Topical Rept Safety Evaluation of WCAP-13524 & WCAP-13524, Rev 1, Apollo-A One-Dimensional Neutron Diffusion Theory Program, Rept Acceptable Due to Favorable Comparison W/Those Calculated by 3D AncML20140E225 |
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ML20140E177 |
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NUDOCS 9706110283 |
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Category:TEXT-SAFETY REPORT
MONTHYEARML20217L8831999-10-21021 October 1999 Safety Evaluation Supporting Proposed Alternatives to Code Requirements Described in RR-V17 & RR-V18 ML20217L9371999-10-20020 October 1999 Safety Evaluation Supporting Licensee Proposed Alternative from Certain Requirements of ASME Code,Section XI for First 10-Yr Interval Request for Relief for Containment Inservice Insp Program ML20217K3301999-10-19019 October 1999 Safety Evaluation Supporting Amend 195 to License DPR-61 ML20217J0721999-10-18018 October 1999 Safety Evaluation of Topical Rept EMF-2158(P),Rev 0, Seimens Power Corp Methodology for Boiling Water Reactors, Evaluation & Validation of Casmo-4/Microburn-B2. Rept Acceptable for Licensing Evaluations of BWR Neutronics ML20217H8991999-10-18018 October 1999 SER Approving Licensee Requests for Relief NDE-R001 (Part a & B),NDE-R027,NDE-028,NDE-R029,NDE-R030,NDE-R032 & NDE-R035. Relief Request NDE-036,denied & Relief Request NDE-R-034, Deemed Unnecessary ML20217J4791999-10-18018 October 1999 SER Approving Exemption from Certain Requirements of 10CFR73 for Zion Nuclear Power Station,Units 1 & 2.NRC Concluded That Proposed Alternative Measures for Protection Against Radiological Sabotage Meets Requirements of 10CFR73.55 ML20217K9441999-10-15015 October 1999 SER Accepting Util Alternative Proposed Relief Request RR-ENG-2-4 for Second 10-year ISI Interval at Stp,Units 1 & 2 Pursuant to 10CFR50.55a(a)(3)(i) ML20217K9151999-10-15015 October 1999 SER Authorizing Util Relief Request RR-ENG-2-3 for Second 10-year ISI Interval of Stp,Units 1 & 2 Pursuant to 10CFR50.55a(a)(3)(i) ML20217G0931999-10-15015 October 1999 Safety Evaluation of Topical Rept BAW-10179P,Rev 3, Safety Criteria & Methodology for Acceptable Cycle Reload Analysis. Rev 3 Found Acceptable & Accurately Include Conditions & Limitations for Applicability of References ML20217K0651999-10-15015 October 1999 Safety Evaluation of Topical Rept BAW-10193P, RELAPS5/MOD2-B&W for Safety Analysis of B&W-Designed Pressurized-Water Reactors. Rept Acceptable for Referencing in Licensing Applications ML20217G0191999-10-15015 October 1999 Safety Evaluation Concluding That Licensee Followed Analytical Methods Provided in GL 90-05.Grants Relief Until Next Refueling Outage,Scheduled to Start on 991001.Temporary non-Code Repair Must Then Be Replaced with Code Repair ML20217G2161999-10-15015 October 1999 Errata Pages 2 & 3 for Safety Evaluation Supporting Amend 168 Issued to FOL DPR-63 Issued on 990921.New Pages Change Description of Flow Control Trip Ref Cards to Be Consistent with Application for Amend ML20217K9931999-10-14014 October 1999 Safety Evaluation Supporting Amend 234 to License DPR-56 ML20217H8501999-10-14014 October 1999 Safety Evaluation Supporting Amend 197 to License DPR-64 ML20217G9961999-10-14014 October 1999 SER Accepting First 10-year Interval Inservice Insp Requests for Relief for Plant,Units 1 & ML20217G2041999-10-13013 October 1999 Safety Evaluation Supporting Amend 179 to License DPR-28 