

L . LCCA eveat ita t.te effecttee crimary systes retention of 23 ane IC: for the vesars and aerosols rescectsvely. *

(c) 9 . PAACM C . C;2M ' -

t . Cante st M cale of ej.Ap.g (6) 8901 scrstaieg ef fectiveaets is recuces sue 13 tae recuces soergeece aettMt.

(e) Ten serttaa af t?e fissiam scosucts releases fet,- Pt c:re regica witnin tre tr*.ary siste9 ty;4sses t*e test. ,_

Lf) r:ssets released frari t*e fwel is etrected into fif t*etycantair.*ent gerceat sf tae fissiep :laltRe 12f anscMarge lines esring care eest up and p aseatng seitco a.

~

- . . - - - - . .-m,-_ = 2 i ee ..

A' Table 6.

SHOREHM4 PCOL SCRUBBING DECONTAMINATION FACTORS EVENT SRY DOWNCCMERS Cl ass 1,' 2, 4 3000 100 Class 3 NA 1000*, 100 O

4 e

t 4

- v- - , , ,, ' _.-._,w .. _ _ , , , , , , , . _ , , , . . . , , ,,, ,_ _ . _ ._ . ,_, . , _ _ _ .

e

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• '8 E OE s-9 I. E. E. 5. .

.e

.. ll* I.

- .I .

E EW:

--. . ' .. o. e. e. a.

o. ae .

o e e W g ene - - o -o e -

352 ea

~\ g _.

• . *. M o

-53

- o o o - o e WE .

• b= .a,.gv e. . m.

• e. e.

o a.

e e.

o z

a e

3 - e o e. -

E Y

M NN .

w e. e. e. a.

y g e. a. e. e.

y 3 - -- - -

E h

- y' =

2 EMS 4 e J

'e 4

e 4

e 4

o a

e i

o 4

e 4

mw- .

W l -a g2 ac X {22 8 $ $ e E $ $

m E o f

g I "h a a e 4 a .a 4 ls c .

z W E

i. > . 2_

w . E t$

• W .

% >n4 .

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- . o z

! o O

-e m wU m

e .

• 8 o 3 3 *

• 4 5

. C

• a a 6 e = * *

• 2 m' ,

1 S. 3 '

g 1. :... . t e m z . .

--z * * ~ *

• a a i

• 2 .2 *3 A o wt e - o e m

>- > E- e Sg .21 g f.,

u

' *c ng a , , q . , , g, -

a. . . - e g

. o W =

s e e *. *. .

• L.

oc .

2 . I 'KI

-v. -s w = >l N $*

W 8 3 =a W g *.

$$b

.Q =

• 1 5' 2 a

3 gs e 4'

8 d

I O-awe-e s E .2 .

. -- a h tg gi.

. 24e

.i

=

c ,

j e

l 3 2 N i B r. * * . 8 o .

, M

. '1.. .g t

3.WW

, as 6 = . ,,

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=-a

.,g.

a-  ! *-4 I s Sg*

& C ,

-@ 2 ,

• ]

W e e es g o .- s. f. a. s. -e . . n. ***

.s -

4 6 e o - o a  ;

34.-

. * - .l 6 l .m. , s.

I ) g

. I = .a

• i , :5 ~

i e

aa * . . .

1.

-s .

-e5 J 23 * -=  ;? 2 . , 4, Y

--5 M

t af Je-2.

d. 4 i, J: f-2.3  ; ~- llt 3 .-';

l --

J~ l- = - '

l 2 ; l

- ,. 4

, gae 4a .

I .. a f 3 d. d.

5 e.

! U i .

s% .

. l 1 . !. ' *I 2.

s 2- 7._  :

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8 d* * *

! 3 ."

• i  ; -

I e 44f

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r__.- ,

e

-l st =

-10 OX TE FREQUENCY

_______ ;_EY2!fr_3_t _____ 555"5_'_~_"I______

_l' LIME RICK TOTAL

,0-s _

i j

, -, l i l l l l l l l

~ ll 1- I 3

10 - ' '

~

[$dFf 2PJ c ,

, g 10 9  !

CLASS I CLASS 11 CLASS lit

• CLASSIV rJT MOVA ,

L"?no"'  %%'"

CONTAINMENT Figure [' Sumary of the accident sequence frequencies leading to degraded core conditions sumed over all accident sequences within a class.

t ,, .

-: ( ..

i NOTE: . In 'the other available BWR PRA's ,

there is no clear distinction between core vulnerable and core melt and states.

