ML20247J052

Vol Ii,Book 1 to Limerick Generating Station,Unit 2 Independent Design & Const Assessment, Hazards Program Evaluation Suppl

ML20247J052
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Site:	Limerick
Issue date:	05/31/1989
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O LIMERICK GENERATING STATION - UNIT 2 INDEPENDENT DESIGN AND CClNSTRUCTIC'N ASSESSMENT j O

DESIGN ASSESSMENT HAZARDS PROGRAM EVALUATION SUPPLEMENT l

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STONE & WEBSTER ENGINEERING CORPORATION LIMERICK UNIT 2 - J.O.NO. 18138.00 b DESIGN ASSESSMENT

' ' s# ' HAZARDS PROGRAM EVALUATION SUPPLEMENT EXECUTIVE

SUMMARY

CONCLUSIONS The results of the ' evaluation of the Limerick 2 High Energy Line Break (HELB) and' Seismic II/I programs . provide reasonable basis for Stone &

Webster Engineering Corporation (SWEC) to conclude thats e The design of safety-related systems and structures for Limerick 2 is adequate to mitigate the consequences of a HELB and to prevent adverse impact from Seismic II installations and still achieve safe shutdown.

• The process for evaluating and addressing the potential impact of HELB and Seismic II/I is an acceptable process.

These conclusions are based on SWEC review of selected samples from com-pleted portions of the Project's Hazards Evaluation Program. Since the Project had not completed the entire Hazards Evaluation Program at the time of thir review, these conclusions. are contingent upon Project com-pletion of remaining work in accordance with the observed hazards evalua-tion process.

/~'h SCOPE AND RESULTS V The Hazard Program Evaluation supplement completed the review of the

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Limerick 2 Hazards Program and assessed a sample of six HELBs with re-spect to _ target identification for jet impingement and pipe whip, target evaluation, Lad adequacy of safety evaluation documentation, including flooding. The adequacy of associated Pipe Rupture Analysis and Restraint and support structure calculations was also assessed. In addition, an assessment of internally generated missiles and Seismic II/I impact was performed by reviewing the Pro' ject walkdown documentation and verifying it in the field by conducting a confirmatory walkdown. In completing the assessment, SWEC issued five Observation Reports to identify Hazards Pro-gram concerns. In general, the concerns related to numerical errors in reviewed calculations, undocumented engineering judgments, and trace-ability of supporting documents.

The Limerick 2 Project addressed each concern in formal responses to SWEC. These responses included a review for causal factors and extent of condition, evaluation of significance, and proposed corrective and pre-ventive action where appropriate. Actions taken or planned by the Pro-ject were evaluated as acceptable to resolve these concerns. The concerns identified during the IDA Hazards review were evaluated by the Project as having no ef fect on the ability of plant equipment or struc-tures to perform their intended safety functions, and no changes to plant '

hardware resulted from the review. A summary of actions taken or planned by the Project to resolve concerns as documented in this report is shown below:

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PSAR changes 1 Calculation revisions 5 15356-1813803-HC2/B6 1

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-INDEPENDENT DESIGN ASSESSMENT s .y s HAZARDS PROGRAM EVALUATION SUPPLEMENT e

TABLE OF CONTENTS ~

l Sl etion Title

1. INTRODUCTION b.g. _ 2. iL3ULTS AND CONCLUSIONS

3. HAZARDS PROGRAM EVALUATION DETAILS

4. OBSERVATION REPORTS APPENDIX A - HAZARDS PROGRAM EVALUATION SUPPLEMENT DESIGN OBSERVATION REPORT ACTION

SUMMARY

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3 INTRODUCTION

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1.1 Stone 'E Webster Engineering Corporation (SWSC), under contract to Philadelphia Electric Company (PECo), performed an Independent De-sign and Construction Assessment (IDCA) of the Limerick Generating Station - Unit 2 (Limerick 2). It was performed to evaluate the adequacy of the design and construction process. The results of the

, Design Assessment, with the exception of those elements of the Haz-ards program not yet completed as discussed below, are documented in the Design Assessment Report, IDCA Volume II, which was issued by SWEC in April 1989. The evaluation of postulated hazards by the Limerick 2 Project was not fully complete at the time of issue of (m the Design Assessment Report, and therefore review of that program l

could not be completed. This Supplement documents the results and

. conclusions for the SWEC review of that portion of the Hazards Pro-gram which was not completed and documented in the Design Assessment Report. This supplemental review was completed in accordance with the same Program Plan, protocol, and team members as the original assessment.

1.2 The term " Hazards Program" collectively includes those Limerick 2 i

! Project programs which address mitigation of potential hazards, such as high energy line break (HELB), moderate energy pipe break (MEPB),

heavy loads, internally generated missiles, fire (Appendix R), and evaluation of nonsafety-related installation impacts on safety-l FN related installations (Seismic II/I). .

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( ,/ 1.3 The Design Assessment Report (IDCA Volume II) included SWEC's review of the MEPB evaluation, heavy loads analysis, and Appendix R fire protection evaluation based on the selected " vertical slice." The review of the Project's evaluations of HELB, internally generated missiles, and Seismic II/I could be only partially completed at that time. The HELB assessment included review of FSAR commitments and deeign criteria associated with these evaluations, compartment tem-parature and pressurization ef fects, separation criteria, and calcu-lations for pipe rupture analysis and design. Pending Project issuance of Limerick 2 calculations, SWEC performed its initial re-view of the Limerick 2 program based on completed Limerick 1 calcu-lations. The basis for identification and classification of

,_s potential missiles and the criteria for evaluation of their effects I

\- on plant shutdown were evaluated and addressed in the report. Since Prcject system walkdowns and final safety evaluations of HELB ef-facts had not been completed, review of these portions of the Pro-ject's evaluation was deferred. Final walkdowns for Seismic II/I s

also were not completed and, therefore, were not reviewed by SWEC and not reported in IDCA Volume II.

1.4 Since all Limerick 2 hazards evaluations and walkdowns by the Pro-ject are now completed for the sample selected by SWEC, the results of SWEC's review of the remaining portions of the Hazards Program are documented in this Hazards program evaluation supplemental report.

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_ -1.5 To c6mplete this supplemental assessment, a consolidated review plan was prepared.- The review included verification of . previously reviewed Limerick 1 pipe rupture calculations for applicability'to Limerick 2, verification of HELB locations against applicable. pipe stress calculations and FSAR tables and figures, review of addition-al,' calculations for the sample selected, review of the . jet impingement / pipe whip / internal missiles evaluations and finsi safety evaluations completed by the Project. It also included review of the Project's final Seismic II/I .walkdown results, safety evalua-tions, and conclusions. The Separation Report (BLP-38054) prepared a

by the Project in July 1986 also was reviewed, since the Project indicated that it was bounding for Limer4ck 2 for all system /

g equipment except field-routed items.

1.6 The hazards review also included a walkdown by SWEC for the sample breaks or areas selected to further validate the effectiveness of the Project's evaluation process.-

1.7 As a final activity, SWEC reviewed the final Project HELB Report NPB-131 and selected references to ensure agreement with the documentation reviewed by SWEC and to provide assurance that the evaluation methods used by the Project for the breaks selected by f

SWEC were consistently applied for other break locations.

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_ 2.0 RESULTS AND CONCLUSIONS

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md 2.1 Based on the assessment of the Limerick 2 Hazards Program as de-scribed in this supplemental report, SWEC has a reasonable basis to conclude that the effects of postulated hazards have been properly accounted for in the engineering and design of safety-related Limerick 2 systems and~ structures. The design work reviewed for the samples selected satisfied Project licensing commitments and was determined to be technically adequate. SWEC further concludes that the design process employed by the Project to complete the Hazards Program evaluation is an acceptable process. These conclusions are based upon review of completed work for SWEC-selected high energy line breaks and selected areas subject to Seismic II/I evaluation.

fs Based on this assessment of completed work and contingent upon the

('-') Project's completion of the balance of the Hazards Program evalua-tion in accordance with the observed design process, SWEC has a rea-sonable basis to conclude that the Limerick 2 Hazards Program evaluation is technically adequate, and that safety-related systems and structures are adequately designed to account for the effects of postulated hazards. These conclusions also are based on additional reviews by the Project which extended beyond the specific documents chosen for review by SWEC.

These additional reviews were conducted to bound the extent of con-cerne identified during the IDA review and provide confidence that affected designs outside the sample reviewed were technically ade-fx quate. These additional Project reviews are documented in Project

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responses to Observation Reports. A summary.of.the Project action V

, , taken in -. response to each Observation Report is identified in Appendix A.'

2.2 Deficiencies' identified ~during this review were, in general, minor r m or had no effect on' design adequacy. . In those instances where de-sign documentation was revised, analysis by the - Project indicated that had the revisions not been accomplished, the installed plant hardware would still have performed its intended safety function.

2.3 During the IDA Nzards supplemental ' review, . ona inconsistency was 'l identified between the ' FSAR and other engineering documents for which-the Project. issued a licensing document change' notice'(LDCN)

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to correct the.FSAR.- This inconsistency is discussed'in the de-

-tailed section of-this report. The observed FSAR inconsistency was evaluated as having no significant effect on the acceptability of the final plant design. The SWEC conclusion regarding consistency s

of the hazards evaluation with licensing commitments is based on the SWEC assumption that the NRC will accept this proposed FSAR change.

2.4 ' This supplemental . hazards review was conducted- by SWEC Engineering Department persannel experienced in the engineering and design pro- .

cess. The personnel who conducted the assessment are identified in Table 2A of the IDA Design Assessment Report, Volume II, Book 1, issued in April 1989. These personnel included engineering special-ists in key areas such as pipe rupture and jet impingement. These individuals were added to the IDA team as required to complete

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f'N reviews of these aspects of the design. Prior to conducting the as-l 1 sessment,.a detailed review plan and checklists were developed for >

each review area. This Review Plan was based on regulatory require-ments, accepted industry practices, Limerick 2 FSAR, and appropriate Limerick 2 specifications and procedures. The Re4riew Plan identi-fied both specific review attributes and a preselected semple of high energy line breaks and areas af fected by Seismic II/I consider-

'ations in order to complete the assessment.

2.5 The IDA selected approximately 40 primary documents for its sample of review and, upon completion of the Supplemental Hazards Review,

'had reviewed approximately 80 documents and- completed over 300 separate evaluations, reviews, or attribute checks. Review Plan checklists were completed to evaluate the adequacy of the Project's hazards evaluation and resulting engineering products and were in-cluded in the review plan. No Action Items were prepared during this supplemental review. Concerns were documented on Design Obser-vation Reports (DORS), which required an individual response from I the Project and a formal evaluation of that response by the IDA.

DOR responses from the Project included their analyses for cause, i extent of condition and significance, and provided commitments for j corrective action and action to prevent recurrence where appropri-ate. Five DORS were initiated during this assessment. A discussion ,

I of the concerns, the Project responses, and Sk'EC evaluations is in-cluded in the detailed section of this report.

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' 3 .1 . HAZARDS' PROGRAM EVALUATION DETAILS l

J 3.1 Scope of Review I

The purpose of- the review was to document the results and conclusions of' l.

the SWEC review of that portion of the Hazards Program.which was not com- .

plated and' documented in the Design Assessment Report (IDCA Volume II) . il This review evaluated a sample of Unit 2 Hazards evaluation design docu-c,.- ments ~ including calculations, specifications, drawings, reports, FSAR',

walkdown information, etc. To the greatest extent possible, the selected sarples were related to the RHR-LPCI inside containment and HPCI outside

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. containment systems. In order to select a sample of representative high-

- , . energy line breaks, the Separation Report (BLP-38054) issued by the Pro-ject in' July 1986 was reviewed. This enabled SWEC to identify six breaks with targets significant to safety and requiring further engineering evaluation /analysic for the mitigation of consequences, or requiring pro-tactive shields. Appropriate design, analysis, or walkdown documents in the following categories were reviewed:

l e High-energy line break (HELB) and internally generated missiles (IGM) evaluation e HELB/ IGM field walkdown evaluation f3 e seismic II/I safety impact review and field walkdown evaluation U i f - 15356-1813803-HC2/B6 9 l

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• HELB postulation /FSAR figures and-tables, and applicability of

! Unit 1 pipe break' calculations to Unit 2 (RHR-LPCI - inside containment)'

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e Pipe rupture analysis and break exclusion area evaluation (HPCI - outside containment) e Pipe rupture restraint design (zero gap restraint / bumper for HPCI - outside containment) l Calculations and other relevant documents were reviewed to verify input completeness and accuracy, technical adequacy, compliance .with project

,. s conuaitments, resolution of as-built differences, and incorporation of

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results into affected documento, A walkdown also was conducted by a SWEC team to verify the validity and completeness of the Project walkdown findings and evaluations. Section 3.6 provides a listing of the docu-ments reviewed.

s 3.2 Results of Review

1. High-Energy Line Break (HELB) and Internally Generated Missiles (IGM) Evaluation In general, the reviewed documents were technically adequate and acceptable. As a result of the review, several concerns were raised pertaining to the clarification of the 25-f t versus 20-ft separation distance criteria limit used in the jet 15356-1813803-HC2/B6 10

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. impingement program, the' confirmation'of the acceptance of GE

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jet pump nozzle loads, the source document for pipe whip load-ing in barrier design Calculation 25.5P, the basis ' for using impact factor of 1.25, and justification for using nonfactored loads with ultimate strength design allowable for the concrete bearing calculation. During the course of evaluation, the Project provided references and clarifications that satisfac-torily resolved these concerns. However, several concerns were not resolved and resulted in the following observation reports. f HS-DOR-002 was written because the quadratic equation used in

Calculation 25.5P, Rev. O to ev.aluate the load on the through-j- bolt contained an error in units which rendered the analysis incorrect. In response to the Observation Report, the Project provided a revised calculation which corrected these errors and demonstrated that the installation was still adequate. The response also addressed the extent of condition by checking s

five additional calculations involving the same preparer or checker. It was concluded that such errors were isolated, since similar errors were not found in the sample calculations reviewed. Therefore, the concern was resolved and the Observa-tion Report was closed with no further action required.

