ML101930464
| ML101930464 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 07/12/2010 |
| From: | Weidong Wang Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| wang w. | |
| References | |
| Download: ML101930464 (69) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION ADVISORY COMMITTEE ON REACTOR SAFEGUARDS WASHINGTON, DC 20555 - 0001 July 12, 2010 MEMORANDUM TO:
ACRS Members FROM:
Weidong Wang, Senior Staff Engineer /RA/
Reactor Safety Branch B, ACRS
SUBJECT:
CERTIFICATION OF THE MINUTES OF THE ACRS SUBCOMMITTEE ON THE AP1000 REACTOR, APRIL 22, 2010, ROCKVILLE, MARYLAND The minutes of the subject meeting were certified on June 23, 2010, as the official record of the proceedings of that meeting. A copy of the certified minutes is attached.
Attachment:
As Stated Cc w/o
Attachment:
E. Hackett A. Dias
UNITED STATES NUCLEAR REGULATORY COMMISSION ADVISORY COMMITTEE ON REACTOR SAFEGUARDS WASHINGTON, DC 20555 - 0001 MEMORANDUM TO:
Said Abdel-Khalik, Chairman ACRS FROM:
Harold B. Ray, Chairman..
ACRS AP1000 Subcommittee
SUBJECT:
CERTIFICATION OF THE MINUTES OF THE ACRS SUBCOMMITTEE ON THE AP1000 REACTOR, APRIL 22, 2010, ROCKVILLE, MARYLAND I hereby certify, to the best of my knowledge and belief, that the minutes of the subject meeting held on April 22, 2010, are an accurate record of the proceedings.
/RA/
June 23, 2010 Harold B. Ray, Chairman Date ACRS AP1000 Subcommittee
Issued: June 22, 2010 Certified Copy REVISION 17 TO AP1000 DESIGN CONTROL DOCUMENT And VOGTLE ELECTRIC GENERATING PLANT COMBINED OPERATING LICENSE APPLICATIONS April 22, 2010 ROCKVILLE, MARYLAND INTRODUCTION The Advisory Committee on Reactor Safeguards (ACRS) Subcommittee on the Westinghouse Electrical Companys AP1000 advanced pressurized water reactor (PWR) design met in Room T-2B1 at the Headquarters of the U.S. Nuclear Regulatory Commission (NRC), located at 11545 Rockville Pike, Rockville, Maryland, on April 22, 2010. The Subcommittee was briefed by representatives of the Westinghouse Electrical Company (WEC), the NuStart1 Energy multi-utilities consortium, and NRCs Office of New Reactor Licensing (NRO) on two main items. The first item was the information briefing on the AP1000 PWR reactor containment shield building design for the proposed amended Design Control Document (DCD). The second item concerned the part of standard contents of the Combined License Application (COLA) Safety Analysis Report (SAR) submitted by the Southern Nuclear Operating Company (SNC), for two additional units at the Vogtle Electric Generating Plant (VEGP) site. The NuStart Energy consortium has designated the Vogtle COLA as the reference COLA or RCOLA for any future AP1000 reactors that might be licensed at other consortium sites. As part of the respective review processes, NRCs regulations under 10 CFR Part 52 direct the staff to consult with the ACRS on safety issues before any reactor design can be certified or any NRC operating license can be approved.
The staffs SER review was organized based on the various chapters found in NUREG- 0800 -
NRCs Standard Review Plan (SRP) for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition. To this end, the Subcommittee planned to gather information, analyze relevant issues and facts, and formulate proposed positions and actions, as appropriate, for deliberation by the full Committee of the ACRS at a later date. This was the fifth Subcommittee meeting on the proposed amended DCD and the third Subcommittee meeting on the standard contents of RCOLA.
The Chairman for this ACRS Subcommittee was Mr. Harold Ray. Mr. Weidong Wang was the cognizant ACRS staff engineer for this topic and served as the Designated Federal Official for this meeting. Peter Wen, an ACRS staff engineer, supported this two-day meeting as well. Part of meeting was open to public attendance and part of the meeting, involving with the proprietary/security information discussion, was closed. The Subcommittee received no written comments or requests for time to make oral statements from any members of the public concerning the subject of this meeting. This one-day meeting convened at approximately 8:30 am and ended around 6:50 pm.
1 The NuStart Energy LLC consortium consists of Constellation Generation Group, Duke Energy, EDF International North America, Entergy Nuclear, Exelon Generation, Florida Power & Light Co., Progress Energy, Southern Nuclear Operating Company (SNC), General Electric Energy, TVA, and WEC.