ML20217J1101999-10-13013 October 1999 Safety Evaluation of Topical Rept TR-108727, BWRVIP Vessel & Internals Project,Bwr Lower Plenum Insp & Flaw Evaluation Guideline (BWRVIP-47). Rept Will Provide Acceptable Level of Quality for Exam of safety-related Components ML20217D3061999-10-13013 October 1999 SER Accepting Licensee Proposed Changes to Edwin I Hatch Nuclear Plant Emergency Classification Scheme to Add Emergency Action Levels Related to Operation of Independent Spent Fuel Storage Installation ML20217C9121999-10-12012 October 1999 SER Input Authorizing Licensee Proposed Request to Modify Definition of Core Alteration in Section 1.0 of TS & Update Sections 3/4.1,3.4.3 & 3/4.9 to Reflect Proposed Definition Change ML20217C1311999-10-0808 October 1999 Safety Evaluation Supporting Amend 153 to License DPR-3 ML20217B5401999-10-0606 October 1999 Safety Evaluation Supporting Amend 193 to License DPR-40 ML20217B1641999-10-0505 October 1999 Safety Evaluation of Topical Rept BAW-10228P. Science. Rept Acceptable for Licensing Applications,Subject to Listed Conditions in Accordance with Fcf Agreement (Reference 4) ML20212M2141999-10-0505 October 1999 Safety Evaluation Concluding That Topical Rept EMF-2158(P), Rev 0,acceptable for Licensing Evaluations of BWR Neutronics Designs & Applications,As Per SPC Agreement (Ref 9) Subj to Stated Conditions ML20217B4331999-10-0505 October 1999 Safety Evaluation Supporting Amend 233 to License DPR-56 ML20212L0881999-10-0404 October 1999 SER Accepting Licensee Requests for Relief 98-012 to 98-018 Related to Implementation of Subsections IWE & Iwl of ASME Section XI for Containment Insp for Crystal River Unit 3 ML20212J6311999-10-0101 October 1999 SER Accepting Request for Relief from ASME Boiler & Pressure Vessel Code,Section Xi,Requirements for Certain Inservice Insp at Plant,Unit 1 ML20212J9251999-10-0101 October 1999 Safety Evaluation Accepting Licensee Relief Request IWE-3 for Second 10-year ISI for Plant ML20212L1141999-10-0101 October 1999 Safety Evaluation Granting Request for Exemption from Technical Requirements of 10CFR50,App R,Section III.G.2.c ML20212J8631999-10-0101 October 1999 Safety Evaluation Supporting Licensee Proposed Alternatives to Provide Reasonable Assurance of Structural Integrity of Subject Welds & Provide Acceptable Level of Quality & Safety.Relief Granted Per 10CFR50.55a(g)(6)(i) ML20212J2011999-09-30030 September 1999 Safety Evaluation Supporting Transfer of Dl Ownership Interest in Pnpp to Ceico ML20212K9781999-09-30030 September 1999 Safety Evaluation Accepting USI A-46 Implementation Program ML20212J1301999-09-30030 September 1999 Safety Evaluation Concluding That Topical Rept WCAP-12472-P-A,Addendum 1, Beacon-Core Monitoring & Operations Support System, Acceptable for Licensing Applications Subj to Pertinent Restrictions ML20212J9141999-09-29029 September 1999 Safety Evaluation of Topical Rept TR-108724, BWRVIP Vessel & Internals Project,Vessel Id Attachment Weld Insp & Flow Evaluation Guidelines (BWRVIP-48) ML20212J9661999-09-29029 September 1999 Safety Evaluation of Topical Rept TR-107285, BWRVIP Vessel & Internals Project,Bwr Top Guide Insp & Flaw Evaluation Guidelines (BWRVIP-26), Dated Dec 1996.Rept Acceptable ML20212F7671999-09-24024 September 1999 SER Granting Relief Request C-4 Pursuant to 10CFR50.55a(g)(6)(i) for Unit 2,during First 10-year ISI Interval & Relief Requests B-15,B-16 & B-17 Pursuant to 