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l HS-DOR-003 was written becaus,a of concerns that Calculation NPB-119, Rev. O, prepared by the Project to fully document the safety evaluation for the selected breaks may be deficient in l

including all targets and performing the proper evaluation.

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( The concerns stemmed from the. fact'that a number of' pipe whip restraint targets- were' not identified and were excluded from the scope . of the. safety evaluation within NPB-119. : In addi-tion, SWEC identified _ Project. memorandums that acknowledged

-, that ' certain L st'ructural members u were < overstressed, and . load reductions were necessary'for their reconciliation.: It was not clear how this was going.to be accomplished,'since the items were'not identified as open items.' .In response tho' Project explained that NPB-119 was not provided as a complete safety evaluation document for the . six selected breaks, and that. cora-o j' sistent with tho ' scope of ' Appendix G for the . walkdown proca-dure, structural ' items such as pipe whip restraints were . not '

. within ths' acope of the walkdown and the associated evaluation, .

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L(;, Calculation No. NPB-119. Such items were explained to be con-sidered in other calculations. Also,.the Project acknowledged-that the open items related to reconciliation of stated over-stress areas were reflective of the ongoing design pro' cess and s

that. preliminary results seem to have resolved the'overstress concern. The Project provided copies of the applicable mechan-ical and civil calculations. Based on a review of these calcu-L 1ations, the concern regarding the stated overstress areas was-resolved and the Observation Report was closed with no further action required.

During the HELB review regarding target evaluations and methods i for safe shutdown including single failure criteria, it was 1

determined that the methods for safe shutdown were adequately 15356-1813803-HC2/B6 12 i

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't i defined and were consistent with the FSAR.

Q evaluation calculation did'not clearly address the following, and ' Observation Report No. HS-DOR-004 was issued to address these concerns:

• Ruptured target lines associated with the "Drywell . Gas Supply" may result in additional pressurization of - the drywell due to the addition of nitrogen. The observation Report response explained that the ef fect on drywell pres-surization due to nitrogen from ruptured target lines as-I sociated with the "Drywell Gas Supply" would be minimal.

Based upon a further review of the FSAR and Calculation No. H-59-7, it was agree'd there would be minimal ef fect on f%

3 drywell pressurizatiori and the concern was resolved.

e Remaining combinations of Emergency Cora Cooling' Systems (ECCS) following a postulated HELB appeared not consistent with the FSAR licensing commitments. The observation re- j port response explained that FSAR Section 6.3.1.1.2,-

Paragraph (e) and FSAR Table 6.3-3 tabulate the available ECCS after an assumed single active failure for the whole spectrum of breaks regardless of break sizes, location, or fluid state of the reservoir. The response also explained l

that the minimum ECCS requirements are provided in the Probabilistic Risk Assessment (FRA) as referenced in Cal-culation No. NPB-71, Revision 5, and submitted to the NRC i

l p via PECo letter from E. J. Bradley to H. R. Denton, dated i

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March 17, 1981. Based upon the response and a review of L Calculation No. NPB-71, Sheet 28 of 19, Revision'3, "Ma-trix for Use of PRA Table 1.2 Data," the concerns :were l

resolved.

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• . Traceability to minimum available ECCS acceptance crite-ria, such as GE criteria, for ECCS requirements following a HELB were not provided. The observation report response .;

explained that the PRA was developed by GE for PEco at the request of the NRC and submitted to the NRC via PECo let-

.ter f rom E. J. Bradley to H. R. Denton of the' NRC, dated March:17, 1981. The respense also explained how Calcula-tion No. NPB-71, Revision 5 is referenced and integrated l

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^%_/ - into the HELB program via Specification No. 8031-G-23 and Circulation No. NPB-119. Based upon the response and a review of Specification No. 8031-G-23, Appendix F and Cal-culation No. NPB-119, Sheets 9 through 12, the concerns s

were resolved. ,

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• Traceability for a target identification and associated reference sheet were not provided. Based upon the expla-nations presented in the observation report response and a further review of Calculation No, NPB-119, Revision 0, the concerns regarding target traceability were resolved.

,, e There appeared to be inconsistencies within the documen-k- m tation regarding " manual action." The observation report 15356-1813803-HC2/B6 14 1:

s L,W fu; response explained that the "M" indicated on Shset 52 of Calculation No. NPB-119, Revision 0, is.for the actuation of the D: loop of RHR suppression pool cooling and that the

' A loop of RHR suppression pool cooling is available for long-term couling without manual action. This is consis-

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tent with Calculation No. NPB-119,' Sheet 52, and the cri-4 The response teria in Calculation No. NPB-71, Sheet 2B.

resolved the concern. Also the observation ~ report re-sponse explained that the containment . isolation valve No. M57-HV-224 is normally cloned as indicated by "NC" on' Sheet 131 of Calculation No. NPB-119, under '"Radionale for

• ' Acceptance." Therefore, based upon the applicable MEPB hazard effects, the response concluded that containment

.b. isolation is maintained and manual action is not required .

if a single active failure of the redundant containment isolation valve is postulated. Based upon the response, a further review of Calculation No. NPB-119 and a review of FSAR Figure 9.4-5, -Sheet 4 : of 6, coordinate C-4, which shows Valve No. M57-HV-224 normally closed, the concern L was resolved.

M e There appeared to be certain editorial' inconsistencies l within the calculation associated with the safe shutdown flow chart and its legend for the " items assumed lost by l additional single failure." The observation report response explained that the symbol "e" for items assumed

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, process and. .that there is no need for revision, as the original calculation.is sufficiently clear with regard to.

' sing 1s' failure. . Therefore, the response resolved the.

concern.

1 These responses ' satisfactorily resolved SWEC's concerns and'the observation report was closed with no further ac-tion required.

During the HELB review regarding flooding it was determined-that flooding due to HELBs was addressed by the project in the HELB evaluation program. Ilowever, - the HELB flood evaluation -

calculation did not-clearly address the following and Observa-tion Report HS-DOR-005 was issued to address these concerns e The basis for the flood heights established by the walk-down was not provided and traceability to a reference doc-ument which established the HELB flood heights as compared to the flood heights established by the walkdown was not provided. Also, it was noted during the review that there was no traceability to a reference document which esta.b-lished the moderate-energy pipe break (MEPB) or " exterior nonpiping systems" flood heights as compared to the walk-down flood heights. The observation report response ex-plained that the flood heights listed in the calculation tO should have been consistent with the MEPB evaluation

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.g kj results, and the inconsistency was attributed to human er-ror. It was determined .by the Project to be an is' olated-case, and the project committed to revise the calculation to correct the flood height and provide the appropriate reference. Therefore, the concerns were resolved.

• It appeared that the MEPB analysis flooding results had-t been applied to HELB flooding mitigation without trace-ability to a HELB flood height to justify that the MEPB flood height and associated protection enveloped flooding due to the HELB. The judgment that the postulated worst-case MEPB flooding event enveloped the HELB flooding events for fire zone 66 (Room 376) was supported by the

! ) reasons provided and the concern was resolved. Verifica-

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tion of the sampled MEPB flood detection . instrumentation installation was performed during the MEPB site walkdown review. It was noted during the response evaluation re-view that areas such as the main steam tunnel which have flood heights due to HELBs that may not be enveloped by the MEPB flooding evaluations appeared adequately ad-dressed in Calculation NPB-15, Revision 1. A review of this calculation as compared to the MEPB Calculation NPB-14, Revision 3, showed that the MEPB flood Mights enveloped the safety-related area HELB flood heights ex-cept for the main steam tunnel which appeared appropriate-1 ly addressed. It was understood during the review that l

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' V} breaks but will be walked down and the associated documen-tation . completed upon the Project's finalization of the HELB Evaluation Program.

These responses satisfactorily resolved SWEC's concerns and the observation report was closed with no further ac-tion required.

2. HELB/IGH Field W.sikdown Evaluation This review- included the assessment of Project Specification No. G-23, Appendix G separation review walkdown conclusions in con- i

-/] junction with' a confirmatory field walkdown by SWEC engineers.

V The field walkdown conclusions were generally acceptable. The SWEC walkdown evaluation verified the targets from the six' selected high energy line breaks, the sample cold gap measurements at whip . re-I a straint (B-3P), the consistency of the missiles / barriers identified l

i in the design documents with the actual configurations in the field.

As a result of walkdown, the break locations, jet geometry, targets, l- shields, and barriers were confirmed and found to be consistent with Appendix G hazard evaluation documentation. No additional missiles were identified during the field walkdown. The cold gaps at whip restraint (B-3P) were consistent with the design drawing and calcu-lation. No concerns were identified during this evaluation.

3. Seissnic II/I Safety Impact Review and Field Walkdown Evaluation 1

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This review included the project Seismic II/I safety impact documen-tation review in conjunction with a confirmatory field walkdown by SWEC engineers. The Seismic II/I Safety Impact Review sample con-sisted of three rooms (179, 376, 473). Rooms 376 and 473 were se-lected for reismic II/I Review to correspond with the areas affected by the six breaks selected for the HELB Review (three breaks located in each room). In addition, Room 179 also was reviewed to verify the validity of the earlier IDA inspection conducted as a part of the initial Hazards Review. (At the time of initial review the safety impact review status was preturnoverl this status was final for the present review.) No concerns were identified during this review and field walkdown evaluation.

4. HELE Postulation /FSAR Figures and Tables, and Applicability of Unit 1 Pipe Break Calculations to Unit 2 (RHR-LPCI - Inside Containn:ent)

It was explained that the Project does not prepare and issue formal HELB postulation calculation. Therefore, Limerick 2 Pipe Stress Report No. SR-8031-2300-2 for RHR-LPCI inside containment and stress Calculation 2-10-8') for HPCI outside cor'ainment were reviewed to confirm the break locations and stress dua def:. tic ' in FSAR Figures 3.6-33a, 3.6-22a, and FSAR Tables 3.6-22a, 3.6 *- .

As a result of the review, a concern was raised pertaining to the l

incorrect pipe break stress limits defined in FSAR Table 3.6-14a, Rev. 56. The Project acknowledged that there was a typographical E 15356-1813803-HC2/B6 19

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error in this stress value, and subsequently issued LDCN-FS1687 to resolve the discrepancy.

Also, the review of Calculation S/18240/FB-015 which contained a-comparision of~desi p data used in Unit I and Unit 2 confirmed that-t

. the applicability of Unit 1 pipe break forcing function calculations to Unit 2 for RHR-LPCI inside containment was appropriate.

' 5. Pipe Rupture Auaiysis and Break Exclusion Area Evaluation (HPCI - Outside Containment)

The HELB break exclusion' area evaluation including isolation valve operability, forcing function, and zero gap restraints for the HPCI

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system outside containment was evaluated. To accomplish this, three pipe rupture calculations were reviewed. As a result of the review, concerns were raised pertaining to the source document for the al-lowable stress 1.1Sy for the break exclusion zone, the assurance of valve operability dus to high acceleration G values-in the pipe rup-ture break exclusion zone evaluation, the differences of the as-built cold gap . measurements and the design calculated values for bumper restraint B3 and B4, and the discrepancies of the design in-put parameters for Relap4 forcing function calculation and the cor-responding piping specification design values. These concerns were resolved when the Project identified the source documents and additional references, and no observation reports were issued.

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/~'N d,,s,) 6. Pipe Rupture Restraint Design (Zero Gap Restraint / Bumper for HPCI Outside Containment)

Two sample design calculations were reviewed. As a result of the review, concerns were identified pertaining to calculation errors in evaluating local stress for beam G 24 associated with valve opera-bility restraint PR-10, the incorrect Nelson stud (7/8" 0 x 8")

pullout capacity, and the omission of an evaluation of the bending stress of the baseplate for bumper . restraint B4. These concerns were not resolved. Therefore, Observation Report HS-DOR-001 was written.

In responsa to this Observation Report, the Project acknowledged that O

x s/ the discrepancies were caus'ed by errors made by the originator which were not detected by the checker and f ailure to document engineering judgment. To evaluate the extent of the condition, all other calcu-lations for embedmont designs using Nelson studs were reviewed by the Project, and no similar errors were observed. Also, the Project stated tha't baseplates without shear lugs were evaluated for bending stress with backup calculations, and the use of judgment was not exercised. The discrepancies stated in the observation Report were corrected by revising Calculation 25.5M-1. The results and conclu-sions of the calculation were not affected and the concerns were l

. resolved.