CERTIFIED COPY 2
The detailed agenda identifying the specific presentation topics comprising this meeting can be found in Attachment 1. Both during and following the scheduled presentations, the speakers responded to specific questions and comments from the ACRS Subcommittee members. The scope of the questions, comments, and the speakers responses has been captured in the verbatim meeting transcript. As a result of Member questions and comments and speaker responses, follow-up actions were identified for further discussion at subsequent Subcommittee meetings. These follow-up actions are tracked by the ACRS staff.
ACRS Subcommittee meeting transcripts can be found at the following NRC Internet website location: http://www.nrc.gov/ reading-rm/doc-collections/acrs/tr/subcommittee/.
ATTENDEES The following list of Individuals (and their affiliations) attending this meeting was compiled using both the sign-in sheets (Attachment 2) and the Subcommittee meeting transcript.
ACRS H. Ray, Subcommittee Chairman S. Banerjee, Member D. Bley, Member M. Bonaca, Member M. Ryan, Member W. Shack, Member J. Armijo, Member C. Brown, Member J. Stetkar, Member S. Abdel-Khalic, Member J. Sieber, Member T. Kress, Invited ACRS Consultant W. Hinze, Invited ACRS Consultant B. Stojadinovic, Invited ACRS Consultant P. Wen, ACRS Staff W. Wang, ACRS Staff NRC Staff E. Powell, NRO D. McGovern, NRO D. Andrukat, NRO R. Joshi, NRO T. Spicher, NRO J. Honcharik, NRO E. Reichelt, NRO K. Hsu, NRO C. Ng, NRO G. Bagchi, NRO L. Dudes, NRO B. Gleaves, NRO B. Thomas, NRO L. Mrowca, NRO G. Kelly, NRO E. McKenna, NRO Others E. Cummins, WEC C. Brockhoff, WEC Bob Sisk, WEC P. Kotwicki, WEC M. CORLETTI, WEC R. Orr, WEC
CERTIFIED COPY 3
M. Melton, WEC N. Haggerty, NuStart R. Grumbir, NuStart E. Grant, NuStart/EXCEL J. Sims, NPP Security Consulting, LLC W. Sparkman, SNC B. Kennedy, Struct Mech A. Varma, Purdue D. Moore, SNC B. Ebbeson, Shaw Group B. Wharton, SC Elect & Gas Lee Tunon-Sanjur SCHEDULED PRESENTATIONS Opening Remarks Subcommittee Chairman Ray made the opening remarks. He stated that the purpose of this Subcommittee meeting was to review (1) the status of Vogtle Units 3 and 4 AP1000 COL application in the area of Loss of Large Areas (LOLAs) of the plant due to explosions or fire, (2) the status of the shield building redesign activities for the AP1000, and (3) action items from the past AP1000 Subcommittee meetings. This review is part of the ongoing review of a proposed amendment to the AP1000 pressurized water reactor DCD and review of the associated RCOL application. In the past, the subcommittee held four two-day AP1000 meetings in July, October,,
November 2009, and in February 2010. The portions of the meeting, that were considered to be proprietary or security-related, were closed to public.
Ms. McKenna, the NRO Branch Chief responsible for AP1000 DCD and RCOLA reviews, also made an opening statement. She pointed out that the first topic this morning is a combined license topic and NuStart and the staff will provide the informational briefing. The staff does not have an SER with Open Items at this point yet and the purpose of the briefing is to have the opportunity to have a dialog and exchange on the topic before NRC reaches the final SER stage.
The presentations followed the published meeting agenda which included the following topics:
Loss of Large Areas due to Fires/Explosions Informational briefing on shield building design Action items lists from previous meetings o
RCP materials and other questions o
Elbow taps o
Screening criteria for striping o
HDPE connections Presentations on Loss of large areas due to fires/explosions and shield building designs are in closed sessions due to the security and proprietary information. The open sessions discussed action items.
The briefing slides with non-proprietary information can be found in Attachment 3 and the slides with proprietary information are in Attachment 4.
CERTIFIED COPY 4
CONSULTANTS REPORTS Two ACRS consultants, Dr. Hinze and Dr. Stojadinovic, produced meeting reports. These two reports are in Attachments 5 and 6 respectively.
SUBCOMMITTEE FOLLOW-UP ACTIONS The action items were listed in Attachment 7. Those action items from the previous meetings were discussed and, with agreement, items 29, Screening criteria for striping, and item 40, HDPE connections, were closed. The meeting discussed action items 4 and 10 and updated the actions. The three new action items related to the shield building design were produced and They were numbered as Items 51, 52, and 53 in the table.