-3 .

10

^

8

• 6 - sts "0CK 'sacas v '. 5 -

PolNT FERRY 4 - 1 REP -

'3 . ,

g 2 -

e v 10 4 -.

/ /

• s

=

CRAND GL'J a -

RSSPAP g ,

SP.CREHAM- WAs

• 14C0 i ! /

~

/ F F n> /- -

/ / >/

/

= -

/ /

10- -

a / $ s

+

r ,a s# / s ,/ ,

I "g MEAM MEAN MEAN MEAN MEAN *

, (SEE (5EI E (SEE CCRE APP. P) APP.P) APP. P) CORg .

Y 8LE

.Q YULNERABLE AND CCRE CORE VUL.*;EMABLE

1. • ;3 it CCRE y.M ERABLE CORE MILT VUL1ERAELE 'IC3C?>3LE e CCRE F.LT -

CCR ."ELT CCR ELT W .

[

l .., PUBLISHED SWR PRI e ".< .1 ~

Ficure- 2 Cc.mcarisen of Frecuency of Core Vulneracle/ Core j , Melt fre.m Published *::,WR PRAs.

#[

, , , . . . . , . . .,._,--.-e,h-w.,_ .,. ,._.,,e-,_,. .,m%-.,r,-,--e,-,,_.,-,.,,. , , , _ . . , , , ., . .,y.%y.o,, y,

P "O

9 .

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?.adial Disp 1 (

II

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t i l

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r 4

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~

i 577.AL shDR RI.1r.

RGC" 2 e

- SUPPORT CONCRCE ' g *' d4

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dk N ccaC:nx  ; ,

W.AWA Figure i Reactor Fedestal Schematic Shewing Reactor Ocwndemer

• Gecretty O

e 5

e. e a

(

ATTACHMENT 1 Definitions Used in the Shoreham PRA Accident Sequence Classification O

P e

9 9

0 4

-. - . ...g

3 e

e-

w. o

.3 ... .

3 .

. -. .... t.-

. o.

.1 .

. .o

.7

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2E 3 .3 t 32 3 . --

3

. .3 .

.- W.. .3 .7 . . .s

. 7 x ....

• > K. k.. < .

e_

S*

.I. . .-

g . _.

.w 3 . .

1. . 4 w

t-* ...

t 3. .,! ..

3 Es .2 . .

2. 2 - .5

m. w =

3... F-

. 3 s.

w w .3?-- -

1

. t.

w. - .

f.1. . ... .. .t .. ..

m.

m

s. .

.. ., 3 3

.. ....I.

3.

t.

... . Y,.

. . .1,4 _-

,_.3 w

z. .-.

r -

3 ...8 .

.x- *=. ,8.

3.

c ..

.- 8.

.. ,,. me.--

3 . . .

.a g

,,. ..t.. ..

i w m.m -

5 o - -.

.E..

I.-

3.

4..

ee

. m m z

.. 1 5.1

.. 4 T.-.-

. s

-a4 M,...

....t 2.

.. 3 R. -

33,

= r -3. .-- -- -- - ..

e <

' & U -

w

• m,. _5 ".1 >

A3  :=

I ...

.1 m .......

..... .. s g

W

==

..=

. -2 b

.45..- * ..

.M

$e .

W

. -. . . W .T .s

• W e

. . m...e.

Q E . = . .. .

~3.

=--..

-2.3 -

1s.

y --

c. .g .. .

- - .m. .* a.. . ..J . .d..

4, ..

I *.* I 4 . .... g w

h W

e-

- .. T.

. .E a. s. .

....3.e .

..W..

, .=.

- T- e .

.3 .- .

w-.

.W W Q@

- 4,

e. .

.g... .

p g

h a

3 & .-.. ]..h.

w gm. . -&-X-- W

.- ., M & g_g g d .d a

.b*

h5 9

. a .** . .5 1 *

• P#

.

• 1.* ..

h

s. J N.

h .,. .t 4o h .-..

.m t . . h.. .* s h. h.-

~ - -

.m.,. ...g w -,.3- 4. ,L m .

b... --..

W 4.. .

m M. - M. ..b .W-

--J

$ 6 9. . - .W . .

U . . m, g -

s

b. .h . .

. . h J

a--a e-=.I a.l. - - s ] .m a1 . 4 . a.

m . 6

-w M N W # M

- Q w M O g$4 u w w M s 355

.u-

=

~

a gg* . . . . .