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, c 3.3 Conclusions-Based on the results of the hazards review addressed in this supplement, it can be concluded that the effects of HELBs are properly evaluated and 1

accounted for in'the overall safety evaluation. It also can be concluded that HELB effects and internally generated missiles are properly assessed and documented in the Project's separation review walkdown calculation, and that tho' Seismic II/I safety impact review and associated walkdown evaluations are performed' adequately to ensure the integrity of safety-related systems. The SWEC walkdown results confirmed the adequacy and completeness of the Project walkdowns. The Project calculations per-formed to document the rationale for the applicability of Limerick 1. pipe break analysis to Limerick 2 were found to be technically adequate and consistent with the applicable Project FSAR stress tables and figures.

It can be concluded that the reviewed documents are also consistent with the applicable design criteria and licensing requirements. Also, during the resolution of certain Observation Reports, the Project performed ad-ditional reviews to: address the extent of condition and significance which confirmed the adequacy of .the applicable project documents beyond the initial scope of the review.

3.4- Observation Reports j The following Observation Reports were issued as a result of this review activity:

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1. HS-DOR-001'Rev. O Calculation 25-SH-1 has deficiencies in inputs ar.d documenta' ion of source data.

2. HS-DOR-002 Rev. 0 The analysis for anchor bolt loads .of Calculation 25.5P Rev. O is incorrect and does not demonstrate the adequacy of the bolts.

3. HS-DOR-003 Rev. O Calculation NP.'-119 may be deficient in inclusion of all targets and in performance of proper evalua' tion.

'4. HS-DOR-004 Rev. O Calculation NPB-119 does not appear to meet FSAR requirements f

~

minimum ECCS following HELB.

5. HS-DOR-005Rev)O HELB G-23 Walkdown and Calculation NPB-119 lack Basis / Traceability for

! Flood Heights and Evaluation.

3.5 Action Items t-No Action Items were issued as a result of this review activity.

I 1

l 15356-1813803-HC2/B6 23

t, 3.6.. Documents Reviewed f~j ,

U The.following documents were reviewed for_the Hazards Program Evaluation.

1. ' Calculation No. NPB-26, Rev. O, Jet Loads on Structural St' eel' Work Inside - and Outside Containment for LGS 1 and 2, dated 07/19/84.

2. Calculation No. NPB-43, Rev. O, Unit 2 Jet 2. Computer Code Runs De-veloped'for. Jet Impingement Loads Determination on P.W. Restraints ,

and Bumpers, dated 08/13/84.

3. Calculation No. NPB-73,-Rev. 2, Jet Impingement Code NE 155 Results for Various High-Energy Line Breaks, dated 10/07/85.

4 4. Calculation No. NPB-119, Rev. O, G-23 Hazard Review Field Walkdown of 11/11/88, dated 03/20/89.

5. Calculation No. NPB-26, Rev. 1, Jet Loads on Structures, dated 03/21/89.

6.- Calculation No. NPB-93, Rev. O, Acceptable Loading .of Electrical conduits from Jets and Dropped Tools, dated 02/22/86.

7. Calculation No. NPB-121, Rev. O, Jet Loads on Post-LOCA Monitoring System Inside Drywell, dated 01/31/89.

8. Calculation No. NPB-128, Rev. O, Jet Impingement Loads on Pipe Whip j j

Restraints Inside and Outside Containment of LGS Unit 2, dated 03/21/89.

L 15356-1813803-HC2/B6 24

4-f N.

(,)k 9 BLP 38054 Rev. O, Separation Review Report for LOS No. 2, dated 07/17/86.

10. BLP 33323 (DC No. 183640), MSIV Jet Impingement From A Reactor Re-circulation Loop Circumferential Pipe Break, dated 07/03/84.

.11. DC . No. 23Gdl, LG No. 2 Jet Impingement Loads on Pipe Whip Re-strainte and Structures, dated 03/21/89.

12. Calculation No. NFB-77, Rev. O, Pipe Break Jet Impingement Load Cal-culation, dated 03/11/85. ,

13. DC No. 238043, Jet Loads on Post-LOCA Monitoring System Inside Dry-( '

well, dated 01/27/89.

14. CCN.239375, Jet Loads on Post-LOCA Monitoring System, dated 03/08/89.

15. Stress calculation 2-01-04, Rev. 4, Pipe Stress Analysis - Mein Steam Line D, dated 02/24/89.

16. Stress Calculation 2-39-00-09, Rev. 2, Jet Impingement Calculation, dated 02/28/89.

17. Stress Calculation 2A-399, Rev. O, Jet Pump Nozzle Loading, dated

g. 02/29/89.

U 15356-1813803-HC2/B6 25

bl 18. DC No. 240190, Jet Impingement Loads on Pipe Whip Restraints for-LGS, Unit 2, dated 03/29/89.

-i. 19. DC . No. 240232, Jet Impingement Load Evaluation of Pipe Whip Re-

straints and Bumpers, dated 03/30/89.

20. DC No. GO50571 FDDR No. HH2-8647, Jet Pump Nozzle Loadings, dated 04/08/88.

21. Calculation No. 25.5P, Rev. O, RWCU Pump Room Barriers, dated 11/21/80.

p 22. DC No. 064952, Barriers for Protection of Steam Flooding Dampers i

Trom High-Energy Pipe Break, dated 07/31/79.

23. Calculation No. 17-S-9A, Rev. O, Containment Structure MS Loop C, Break at Node 48 Pipe Restraint PR-219 Evaluation, B1 272 ft-9 in.

Local Effects, dated 03/27/89.

24. Calculation No. S/18240/PB-15, Rev. O, Evaluation of Pipe Whip Re-straints on LPCI System Inside Containment, dated 11/30/88.

25. Stress calculation No. 2-10-83, Rev. 4, Piping Stress Analysis of RHR Loop B - Outside Wetwell, dated 05/21/88.

r.

15356-1813803-HC2/B6 26

32 ,

r Mj -

.]

D '26. ~ Stress Report SR-8031-2300-2,' Rev. O, ASME.Section III Class I Anal--

ysis of' the Low-Pressure Coolant. Injection Systems' for Limerick Unit

? ,

l 2,. dated 04/03/89.. ,

I s

'27. Calculation No. S/18240/PB-003, Rev. 1, Pipe Break Dynamic Analysis' for Evaluation of Whip Restraints on HPCI (OC), . dated 11/12/88.._

28. Calculation No.'S/8031/PB-012,'Rev. 3, Pipe Break Dynamic Analysis for Isolation. Valve Operability of HPCI (OC), dated 01/09/89.

29. Calculation No. 4002, Rev. 5, Pipe Break Forcing Function, dated 10/15/83.

4

30. ' Calculation No. EBB-208-C48, Rev. 2, Pipe Support Design Calculation Hanger No.' EBB-208-H48, dated 07/29/88.

31.- Calculation No. 25-SM-1, Rev. 2, Unit 2 HPCI Pipe Whip and Valve Operability Restraints and Bumpers (Outside Containment), dated 01/10/89.

32. Calculation No. 17-T-64, Rev. O, Jet Impingement Loads - LPCI Loop A (I/C) Pipe Break Nos. IB-90CD ' "'

u'

~

IB-100L - Bumpers B5 and B6 and Supporting Frame / Platform El 296 ft Evaluation, dated 05/06/89.

O 15356-1813803-HC2/B6 27 l

_ _ . _ .__._._________._.____.-._____._...__-..____.__.________..m___. ___._______________________m__u

.k

33. Calculation No. 17-T-6B, Rev. O, Analysis' ' of Box Beam. Frame at El- 296 : for Loade Du's to LPCI' Pipe Rupture,J Jet Impingement, and I

, . Thermal,. dated 05/06/89.

l 3 4.' - Calculation No. NPB-131, Rev. O, High Energy Pipe Break Report, dat-.

~

ed 05/04/89..

O f.

I O

15356-1813803-HC2/B6 28

. ,m i- 4. : OBSERVATION REPORTS 1

i This section contains the Hazards Supplement Design Observation Re-port ~(HS-DOR) packages for HS-DOR-001 to HS-DOR-005 issued by SWEC during the Limerick 2 Independent Design Assessment (IDA) Hazards Review. Each HS-P;d package contains the following:

1. HS-DOR PART: I: SWEC Initiation

• HS-DOR PART II: Bechtel Response

• HS-DOR PART III: SWEC Response Evaluation k_ / Where necessary, selected reference documents have been ' included with the DOR packagna to ensure a clear understanding of the DOR and its resolution.

Observation TAB Report No. Number Title / Description of Observation Report 1 HS-DOR-001 Calculation 25-5H-1 Deficiencies in Inputs and Documentation of Source Data 2 HS-DOR-002 Calculation 25.5P Analysis of Anchor Bolt Loads Incorrect and Does Not Demonstrate Adequacy 1

15356-1813803-HC2/B6 29 l

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' i -_;- 2 q.

(

~3 HS-DOR-003 Calculation NPB-119 ' Deficient . in Inclusion of Targets and in Performing Proper Evaluation:

.. 4: HS-DOR-004 Calculation NPB-119 Does Not Appear to Meet FSAR Requirements ' for Minimum ECCS Following HELB

-5 HS-DOR-005 HELB 0-23 Walkdown, Calculation NPB-119 Lacks Basis / Traceability for Flood Heights and Evaluation l'

.I-i O

15356-1813803-HC2/B6 30

_ ._. _ - - _ __ __---_ _ _ - _ _ _ _ _ _ _ _ - _ _ - _ .]

STONE & WEBSTER ENGINEERING CORPORATION-LIMERICK 2 IDCA

.x- (J.O. NO. 18138).

r vU t/ - OBSERVATION REPORT Observation Report No. HS-DR- 001- 'Rev. J Review Plan LK- D - 1915 -

MC Rev. _y1

' Reference AI No.: N/A' PrtT I - IRITIATION

~1. .

Description of Concern The following deficiencies exist in Calculation 25-SM-1, Rev. 2, for the design of-Pipe Rupture Restraint Supporting Structures. These deficiencies could lead to possible design inadequacy.

1. Page 16 ~ of Calculation 25-5M-1 used incorrect web thickness / depth to evaluate local stress of G-24 for HPCI valve operability restraint PR-10 supporting structure.

2. The ' source . document of ' Nelson Stud (7/8" 6 x 8") pull out capacity-To (=48.6 K) used on Page 28 of Calculation 25-5M-1 was not identified.

3. The bending stress of the baseplate (28" x 28" x 1") for the bumper B4 supporting structure. on Page 28 of Calculation 25-5M-1 was not

n, calculated.

t .-

\*) 2. Supporting Information ,

1. The web thickness of G-24 identified in Ref. Dwg. C-201, Sheet 2 is 1.5 inch. The design calculation 25-SM-1 used thickness of 2.16 -

inch instead of 1.5 inch to calculate section modulus of the- web and... also used web depth of 81.59 inch instead of 36.0 inch to calculate the bending moment. . As a result of these incorrect - input data, the . bending stress will increase from 5.5 kai to 37.1 ksi, which exceeds the allowable stress of. 32.4 ksi. Therefore, the calculation is deficient in this regard.

2. The tensile capacity To (=48.6 k ) of Nelson Stud (7/8" 0x 8") ha's been used to evaluate the embedment of HPCI valve operability bumper -

B4 . supporting structure. This allowable load 48.6k appears to be too high for 7/8" 9 anchor as compared to the design value of 32.47 k on- Nelson Stad Manual. Calculation 25-5M-1, Rev. 2 provided no reference document for this allowable load. Therefore, calculation is deficient in not providing valid design input value and source.

CONTINUED ON ONE PAGE.

........... ..................................................................=..=....

Additional Documents Attached:

None, n .......................................................................................

Xt-}~Laf #9. C CLR w.wte eMn Lead Engineer Signature '/ Date AFM Signature / Date Page 1 of M

b STONE'& WEBSTER ENGINEERING CORPORATION LIMERICK 2 IDCA (J.O. NO.'18138)

OBSERVATION REPORT' Observation Report No. HS-DOR- 001 Rev. O PART I'- INITIATION -

CONTINUATION:

3.- -The bending stress of the baseplate due to pipe rupture loads was not . evaluated in the design of the bumper . restraint B4 supporting structure. Based on design rnpture-loads (327.k tencion, 1190k" bending moment), the stresses induced to baseplate (28" x 28" x 1") could be significant. No . justification was provided in the design  !

calculation 25-5M-1 for ignoring the baseplate bending stress analysis.

Therefore, the calculation is deficient in this regard.

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• Os-03-89 MAY 0 51989-( ,/ STONE & WEBSTER ENGINEERING CORPORATION LIMERICK 2 IDCA (J.O. NO. 18138) f, L 7 .-/ )

OBSERVATION REPORT Observation Report No. HS-DOR-01 Rev O-PART II - RESPONSE The following is an amended response provided in accordance with egreements reached between SWEC and Bechtel during'a telephone conference call on April 28, 1989.