Attachments
- 1. Meeting Agenda
- 2. Sign-In Sheets
- 3. Presentation Materials with non-proprietary information
- 4. Presentation Materials with proprietary information
- 5. B. Stojadinovic Report
- 6. B. Hinze Report
- 7. ACRS AP1000 Subcommittee Action Items Table Advisory Committee on Reactor Safeguards Meeting of the Subcommittee on the Westinghouse AP1000 DCD and AP1000 Standard Content COL Rockville, MD April 22, 2010
- Agenda -
Cognizant Staff Engineers: Weidong Wang (301-415-6279, Weidong.Wang@nrc.gov)
Peter C Wen (301-415-2832, Peter.Wen@nrc.gov)
April 22, 2010 Item Topic Presenter(s)
Time 1
Opening Remarks and Objectives Harold B. Ray, ACRS 8:30 - 8:35 a.m.
2 Introductions and Opening Comments E. McKenna, J. Cruz, NRO 8:35 - 8:40 a.m.
3 Loss of large areas due to fires/explosions - applicant CLOSED W. Sparkman,NuStart 8:40 - 9:15 a.m.
4 Loss of large areas - staff CLOSED L. Mrowca, NRO 9:15 - 10:00 a.m.
Break 10:00 - 10:15 a.m.
5 RCP materials and other questions WEC 10:15 - 10:35a.m.
6 Elbow taps WEC 10:35 - 10:55 a.m.
7 Screening criteria for striping WEC 10:55 -11:15 a.m.
8 HDPE connections WEC 11:15-11:30 a.m.
Lunch 11:30 -12:30 p.m.
9 Informational briefing on shield building - CLOSED WEC 12:30 - 2:30 p.m.
Break 2:30-2:45 p.m.
10 Shield building - CLOSED WEC 2:45-4:45 p.m.
11 Committee Discussion and action item review Harold B. Ray, ACRS 4:45 - 5:30 p.m.
Adjourn 5:30 p.m.
Notes:
Presentation time should not exceed 50% of the total time allocated for a specific item.
Number of copies of presentation materials to be provided to the ACRS - 35.
CLOSED Sessions for the purpose of discussing proprietary and/or SUNSI information.
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1 AP1000 Reactor Coolant Pump Flywheel April 22, 2010
2 Purpose Respond to ACRS request for information on the reactor coolant pump (RCP) flywheel failure frequency used in the AP1000 Probabilistic Risk Assessment (PRA) model
3 AP1000 PRA Model Information AP1000 PRA does not explicitly model the failure of the RCP flywheel A RCP flywheel failure frequency has not been used in the AP1000 PRA model
4 AP1000 PRA Model Information RCP flywheel failure could result in a locked rotor initiating event The locked rotor initiating event is combined with other single loop loss of reactor coolant flow initiating events Single loop loss of reactor coolant flow events are combined with other initiating events in the Transient with Main Feedwater event category
5 AP1000 PRA Model Information Transient with Main Feedwater event frequency is dominated by spurious reactor trip and turbine trip initiating events The RCP flywheel failure initiating event is
- a subset of locked rotor events
- which are a subset of single loop loss of reactor coolant flow events
- which are a subset of Transient with Main Feedwater events Therefore a RCP flywheel failure frequency has not been used in the PRA model
6 AP1000 RCP Outline Upper Flywheel Assembly Lower Flywheel Assembly
1 ACRS Meeting AP1000 RCS Flow Measurement April 2010 Chuck Brockhoff AP1000 System Design
2 Purpose Provide information regarding RCS flow measurements and uniformity of flow ACRS Question
- Elbow taps for RCS flow measurement
- Request additional information including a discussion of the uniformity of flow
- Please provide additional background information on the Westinghouse change for monitoring RCS flow reflecting an alternate testing method to the precision heat balance
- The alternate testing method includes utilization of d/p measurements on both hot and cold legs
3 AP1000 RCS Flow Measurement Westinghouse Improved Standard Tech Specs (ISTS) prescribes precision calorimetrics as the method to measure RCS flow.
The feedwater calorimetric measures reactor power and then uses delta-T (T-hot to T-cold) to calculate the RCS flow Accuracy is impacted by hot leg temperature streaming (non-uniform temperatures in hot leg)
- AP1000 geometry and low leakage loading pattern may contribute to hot leg streaming Technical Specification SR 3.4.1.4 allows the use of alternative precision flow methods in addition to the traditional calorimetric
- This alternate approach is to use in-situ calibration of the hot leg elbow and cold leg bend d/p channels
- Precedent exists for this method - Farley / South Texas /
Diablo Canyon / Seabrook / Watts Bar
4 AP1000 Plant Application DCD Rev 17 Baseline RCS Measurement of RCS flow at the time of plant startup utilizing multiple sources Use that flow determination for in-situ calibration of the RCS flow elements
- Hot leg elbows and cold leg bends Use those flow elements for all further RCS flow measurements
5 AP1000 Reactor Coolant Piping e) Westinghouse
6 Requirements for Plant startup The following reactor plant startup requirements apply:
- DCD 14.2.10.1.17: The estimated reactor coolant flow rate from data taken PRIOR to initial criticality equals or exceeds 90 percent of the minimum value required by the plant Technical Specifications for full power operation.