3 i. ,

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. 6

.s. .

e,... . ..- . ~ . ,

[.s

l l

l

. Table 3.5-9 l

SUMMARY

OF CET CATEGORIZATION DESIGNATOR DESCRIPTION ATTRIBUTE GENERIC ACCIDENT SEQUENCE CLASS Cy Class I Pool scrubbing prior to transport in contain-ment ,

C 2

Class II Pool scru bing prior to transport in contain-ment C

3 Class III Pool scrubbing is by-passed prior to transport in contain-ment

~

C 4

Clas.s IV Pool scrubbing prior to transport in centain-

. ment ,

C 5

Class V Pool scrubbing and containment are bypassed RELEASE TYPES Rg Gap Release Recovered accident after initial core overnest R2'R3 Gao and Melt plus Recovered accident after oxidation release significant core .gelting R4,RS Gao, melt, and Unrecovered meltecwn vaporization accident -

release plus .

oxidation release l

, 3 217

[- , ., n . ,

Table 3.6-9

SUMMARY

OF CET CATEGORIZATION DESIGNATOR- DESCRIPTION ATTRIBUTE GENERIC ACCIDENT SEQUENCE CLASS C

1' Class I ' Pool scrubbing prior.to transport in contain-ment ,

C 2 Class II Pool scrub 5f'ng prior to transport in contain-ment C

3 Class III Pool scrubbing is by-passed prior to transport in contain-ment C4 Clas.s IV Pool scrubbing prior to transport in ccntain-

-ment C

S Class y Pool scrubbing and containment are bypassed RELEASE TYPES R

t . Gap Release Recovered accident after initial core overheat R2'N3 Ga and Melt plus Recovered ac:ident after oxidation release significant core melting Rg,R5 ' ' * * ' '" "#'" "'I' ' #*"

vaoori:ation accident release plus

• oxidation release 0

3 417

,m

V: ,

.s.

Table 3.6-9 (Continued)

SUMMARY

OF CET CATEGORIZATION ,

DESIGNATOR DESCRIPTION ATTRIBUTE GUNIAINMLNi FAILURE TIME Ty Time phase T Containment is failed t

before core degradation T

2 Time phase T Containment fails during 2

core neltdown in vessel T.3 Time abase T 3 Containment fails during cofe-concrete interaction T4 Time phase T 4 Containment fails in the long term CONTAINMENT FAILURE MODE .

-BP, CI Containment Sypass Containment isolation -

or Isolation Failure fails or containment is bypassed 6 Leakage in the Ory- Leakage sufficient te well preclude overpressure failure 8 Leakage in the Wet- Leakage sufficient to well preclude overpressure failure

,. OP Overpressuri:ation Containment over-Failure pressure failure, small or large break 7 Gross Containment Drywell .

Failure Location 7' Gross Containment Wetwell airspace Failure Location 7" Gross Containment Wetwell'below the Failure locatien waterline 3 418 u .. - .. ,. . . . . - -

.- . u . - - . . .

Table 3.6-1 TYPES OF POTENTIAL RELEASE FROM FUEL-

- lG1 No' release .

Rg - Core heatup (gap)

R 2- ' Core heatup and melt release (gap' and melt)

R, . Core heatup and melt release with potential for oxidation release (gap,. melt and oxidation)

R 4

Core heatup and melt release, and vaporization release (gap, melt and vaporization) c, R

S Core heatup and melt release, oxidation r lease, and vaporization release (gap, melt, oxidation and vaporization)

Table 3.5-2 DISCRETE TIME PERIGOS DEFINED TO MODEL THE VARYING E.rtCTS OF CHANGES IN CONTAINMENT FAILURE TIMING T

1 From the time of acci dent initiation to initiation of core overheating JT 2 From the ' time of initiation of core overheating until the time of pressure vessel failure T From the time of Sessel failure until soon after vessel failure 3 -

or when core-concrete interaction occurs T

4 Long after vessel failure or vaporization release has occurred -- ;

o 6 .

- m _ pw M= 9  % , *

k. l i

. l

\

ATTACHMENT 2 Conditional Probabilities for all Release Categories D

9 0

sep 4

O 4

e h_ p ow- * -m.s s - = w

4 9-

e. .

u.

m.

1 o

7 ge,g,, ,.,, ,,,, ,, , ,

a .

_: H . y * - * .. . .

wwww .

.,I; g

w u. . .sw usum A gg e' "

44 4

• 444 4444 w w w. .w . .g d

- a'a4 a

-g1j g

- e yy ev =3IJ=

as= a. *c '

xx*' - -

g2 44 *

• ca:cs t ' ' '

n. a a

. E s

&s ..T7 uu

. ea .