1. Observation Concurrence

_X_ Concur with observation

___ Do not concur with observation (Note: if not in concurrence, explain in " remarks below")

2. Response to Observation:

A. Causal Factor (s)

Items 1&2 The discrepancies noted in the section modulus & moment calculation for PR-lO and the embedment design are caused by errors made by the originator which were not detected by the checker of the calculation.

In the embedment design, an incorrect Nelson stud pull-out capacity was inadvertently used.

~

The originator mistakenly increased the design value given in the Nelson catalog by 50% in the design f or a faulted condition, postulated pipe break load. Th0s allowable increase is typically used for steel design in determining the f aul ted condition allowable f rom the AISC working stress allowable values.

Item 3 The bending stress of the baseplate was evaluated by engineering judgement which considered the additional stiffness and strength provided by the embedded shear lugs of this embedment. This judgement wan not documented within the calculation.

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f(g - STONE & WEBSTER ENGINEERING CORPORATION LIMERICK 2 IDCA (J . D. NO. 18138)

OBSERVATION REPORT Observation Report No. HS-DOR-O'1 Rev O' B. Extent of Condition-Item l' The noted di screpancies ' were reviewed and determined to-be minor and do not affect the basic conclusion of the calculations. Similar minor errors may be.present in other calculations, but their significance would be expected to be the same.

Item 2 All other calculations for embedment designs using Nelson studs'were reviewed and'it was found that the correct pull-out capacity value was used. Therefore, the cited condition is concluded to be an isolated occurrence.

Item 3 The bending. stress of the baseplate, based on engineering judgement, is considered adequate because of the additional stiffness and strength provided by the

.( )

\~/-

embedded shear lugs of this embedment. The bending stress of the baseplate has been evaluated and concluded that the judgement of baseolate bending adequacy is correct. Undocumer.ted engineering judgement can be .;

expected in other calcul ations since 2 t was not the practice to require all judgements documented in the c al cul ati ons.

Based on a review of the design calculations,'baseplates without embedded shear lugs were evaluated for bending stress with backup calculations. The use of judgement was not excercised.

4 11 Page, of ,h g

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y* STONE & WEBSTER ENGINEERING CORPORATION

' LIMERICK 2 IDCA (J.O. NO. 18138)

OBSERVATION REPORT Observation Report No. HS-DOR-01 Rev 0 C. Significance Item 1 The significance of the ' incorrect web dimensions used in -

the design calculation f er PR-10 i s inconsequential . The design has been reevaluated using the correct web thickness and web depth to calculate the section modulus and to check the bending stress. All of the design requirements are still satisfied as demonstrated in Pages 16 & 16a of Calculation 25.5M-1, Revision 3'(Transmitted to SWEC via Transmittal No. 0786). Correction of the errors did'not affect the basic conclusion of the calculation.

Item 2 ~The. significance of the incorrect Nelson stud allowables used in the design calculation f or the embedded baseplate is inconsequential. The baseplate design in question has r been reevaluated using the correct allowables for the

- (' Nelson stud and the reduced applied pipe whip load provided by Plant Design discipline after further refinement of the piping stress analysis. The results of the reevaluation satisfy the design requirements as demonstrated in Pages 27a-e of Calculation 25.5M-1, Revision 3 (Transmitted to SWEC via Transmittal No.

0786). Correction of the errors did not affect the basic concl usion of the calculation.

j Item 3 The. undocumented engineering judgement of the baseplate L bending stress is confirmed to be valid by the revised I calculations as referenced in Item C2 above. Engineering l Judgements are generally made on designs with obvious conservatism and the lack of documentation for such engineering judgerents has no effect on the basic conclusion of the calculation.

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\s,) STONE & WEBSTER ENGINEERING CORPORATION LIMER!CK 2 IDCA (J . D. NO. 19138)

! OBSERVATION REP 0AT Qoservation Report No. HS-DOR-01 Rev 0 ,

D. Corrective Action Calculation 25.5M-1, Revision 3 was revised to demonstrate that discrepancies noted under items (1) and (2) and the undocumented engineering judgement noted under Item (3) were not significant.

E. Action to Prevent Recurrence None required because the basic conclusion of the calculation is not affected and as stated in response to DDR-118, Part E.

($$)

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.=.....................................................................

• Remarks None

.=.....................................................................

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2 .2 '_.g__ffjzJt3L__ d r __b__l Q' _r_.8_w_v__ _5/___54_

_ __Jdt_ _9 Secnta Approval Signature /Date P Co Revt w Signature / Data

& il e,n. ,Af no,pV jc ja -

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[N . .; - STONE & WEBSTER ENGINEERING CORPORATION

(,/ ~ LIMERICK 2 IDCA (J.O.NO. 18138)

OBSERVATION REPORT Observation Report 'HS-DOR-001 Rev. O_

Review Plan: LK-D-1915-MC Rev. O PART III - RESPONSE EVALUATION The response to this observation report has been evaluated as follows:

A. Causal Factor (s): X Acceptable Not Acceptable (Explain):

See attached page.

B. Extent of Condition: X Acceptable Not Acceptable

.(Explain):

See. attached.page.

C. Significance: K Acceptable Not Acceptable (Explain):

See attached page.

D. Corrective Action:. A Acceptable Not Acceptable (Explain):

See attached page.

E. Action to Prevent Recurrence: X Acceptable Not Acceptable

. (Explain):

See attached page.

I I

t Additional Action Required: X No Yes (Explain)  !

l l

l l Xt~/dd Lead Engineer Signature

~

TNee

/Date APM MLth mo shk?

I

. Signature /Date t

7 ll l

l. 15685-1813803-HC2 Page / of /

l JK F

c. __ _. - _ - _ - _ _ _ _ _ _ _ _ _ _ _ - _ -

STONE & WEBSTER ENGINEERING CORPORATION LIMERICK 2 IDCA  :

i (J.O.NO. 18138)

}. OBSERVATION REPORT LJ Observation Report HS-DOR-001 Rev. O  !

PART III - RESPONSE EVALUATION CONTINUATION:

A. CAUSAL FACTOR (S): ACCEPTABLE  :

Item 1: The cause of calculation discrepancy u.s acknowledged to be the error made by the originator that was not detected by the checker.

Item 2: The Nelson stud pullout capacity was mistakenly increased by a factor of 1.5 x it s original design value by the calculation preparer.

Item 3: The undocumented engineering judgment was the cause for omis-sion of evaluating the bending stress of the baseplate.

B. EXTENT OF CONDITION: ACCEPTABLE Item 1: The noted discrepancies were evaluated and concluded to be not affecting the basic conclusions of the calculation. Also, Bechtel's response stated that similar cases may appear in the other calculations and their significance would be expected to

,-ss be the same.

/ \

1. Review of all other calculations for embedment designs using ws Item 2:

Nelson studs confirmed that this was an isolated occurrence for using incorrect Nelson stud pullout capacity.

Item 3: The bending stress of the baseplate was evaluated and found to be acceptable, thus confirming the validity of the undocumented engineering judgment of the additional stiffness and strength provided by the embedded shear lugs of this embedment. Also, based on a review of the other design calculations, Bechtel stated in an amended response that baseplates without embedded shear lugs were evaluated for bending stress with backup calcu-lations and the use of judgment was not exercised.

C. SIGNIFICANCE: ACCEPTABLE 1

Calculation 25-5H-1 has been revised to correct the discrepancies related to incorrect web dimension and Nelson stud allowable and to include the baseplate evaluation considering additional stiffness and strength due to embedded shear lugs. A review of this calcula-tion has confirmed that the stresses are within acceptable limits.

D. CORRECTIVE ACTION: ACCEPTABLE Calculation 25-SM-1 Rev. 4 has been revised to correct the discrep-g-~s ancies noted under Items 1 and 2, and to demonstrate the undocumented engineering judgment noted under Item 3 to be

(") acceptable.

$ ll 15685-1813803-HC2 Pagef( of)f I

/t /< ) ;

J

STONE & WEBSTER ENGINEERING CORPORATION LIMERICK 2.IDCA >! '

(J.O.NO.:18138) l ' ' /'N - OBSERVATION REPORT

~

Observation Report HS-DOR-001-Rev. O,

~ E .- ACTION TO PREVENT RECURRENCE: ACCEPTABLE None required since the conclusions of the calculation were not af- i fected. Also, in accordance with project response to DOR-118, PECO will evaluate ' the condition .of existing design documentation (in-ciuding calculations) and establish appropriate actions for enhanc-ing post fuel' load plant modifications.

3 i

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9 l 15685-1813803-HC2 Page / of /

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, Id LIMERICK IDCA (J.O.NO. 18138.00).

-TELEPHONE RECORD L ,

SER:H),-pTR- 002-Review Plan: LK-D- 1915-MC Rev.- 0

, g i; ,

Call Date:' 4- /,j[j,/_jl Time: _,_2, E)dtt/PM Incoming: 1 Outgoing: __,,

Participants Names

_SWEC  : . .

J. Bisti, N. Motivala, C.K. Chin, W.- Dykstra

< , Bechtel: .

- . _ _ l R. Bulchis, M. Bhatia, V. Aggarwal, G..Ong .l PECo  :

D. Helwig 100GWt-  :

NRC R. Parkhill

Subject:

Telephone Conference Agenda related to Observation Reports HS-DOR-001 and -002 (Attachments #1 and #2).

.q Summary:

HS-DOR-001: 1. Bechtel .to . provide calculation addressing all the concerns of HS-DOR-001.

2. Bechtel to clarify in the revised response that such undocumented engineering judgements are made.

only 'for 'baseplates with shear lugs. (which. are stiffer), _ and not for other baseplates, where calculations are performed to qualify the' designs.

3. Projected schedule of the revised response is:

response to PECo by Mon., 5/1/89, and to ' SWEC by-Wed.,-5/3/89.

1. Bechtel provide a copy of the- calculation I HS-DOR-002: to addressing the items of concern of the DOR.

2. SWEC explained that the extent of condition be evaluated for this preparer-checker team for similar calculation, or on some rational basis. A reasonable sample of calculations should be evaluated for extent of condition and the significance; in that order. Bechtel agreed. SWEC asked that Bechtel state the basis by which they picked the (random) sample for this evaluation.

AkLLA-Originator .

scGx L Ow.

As !M.s t an t Program Manager 4 5 - 004 -ool pye se of n

, t TELEPHONE CONFERENCE AGENDA m

I \ RELATED TO OBSERVATION REPORT HS-DOR-001

- (j.

ITEM 1: SWEC does not agree with response .that "no corrective action-was considered to be necessary because the basic conclusion of " the calculation ss not affected."' As stated in the DOR, two incorrect inputs are used which result in underestimating the stress by an order of magnitude.- SWEC estimates = that using '

the correct inputs, the actual. stress will exceed the allowable.

Thtis , SWEC concern (quantitative) has not been resolved by the qualitative response, without a backup calculation. Provide-this calculation for SWEC review.

ITEM 2: Need a copy of the revised calculation for SWEC review.

ITEM 3: From the explanation that engineering judgement was used in assessing the adequacy of base plate for bending stresses, SWEC's concern is not resolved. It is not intuitively obvious to the reviewer (SWEC) that the plate under question is adequate - for

, the imposed loads without the benefit of a detailed calculation, j 1

Provide a backup calculation. Also, the extent of condition should address whether oimilar undocumented engineering judgements are made only for base plates with shear lugs or for all baseplates, t

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1 j STONE & WEBSTER ENGINEERING' CORPORATION

.,._s. ,

LIMERICK 2 IDCA I

[ j (J.O.- NO.~ 18138) l

.() 'I

-1 OBSERVATION REPORT Observation Report No.HS-IUR- 002 Rev. 1 Review Plan: LK- D - 1915 :- MC Rev. 0 .j i

Reference AI'No'.: N/A j I

Reference:

HS-DTR-901 TELEPHONE CONFERENCE PART I - INITIATION NOTES l1

1. Description of Concern 1

The analysis for anchor bolt. loads on Sheet 5 of calculation 25.5P Rev. l 0 is incorrect and does not demonstrate the adequacy of the bolts. 1 f

2. Supporting Information The load on the through-bolt is calculated using a quadtatic equation.

The units for the applied moment term in this equation are lips and feet.

The units for the. balance of the equation are kips and inches. Due to the inconsistency in the units, the solution to the equation is incorrect.

The calculation results show that the bolt loads total 17.8K and the bolt capacity is' 18.4 kips (2-bolts). Since the calculation shows that the h bolts are loaded to 97 percent of their capacity, and the solution to

!* j' the equation is incorrect , ' the adequacy of the bolts is not demonstrated by this calculation. ,

s Additional Documents Attached:

None O sa/m. Lead Engineer Signature S's*

/ Date caber c.o.w,ne AYM Signature e/m/,2

/ Date Page 1 of ],

locAt % 7.

MAY 5 - 1989

&, /--

STONE & WEBETER ENGINEERING CORPORATION O'-0793)

LIMERICH 2 IDCA .