- DCD 14.2.10.4.11: The reactor coolant system flow determined from the measurements at approximately 100 percent rated thermal power equals or exceeds the minimum value required by the plant Technical Specifications.
Westinghouse expects that:
- The precision calorimetrics method will be adequate to meet this requirement
- Better accuracy can be achieved by evaluating data available from multiple test sources
7 Baseline Flow Measurement The Baseline Flow Measurement will be documented in an engineering report based on all measurements available of RCS flow at time of plant startup These measurements and tests include:
- RCS pump d/p (compared to factory tests)*
- RCS pump motor power (compared to factory tests)*
- Hot leg elbow and cold leg bend d/p*
- All other RCS d/p measurements available*
- T and calorimetric during power escalation
- Core exit T/C, T-cold, calorimetric power The engineering report will reconcile all measurements and report the determined flow (X +/- Y gpm) at specified conditions
- = Used for pre-criticality test flow confirmation
8 Baseline Flow Measurement Baseline Flow Measurement will be used to calibrate the RCS elements (hot leg elbow and cold leg bend d/p channels)
All future RCS flow measurements will be based on measurements of d/p channels in hot leg elbows and cold leg bends
- The observed d/p will be converted to a measured flow based on the d/p corresponding to the baseline flow measurement
- Instruments used to measure d/p will be calibrated at refueling intervals Uncertainty will include allowances for:
- Uncertainty in baseline flow measurements
- Uncertainty in d/p measurement channels in hot leg elbows and cold leg bends
9 Baseline Flow Measurement The 12-hour RCS flow check (SR 3.4.1.3) will be made with installed process instrumentation (consistent with operating plants)
- The current licensing basis is determination of gross change in indicated RCS flow on a relative basis The refueling interval RCS flow check (now SR 3.4.1.5) will be performed to measure flow based on calibrated loop differential pressures with consideration of appropriate instrument uncertainties in the error allowance
10 Uncertainties Both the hot leg elbow and cold leg bend d/p channels are expected to have uncertainties that cannot be resolved until as-built plant startup measurements are performed
- The hot leg elbows have nearby piping connections that may introduce d/p measurement uncertainties
- The cold leg bends (with taps at the end of the bend) have a large bend radius that causes a low d/p signal Therefore Westinghouse has taken the precaution of using either or both as an alternate to the precision calorimetric method of RCS flow determination
11 Summary The RCS flow measurement strategy provides an accurate and verifiable method of demonstrating that RCS flow meets requirements The accuracy (and value) of measured RCS flow will be established in the Reactor Coolant Flow Measurement Report following plant startup
12 Questions e) Westinghouse
1 Screening Criteria for Thermal Stratification, Cycling and Striping (TASCS) in AP1000 April 2010
2 Screening Criteria Document Materials Reliability Program: Management of Thermal Fatigue in Normally Stagnant Non-Isolable Reactor Coolant System Branch Lines (MRP-146), EPRI, Palo Alto, CA, June 2005, 1011955
3 MRP-146 Screening Identify all normally stagnant branch lines connected to the RCS piping with a potential for:
- In-leakage via valves from a high-pressure source toward the RCS header piping
- Potential for turbulence/swirl penetration Piping and instrumentation diagrams (P&IDs) are used to identify these paths
4 Lines with Potential for Valve Inleakage Example of an up-horizontal (UH) branch line piping configuration
5 Lines with Potential for Valve Inleakage Example of a horizontal (H) branch line piping configuration
6 Lines with Potential for Turbulence/Swirl Penetration Example of a down-horizontal (DH) branch line piping configuration
7 MRP-146 Screening Significant Temperature Threshold For steady stratification during normal operation, a guideline of 50°F measured metal top-to-bottom temperature difference is provided.