10CFR50.55a(g)(6)(i) ML20216H7091999-09-24024 September 1999 Safety Evaluation Supporting Amends 229 & 232 to Licenses DPR-44 & DPR-56,respectively ML20212F4761999-09-23023 September 1999 Safety Evaluation Supporting Amends 246 & 237 to Licenses DPR-77 & DPR-79,respectively ML20212F5641999-09-23023 September 1999 SER Concluding That All of ampacity-related Concerns Have Been Resolved & Licensee Provided Adequate Technical Basis to Assure That All of Thermo-Lag Fire Barrier Encl Cables Operating within Acceptable Ampacity Limits ML20212E6341999-09-23023 September 1999 Suppl to SE Resolving Error in Original 990802 Se,Clarifying Fact That Licensee Has Not Committed to Retain Those Specific Compensatory Measures That Were Applied to one-time Extension ML20212F0831999-09-23023 September 1999 Safety Evaluation Granting Relief from Certain Weld Insp at Sequoyah Nuclear Plant,Units 1 & 2 Pursuant to 10CFR50.55a(a)(3)(ii) for Second 10-year ISI Interval ML20212F5261999-09-22022 September 1999 SER Approving Request Reliefs 1-98-001 & 1-98-200,parts 1,2 & 3 for Second 10-year ISI Interval at Arkansas Nuclear One, Unit 1 ML20212H2381999-09-22022 September 1999 Safety Evaluation Supporting Amend 228 to License DPR-49 ML20212E6911999-09-21021 September 1999 Safety Evaluation Supporting Proposed EALs Changes for Plant Unit 3.Changes Meet Requirements of 10CFR50.47(b)(4) & App E to 10CFR50 ML20212J0501999-09-21021 September 1999 Safety Evaluation Re Licensee Implementation Program to Resolve USI A-46 at Plant,Per GL 87-02,Suppl 1 ML20212D3831999-09-20020 September 1999 Safety Evaluation Supporting Proposed Rev to Withdrawal Schedule for First & Third Surveillance Capsules for BFN-3 RPV ML20212D1911999-09-20020 September 1999 SER Accepting Exemption from Certain Requirements of 10CFR50,App A,General Design Criterion 57 Closed System Isolation Valves for McGuire Nuclear Station,Units 1 & 2 ML20216F9831999-09-20020 September 1999 Safety Evaluation Supporting Amend 11 to License R-115 ML20216H9901999-09-20020 September 1999 Proposed Final Rept Impep Review of South Carolina Agree- Ment State Program 990712-16 ML20212D4471999-09-20020 September 1999 Safety Evaluation Supporting Amend 31 to License R-103 ML20212C2551999-09-17017 September 1999 Safety Evaluation Supporting Amend 175 to License DPR-28 1999-09-30
[Table view]Some use of "" in your query was not closed by a matching "". Category:TOPICAL REPORT EVALUATION
MONTHYEARML20217J0721999-10-18018 October 1999 Safety Evaluation of Topical Rept EMF-2158(P),Rev 0, Seimens Power Corp Methodology for Boiling Water Reactors, Evaluation & Validation of Casmo-4/Microburn-B2. Rept Acceptable for Licensing Evaluations of BWR Neutronics ML20217K0651999-10-15015 October 1999 Safety Evaluation of Topical Rept BAW-10193P, RELAPS5/MOD2-B&W for Safety Analysis of B&W-Designed Pressurized-Water Reactors. Rept Acceptable for Referencing in Licensing Applications ML20217G0931999-10-15015 October 1999 Safety Evaluation of Topical Rept BAW-10179P,Rev 3, Safety Criteria & Methodology for Acceptable Cycle Reload Analysis. Rev 3 Found Acceptable & Accurately Include Conditions & Limitations for Applicability of References ML20217J1101999-10-13013 October 1999 Safety Evaluation of Topical Rept TR-108727, BWRVIP Vessel & Internals Project,Bwr Lower Plenum Insp & Flaw Evaluation Guideline (BWRVIP-47). Rept Will Provide Acceptable Level of Quality for Exam of safety-related