N = 8.D SD 8. 9. es f.t p.

.' 8 8 se s.

g

• • g N$$$

44da dNN$

4444 f $ $'D id $

8 44 e4 4 w .

) .:

w 77?? ? ? ? "'t

?7 i 3  ??

W . .W E. W.' '. M. M. N. 3 M. M.

w e un e. n e. e es = = = .i.M.en 3 m I I -

4 w

a w . ... .

E 3 4

i. ,

X. X. -

' M. M.

W

>= lr

< ,, m. n. =. e e. e. o. e. w =. =. =.

. . =. we e.

we t =.=s . ....

> *=

3 XXXX XWXX XXXX MMWM MM M3 m 44

• 4 4444 444

• 44a4 I

4a (4 a b ,

5 N

c I

~~ ~ . . ee e-~~ .e i. . . .

N. N. N. b. k. N. k. b. N. k. $. k. h. N. h. ek. $. h. k. N.

.. n ee =en . e,

.- e C, E

( .

2* = ..

-

• m. . . l'. .. .

3 47 =

vs a-N.

3 I5

.K l

g*

4 .M r <

• I J

u E5 JJ lX44X i

8 w  :

m E w 44 .

5N

> 4a I

^aa

. E. .. ..

= - -

< a 8! 8 i .m . .u 8

cc G=

m. e. e. e. e. a. wo e.

.a

< ** I a

2*WW WWX* MN gXX g 4444 4444 44 4 44 m

~

i  ??**  ???* **

??

G E * **NW **** *

• um S

v 4 444a 4444 4A 4a W

3_ _".

3 2 W N ar.

w -  : : ,.,  : ..

.  :  : 2.. !

=-,::: T._

w a s e a a a u a a is a

.. . .. i. . o ,

w a m z a m z a I m w a ma m u - w n =

. O W. W.

2 '

3 5 ,

a1 . .3

- H.63

3.-

"**WW

• • ** ? ** ? '" ? 17  ? ? ?! = .pi If3*g*+*

20 -

3*** '3 3 3 g!s s s s {IT t 8 * ~""~ 55.__3 i ~ a e d;' ~ -

i ~ ~ ' r-1, =. g_s 1 I

_1I_:

2 25 2

_I l,l . -_

• 2 _2; i s_ i. . 22:t.t i

. l -i .

t i.

. :5 a

I m.

w -

l g' g ~5 - ,

l .

-u  ! l W =

--w.

- s . .

. <v i  :

I  ;

.w

• I

<w d .

w l .

as .

m 5 l ,.

3 2 .

w i= .

. l m -

3 I  ;

w e

< -..i ... _.

! l E

=

l l

[

w a[

e - 1 I e

<- a N

C. . ,

'. 3 .

n - ,

.= m ... .._. ..i.

4 m  ;

>- 4 .

a w - 3 .

t h

w e I [

m 5 ,

+  ;

- l .

a

- t 3 i e ,.

.a

< i t g - -I 1 I

j v

I l-e J. '

5

! I l

i

.I l

i i

i

.l ss ,

}

I i i i 6.

l

.= ,.

ts -

: ! .: i .: Il . : ! . : I. : ! .: .: I .

lE !!!

iETv

• ";iti-iii;itiisec v;;av'iihi bb' l .i e Il e i

-s I a: .

l l' al I

3. 3- .

.  !!* N

~

e l i

TTTT TTTT TTT*T???

3 -

g **** ==M=

sm**immus:

4asiwas4j 55

-_y

-! I.

~ ~_ _ .. . . g g s g5=,

I  ?? =? 35j:==

wa -

w. =.

s a=I 44 *4 ',~7, 1

p ~ ~. . . ~.

3 , za d4 44 xz l

0 t i e M ~~~~ ~~ .  : 9 ~~

E .

3 ssss ssss i zu ss g a44a s4;e

- - l2 8 m .. ,

3 3

??

• • MM

? ~v??

I l -ss- : is=s~

w- -~~- . . - ~ _ .

a s ,s s W

w a

w . .. ..

= 3 ww ww u 1  %. au se t ---- -r, -,-- ,- , ,, ,  !- -

M 3 X*** W33W WX3* *3*4

• 33 Iw 3 44 44 84 4

, y 4444.4444{*444 .

_ _ _ . . _ . t

????  ??*? i I

???  ????  ? g?-

C E E333 W33* **** *E** *s

_e -

i 44a 44s4 4444 dia6 an lM as3 0N t

g .