( J. O. No. 18134) I OBSERVATION REPORT observation Report No. MS-DUM-52, Rev. 8 P/RT II - AMEMDED RESPOMER The fellowing is an amended response provided in accordance with agreements reached between SWEC and BECHTEL during a telephone conferense call on Acril 28 . 1989.

1. Observation Concurrence

_1_ Concur with observation Do not moneur with observation (Notes if not in concurrence, explain in remarks below.

2. Response to Observations A. Causal Factor (s)

The dimorepancy noted is caused by error made by the originator which was not detected by the chesker of the calsuistion.

8. Extent of Condition

! Calculation 25.5P was reviewed for similar errers l and none were identified. A survey of 85 calculations has been performed and 5 calculations were ident4fied which were performed by the originator or checker of omiculation 25.5P .

These calculations were reviewed in detail and no calcult. tion errore similar to one identified by SWEC were detected. Therefore, the error identified by SWEC is beliwved to be isciated same.

C. Significance The significance of the inadvertent error in the calculation is inconsequential because of the conservattom used in the design calculation. The l design conservatism included:

O

...e it of 2.

IDcA /% 7 STONE E WE55 TEM ENGINEERIMO CORPcRATZoM LINERICK 2 IDCA

( J. D. No. 18138) l 035ER*.'ATION REPORT Observation Report HE-DDR92, Rev. 9 PART TT AMEMBED etsPSMst COMTTMUEB (1) The pipe break load effect was assumed to act as a point load at the most critical distributed leastion on the lead barrier rather than the actual pattern on the barrier.

(2) Only two anchor bolts were assumed to resist In the sffset of*-the lead on the barrier.

reality, because of the distributed load and the effect of stress pattern redists'ibution at load point through the barrier steel to the anchors, the minimum width at the anchor effective resistance bolts would equal to four feet or six anchors O bolts.

The design have been reevaluated considering error along with the available this conservatism and the design requirements are still satisfied. Correction of the error did azzecs sne meets wwuciusten as the ,

not calculation.

D. Corrective Actions 25.5P has been revised to calculatten demonstrate that the error identified by SWEC is insignificant. (Revised calculation 25.5P Rev.1 has been transmitted to SWEC via transmittal # P-8376 dated five 5/1/89.)

calculations In addition a review of involving the originator or checker of calculation 25.5P was performed.

O Par 3 of _2_

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• ETONC & WE857ER ENGINEERING C0FORATION LINERICH 2 !DCA

( J. C. No. 18138)

CBIERVATION REPORT Observation Report MS DDR 02, Rev. 8 Pant YT AMEMBES REBoSWEE E8WTfMURB l E. Antion to Prevent Recurrenset Me action to prevent resurrense is required of the because the basis senelusion calculation is not afgested. As discussed in response to DDR lit, to enhance the design presens for post fuel-load plant modifications, PECA will evaluate the condition of existing design documentation establish (including sacculations) and improvement actions em appropriate.

l lO

/RbdRe-uk haw sl4lr9 @la(7)$Ah nachteV Approval hgnature'/Date

/ArzKNn PEco Revsv4 signature /Date S

e Page,T,et.2.

STONE & VEBSTER ENGINEERING CORPORATION LIMERICK 2 IDCA

, (J.O. NO. 18138)

OBSERVATION REPORT Observation Report @ R- 002 Rev. J Review Plan: LK- D -

1915 -

MC Rev.1 'l PART III - RESP 0BSE EVALUATION The response to this observation report has been evaluated as follows:

A. Causal Factor (s): 'X Acceptable Not Acceptable (Explain):

The response acknowledges that the discrepancy was an error which was not detected by the checker.

B. Extent of Conditions X Acceptable Not Acceptable (Explain):

The project's review of 5 calculations performed by the preparer or checker of the referenced calculation did not identify any other occurrences of this type of error. Therefore the error can be considered to be an isolated case.

C. Significance X Acceptable Not Acceptable (Explain):

'S

/ Due to the amount of conservatism in the calculation, the

(,) results of the calculation were unaf fected af ter correcting the error, and the concern was considered not significant.

-D. Corrective Actions X Acceptable Not Acceptable (Explain):

Calculation 25.5P was revised to correct the error.

E. Action to Prevent Recurrences x Acceptable Not Acceptable (Explain):

Since the concern was considered an isolated error, no action to prevent recurrence is required.

..............................................................=...===..=.==============

Additional Action Required: y No Yes (Explain)

' f %> ......................................................................................

it~}n&d Lsad Engineer Signature Shole9

/ Date MA oto APM Signature s/ib7

/ Date Page E of 1

ty,

.. 'J.O..No. 18138.00, b *i . . Lim: rick - Unit'2

'IDCA .

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P

?/N LIMERICK IDCA (J.O.NO. 18138.00)

TELEPHONE RECORD SER:HS'-DTR- 002 Review Plan: LK-D,- 1915-MC Rev. LC Ny' Call Date: 4 /_g)_/_gp_ Time: J:,15_28tt/PM Incoming: 1 Outgoing:

Participants Names

~

SWEC.  :

J. Bisti N. Motivala, C.K. Chin, W. Dykstra

.- Bechtel: .

R. Bulchis, M. Bhatia, V. Aggarwal, G. Ong PECo  :

D. Helwig XXMME :

NRC R. Parkhill

Subject:

Telephone Conference Agenda related to Observation Reports

- HS-DOR-001 and -002 (Attachments #1 and #2).

LDIV Summary:

MS-DOR 001: 1. Bechtel to provide calculation addressing all the

-concerns of HS-DOR-001.

2. Bechtel to clarify in the revised response that ,

such undocumented engineering judgements are made  !

only fa- baseplates with shear lugs (which are stiffer), and no: for other baseplates, where calculations are performed to qualify the designs.

) 3. Projected schedule of the revised response is:

response to PECo by Mon., 5/1/89, and to SWEC by Wed., 5/3/89.

HS-DOR-002: 1. Bechtel to provide a copy of the calculation addressing the items of concern of the DOR.

2. SWEC explained the the extent of condition be evaluated for this preparer-che:ker team for simila-calculation, or on some rational basis. A reasonable sample of calculations should be evaluated for extent of condition and the significance; in that order. Bechtel agreed. SWEC asked that Bechtel state the basis by which they picked the (random)-

sample for this evaluation.

2010-Originator . ,

uswa w As M s tant Program Manager H S - D04 - c> o .1 Pap c,oC7

El i.: '

h & c. b m en d ~ .2 j -

TELEPHONE CONFERENCE A0ENDA

( RELATED TO OBSERVATION REPORT HS-DOR-002 L<j ITEM 1 . Extent of condition is not adequately addressed. Incorrect units can result in errors that are not minor in nature. Extent of condition should be evaluated before any conclusio is reached on the significance of the error. i.e. not all cdwiv9 ns will have the same degree of conservatism that would al M' a blankee buyoff of errors that could . underestimate loads and stresses by . a factor of 12. Significance should be determined from this error and any others detected during the review for extent of condition.

ITEM 2 - Significance shou!i be reevaluated based on the results of any errors detected during the review for extent of condition.

ITEM 3 - Corrective action is not adequately addressed. The calculation does not perform its intended function (demonstrate the adequacy of the installation). Using the input, methodology and assumptions listed in the calculation and correcting the units error ' in this calculation will demonstrate that the bolts are not adequate for the loading imposed on the restraint. This does not support' the Bechtel's claim that the conclusion of the calculation is not affected. Therefore this calculation

" ; y~ 'should be revised incorporating any refinements and correcting

'g the error in units' to correctly demonstrate the adequacy of the bolts. Otherwise SWEC's concern is not resolved.

ITEM 4 - Provide a copy of the revised calculation for SWEC's review.

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H 5 - 004-oo a age 2 0 l e -- - . _ ---- _ _ - _ _ ___2&&J "M

L STONE & WEBSTER ENGINEERING' CORPORATION i fm. LIMERICK 2 IDCA (J.O. NO.'18138)

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OBSERVATION REPORT Observation Report No. HS-IDR- 003 Rev. O Review Plan . LK- D - 1915 - MC Rev. O_,

Reference'AI'No.: N/A PART I - INITIATION 1-. Description 2f Concern Calculation NPB-119 Rev. O, prepared to fully document the safety. evaluation to address the High. Energy Line Break (HELB) ef fects from selected breaks, may be deficient in including all targets and performing the proper evaluation.

2. Supporting Information l

The SWEC assessment of Bechtel's High Energy Line Break (HELB). evaluation i

document incorporating the Specification G-23, Appendix G walkdown was deferred since - such documentation was not complete. It was agreed that ~

Bechtel would compile and issue complete safety evaluation documentation

[ for a limited number of breaks that SWEC selected. Consequently, Calculation NPB-119, Rev. O, was prepceed and transmitted to SWEC for L

); g review of complete documentation for the SWEC identified six breaks.

'('j, During the review of this calculation (signed out on March 20, 1989),

the following deficiencies were noted:

1, Field walkdown packages (Ref. page 9 of calculation) for the intermediate breaks #90c on LPCI line loop A, and #100c on LPCI line loop D did not identify all jet impingement targets within 25' of break locations. Specifically, pipe whip restraints PR-219, PR-221, PR-8R, PR-o-2, PR-13-P, Bumpers B-4, B-5, and B-6 were not identified as targets and were excluded from the scope of the safety evaluation.

2. Calculation NPB-119 Rev 0, which was provided as a complete safety evaluation documentation package for the SWEC selected breaks, failed to address by inclusion or by reference the reconciliation of jet impingement loads on civil structures.

In response to a SWEC question during a meeting at Bechtel San Francisco on March 21-22, about this issue, BecLeel subsequently provided three separate memos listed as references 1 through 3 below:

C,0,NgI g D ,0N,0NE,P, ACE _ _ _ _ _ _ _ _ _ _ _ _ , _ _ _ _ _ _ ,,,_

Additional Documents Attacheds None q ................................... ...................................................

NbA 4'l!3lB1

/ Date QlfJC&b.Mik- 4/tr/M APF1 Signature / Date l' Lead Engineer Signature l

Page 1 of I

1 1

k STONE & WEBSTER ENGINEERING CORPORATION LIMERICK.2 IDCA (J.O. NO. 18138)

OBSERVATION REPORT LJ Observation Report No. HS-DOR- '003 Rev. O CONTINUATION:

Ref. 1. IOM from O. A. Nossardi to V. Aggarwal/S. Desai dated 3-21-89, D.C. #239881; subject - LGS #2 jet impingement loads on pipe whip restraints and structures.

Ref. 2. IOM from O. A. Nossardi to S. Desai/V. Aggarwal dated 3-29-89, D.C. #240190; subject - Jet impingement loads on pipe whip restraints.for LGS Unit 2.

Ref. 3. IOM from S. Desai te O. A. Nossardi, dated 3-30-89, D.D. #240232; subject -

Jet impingement load evaluation of pipe whip restraints and bumpers.

The Project action of transmitting . jet impingement loads (Ref.

1 and 2) was initiated after the issuance of the Calculation NPB-119, Rev. O. Reference 3, in response identified two overstress areas on the pipe whip restraints / bumpers / structures, associated with break #90-IB-C (erroneous?y identified as 90-TE-C '

.S in the reference), and 100-IB-C (erroneously identified as

( j) 100-TE-C in the reference). It further implied that followup actions by plant servic s and civil groups were required to close out the open items. It should be noted that - the same i structural members, i.e., beams 61, 72, and 76, were the subject of DOR-060. In response, Bechtel had revised the calculations to include D+L loads in the load combination. The rei.olting stresses were very close to the allowable limit. The same beams now must be evaluated for added jet impingement loads.

The concern remains that these items were not included in the conclusions of Calculation NPB-119 Rev. O, or flagged as open items still under evaluation. In fact, since NPB-119 Rev. O was provided as a complete safety evaluation document for the selected breaks. IDA has further concern about the adequacy of the safety evaluation in ensuring that all targets are properly addressed. Also, the interdiscipline interface seems inefficient, since calculations revised to incorporate concerns of DOR-060 failed to incorporate jet impingement loads.

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STONE & WEBSTER ENGINEERING CORPORATION LIMERICK 2 IDCA fpg g

.q (J.0. No. 18138)

Q MAY 3 - 1989  !

OBSERVATION REPORT s- o 78D Observation Report No. HS-D OR- 003 Rev. O PART II - RESPONSE

1. Observation concurrence:

Concur with observation

_XX._ Do not concur with observation (Note: if not in concurrence, explain in "renarks" below)

2. Response to Observation:

A. Causal Factor (s)

B. Extent of Condition C. Significance D. Corrective /-tion

! p)

(

V E. Action to Prevent Recurrence

========================================================================

Remarks Bechtel does not concur with the concerns stated in the observation Report. NPB-119, Revision 0, was not provided as a complete safety evaluation document for the six selected breaks. As stated in the calculation Introduction and Purpose, the evaluation documents the review of the field walkdown review safe shutdown capability following l postulated hazards identified in Specification 8031-G-23. Specification 8031-G-23, Appendix G, details the separation program review walkdown procedures. Jet load effects on pipe whip restraints and other structures are considered in other calcu-lations.