As long as this limit is not exceeded, no further action is required (Section 2.1.5)
8 MRP-146 Screening No further evaluation required if any of the following conditions are met:
- For UH lines, piping from RCS nozzle to first check valve is 2 inch nominal pipe size
- In-leakage path includes pressure relief or other pressure control devices
- For top connected piping, the vertical section is sufficiently long such that swirl penetration cannot reach the upper horizontal sections
- For bottom connected piping, vertical length between RCS piping and horizontal section is greater than the maximum, or less than the minimum specified in MRP-146, Sec. 2.2.3
9 AP1000 Lines Susceptible to TASCS PRHR supply line from RCS hot leg to PRHR heat exchanger Passive residual heat removal (PRHR) return line from PRHR heat exchanger to steam generator channel head Automatic Depressurization System (ADS) stage 4 lines from RCS hot legs to the stage 4 depressurization valves RCS hot leg lines RCS cold leg lines Pressurizer surge line Normal residual heat removal suction lines from the hot legs to the isolation valves Direct Vessel Injection (DVI) lines Chemical and Volume Control System (CVS) purification return line (Reference DCD 3.9.3.1.2)
10 Evaluation and Further Actions
- 1. For susceptible lines, a CFD analysis is performed to study the flow mechanism and determine the temperature distribution
Thermal gradients used to obtain bending stresses
Thermal gradients also included in fatigue analysis
- 2. Recommendations are provided to avoid the potential for thermal fatigue degradation
11 Evaluation and Further Actions Results will be available during piping DAC closure/audit
1 AP1000 HDPE Follow-up Questions April 22, 2010
2 Purpose Provide information regarding the criteria for use of high density polyethylene (HDPE) piping in AP1000 applications List all AP1000 systems using HDPE piping Summarize advantages of HDPE piping
3 HDPE Use in AP1000 ACRS Question
- HDPE - Underground piping (fluids) and conduit (electrical) and how they perform with regard to groundwater intrusion and surface water infiltration. The concern includes the pipe, connections and material performance at the connections (joint adhesives welding materials, etc.). A related question are any of the tritium task force results and recent experiences reported for Vermont Yankee and Indian Point raising issues for such piping. (Mike Ryan)
4 AP1000 HDPE Application Criteria HDPE piping is not used in safety-related fluid systems applications in AP1000
- usage adheres to requirements of Code Case N-755
- NRC has approved safety-related applications of HDPE piping in at least two operating plants HDPE piping is used in underground applications only HDPE piping is not used in systems that carry normally radioactive process fluids
- complies with RG 1.143 restriction
5 AP1000 HDPE Application Criteria HDPE piping is used only for
- SWS blowdown and alternate makeup lines
- May be used in certain site-specific RWS and WWS applications HDPE piping is routed underground to eliminate the possibility of impact damage and material degradation (embrittlement) due to UV exposure Underground installation methods used ensure protection of piping from distortion and damage by above-ground live loads
6 Advantages of HDPE Piping HDPE pipe materials are essentially inert and are not affected by chemical or galvanic corrosion The operating lifetime of properly constructed HDPE piping systems is estimated to be up to 100 years Joints produced with proper fusion conditions are leak-free and not susceptible to degradation caused by exposure to process fluid or ground water, or by surface water infiltration around the exterior of the pipeline
7 Ensuring Long-Term Leak-Free Performance of HDPE Piping HDPE pipe sections and associated fittings are joined in the field by fusion (butt welding) using specialized equipment [ SLIDE 9 ]
The fusion conditions required to produce a strong, void-free weld zone between adjacent HDPE pipe sections are well-known Key fusion parameters
- temperature of fusion zone
- compression pressure on pipe faces being joined
- fusion time
8 Ensuring Long-Term Leak-Free Performance of HDPE Piping A non-destructive means of evaluating fusion joint integrity is available
- Time of Flight Diffraction (TOFD) - ultrasonic Appropriate installation methods and supports are needed to control stresses and moments in systems using HDPE piping
- ASTM and manufacturer installation standards exist
- thermal expansion coefficients are higher than for metallic piping and must be accommodated
9 Butt Fusion of HDPE Piping e) Westinghouse
10 Conclusion HDPE piping use is not a regulatory issue for AP1000
11 Questions e) Westinghouse
Presentation Materials with Proprietary Information (These Slides Will Be Maintained Separately)
Report on the Outcomes of the
NRC ACRS AP-1000 Sub-Committee Meeting on April 22, 2010
Bozidar Stojadinovic, PhD
April 23, 2010
Westinghouse staff and consultants presented a comprehensive review of Design
Report for the AP-1000 Enhanced Shield Building Revision 1, dated March 22, 2010
and additional work conducted between report submission and the day of the ACRS
meeting.
Westinghouse responded to the issues raised by NRC staff in their October 15, 2009
letter and made significant changes in design of the shield building to increase its
strength and robustness. Westinghouse approach to the design process is sound and
transparent. The design is based on the accepted US design codes for reinforced
concrete (ACI 349) and steel (AISC 690N) where they apply. Where the US design
codes do not apply, Westinghouse developed and is in the process of executing a test
suite to demonstrate that the response of the strength of the SC walls can be safely
computed using the ACI 349 strength equations and that they poses the deformation
ductility capacity that exceeds that assumed in the design. Westinghouse presented
the calibrated analysis models they are using to evaluate the seismic demand on the
structure and the three-level analysis process they are conducting. The results of the
demand analyses will be presented in the next revision of their shield building
design report. In my opinion, the shield building design is moving in the right
direction.