3

??

mx 'u m It 'e of i n4 l4 4 .

.m - . - - . . . .

4 W l l

>= M 4 ** f * **

d - I W3 f3*

" 44 !d 4 l [

5

??  ??

lJ*Wd l3s4X M 3 q

d

~

we **e

- s I

N N ls;as ea

?  ????  ???? I YY l**

~

g x nsxn unt5 l M5

-- . ~ -

IM

• s s 4 .: 4  ;;se t D  ?  ????  ????  ?.?  !

.s... . . . mszz xmms zw *z 3

gl a? s ?

8-v 4 44a4 laaJ4 4a

" l W

u I

E  : i l 3 c , i W 3 . . . . l' .{ . s . . . .

t .

. !! ; = . . . . .

w f l-Gf77;;'7;2;;*;;;'T;*7-fCCC II ; ; ' h' *= : *

. ; t i

b6 10 p

• 2 -

I 8 sl a i _I

.. H-6$

- - + , . . n . -,

e

.. .) .

I

. , s .,

af. .= , . . ,,e, - ,ji -

33 . .  ;

_ ,= _1

~ : t t1 al . .

g g, ~  : ==

su .m... 23:ja

4 ,.

u u .u n

.g .

l  ; se se w I

~ 99,~ ever - 99 99

.r 5 umme sxwn sea; i as

-d

was=

4Aae  !. l w

6 -

??vi et T e .- u w I swww wwwm l s s ;i-,s-3 w

.... .--. g g4 ,g s a ,

lit te it ?

a E

. sw mu w

l *.. e4 44

< i G .  ????  ???? l  ??  ??

E zwxx zuzz o ww su saad aAas i s as aa a 5 444~ even  ; 44 44 zwxx zuzz xn ,x

=. "

4444 4444 i 5

- i-.

w

_:- r N "

• g NE 3R

- 44 44

.J3 m _

AN s e I~ ~ -

d g ==

. [.xx .

8 w ,

m .. ..

d I .k k. , lk. .k.

~

?? '? T l

. 55 N5 5 44 4d

. j'

,, " ** ? ?  ???? ?7  ??

I 5

, , , **** 5*** WW XX

=

~ 4444 dass 44 aa

?  ??TT TTTT  ??  ??

I.

• 3 2 . . .

a

. . . . ***u 4444 uzum 4444 ww di zz aJ I

$l '

i l El E sE a g l '

l [ g ,

3I l t .  ;

4.N *  : . .: . . *.  ;. . .

!'Il1-hih!?hhkIhIIIIIiffkII T h i'i 6 'i h-i b .

.i l

- 3 .

' - 1g ,

e_g e 13 3

~

=

t.

-s ,- , , a e.

i 3 **~

.  ????  ??T?

I*

i; =x a444 awz=m g 4aa4 SE I s' .

SS 8~

os s 1 i l

I e 3 I w i I m # 3

>=

6 s .

w El m e 4

W .

w 3 a t .

1 .

1. 31 l m t  !

mm

~* aC +

8 .4 w w E dg as . w

.a

?

• 'V

.3 3I

' q e w ,

>== .= , -

> 8 l

=.

" pl 3l-1 L

a x I, c.

g  ? *l*

I? ?

3 lM N EE

.: a 4a .

E. , ~~~, r-

>=

~ ** I &

K

,7 WMWM *53N m --

is 3 x3

-s

==

44aa aaaa ta a aa 32 W

. ~~.m - - i~ * =

lI gs X $$S$*E$$

ause'adea. I  !$ 5 l u$5 l' *

'a a saai.fti2l ll 8  !

• 2 g ;= .. . , -

. . f 1L g y i

- C-1 . ...  !:  : :

. . . . . ~ *~ .

i sykkk:~ bib,  ; ;

4 2 2 C ' .t = = l 2 4  : : : : '; .: ;': : : ji: 'ig?i 1~

• 2C .

6 g-n I

im G

!!-73 9

L 3- , ,y m e- -,. .

-7_

2-I' l 1 - .

• ?  ?  ?  ?'  ? - = . I Ig g!"

, .e l

.i

• * ' z'

.l ' a-

• x !. 4.'=

i*s 4:. 4 s

4i 3g3.

. M. . _r .

.m rj = r 1

11 1 8 3 ". -

agg '_ ,s ' ' ' ;; *

• 5' i sia3 5

- i .: :

4 .

l

.3  ? *?!