As described in Specification 8031-G-23, Revision 0, Appendix G, Section G.1.0, Scope, high energy pipe break (HEPB) jet and pipe whip effects on structures and design / installation adequacy of pipe whip restraints and barriers are not within the scope of the G-23, Appendix G walkdown review. As stated in Appendix G, Section G.1.3, the walkdown reviews are to identify the separation and design installation of safety related and non-safety related commodities in each critical area, the protection by natural and design structures, and the actions necessary to establish plant safe shutdown. The commodities included and not included for review are listed in Section G.1.4.

As the result of the spec.ific scope of Appendix 0 walkdown review, the pipe whip restraints and structural steel listed in the observation Report are not included in I

[~ Calculation NPB-119 Revision O. The review of HEPB jet and pipe whip effects on j ( structures, barriers, and restraints is performed on an individual system basis (i.e. ,

l identify all structural items, pipe whip restraints impacted by individual postulated I breaks of each system). Each system's HEPB effects on the impacted structures, Page _1_ of G

STONE & WE58TER EMOINEEA!WO CORP 074710N LIMERICK 2 IDCA (J.C. No. 18188) Jpd /f g OBsskVAT!0W REPet,T Observation Report No. MB-D OR ,jtGL. Re v ,_L 1

j FiaY fI = RESPONSE ooWTfWifEB barriers and restraints are documented by a separate NPS calculation that determines the jet pressure and the location of impact. The results are then summarised and When civil ir.corporates the jet provided to civil via somos for their evaluation. j impingement and pipe whip leads in their final design, which indicates that the design '

is adequate, the HEPB jet and pipe whip effect evaluations on structures, barriers and restraints are considered to h elesed.

In the case of the sis break 6 (dentitled by 8Wte, the jet-effects calculations are provided in NP3 its, Revision 0, and NPR-26, Revision 1, transmitted to sWgc via 30727 on March 21, 1989.. All impacted targets have been identified in these calculations.

. specifically, the restrainte listed by sWEC in the concern are listed in Calculation Npt=128, Revision 0, on pages 14, 27, 85. 52, and St. The menos ref erenced in the Observation Report reflect the ongoing design process. (Reference 1 specifically ref erences Calculation NPS-128. Revision 0, not NPS-ii9.) Preliminary results from refined calculations by the Mechanical dieelpline for jet leads resulting from CJ 'the Civil Group have reduced the leading on structures to bring the total lo to an acceptable level.

90C and 1000 included the effect of dead and live load discussed in response to DCR-060. Following completion of the Mechanical calculation, civil vill complete their design calculattens to assure that the a!!avable limit for the affected structures is not exceeded. This process is espected to be complete for these postulated break locations by May 5, 1989.

i 4

... ........ssessesseness....re....sessesses. ... .. massesse=======esassesseessus==

UA0 L= W5 33s br / 7f $ Vb,r/h

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Sechtel Approval signature / Date PEco Review signature / Date 7 Page T of .fc_

l. 1 i

4 STONE & WEBSTER ENGINEERING CORPORATION LIMERICK 2 IDCA (J.O. NO. 18138)

,im i [ OBSERVATION REPORT 1

. %J - .

Observation Report HS-DOR-003 Rev . _0_, j Review Plan: LK- D - 1915 - MC . Rev. 1 PART III - RESPONSE EVAIRATION l

The response to this observation report has been evaluated as follows: i A. Causal Factor (s): Accepteble Not Accepable (Explain):

Not Applicable; see attached.

B. Extent of Condition: Acceptable Not Acceptable (Explain):

Not Applicable; see attached.

C. Significance: Acceptable Not Acceptable (Explain):

O' V

Not Applicable;'see attached.

D. Corrective Action: Acceptable Not Acceptable (Explain):

Not Applicable; see attached.

E. Action to Prevent Recurrence Acceptable Not Acceptable (Explain):

Not Applicable; see attached.

Additional Action Required: X No Yes (Explain) pJ................,......................................................................

Lead Engineer Signature 9ak A c.1 s/w/st

/ Date ma APWSignature sAz/e,

/ Date Page i of i

STONE & WEBSTER ENGINEERING CORPORAH ON.

LIMERICK 2 IDCA (J.O. No. 18138)

, OBSERVATION REPORT Observation Report HS-DOR-003 Rev. ,0_

PART III - RESPONSE EVALUATION CONTINUATION:

In order to support SWEC's review of the High-Energy Line Break (HELB)

Hazards evaluation, the Project agreed to provide a complete HELB Safety Evaluation document for a number of breaks identified for review by SWEC.

Accordingly, Bechtel prepared and provided Calculation NPB-119 Rev.

O for SWEC's review. During the review of this calculation, SWEC noted that certain targets such as pipe whip restraints and Civil Structures and structural components were not identified as HELB targets and were excluded from the scope of the calculation. It also was noted that certain structural members were acknowledged by the project to be overstressed by HELB -

induced loads and it was not clear how they were going to be reconciled. Therefore, HS-DOR-003 was prepared to document these observations.

In response, Bechtel explained that calculation NPB-119 was not provided as a complete safety -evaluation document for the selected breaks, and that consistent with the scope of specification 8031-C-23, Appendix G, structural items such as pipe whip restraints were not within the scope of the walkdown and the evaluation documented in calculation NPB-119.

Such items were explained to be considered in other calculations. Bechtel provided specific . references to other calculations that evaluated the whip restraints listed in the Observation Report. Also, Bechtel g acknowledged that the memoranda listed in the Observation Report reflected the on going design process and that preliminary results from applying the refined jet impingement loads to the affected structures had apparently resolved the overstress concerns. Bechtel subsequently provided revised mechanical calculations and civil calculations 17-T-6A, Rev. O, 17-T-6B, Rev. O, and 17-n-17, Rev. 2 which addressed the total reconciliation process. Based on a cursory review of these calculations by SWEC, Bechtel's preliminary results are confirmed. The concerns of the Observation Report are therefore adequately addressed and require no further action.

Regarding the concern about the adequacy of structural members addressed in DOR-060, the response explains the on going desi F9 process and since the final reconciliation includes all applicable loads, there is no further concern.

1 t

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STONE & WE5 STER ENGINEERING CORPORATION LIMERICK 2 IDCA

,, (J.O. NO. 18138)

! \

'd

• OBSERVATION REPORT Observation Report NoHS-D OR-004 Rev. O Review Plan: LK ' D - 1915 -MC Rev. [

Reference AI No.: Not Applicable PART I - INITIATION

1. DESCRIPTION OF CONCERN The review of the High Energy Line Break (HELB), G-23 Hazard Review Field Walkdown of 11/11/88, Calculation Number NPB-119, Revision 0 resulted in-the following concerns:

1. Ruptured target lines associated with the "Drywell Gas Supply" may result in additional pressurization of the drywell due to the addition of nitrogen.

2. Remaining combinations of Emergency Core Cooling Syste ms .(ECCS) following a postulated - HELB are not consistent . with the FSAR

• licensing commitments.

3. Traceability- to minimum available ECCS acceptance criteria, such as GE criteria, for ECCS requirements following a HELB v). is not provided.

4. Traceability. for a target identification and associated reference sheet is not provided.

5. There appear to be inconsistencies within the documentation regarding " manual action".

6. There appear to be certain editorial inconsistencies within the document associated with the safe shutdown flow chart and its legend for the " items assumed lost by additional single failure."

2. -SUPPORTING INFORMATION Reference 1 -

G-23 Hazard Review Field Walkdown of 11/11/88, Calculation Number NPB-19, Revision 0, dated 3/29/89.

. . .C.O.N.T.I.N.U.E.D. .O.N. .T.W.O. .P.A.G.E.S. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . = = =

Additional Documents Attached: None

................... E f " qf~)~CA O!n. 6 C& M.wille 4/wls1 l Lead Engineef Signature / Date A141 Signature ' / Date l

l Page 1 of 1 1

y_____.______.-_ __ _ _ _ _ _ _ _ _ _ _ _ _ __ __

STONE di WEBSTER ENGINEERING CORPORATION LIMERICK 2 IDCA i (J.O. No.'18138) l: Y OBSERVATION REPORT

. L /i

)

Observation Report No. HS-D OR- 004' Rev. 0 l

PART 1 - INITIATION D CONTIEtIATION:

1. Reference 1, Sheets 53 and 54 identify targets 1" . HCC-232, 234 and 1"'JCD-211 "DW Gas Supply." Nitrogen Instrument Cas Bottles supply back-up nitrogen to the Primary Containment Instrument Cas System. If following the postulated HELB, valve M59-HV251B.

remains open as designed and valve M59-SV252B fails open as a result of a single active failure, there is a potential effect upon the drywell pressure due to - the addition of nitrogen gas through ruptured target lines - 1"-HCC-232, 234, and 1"-JCD-211.

The magnitude of this potential effect has not been demonstrated.

by Reference 1.

2. a. Reference 1, Sheet 131: Target #3 identifies LPCI D. A postulated loss of LPCI D combined with the stated worst single active failure (WSAF), loss of Division 1, on Sheet 134 of Reference 1, would result in LPCI B and C remaining to support safe shutdown. This is inconsistent with FSAR Section 6.3.1.1.2, paragraph e (1) and FSAR Table 6.3-3, note 2, which shows 3 LPCI loops available without the availability of HPCI.

b. Based upon the ADS being targeted, Reference 1 Sheet 97, .

under " Remarks" it is stated that "the ADS are not needed to depressurize the RPV as the break is large enough that

.the. low pressure ECCS will be actuated.' This is inconsistent with FSAR Section 6.3.1.1.2, paragraphs, e(1) and e(2) and FSAR Table 6.3-3, note 2 which show ADS available for this HELB.

c. Reference 1, Sheet 98, under " Comments" states that "the PSD evaluation will assume that the items impinged by the jet will fail (i.e. , LPCI A, LPCI C, and CS A) plus a WCSAF of B-DG". Based upon this scenario only one LPCI loop (LPCI D), will remain in service and no CS will be available for safe shutdown. This is inconsistent with FSAR Section 6.3.1.1.2, paragraph e(1) and FSAR Table 6.3-3, note (2).

3. Traceability to minimum available ECCS acceptance criteria, such as CE criteria, for ECCS requirements per PRA shown in Calculation NPB-71, Sheet 2B of 19, Revision 3 is not provided.

Also, traceability to this calculation is not provided in Reference 1.

4. Reference 1, Sheet 131, Target #5 identifies "AI-006" and states

" sea Sheet 3". The description of this target is not provided.

Also, sheet 3 cannot be traced in Reference 1.

O CONTINUED ON ONE PAGE Page 1 of 9

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STONE & WEBSTER ENGINEERING CORPORATION LIMERICK 2 IDCA :

-(J.0. NO. 18138)

M '

OBSERVATION REPORT 9N f .

Observation Report No.HS-D OR- 004 Rev. O PART 1 - INITIATION CONTINUATION:

5. a. Reference 1, Sheet 52, lisis "M", which is shown in the

~1egend as ' "by manual means/ help", under "RHR . Suppression Pool Cooling". This . appears inconsistent with Reference

1. Sheet 6, line 6 which indicates no manual action.

b. Reference 1, Sheet 132, Target # 6 identifies valve M57-HV-224 which is the ' containment isolation valve - for the suppression' pool for containment ATM control.'

Postulating that this . target fails and a single active failure is postulated for the . redundant isolation . valve, it appears containment isolation (CI) would not be maintained without manual action. It is agreed that CI is not required for this HELB; however, Reference 1, Sheet 135, shows "yes" for containment isolation available and states that no manual action is required.

6. Reference 1, Sheet 52 shows the legend for "e" as " item assumed 7

lost by additional single failure." It appears the legend should

( read "@" instead of "e" to be consistent with the notations used in the flow chart.

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' STONE F WEBSTER ENGINEERING CORPORATION.

LINERICK 2 IDCA ,[ p g [ / ((

(J.0. No. 18138) {

OBSERVATION REPORT (S- o 7 N)

MAY 5 - 1989 -

Observation Report No'. HS-D OR ,,.Q9_I_ t Rev. O PART II - RESPONSE

1. Observation Concurrence:

Concur with observation i H_ Do not concur with observation (Note: if not in concurrence, explain in

" remarks" be1ow) J s

j

2. . Response to observation: 1 i

A. Causal Factor (s)

B. Extent of Condition C. Significance D. Corrective Action

.j E. Action to Prevent Recurrence U ....................................................................................-

Remarks' Bechtel does not-concur with the concerns stated in Part I of the Observation Report for the reasons given below. Item numbers correspond to those of Part I, Item 2, Supporting Information.

1. If ' valve SV-59-252B is assumed to f all open, the total N2 ges injected into the drywell from three gas bottles (FSAR Figure 9.3-2, Sheet' 3) is approximately 750 scf. which will have minimal effect on drywell pressurization. The calculated drywell. pressurization from the postulated main steam line break is approximately 37 psig (FSAR Figure 3.6-12), which is well below the containment design pressure of 55 psig (FSAR Table 6.2-1) .

2 .. a. .The sequence of required actions and the components needed for safe l shutdown due to a postulated pipe break event inside containment - is a function of break size, location, and fluid state of the reservoir. FSAR Section 6.3.1.1.2 paragraph e and FSAR Table 6.3-3 tabulate the available ECCS af ter an assumed single active failure for the whole' spectrum of breaks regardless of break sizes, location or fluid state of the reservoir.