I am particularly impressed with the dedication of the Westinghouse staff and
consultants to the task of re-designing the shield building using the SC wall
composite structural system. This is, indeed, a first-of-its-kind structure in the US.
The challenge of designing this structure without support in US design codes and
significant US research is significant. Westinghouse reliance experimental
investigations conducted at Purdue University by Dr. Amit Varma, on the Japanese
and Korean experience, and engagement of leading US experts in this field is to be
commended. I am also impressed with the commitment of NuStar partners to
support Westinghouse design efforts.
However, Westinghouse still needs to conduct a significant amount of work to
complete their shield building design. The following issues for Westinghouse to
clarify emerged during the meeting:
- 1. Details of the SC wall steel plate-to-plate horizontal and vertical connections,
including weld type and geometry, weld metal, welding procedure
specification, weld and base metal notch toughness data, and weld inspection
procedure. If welding procedures for welding the SC wall modules in the
staging area are different from those planned for welding the SC wall
modules when lifted into place, both need to be provided.
- 2. Details of the connection between the SC wall and foundation and the SC wall
and the RC wall of the auxiliary building (they are different). This submittal
should include weld details of the transfer seats on the SC wall plates,
location of the D2L bars in this region, details on the connectors used to
engage the RC wall reinforcing bars, details on the confining reinforcement in
the connector region and details of the development length of the reinforcing
bars in the RC wall of the auxiliary building. In addition, details on the
connection between the roof and portions of the auxiliary building to the
shield building SC wall should be provided. Other members of the sub-committee requested data on the behavior of this connection under seismic
loading.
- 3. Details of the connection between the SC wall and the tension ring, including
the geometry of the wall and the steel tube air inlets, D2L bars and studs, and
the connection between the SC wall steel plates and the tension ring. In
addition, the force transfer mechanism between the ring and the wall needs
to be explained.
- 4. Details of steel roof beam to tension ring connection, including connection
details showing welds between the top flange and the roof steel plate, studs
on the top flange, web connection (if any), welds between the beam bottom
flange and the seat, welds between the seat and the tension ring, details of
diaphragms inside the tension beam in the vicinity of this connection, and
details of the anchorage of the roof plate reinforcing bars into the tension
ring.
- 5. Design of the compression ring and the water tank connection. This
submittal should also include an explanation of how forces used to design the
connection were computed and an explanation of the load path to transfer
the tank forces to the roof structure.
- 6. Results of the Level 1 analyses, including the elastic vibration properties of
the shield building, the design response spectrum, the ground motion time
histories used in the analyses, and the ground motion response history
summaries.
- 7. Results of the Level 2 nonlinear pushover analyses, including the method for
determining the pushover forces, consideration of higher vibration modes,
combination of forces in different directions, combinations with other loads,
and determination of the locations and magnitudes of critical force demands
at the three demand consideration levels (SSE, RLE and three times SSE). The
results should include a summary of the conducted nonlinear time history
analyses (if any), explaining the overall inelastic deformation of the structure
during beyond design basis events and the local inelastic demands at critical
locations of the shield structure.
- 8. Results of the Level 3 analyses, including the method for transferring the
boundary conditions from Level 2 to Level 3 models, an explanation of the
behavior of the Level 3 models to demonstrate if the SC wall behaves as a
unit, and the results indicating the critical stresses and strains observed
during the analysis. Of particular interest are the radial stresses and strains
(oriented along the radius of the shield building): the D2L bars must be
capable of carrying such splitting stresses.
- 9. Design calculations showing that at the critical locations identified in the
analyses the SC wall itself and its connections to the tension ring and the
foundation and the auxiliary building have sufficient capacity using the US
code (ACI 349 and AISC 690N) based acceptance criteria. Based on the
Westinghouse explanation, it is assumed that the capacities will be well
above the SSE demands and slightly above the RLE demands. In addition,
Westinghouse should demonstrate that at the three times SEE demand levels,
when the response of the shield structure is expected to become nonlinear,
the deformation capacity of the SC walls, as established by testing, is not
exhausted. Based on the Westinghouse explanation, the SC walls are
expected to be able to sustain deformations as large as four times the yield
deformation in in-plane and out-of-plane bending. Westinghouse should also
demonstrate that the number of inelastic cycles imposed on the structure
does not exceed the low-cycle fatigue capacity of the SC walls. Furthermore,
Westinghouse should discuss how the earthquake-induced inertial forces are
transmitted from the top of the shield building to its foundation and identify
the redundant load paths that are activated after significant inelastic
response occurs at critical locations in the structure. Finally, Westinghouse
must clearly demonstrate that under no circumstances the out-of-plane and
the in-plane shear force capacity of the SC walls and its connections to roof
and the foundation structures are exceeded. This (shear force related) design
principle was clearly stated by Dr. Robert Kennedy during this meeting: I
fully agree with it and expect Westinghouse will design their structure
accordingly.