• m l

• W 5 W 4 -

4

• il 6

8

.? E  ?  ?  ? i  ?

g_ ' l' ' s? **

• u

?

.c l 4 4 4 4

, 's w -

g 4 ! 4 g . -

w I

• e I

i  ?  ?  !.g.3  ?  ? - I

?

6 a l3 t

33 4 4 4 4

.I' i

..y

.w -l 4 E

.m e g

W .

• S lg 's 5

> .a 5

l 4 e -

4

1. l 3 w .  ?  ?  ?  ?  ? * *

• g? !*3 k?

3 *3e x a y*3 *

?

4 4 4 4

• 3*3 4 g'3 .}

4. 4 4

• 4 1 4

• .- .. . . I e  ?  ?  ?  ?

=

• 3

?  ? *

?  ?

R .* .* 3.* .* .* . W.*4  ?

4 4 4 4 4 4 4 . *W ,'4 , s

= .a

. s 1

a

• si a

I 3

i'

== =-

4 g .

3 , g,

& - ,M m 4 g 4

'M .. .

-c _

~

n  ?

g .

• w t ' .s? .

w e I w 3  ? '

?

• W l'N d i d w

.=

m

?  ?

a C

3 'W 4 '

4

. ~ ~

=- y . .

' r. e g m

• n.

• x.

b n s. ' N.

~ ~ l e

l. = . =

9 .

g 3 , x x i . i y

.s m 4 a  ; - 4  ;

j=

, 4

=

4 i

i ee

• l l  !

= I i l r

.* l' l E E l  !

i ,

2 ' l [ .

t

. i 11 j 4;

,- S i ta 5 S t.: E

.  : .  : i it .  : I

':i t i : .: :: !:! 1 : !!::1 :  :

::=  !!: ! i: c-  !.

I

l. e 8

n , l

I

^

6 g* ,e '

l af Ja8

,. H-?7

, - e, 4 : ., .

', - 3 ,,,- I ~ * .

• e*

as T.

xx

?

u

?

= l, T

= '

Ti e; =

? , ? l x'; k 'I

!s t

• a e e a. e a-It 4

a! ,

l a; i l

3 .j*:.,I q:r.

gr _

n- II M- 'M- v u

" 3.58:

a

- *

• a -

ata:g:

. -3l l . . .

e, l = *

.E ,- . g .f -

( . 4 a m ,

N' . T T T 7 7

. In m. w.

a w x.

- 8 .i

= = -

=  !. ..

w I. _g_

b 7 7 7 i I

?  ?

w a

a '

m'* 'w = i -

m:=

i w

=J w

g 6

e. . e.

3 l*W m E I ',

. a I, a w ^

> a ,

.a n

?  ?

= -

?

='w

?

?

s's4

?  ?

wx T

1 t -

?

= l.?m y 4 .; 4 4 4 4 4 e d

>~ - . L 5-

?  ?  ?  ?  ?  ?  ?  ?

8

? T l

C I '3 x 's's 's's 'w's .

3 *

• g 7 ,* 4 4 3 4 4 4 4 . 4 l

J w R

-e . .

~

N* 3 N

.a ==

.i ' .S g J' -. j. .

>=

p .. .

< ~

n .

it.N d '

=~".

g I -

w  ?

e E

• s w

==

4 .l'J 9

==

a  ?

" . s e n l' e s?

E A

@ .== . . . -

d I .,,

8 E .

f b m e e e  ? * .

m

• W !*$

f

] $

a 'N'il'$'$

4 4 's 4 l n

t 4

• • • l s

> *

• e e  ? we

• 7 '

M ! ' .54 G

8.

I w

- '$'S'3 e e s 4 -

l W . .

=

l

' :l l j .i

= t #l l

6 e a ,

lo 0

• l l

a

=I E

b!

l ,l - '

4 s -l ll . : .f . :

5 .:! . : . .

+

f

• E ~' s ' *

• i b i bis k h k !: t h h C h b b t b b*h b 'b b b & bb' l

< . ,! . .f

g. 4, -

35 .f. I i '5* $3 Ls . -

l 4.

- 4 \

1

.I

• 3- i

• i '- .

fj g*

5: 'i 9 1 gI a

i

=

w

~

a.u a:' n . x4 s ~ 5 ,.

g: . .'.--= r .

s.h o

-t

• 4 3 ! '

ha,,,IN sui lu sg

.E, a

i aga3p5 i-i.: : ..

,. rg .  ?