The referenced FSAR section and the table tabulate the available ECCS con-sidering an assumed single active f ailure af ter the postulated initiating pipe break event (l'.e., LOCA) has occurred in one of the ECCS pipes. The l minimum ECCS requirements are provided in the Probabilistic Risk Assessment I- (PRA) as referenced in NPB-71, Revision 5, and submitted to the NRC via l

PECo letter E.J. Bradley to H. R. Denton, dated March 17, 1981. Based on l

Table 1.2 of the PRA, the minimum ECCS requirement for a large LOCA is one

! LPCI loop or one core spray loop, and one RHR loop in suppression pool i

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STONE & WEBSTER ENGINEERING CORPORATION

,m (J.0, N . 181 8) DCA / 948 OBSERVATION REPORT Observation Report No. HS-D OR- 004 Rev. O PART II - RESPONSE CONTINUED cooling. Hence, the evaluation provided on page 145 (identified as page 134 in the DOR) of Calculation NPB-119, Revision 0, is correct as stated.

In addition, the Protection Sequence Diagram (PSD) provided on page 145 is for break TE-105C of RCIC steam supply line outside containment.

Because the break will be isolated by the inside'or outside containment isolation valves, due to high rlow through the break, the ECCS may not be needed as normal shutdown capability is available. However, for conservatism the PSD did not take credit for the availability of offsite power er normal shutdown capability.

b. As stated in response 2.a. , FSAR Section 6.3.1.1.2, paragraph e(1) and e(2) and FSAR Table 6.3-3, Note 2 do not provide the minimum ECCS requirements for plant safe shutdown. Therefore, there is no inconsistency ,

between the FSAR and Calculation NPB-119, Revision O. Also, the statement l' provided in the " Remarks" merely stated that ADS is not needed to depressurize the RPV....for the specific postulated pipe break event as evaluated in the referenced section of Calculation NPB-119 Revision O.

.[d It does not imply that the ADS is not available, t

c. For the same basic reason as stated in response 2.a. and.2.b., there is no inconsistency between the FSAR and Calculation NPB-119, Revision O.

3. The PRA was developed by GE for PECo at the request of the NRC and submitted to the NRC via PECo letter E.J. Bradley to H.R. Denton of the NRC, dated March 17, 1981. .

The adequacy of PRA application for the development of minimum ECCS requirements has been concurred with by GE and PECo.

Calculation NPB-71, Revision 5, Sheet 2B is referenced on Sheet 2A (i .e. , PSD) which is provided as Attachment F-2 to Specification 8031-G-23, Appendix F.

Also, NPB-71 discussed the usage of Sheet 2A for other prime calculations. In addition, the " Procedure" section of Calculation NPB-119, Revision O (Sheets 9 through 12) provided the methodology for the use of Attachment F-2.

4. The subject phrase "See Sheet 3" refers to Sheet 3 of the discussion provided, which is Sheet 140 of Calculation NPB-119, Revision O. The section of " Rationale for Acceptance," on Sheet 131 of Calculation NPB-119, Revision 0, referenced the discussion and description of tsrget #5.

l

5. a. There is no inconsistency between the two sheets referenced above. The "H" indicated on Sheet 52 of Calculation NPB-119 Revision 0, is for the actuation of the D loop of RHR suppression pool cooling, which is not the normally aligned loop of the RHR suppression pool cooling. The definition

1. q of manual action for RHR suppression pool cooling is provided in NPB-71, Revision 5, Sheet 17.

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ETONE & WE5BTER ENGINIn lNO CohPOU310W i LINERICR 2 !DCA  ![ i O (J.C. NO. 18188) l l

055ERVATION ktPCAT

• i observation Report No. HE-D OR ,,2lL Rev..,9 PART 11 - RttPONE{ CONT 1WUED Because Loops A and 8 are the normally aligned RHR suppression pool cooling loops and Loop B is assumed to be disabled due to the assumed WesAF of the 5 diesel generator. Loop A becomes the only normally aligned. RMR i suppression pool cooling loop. Based on the PRA. only one RHR suppression j pool cooling loop is needed for long term cooling and Loop A is available. 4 Therefers, sheet 4 of calculation NP8-119, Revision 0, indicated the "no manual action required."

k. As indicated in " Rationale for Acceptance" provided en sheet 181 of Calculation NP8-iit. Revision 0, valve NY-57-gg4 is ' motor operated (HC)*

and "normally closed (NC).* The hasard identified is HEPR spray effect (i.e., vetting effect) onto the bottom of the valve (see figure provided ,

on sheet 149 of the calculation). Because the Valve Is normally closed, containment isolation is maintained and manual action is not required if a single failure of the second containment teolation valve is postulated.

Therefore, the evaluation provided on sheets 131 and 135 is correct as stated.

' as shown on the legend of sheet 52 of Calculation NFB-119 The symbol Revision 0, has* @become indistinguishable from the symbol "*

• during the copyi

( process when a copy of the calculation was transmitted to $WIC. There is no need for revision as the original calculation is sufficiently clear to distinguish j ,

between the tvo symbols.

l ausses ...ma s e sess emas s eems ....s moe spe == =mu sassene s a sensa s =====essess e s....u....we e l,

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[" STONE & WEBSTER ENGINEERING CORPORATION LIMERICK 2 IDCA (J.O. NO. 18138)

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OBSERVATION REPORT Observation Report HS-DOR-004 Rev. O Review Plan: LK-D -

1915 - MC Rev. 1 PART III'- RESPONSE EVALUATION Tha' response to this observation report has been evaluated as follows:

A. Causal Factor (s): Acceptable Not Acceptable (Explain):

Not Applicable.

B. Extent. of Condition: Acceptable Not Acceptable (Explain):

Not Applicable.

C. Significance: Acceptable Not Acceptable (Explain):

i Not Applicable.

D. Corrective Action: Acceptable Not Acceptable (Explain):

Not Applicable.

E. Action to Prevent Recurrence: Acceptable Not Acceptable (Explain):

Not Applicable.

.......................................u............==.................====...=.. .====

Additional Action Required: Lo N Yes (Explain)

See Attachment.

o.....................................................................................

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h $U b LaTd'Enginebr Signature

/ Date APfl Sidnature / Date Page 1 of 1

STONE & WEBSTER ENGINEERING CORPORATION LIMERICK 2 IDCA t ,

(J.O. No. 18138) p k[ OBSERVATION REPORT Observation Report' HS-DOR- 004 Rev. O PAP.T-III - RESPONSE EVALUATION CONTINUATION:

Based upon the response, a review of FSAR Figure 9.3-2, Sheet 3,

'1.

6.2-12, FSAR Table 6.2-1, and Calculation M-59-7, FSAR Figure Revision 0, Sheets 3 and 4, it is agreed that there would be minimal' effect on drywell pressurization and the concern is resolved.

2a. The response explained that FSAR Section 6.3.1.1.2, Paragraph e and FSAR' Table 6.3-3 tabulate the available ECCS after an assumed single active failure . for the whole spectrum of. breaks regardless of break sizes, location, or fluid state of the reservoir. The response also explained that the minimum ECCS requirements are ~provided in the Probabilistic Risk Assessment (PRA) as referenced in NPB-71, Revision 5, and submitted. to the NRC via PECo letter E. J. Bradley to H. R.

Denton, dated March 17, 1981. Based upon the response and a review of Calculation NPB-71, Sheet 2B of 19, Revision 3, " Matrix for Use of PRA Table 1.2 Data", the concern is resolved.

2b. The response resolves the concern based upon the discusdon and review performed as stated in 2a of this response evaluation. The review of Calculation NPB-71, Sheet 2B of 19, Revision 3, showed that ADS availability is not required for the subject HELB.

2c. The response resolves the concern based upon the discussion and review performed as stated in 2a of this response evaluation. The review of Calculation NPB-71, Sheet 2B of 19, Revision 3, showed that the ECCS availability consisting of one LPCI loop with no Core Sprays (CS) available is acceptable.

3. The response explained that the PRA was developed by CE for PECo at the request of the NRC and submitted to the NRC via PECo letter E. J. Bradley to H. R. Denton of the NRC, dated March 17, 1981.

The response also explains how Calculation NPB-71, Revision 5 is referenced and integrated into the HELB progria via Specification 8031-G-23 and Calculation NPB-119. Based upon the response and a review of Specification 8031-G-23, Appendix F and Calculation NPB-119, Sheets 9 through 12, the concerns are resolved.

4. The response explained that "see Sheet 3" refers to Sheet 3 of the discussion provided, which is Sheet 140 (should read 139) of Calculation NPB-119, Revision 0. A review of calculation sheet 139 shows that target #5 "AI-006" is defined and addressed accordingly, which resolves the concerns.

Sa. The response explained that the "M" indicated on Sheet 52 of Calculation NPB-119, Revision 0, is for the actuation of the D loop of RHR suppression pool cooling and that the A loop of RHR suppression p pool cooling is available for long term cooling without manual action.

' This is consistent with Calculation NPB-119, Sheet 52, and the criteria in Calculation NPB-71, Sheet 2B. Therefore, the response resolves the concern.

CONTINUED ON ONE PAGE. Pye F of 9

STONE & t!EBSTER ENGINEERING CORPORATION LIMERICK 2 IDCA (J.O. No. 18138) p-y) . OBSERVATION REPORT Observation Report HS-DOR- 004 Rev. O PART III - RESPONSE EVALUATION CONTINUATION:

Sb. The response explained that the subject valve is normally closed as indicated by "NC" on Sheet 131 of Calculation NPB-119, under

" Rationale for Acceptance". Therefore, based upon the _ applicable MEPB hazard effects, the response concludes that containment isolation is maintained and manual action is not required if a single active failure of the second containment isolation valve is postulated.

Based upon the response, a further review of Calculation NPB-119,.

(Sheets 131 and 149), and a review of FSAR Figure 9.4-5 Sheet 4 of 6, coordinate C-4, which shows valve M57-HV-224 normally closed, the concern is resolved.

6. The response explained that the symbol "d' has become undistinguishable from the symbol "*" during the copying process and that . there is no need for revision as the original calculation is sufficiently clear. The response resolves the concern.

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l Page 9 of 7

(

STONE & WEBSTER ENGINEERING CORPORATION LIMERICK 2 IDCA-i.

(J.O. NO. 18138) y

' OBSERVATION REPORT (v) .

Observation Report No. HS-It)R-- 005 Rev. O_ ,

Review Plan: LK- D - 1915 - MC Rev. ,0, o Reference AI No': . Not Applicable hARTI-INITIATION

1. Description of Concern The review of the High Energy Line Break (HELB) G-23 Hazard Review _

Field .Walkdown of 11/11/88, Calculation Number NPB-119, Revision 0 resulted in the following concerns regarding the review for flooding due to a HELB:

1. The basis for the flood heights established by the walkdown is. not provided and traceability to a reference document which establishes the HELB flood height' as compared to the flood height established by the walkdown is not provided.

. Also, it was noted during the review that there is no traceability to a reference document which establishes the Moderate : Energy IPipe Break (MEPB) or " exterior non piping systems" flood height as compared . to the walkdown

/ flood height, b

2. It appears that the Moderate Energy Pipe Break (MEPB) analysis flooding results have been applied to HELB flooding mitigation without traceability to a HELB flood' height to justify that the MEPB flood height and associated protection envelopes flooding due to the HELB.

2. Supporting Information Reference 1 - G23 Hazard Review Field Walkdown of 11/11/88, Calculation Number NPB-19, Revision 0, dated March 29, 1989.

1. Reference 1, Sheet 130 for Room Number 376, Fire Zone 66, lists the flood height as 20". There is no basis provided in Reference 1 for this walkdown flood height and there is no traceability to a reference document which establishes the HELB flood height as compared to this value (20").

CONTINUED ON ONE PAGE s a ams mosam smmm mmm mmm m mmm m mmmm m m m ma s e mmm m m sma a m m m m mmmmmmmmm m mm ma sa ss ans s a m m a s sa mm m m m mm ma Additional Documents Attached: None m a ap a a m m a a m m a s s a m a m e s a m m a s s m e m a s s u s p a s a s s m o n e s s e m a s s a u s s a m m a s s m u s s a m s m a s s s a m a m m m m m m m a s s Lead EnTneer Signaturc l% h _ . k . Yh lA D. Wh W20lG

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/ 'Date p Signatureg /

Page 1 of 1

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( STONE & WEBSTER ENGINEERING CORPORATION LIMERICK 2 IDCA {

(

(J.0.'NO. 18138) i OBSERVATION REPORT

/]

' Ql ^

Observation-Report No. HS-DOR- 005 Rev.

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0

'PART 1 - INITIATION CONTINUATION:

Also. . this Reference 1 sheet does not provide traceability to a reference document which establishes the Moderate Energy Pipe Break (MEPB) or " exterior non piping systems" flood height as compared to this value (20"). The review showed that the MEPB Analysis Report, Appendix D, . Revision 2, Table I, . Sheet 6, established the flood height for Fire Zone 66 at '24". These concerns also apply t o. Reference 1, Sheet 193 and 202.