Components ML20212M2141999-10-0505 October 1999 Safety Evaluation Concluding That Topical Rept EMF-2158(P), Rev 0,acceptable for Licensing Evaluations of BWR Neutronics Designs & Applications,As Per SPC Agreement (Ref 9) Subj to Stated Conditions ML20217B1641999-10-0505 October 1999 Safety Evaluation of Topical Rept BAW-10228P. Science. Rept Acceptable for Licensing Applications,Subject to Listed Conditions in Accordance with Fcf Agreement (Reference 4) ML20212J1301999-09-30030 September 1999 Safety Evaluation Concluding That Topical Rept WCAP-12472-P-A,Addendum 1, Beacon-Core Monitoring & Operations Support System, Acceptable for Licensing Applications Subj to Pertinent Restrictions ML20212J9661999-09-29029 September 1999 Safety Evaluation of Topical Rept TR-107285, BWRVIP Vessel & Internals Project,Bwr Top Guide Insp & Flaw Evaluation Guidelines (BWRVIP-26), Dated Dec 1996.Rept Acceptable ML20212J9141999-09-29029 September 1999 Safety Evaluation of Topical Rept TR-108724, BWRVIP Vessel & Internals Project,Vessel Id Attachment Weld Insp & Flow Evaluation Guidelines (BWRVIP-48) ML20216F4771999-09-16016 September 1999 Safety Evaluation of Topical Rept TR-108823, BWR Vessel & Internals Project,Bwr Shroud Support Insp & Flaw Evaluation Guidelines (BWRVIP-38).Requests That BWRVIP Be Reviewed & Resolve Issues & Incorporate Concerns in Revised BWRVIP-38 ML20211Q3171999-09-0909 September 1999 Safety Evaluation Accepting BWROG Rept, Prediction of Onset of Fission Gas Release from Fuel in Generic BWR, Dtd July 1996 ML20212B2501999-09-0202 September 1999 Safety Evaluation of TR WCAP-14696, WOG Core Damage Assessment Guidance, Rev 1.Rept Acceptable ML20211K5711999-09-0101 September 1999 FSER by NRR Re BWR Vessel & Internals Project,Instrument Penetration Insp & Flaw Evaluation Guidelines (BWRVIP-49), for Compliance with License Renewal Rule (10CFR54).TR Acceptable ML20209H9571999-07-15015 July 1999 Safety Evaluation Accepting EPRI Rept TR-105696-R1, BWR Vessel & Intervals Project:Reactor Pressure Vessel & Internals Examination Guidelines (BWRVIP-03) Rev 1, ML20209J1131999-07-15015 July 1999 Safety Evaluation of Topical Rept NSPNAD-8102,rev 7 Reload Safety Evaluation Methods for Application to PI Units. Rept Acceptable for Referencing in Prairie Island Licensing Actions ML20209F1571999-07-0808 July 1999 Safety Evaluation of Topical Rept TR-108695, BWR Vessel & Internals Project,Instrument Penetration Inspection & Flaw Evaluation Guidelines (BWRVIP-49). Rept Acceptable.Rept Demonstrates That Aging Effects of Rv Components Adequate ML20209F1261999-07-0808 July 1999 Safety Evaluation of Topical Rept TR-108709, BWRVIP Vessel & Internals Project Low Alloy Steel Vessel Materials in BWR Environment (BWRVIP-60). Rept Acceptable for Assessment of SCC Growth in BWR Low Alloy Steel Pressure Vessels ML20209D9651999-07-0707 July 1999 Safety Evaluation of Topical Rept WCAP-14750, RCS Flow Verification Using Elbow Taps at Wesstinghouse 3-Loop Pressurized Water Reactors. Changes to TS Bases Acceptable ML20196J3791999-06-30030 June 1999 Safety Evaluation of TR WCAP-14750, RCS Flow Verification Using Elbow Taps at Westinghouse 3-Loop Pwrs. Rept Acceptable ML20196G6321999-06-15015 June 1999 Safety Evaluation of Topical Rept EMF-2087(P),Rev 0, SEM/PWR-98:ECCS Evaluation Model for PWR LBLOCA Application, Rept Acceptable ML20195J2681999-06-14014 June 1999 Safety Evaluation of Topical Rept TR-108726, BWR