.g m ' A w

.=

I g ,

l'. **?  ? = a

.? 3 **'s *

'si 3

w , g " , s

"

• 4 *

(

W

. ..a.

i e

. M 3

I

-'*?l

• 4

?

'W'3 4

?

s l .

• .s4

=

g .

A w

as '

u . ' .

we t., . g j. g g 4 8 4

>= 8

• -

• 1

~  ? i  ?  ?

3 't'n 'u's '

u bl 4 4 a 4 ,

l'*x .

. .j - . ,l .

2  ?  ?  ?  ? l * .

N. >- I 'W'* ***I *

$ ?'s

,. g

• a

= c 2 ~~

• g *

.i .

a i c's m - a m

al . . .

m i .

4 '  ?  ?

d " I '

N {*I.

s w

m w I '

..l w

~

g .

e em emmI

?

• g

. W 3.3 .

3 . I a m .. .

g ,s

• S '. i '$'i 4 e 3'! l *

, 4 J, 4 4, *

• g- . *

.l

. - - e

• y 3 2 '$

4

'i *S 4 4

• $'$4 4 9l'

- e l

N-E  !- '

I f

7 2 W l  ! .

$ly . : .

! 7 k i h l,2 h h Y . 7 h k k !! I I i f h if if 't b b'b b i. *i . :b'S k Dh'

~

E -

,, e le '

..: I *  !

i !I li I#I I

u. . 3 0

. ..I-I- . .

a. l

.t 4 l '. .

r- g .-

'M T

t

• W*M t y.  ;

M ' . ::

.s,s 1.r I s3 l' s .: s II g:s - . .j  ;!

I

r,

- r.ja

- tr

- 3

.1 1=-

i 85;n. f, asa3:5 sl ,  :

8

• 6

.t g m I' w i

- 1 .

g w 1

• ,I ,

>- [ 2 _ . .

4, .

w fg m *  !

es:

• w l J e W -

E i I +. I w . .

- I 4 .

P-

• t*

. i. .L..

N N >= 13

. m .

b d * ,

e$ O'M 5 .

g

>= ' J. .

m y E ,

I w

s -

M w I N

ao an.d  ?

g 80 .

I '

-

• 4*

eme.

.en Y T d -

w

=

l .

3 eu. - lI ,

b

= .

M 3 e a

y i 4 u

I  ;

=

=

• I 2 f,  !

= a i i ,

i r

=

c.

E

.: .: I

.: l .: .: l ' . : l. : :. : ;. : .  :

.I II s - h

• h t I h h ;; b b b ei IIICbbb M h I h.h 'h b'h k  :

'bb It g

4 og

Eg

!! .I H-100 '

s ' I i

4 -

• e W

?  ? ? ? ? ft ? ? ? ,

mz.s=

E *! x a!

J diaa14444 ll we l

. ~ -

Is

=

h=5 ,

m I w

. = = g I

w # B w

W . g w I ,

r., e l v, . g w .

• d w W 3 m. g E %l 3 3

US 3 d

e g-N w- l 4" a 1

~ .

= s I

~

.a w m l 6 .,. I  :

4 ==

>= >=

• a # $ * .

= s J

1 . t

.? ? '

..-l s

5 xx ~~

• • I

.a -

- , ==== we== =  ?? .

jI 3 s a 44.4.4 .. .4.44.4

. t 43 ,55

. ss

. . ,t ? ? ?  ?. ??? l 6

19 ? ,*

g s ssus ass l l wus = a s ssaa s4.; .

Is ==  ;;

{ 3 i .

2 u l l

. } -

y .: . : . : .: .  : .: .  : .: .  : .--I.a

i 1 - i ' i,r i k i;; i i t i; i ; i tc h i k s ' ~ "i h 'h i9 i . :ih h 28[

1. eM

-3 y II !n

, 1t=107

'.a-

1 -- . .1

. 4

, {

. o e'

~

4

~

I" 34 s a

- =Q

4  : e gg . .

. .. -=

Is -

E-

.a .

s .

E M

• I w

= .

E '.

c w

3 '..

ta=

u

• w 3 a

W z.

" - 3 w

cm e 3 w e N <

s .a

e. v A

= g i n

o w 1 -

a m "

• . g 4 w

> =

>=

= .

=

m 3

- ar.

3 C.

4 5'

~

~ 3  ?"

~

=-

I

. 1. .1 x

. E a -:

3 v 1:=

1 1

s i 1'E 5

= 11 w

• In-

• 4 3 . . . .

. L--E E ,- 3. 5i I *- .!!