2. During the review of Reference 1 it was noted that Sheets 173 through 182 were sheets. extracted from Calculation NPB-14 " Moderate Energy Line Break Analysis: Reactor Enclosure,- Control Structure, . Spray. Pond Pump _ Structure, and Diesel Generator Enclosure Flooding", Revision 4.

Reference 1, Sheet 178 (Calculation NPB-14. Sheet 226E) states that " Fire Zone 66 is also a high energy line zone due to eteam supply lines to HPCI and RCIC pump . turbines.

The consequences of the HELB have been evaluated elsewhere and is out of the scope for this calculation" (NPB-14).

("] Reference 1 includes the statement by a checkers note:

'N / "Per MEPB Report Rev. 2 (Appendix D, Table 1, Sheet 6, and note 19), the calculated flood height is acceptable and no further protection is necessary." There is no traceability to a HELB flood height to justify that the MELB flood height and associated protection envelope flooding due to the HELB.

f v

Page A of 9

STONE & WEBSTER EN3INEERING CORPORATION i

+

LIMERICK 2 IDCA.

(J.0. No. 18138)

[ k[

v

. OBSERVATION REPORT NAY 3 -1989

[.bO Y '

j Observation Report No. HS-D OR _,09.L Rev . O PART II - RESPONSE l

1. Observation Concurrence:

_IL concur with observation  :

Do not-concur with observation (Note: if not in concurrence, explain ir

" remarks" below)

2. Response to Observation:

A. Causal Factor (s)

Flood heights are not established by walkdown. They are calculated in NPB-14 for areas outside of containment. The flood height listed on Sheet 130 of Calculation NPB-119. Revision 0, should have been 24". This value is obtained from Sheet 294 of Calculation NPB-14, Revision 3, which was transmitted to SWEC via S0032. The discrepancy between the flood height of 24" and sheet 130 of Calculation NPB-119 Revision 0, with flood height of 20" was caused' by inadvertently copying the wrong flood ' level . The

't traceability to Calculation NPB-14. Revision 2, or Moderate Energy Pipe Break (MEPB) Report, Revision 2, (transmitted to SWEC via S0032) for flood level was also inadvertently left out of the " Reference / Comment" column t on' Sheet 130 of . Calculation NPB-119 Revision O. The error occurred because the rooms outside of containment were added to the calculation to provide the safety evaluations for the six breaks chosen by SWEC for review. Calculation NPB-119 was originally intended to cover the safety evaluation for the drywell and suppression pool only.

Reference is not given in the calculation to the high energy pipe break (HEPB) flood height. The calculated HEPB floco level (i.e., 60" without operator action or 24" with operator action as. stated in MEPB Report, Revision 2 Sheet 6, Appendix D, Table I) from the postulated worst case MEPB event in this room envelopes the resultant flood level from the largest postulated HEPB in this room (i.e. , HPCI steam supply line break) .

This was a judgment which was not documented in the calculation.

B. Extent of Condition Calculation NPB-119 is the only Mechanical calculation completed for Unit 2 to document the safety evaluation for flooding effects. The calculation has been reviewed for other cases of this type of error. The flood levels used in the evaluation for Rooms 374 and 375 (Sheets 193 and 202) are <

correct as stated. There are no other Reactor Enclosure rooms considered p in NPB-119 Revision 0, as the remaining areau and rooms are inside the Q drywell. Therefore, the discrepancy identified by SWEC is a unique case.

l l

Page _)_.,of 9

l STONE & WEBSTER ENGINEERING CORPORATION LIKERICK 2 IDCA (J.0. No. 18138) .f 1"l)C/9/9P66 d

( OBSERVATION REPORT l-

[. Observation' Report No. HS-D OR _QQg_ Rev. 0 1

PART II - RESPONSE CONTINUED The following rationale is provided to demonstrate why the condition does not extend to the flood levels used for Rooms 374 and 375. ,

1 1. Sheet 193 of Calculation NPB-119, Revision 0, addresses the flood level for Room 374 located at Areas 14 and 18 of the plant and Sheet 202 of Calculation NPB-119, Revision 0, addresses the flood level-

' for Room 375 located at Areas 13 and 17 of.the plant. Both of these rooms are located at Elevation 241'-3"'and are concrete platforms with one floor drain each and are accessible only by the ladder at the south side of the rooms above the grating platform in Room 376 (floor elevation 217'-0") . See' figure provided on Sheet 196 of -

Calculation NPB-119. Revision 0, and FSAR Figures 1.2-7; 1 '. 2-49 , 3 i

Sheet 2; 1.2-50, Sheet 2: 1.2-51, Sheet 2; and 1.2-52, Sheet 2 for the exact orientation of these two rooms relative to Room 376.

2. As noted in the " Comment" section of Sheets 195 and 203 of Calcu-lation NPB-119, Revision 0, Rooms 374 and 375 contain containment isolation valves for the drywell instrumentation. Hence, most of; O the lines in the roca are either instrument tubing or piping that is one inch diameter or smaller. The larger diameter piping is either normally not pressurized or is air purge' piping. Therefore, postulating a moderate or high energy pipe break from any of this piping as an initiating event is not required per FSAR Section 3.6 and'SRP 3.6.1 and 3.6.2.

3. As shown on the figures referenced in item 1 above, the concrete platforms (Rooms 374 and 375) are above all of-the moderate energy and high energy lines in Room 376 at Elevation 217'-0". Therefore, the rooms only receive high energy pipe break effects of pressuri-zation and elevated temperature from either the postulated HPCI steam supply line break or the postulated RCIC steam supply line break as evaluated in FSAR Table 3.6-7. As's result, the flood levels in Rooms 374 and 375 are minimal as only steam condensation on the pipes, walls, and floor, etc. , would result in any water accumulation on the floor and could be accommodated by the existing floor drain.

C. Significance The use of an incorrect value on Sheet 130 of Calculation NPB-119. Revision

'0, the lack of reference to Calculation NPB-14, and use of undocumented engineering judgment to address HEPB flooding levels are not significant.

The safety evaluations performed for flooding effects resulting from the O postulated moderate energy pipe break for Rooms 374, 375, and 376 are Page 4 of 9 i

__ . _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ . a

i STONE'& WEBSTER ENGINEERING' CORPORATION I LIMERICK 2 IDCA .

l (J.O.'No. 18138)

M. /

OBSERVATION REPORT I

observation Report No. HS-D OR ._QQE,_ Rev. O PART II --RESPONSE CONTINUED correct as they were based on the 24" flood level as stated in MEPB Report, i Revision 2; not the 20" value given on Sheet 130.

The correct documentation was used for the safety evaluation, even-though it was not explicitly referenced. Therefore, the lack of reference has r

no impact on the calculation results.

The judgment that the postulated worst case MEPB event envelopes the HEPB was not documented but is valid for the following reasons:

1. As shown on FSAR Table 3.6-6, HPCI steam supply steam line blowdown terminates at 14 seconds af ter the postulated pipe break event.

2. As shown on FSAR Table 3.6-7, the peak' pressure reaches 1.39 psig at the time of 0.19 seconds af ter the break and the peak temperature of 264*F is reached at the time of 13.62 seconds. . Based on the peak pressure occurring much earlier than the peak temperature, most i

(approximately 90%) of the steam blowdown from the postulated pipe -

break will be released through the blowout panel to the plant exterior. The remaining 10% from the steam blowdown may condense onto the walls, floors, and pipes, etc. , in the room. Hence, water accumulation resulting from the condensation will be minimal and could be accommodated by floor drains.

3. Based on the mass blowdown data provided in FSAR Table 3.6-6, con-servatively assuming 100% condensation of the anticipated steam (i.e., no mass release to plant exterior through the blowout panel) the total mass input to the room from the postulated HPCI steam supply line break (i.e., area under the mass flow rate versus time curve) is well below the total mass input from the postulated worst cast moderate energy pipe break. (Reference Sheet 69, item b and Sheet 9, item b, MEPB Report, Revision 2.)

The moderate energy pipe break flooding level clearly bounds that of the high energy pipe break flooding level and the lack of documentation of engineering judgment has no significance. The results and conclusions stated in MEPB Report, Revision 2, remain the same.

D. Corrective Action

.The corrective action consists of revision to Sheet 130 of NPB-119 to show that the flood level should be 24" and to indicate in the

" Reference / Comment" column that MEPB Report, Revision 2, with operator v action, is used for the flood height references. This correction will be made in Revision 1 of NPB-119. The estimated completion date for this Page C of 9

d a > .- s. . ,.

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STONE & WE887ER EWO!NEERING CORPORATION JBCA / 944 ux mier a roca r ( -

(J.0, No. 18188) J L-OsstavATION REPORT Wi-B OR ,,,QQL, Rev.1 Observation Report No. )

t F11T II - RElipeMat MWTfWUfB revision to Calculation NPlaiit is May 5.1989. Based on the discussion in Section 8. he corrective action is needed for shoose 193 and 202 (i.e.,

Rooms 374 and $78 as part of Fire tone 66) of HPS-119. l

)1 E. Action to Prevent Recurrence the originators and checkers involved in calculation NPB-fi9. Revision 0, have been instructed regarding the lessons learned from this observation e.rort.

Remarka O

J %w sie m p " W,A L L L b i r r r/un PEco Review signature / Date Bechtel Approval alsnature / Date 7 ass .4 of .1

___m_ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ . _ _ _ _

STONE & WEBSTER ENGINEERING CORPORATION LIMERICK 2 IDCA (J.O. NO. 18138)

/m i I OBSERVATION REPORT a

Observation ReportHS-DOR- 005 Rev. O Review Plan: LK- D - 1915 - MC Rev. J PART III - RESPONSE ETALUATION Th3 response to this observation report has been evaluated as follows:

A. Causal Factor (s): X Acceptable Not Acceptable (Explain):-

.a See Attached.

B. Extent of Condition X Acceptable Not Acceptable (Explain):

See Attached.

C. Significance: X Acceptable Not Acceptable (Explain):

See Attached.

D. Corrective Actions X Acceptable Not Acceptable (Explain):

See Attached.

E. Action to Prevent Recurrence: X Acceptable Not Acceptable (Explain):

See Attached.

l ..................................................................................=====

-Additional Action Required X No Yes (Explain)

/~N ....................... ..............................................................

hM Sfhf39 NM/ Date Lsad Engineer Signature 5%/9

• Mb' [v 0K/

APW Signature M//[f7

/'Date l Page 1 of ,1

STONE & WEDSTER ENGINEERING CORPORATION LIMERICK 2 IDCA (J.O. No.'18138) jq OBSERVATION REPORT

} f l

Observation Report HS-DOR-005 Rev. O l

PART III - RESPONSE EVALUATION CONTINUATION:

A. Causal Factors:

The . response explained that - the flood heights listed in Calculation NPB-119. Revision 0, Sheet 130 should have been consistent with the Moderate Energy Pipe Break (MEPB) evaluation results and the inconsistency is attributed to human error.

It was noted during the response evaluation review that the 24" flood level is from the MEPB Report and not from Calculation NPB-14, Revision 3, Sheet 294.

B. Extent of Conditions The response explained that the identified discrepancy is a unique case and provided the rationale to demonstrate why the condition does not extend to the flood levels used for Rooms 374 and 375.

C. Significance The response explained that the items of concern are not significant r and provided the supporting rationale. The judgement that the i postulated worst-case MEPB flooding event envelops the HELB flooding event for fire zone 66 (Room 376) is supported by the reasons provided.

By using data from FSAR Table 3.6-6 and Calculation NPB-14, Revision 3, it - was confirmed that the flood level resulting from the mass releaned during the HELB(s) isolation times is less than the MEPB mass released at a flood height of 24 inches.

Verification of the sampled MEPB flood detection instrumentation installation was performed during the MEPB site walkdown review.

It was noted during the response evaluation review that areas such as the main steam tunnel, which have flood heights due to HELB(s) that may not be enveloped by the MEPB flooding evaluations appear adequately addressed in Calculation NPB-15 Revision 1. A review of this calculation as compared to the MEPB Calulation NPB-14, revision 3 showed that the MEPB flood heights enveloped the safety related area HELB flood heights except for the main steam tunnel which appeared appropriately addressed. It was understood during the review that the areas addressed by NPB-15 are not currently included in Calculation NPB-119, but will be walked down and the associated documentation completed upon the project's finalization of the HEPB Evaluation Program.

D. Corrective Actions f The response stated that Calculation NPB-119 will be revised to correct the flood level to 24" on Sheet 130 and include the MEPB report as the reference document by May 5, 1989.

Pap S d T

g. _ _ - . _ _ . - _- . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - -

STONE & WEBSTER ENGINEERING CORPORATION LIMERICK 2 IDCA (J.O. No. 18138)

,/

'\, ,/ OBSERVATION REPORT Observation Report ES-DOR _-005 Rev. O PART III - RESPONSE EVALUATION CONTINUATION:

E. Action to Prevent Recurrence:

The response explained t.ha t the originators and checkers involved in the calculation have been instructed regarding the subject issues and concerns.

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