Vessel & Internals Project,Lpci Coupling Insp & Flaw Evaluation Guidelines (BWRVIP-42). Rept Acceptable for Insp of safety- Related LPCI Coupling Assemblies,Except Where Staff Differ ML20207H1521999-06-0909 June 1999 Safety Evaluation of Topical Rept TR-108708, BWRVIP Vessel & Internals Project,Underwater Weld Repair of Nickel Alloy Reactor Vessel Internals (BWRVIP-44), Sept,1997.Rept Acceptable ML20207G4971999-06-0808 June 1999 Safety Evaluation Re Mods to TR CENPD-266-P-A, Application of Dit Cross Section Library Based on ENDF/B-VI. Rept Acceptable ML20195D3061999-06-0202 June 1999 Safety Evaluation of TR SCE-9801-P, Reload Analysis Methodology for San Onofre Nuclear Generating Station,Units 2 & 3. Rept Acceptable ML20207C7321999-05-26026 May 1999 Safety Evaluation of Topical Rept BAW-2248, Demonstration of Mgt of Aging Effects for Reactor Vessel Internals. Rept Provides Individual B&W Nuclear Power Plant Utility Owner with Technical Details for for License Application Renewal ML20195J2271999-05-25025 May 1999 Safety Evaluation of CE Owner Group Topical Rept CE NPSD-951 Rev 1,justifying, Reactor Trip Circuit Breakers Surveillance Frequency Extension ML20207A6251999-05-21021 May 1999 Safety Evaluation of TR WCAP-14449(P), Application of Best Estimate Large Break LOCA Methodology to Westinghouse PWRs with Upper Plenum Injection. Rept Acceptable ML20207B0241999-05-18018 May 1999 Safety Evaluation of Topical Rept TR-107285, BWR Vessel & Intervals Project,Bwr Top Guide Insp & Flaw Evaluation Guidelines (BWRVIP-26), Dtd December 1996.Rept Acceptable ML20206K7691999-05-0808 May 1999 Topical Rept Evaluation of CENPD-389-P, 10x10 Svea Fuel Critical Power Experiments & CPR Correlations:SVEA-96+. Rept Acceptable ML20206D5441999-04-28028 April 1999 Safety Evaluation of Topical Rept TR-107284, BWRVIP Vessel & Internals Project,Bwr Core Plate Insp & Flaw Evaluation Guideline (BWRVIP-25). Rept Acceptable for Insp & Flaw Evaluation of Subject safety-related Core Interal ML20206D4951999-04-26026 April 1999 Safety Evaluation Supporting Topical Rept BAW-2251, Demonstration of Mgt of Aging Effects for Rv ML20205L9441999-04-0808 April 1999 Safety Evaluation of Topical Rept CENPD-289-P, Use of Inert Replacement Rods in Abb C-E Fuel Assemblies. Rept Acceptable ML20205L9671999-04-0707 April 1999 Safety Evaluation of Topical Rept TR-108727, BWRVIP Vessel & Internals Project,Bwr Lower Plenum Insp & Flaw Evaluation Guideline (BWRVIP-47). Rept Found Acceptable Except Where Staff Conclusions Differ from BWRVIP ML20205F0251999-03-21021 March 1999 Safety Evaluation of Topical Rept TR-108727, BWRVIP Vessel & Internals Project Vessel Id Attachmant Weld Insp & Flaw Evaluation Guidelines. Rept Acceptable ML20207E3821999-03-0202 March 1999 Topical Rept Evaluation of SL-5159(P), Methodology & Verification of Gapp Program for Analysis of Piping Systems with E-Bar Supports. Staff Finds Topical Rept Acceptable for Referencing in Licensing Applications ML20203H7381999-02-18018 February 1999 Safety Evaluation of Topical Rept BAW-2328, Blended U Lead Test Assembly Design Rept. Rept Acceptable Subj to Listed Conditions ML20203A2581999-02-0505 February 1999 Safety Evaluation of TR DPC-NE-3002-A,Rev 2, UFSAR Chapter 15 Sys Transient Analysis Methodology. Rept Acceptable. Staff Requests Duke Energy Corp to Publish Accepted Version of TR within 3 Months of Receipt of SE ML20203C1841999-02-0303 February 1999 Safety