22:(

.! , 3.1 i gLkAi-

- kkii SI EEE

.!i  :::: -- - - -

N In I H-111 b

9 e 4 - - _ _ . - . . - . . _ , - . _ , . , _ , . . . . _ . .. .. - , _ _ _ _ , , _ . _ _ , . - .-_._,..._,-,1... Ji .i , ~ 'm

ENCLOSURE 2 REOUEST FOR INFORMATION

l. .

Table II of Appendix M gives dif ferent pressure limits for the longitudinal reinforcement bars at the base of the containment and in the wetwell region. However, the longitudinal bars appear to be continuous and should therefore have the same stress. Please explain the basis for the different results. -

2. Table II of Appendix' M indicates that the shear bars at the base and

, drywell head have the lowest pressure holding capability (121 psi and 120 -

psi, respectively) but the discussion indicates that the additional reinforcement will preclude this failure mode. Since the containment failure mode is a key ingredient of the release estimates 7 please provide a quantitiative estimate of the additional shear strength provided by the non shear reinforcement bars. -.

i t

1

'~ "'

? _-_ T t_l_~_

6 - ,

3

'3. If' shear failure is precluded'as discussed in Section 3.2 of Appendix M,

'"it appears that the ultimate capacity is controlled by the yield of the longitudinal and the hoop bars at'about 123 psi." These two failure modes-appear to be very important to subsequent fission product release (particularly for Class IV ATWS) since they will both occur in the wetwell region. Please provide an estimate of the size, location and direction (vertical or horizontal) containment failures for each of the three possible failure modes.

..4- Section'3.6 of the PRA takes credit for containment leakage which will prevent gross containm'ent failure for all pressurization rates except the very rapid pressurization associated with large breaks. However, the structural analysis by Stone and Webster (Appendix M).did not identify any significant source of leakage. The basis for the expected leakage source and the leakage rate as a function of pressure should be provided.

5. The basis for the partitioning between release category 10 and 11 (no pool bypass vs. partial pool bypass) should be provided. The phenomenological basis for the estimate of only 10% bypass should be provided. Preliminary results from IDCOR indicate that for some BWR sequences the vessel will fail with only 20% of the core molten. Presumably 80% of the melt release would bypass the SRV's and be released into the drywell.

2

7 y

(

ou

-o. .

'6 . LThe basis for binning into release categories is poorly' described and the transfer:from Tables H.4-8 etc. into the 16 release categories is difficult'to interpret. A-table listing the specific sequences which are binned into each category should be provided.

7.- lThe lack of R5 sequences in the release categories makes it apparent that these releases have been binned " downward" into the lesser. release ,

1 category R4 . The basis for this " downward" binning and any other sequences that are moved to less severe categories should be provided.

5, Table H.4-25 appears to be incomplete in that it does not include sequences 06 and 08. The completed table should be provided.

9. The source escape fractions used for end state screening'(Table 3.6-10) appears to be quite arbitrary yet it greatly influences the importance ranking. In particular: the use of I as the surrogate for melt release ignores the fact that there are noble gases.in the melt release which will not be scrubbed at all; the use of a large scrubbing factor (500) for C 4 transients is inappropriate since most of the melt release will be released directly to a failed containment; the reduction factor of 0.01-for y" failures is indefensible since the event tree precludes everything but large ruptures where the pool will be blown out into the reactor building at high pressures.

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o Table 3.6-10 should be replaced by a table with defensible reduction factors. As a minimum the table should include'a separate category for C4 transients, which recognizes the defined sequence of events (containment-failure before core melt). In addition, a detailed justification for each reduction factor should be provided along with the numerical results of the ranking process. This revised table will provide the basis for our independent importance ranking based on revised estimates of accident-frequency and reduction factors.

10. Sheet 1 of Figure H.4.2 has been reduced so that it is illegible. A full-size legible copy ~should be provided.

11. Appendix L provides a detailed discussion of the disposition of the corium (90% is expected to go down the vent pipes) based on the revised reactor pedestal geometry illustrated in Figure L.3-2. However, this figure is inconsistent with other descriptions of the geometry (e.g., Figure 2.3-2) and provides inadequate information for an independent assessment of the corium disposition. Please provide detailed (as built) drawings of the vent pipes and their covers within and external to the reactor pedestal region. Include a description of whether the air ducts and manways in the reactor support wall will be blocked during operation.

12. Provide the estimate of the fraction of the molten corium which is expected to spread out of the pedestal area through the open manways and air ducts in the reactor support wall.

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