To:WeidongWang,ACRSStaff,NRC From:WilliamJ.Hinze,PurdueUniversity
Subject:
CommentsonACRSAP1000SubcommitteeofApril22,2010 Date:April27,2010 AttherequestoftheUSNRCAdvisoryCommitteeonReactorSafeguards(ACRS)IattendedtheAP1000 subcommitteemeetingontheAP1000ShieldBuildingStructuralReviewonApril22,2010.Thepurpose ofthisinformationalmeetingwastoreviewthestatusoftheshieldbuildingredesigncurrentlyin progressbyWestinghouseanditscontractors.Westinghousehadpresentedaninitialdesignofthis structureinmid2009whichwasreviewedandcommentedonbytheNRCstaff.Thisleadtoarevision ofthedesignbyWestinghouse(Rev.1)onMarch22,2010andananticipatedfurtherrevision anticipatedonMay7,2010.Thepurposeofthisbriefmemoistoprovidegeneralcommentsonthe meetingandWestinghousespresentationonthecurrentstatusoftheirdesignoftheshieldbuilding andthethreelevelsofanalysesofthedesign,aswellastoidentifyissuesthatdeservespecialattention whenreviewingRev.2.
PriortothemeetingProfessorBozidarStojadinovicandIpreparedabriefreportonRev.1atthe requestofSubcommitteeChairmanHaroldRay.InthatreportweidentifiedseveralissuesinRev.1that neededtobeclarifiedanddemonstratedinsubsequentWestinghousereportsandpresentations.These includedissuesthattheNRCstaffreportedintheirletterresponseofOctober15,2009toWestinghouse asaresultoftheirreviewofthedesignoftheshieldbuilding.
InourreporttoChairmanRaywestatedthatWestinghouseinRev.1was,ingeneral,responsivetothe concernsraisedbyNRCstaff.Thisconclusionwassupportedbytheextensiveanalyses,testsand redesignofthestructurereportedbyWestinghouseinRev.1andtheircomprehensivepresentationat theApril22,2010meeting.Theanalyses,tests,andmodelingconductedbyWestinghousehavelargely demonstratedtheabilityoftheshieldbuildingtoperformitssafetyfunctionunderdesignbasisloading conditionsandtheirpresentationclarifiedmostoftheissuesraisedinourpremeetingreport.
However,furtherreviewisnecessarywhenRev.2isavailable.
AcriticalconcernoftheNRCstaffinRev.1andourpremeetingreportinvolvedtheneedto demonstratethattheshieldbuildingwouldactasaunitwhensubjecttodesignbasesloading.
Westinghouseshowedhowtheirdesignrevisionsrespondedinapositivewaytothisconcern.The increasedthicknessofthesteelwallplatethickness,itsimprovedductility,andtheuseoftiebars connectingtheplatesandextendingthroughtheinterveningconcrete,aswellasimprovedconnections betweenthecylindricalwallandthebasemat,AuxiliaryBuilding,andtheroofhaveallimprovedthe capabilityoftheshieldbuildingtoactasaunitduringloading.Areasofconcernthatremainare potentialweakzonesattheweldjoinsbetweenthesteelwallplatesandtheconnectionofthewalls withtheroof.Bothoftheseissuesareworthyoffurtherreviewwhenthefinaldesignanalysesare presented.
Aconcernraisedpriortothemeetingwasthepotentialforstrengthdegradationduetofatigueloading underrepeatedloadingevents.Itisimportantthatthehysteresisresponseofthecomponentsofthe shieldbuildingisstableundercyclicloadinganticipatedoverthedurationofthedesignbaseseventand thattheresponsedegradesonlygraduallyaftersubstantialductiledeformationoccurs.Thefullscale cyclictestsperformedforWestinghouseandreportedattheAprilmeetingindicatedthatthisconcernis beingmet.However,thesetestsarestillongoingandthusrequirefurtherreviewupontheircompletion andreportinginthenextdesignrevisionreportofWestinghouse.Therewasconcernabouttherealism andapplicabilityofthefullscaletestsasreportedinRev.1,butthepresentationattheAprilmeeting clarifiedandjustifiedthesetests,theirresults,andtheirrole.Further,theappropriatenonlinear modelingreportedatthemeetingclearlybenchmarkedtheresultsofthesetestsfurtherconfirmingthe structuralintegrityofthedesign.Itisworthytonotethatthemodelingwasusedtoidentifytheweakest designfeaturesoftheshieldbuildingandthattheseareasweresubjecttomoreintensiveanalyses.