Evaluation of Topical Rept NEDC-32721P, Application Methodology for General Electric Stacked Disk ECCS Suction Strainer, Part 1.Concluded That Use of GE Hydraulics Design Method Acceptable for All Plants,With One Noted Exception ML20203A7461999-02-0202 February 1999 Safety Evaluation of Siemens Power Corp Topical Rept EMF-92-116(P), Generic Mechanical Design Criteria for PWR Fuel Design. Rept Acceptable ML20199L6651999-01-25025 January 1999 Topical Rept/Ser of BAW-10186P, Extended Burnup Evaluation. Rept Acceptable.Staff Finds That Improved Methodology Adequate & Acceptable for Fuel Reload Licensing Applications Subject to Listed Conditions ML20198G1851998-12-15015 December 1998 Safety Evaluation for Topical Rept WCAP-14572,rev 1, WOG Application of Risk-Informed Methods to Piping ISI Topical Rept ML20196A4191998-11-19019 November 1998 Safety Evaluation Accepting QA TR CE-1-A,Rev 66 Re Changes in Independent & Onsite Review Organization by Creating NSRB ML20195F7941998-11-17017 November 1998 Safety Evaluation of EPRI TR-106708 & TR-106893.Repts Found to Be Acceptable for Replacement &/Or Repair of BWRVIP Vessel & Internals Project,Internal Core Spray Components ML20195F7041998-11-17017 November 1998 Safety Evaluation Accepting Topical Rept NEDC-24154P, Supplement 1,for Referencing in Licensing Applications to Extent Specified & Under Limitations Delineated in Rept ML20195C6721998-11-10010 November 1998 Safety Evaluation of Topical Rept WCAP-15029, Westinghouse Methodology for Evaluating Acceptability of Baffle-Former- Bolting Distribution Under Faulted Load Conditions ML20155G3901998-11-0505 November 1998 Safety Evaluation of TR GENE-770-06-2, Addendum to Bases for Changes to Surveillance Test Intervals & Allowed Out-of- Svc Times for Selected Instrumentation Tss. Rept Acceptable ML20155G3031998-11-0505 November 1998 Safety Evaluation of TRs NEDC-30844, BWR Owners Group Response to NRC GL 83-28, & NEDC-30851P, TSs Improvement Analysis for BWR Rps. Rept Acceptable ML20155B6121998-10-28028 October 1998 Safety Evaluation of TR SNCH-9501, BWR Steady State & Transient Analysis Methods Benchmarking Topical Rept. Rept Acceptable ML20154F0711998-10-0606 October 1998 SE of TR WCAP-14036,Rev 1, Elimination of Periodic Protection Channel Response Time Tests. Rept Acceptable ML20155G2611998-10-0505 October 1998 Corrective Page 9 of Safety Evaluation of TR WCAP-14036,Rev 1, Elimination of Periodic Protection Channel Response Time Tests. Typos Made in Original Rept Re Components Covered by Solid State Protection Sys Were Corrected 1999-09-09
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ATTACHMENT SAFETY EVALUATION REPORT BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATING TO TOPICAL REPORTS WCAP-13524 AND WCAP-13524. REVISION 1 APOLLO--A ONE DIMENSIONAL NEUTRON DIFFUSION THEORY PROGRAM WESTINGHOUSE ELECTRIC CORPORATION 1 BACKGROUND By letters dated October 22, 1992, and August 24, 1995, the Westinghouse Electric Corporation submitted the topical reports WCAP-13524 and WCAP-13524 Revision 1, " APOLLO-A One dimensional Neutron Diffusion Theory Program" (References 1 & 2), for the staff's review. The reports give a description of the APOLLO computer code and its application for reactor analyses of Westinghouse pressurized water reactors (PWRs). The reports describe the analyses and present the assumptions, conservatisms, limitations, and results of the APOLLO computer program.
APOLLO is a one-dimensional, two-group diffusion code that was evolved from the NRC-approved computer code " PANDA." Both codes solve the two-group diffusion equations using typical finite difference techniques. The primary difference between the two codes is the method by which the two codes solve for the flux. PANDA solves for the flux at the interface between the mesh intervals, while APOLLO solves for the interval mean flux. Data submitted by the vendor shows that the two methods are fundamentally alike and yield virtually identical results. Westinghouse indicated that AP0lLO has been used for all standard 1-dimensional design analyses since 1974, and that the evolution of PANDA to APOLLO was described to the NRC staff in 1984. APOLLO is used for nuclear design analyses that do not require three-dimensional methods. The calculational accuracy of the APOLLO code for predicting the reactivity and axial power shapes is comparable to the three-dimensional
" advanced nodal code" (ANC).
In APOLLO's current design application, nuclear data for input into APOLLO are provided by a model based on the three-dimensional ANC model. The revision to the one-dimensional APOLLO computer code incorporates into APOLLO the ability to use diffusion constants generated by the three-dimensional ANC program.
This revision will enhance the accuracy of the final results achieved by APOLLO.
2.0 Technical Evaluation -- Methods and Models 2.1 Steady-State Neutron Diffusion Model 2.1.1 Diffusion Difference Eauation the APOLLO computer code solves the diffusion equation on an interval basis rather than on a point-by-point basis. In its numerical approach, it makes use of the average (mean) flux on a given mesh interval and solves the two group diffusion equation accordingly.
9706110283 970609 PDR TOPRP ENVWEST C PDR _
k
j . i 2 :
i APOLLO makes use of group diffusion constants specific to each mesh interval i to perform interval-wise fuel depletion. Incorporated in APOLLO are feedbacks !
! that are very similar to those used in ANC; consequently, APOLLO can model an i j- extensive range of different core conditions.
i l
APOLLO solves the two group diffusion equations by assuming the total reactor geometry is divided into small units of volume. In-these small units of
- volume, APOLLO is forced to assume the flux had a mean value. So the flux in the small unit volume (mesh interval) is a constant. The macroscopic cross d
sections are also assumed to be a constant on these same mesh intervals. At i all times, the current (J) terms must be continuous across the dividing mesh
] boundaries in accordance with Fick's Law.
2.2 Boundary Conditions and Recursion Eauation 4- The procedure for calculating the boundary conditions and the recursion j equations have not been changed in going from the PANDA code to the APOLLO
! : ode or by the revision made to APOLLO. APOLLO utilizes three boundary j conditions: (1) "zero flux", or non-reflective boundary; (2) "zero current",
or reflective boundary; and (3) " albedo", or semi-reflective boundary,
! (Reference 3). The recursion equations are used together with the flux
! boundary conditions to calculate required matrixes to describe the flux
) behavior in going from the left-hand interval boundary to the right-hand (or j bottom-to-top) mesh interval boundary.
i
! Fuel depletion and xenon and samarium buildup calculations remain the same in
{ APOLLO and its revision. The actual fuel depletion takes place before the iterative flux calculation is performed. The flux distribution used is that i j -from the previous case or time step. The group constants and the mean burnup i i increment are from the input deck for the present case or are carried over j
from a previous case or time step.
1
! Fission product poisons, such as Xe(135), Sm(149), I(135), and Pm(149) are
- defined by typical decay chains. The nuclide chains are solved analytically )
, by assuming that the core power level, power distribution, and cross sections i j are constant over the period of integration (i.e., the time-step interval).
Currently, three options are available in APOLLO to deplete the core: (1) deplete the xenon and/or samarium from the previous time step or case, using l the flux distributicn from the previous time step, for a user-specified time i
interval delta T(hours); (2) determine the equilibrium xenon and/or samarium distribution compatible with the current neutron fluxes; and (3) leave the xenon and/or samarium distribution untouched, such that the same distributions from the previous calculation or time step will be applied to the current calculation.
2.3 Cross Section Reoresentation APOLLO computes the effective two-group cross sections for each mesh interval l using the macroscopic cross-section tables (tabulated versus burrup) and microscopic corrections for xenon, samarium, boron, water density, and fuel temperature. These corrections are the same as those applied to the ANC
3 (Reference 4). In the case of steady state, the cross sections are evaluated each iteration. For transient cases, the cross sections are evaluated at the beginning of each time step. Typically, the user supplies tables of various burnup values. Knowing the burnup value for each mesh interval, the code will use the table look-up procedure and interpolate to find matching values of diffusion constants, macro-cross sections, fission cross sections, and so on.
2.4 The Bucklina Model Since APOLLO is a one-dimensional model (thus lacking the remaining two dimensions), corrections must be applied to the model to account for its shortcomings, namely, representation of those components that are transverse to the geometrical representation. In a typical axial (slab) model (geometric representation in the z-direction, neutron leakage out of the top and bottom),
the missing component is the equivalent leakage out of the core in the radial direction. This fact can be represented very conveniently by a transverse buckling. The transverse buckling is established by determining the fast and thermal flux values that will create a mai;h between the APOLLO and the ANC fast and thermal axial flux distributions.
2.5 Automated Seauences APOLLO has a number of automated sequences to facilitate design calculations.
These seeuences include automated depletion using optional burnup dependent data, a transverse buckling sequence, control rod optional sequences to establish rod insertion allowances and limit lines, and differential and integral rod worth sequences. APOLLO calculates integral rod worths with an accuracy comparable to the three-dimensional ANC. This is so because APOLLO has the capability to determine control rod constants from ANC data such that APOLLO and the dimensional ANC rod worths agree, thus enabling APOLLO to be used for integral as well as differential rod worth calculations.
The staff has reviewed the subject reports, including the mathematical models and analytical procedures and methods. The staff finds the approach as described above to be technically sound and reasonable.
2.6 Analysis of Results As part of the submittal, the Vendor provided the staff with data representative of comparisons between APOLLO and the 3D ANC for parameters which are of interest in the types of calculations for which APOLLO is used, i.e. the core reactivity and axial power distribution. As indicated by the data, APOLLO-calculated reactivity and axial power distributions compare very favorably with those calculated by the 3D ANC. These comparisons are also indicative of APOLLO's suitability to perform calculations for which accuracy in these parameters is important. These Condition 11 calculations are associated with both the Constant Axial Offset Control (CAOC) and the Relaxed Axial Offset Control (RAOC) operations, differential and integral rod worth calculations and trip reactivity calculations.
e 4
3 CONCLUSION The staff has reviewed the analyses in Topical Reports WCAP-13524, and WCAP-13524, Revision 1, " APOLLO--A One-Dimensional Neutron Diffusion Theory Program," and concluded that WCAP-13524 and the revision 1 to it, are acceptable. WCAP-13524 is acceptable because it compares very favorably with ,
those calculated by the 3D ANC. The first revision to this same WCAP, is )
acceptable because the use of the three-dimensional diffusion constants over ,
the one-dimensional constant, is an enhancement to the one-dimensional APOLLO '
code, and as demonstrated by the Vendor's analyses, APOLLO's results compare very favorably with those calculated by the three-dimensional ANC. APOLLO is thus well suited for calculations in which accuracy in determining such i parameters as reactivity and axial power and differential and integral rod worth is very important.
l l
5
References:
- 1. Letter from Nicholas J. Liparulo, Westinghouse, submitting Topical Report WCAP-13524 (Proprietary), " APOLLO--a One-Dimensional Neutron Diffusion Theory Program," to the U.S. Nuclear Regulatory Commission, October 22, 1992.
- 2. Letter from Nicholas J. Liparulo, Westinghouse, submitting Topical Report WCAP-13524 (Proprietary), " APOLLO--a One-Dimensional Neutron Diffusion Theory Program, Revision 1," to the U.S. Nuclear Regulatory Commission, August 24, 1995.
- 3. Letter, Nicholas J. Liparulo, Westinghouse, ET-NRC-92-3736,
" Presentation Material from the October 10, 1984 NRC/ Westinghouse Meeting on the Improved Version of Nuetronics Codes Being Utilized" (Non-Proprietary), August 27, 1992.
- 4. Report by Y.S. Liu, et al., "ANC: A Westinghouse Advanced Nodal Computer code", WCAP-10965-P-A (proprietary), December 1985.