OneofthemoreimportantstepstakenbyWestinghouseintheredesignoftheshieldbuildingwasto employtwooutsidestructuralengineerswithinternationallyrecognizedexpertiseinthedesignof nuclearfacilitiestoreviewandmakerecommendationsonthedesignandanalysisoftheshieldbuilding.
Duringthemeetingoneoftheseexpertswithastrongbackgroundinanalyzingtheimpactofseismic loadingonnuclearstructures,RobertKennedy,gaveapresentationofthehistoryandevolutionofhis involvementintheanalysesandredesignoftheshieldbuildingandtheresultsofhisefforts.Ihavenot hadanopportunitytoreviewthetranscriptofhispresentationwhichwasreadtotheACRS subcommittee,buthisstatementinthetranscriptdeservescarefulreviewandconsiderationinthefinal reviewofthedesignoftheshieldbuilding.Itissignificant,however,toobservethatthethreelevelsof analysesoftheshieldbuildingwillbeconfirmedinRev.2usingpushoveranalysesatthreeseismic loadinglevels;safeshutdownearthquake,reviewlevelearthquake,andthreetimesafeshutdown earthquake.ThiswillprovideanappropriateseismicmarginthatwillexceedtheNRCregulations.The resultsofthepushoveranalysespresentedinRev.2needtobestudiedandreviewedtoassurethat theyshowtheintegrityofthestructureundertheseseismicloadings.
AP1000 Design Safety Evaluation Report Meeting ACRS Subcommittee Action Items (DRAFT)
July 23 - 24, 2009, October 6-7, 2009, November 5, 2009, February 2-3, 2010, and April 22, 2010 Revised 4-27-10 1
ID No.
Action Item Status Source (Chapter/
Discussion)
Westinghouse/
Bellefonte application Who has action Comment/Disposition ITEMS Below are from July meeting 2
Non-condensible gases and can they affect flow from IRWST.
a) what ITAAC will be included b) heatup analysis
-Abdel-Khalik, Banerjee open 7/23 Summary discussion Chapter 1, W
W ACTION: Westinghouse provided a discussion during Feb.
meeting on how non-condensible gas issue was addressed.
need to hear rest of story.
Updated in Feb.
4 RCP Flywheel Design; I would like to receive stress corrosion test reports performed by W or pump supplier on the 18Cr 18Mn retainer ring material. I suspect that they have not tested this material sufficiently (if at all) to demonstrate SCC resistance in the coolant environment. Even though the ring is sealed in a Alloy 625 can, the assembly will not be inspected in service, and there will be no way of knowing whether the can will remain leak tight during service.
If SCC of the retainer ring occurs, a serious accident would be likely.
-Armijo Also, interested in RCP locked rotor failure frequency used in PRA.
Tom Kress open 7/23 Summary discussion Chapter 5 W
W DNRL Westinghouse to provide presentation in future ACRS meeting DNRL to provide results of staff review of revised missile analysis when complete. Was discussed during February meeting.
Updated in Feb.
Closed failure frequency concern at 4/22 meeting. Materials were provided to Sam after 4/22 meeting for other left concerns.
AP1000 Design Safety Evaluation Report Meeting ACRS Subcommittee Action Items (DRAFT)
July 23 - 24, 2009, October 6-7, 2009, November 5, 2009, February 2-3, 2010, and April 22, 2010 Revised 4-27-10 2
ID No.
Action Item Status Source (Chapter/
Discussion)
Westinghouse/
Bellefonte application Who has action Comment/Disposition 6
Flow distribution - Lower plenum anomaly and core inlet flow distribution. What is ratio of peak/average and minimum/average bundle flows with the skirt. Provide further information about the tests ongoing in Japan, including scaling methodology, CFD Method used, Reynolds number. What were the assumptions used in setting up the VIPER model and its justification.
-Abdel-Khalik open 7/24 Morning meeting Chapter 5, Chapter 4 W
W/
DNRL/
NEW2 Westinghouse to provide additional discussion in future ACRS meeting. DNRL has provided background documents from AP1000 review that may help ACRS better understand the issue.
It was discussed and updated in Feb. meeting.
Updated in Feb.
9 Turbine Overspeed Protection a) frequency of testing (6 months?)
b) method of testing c) power supply independence d) diversity f) turbine missile analysis, include 1) How W used the available operating experience to justify both the challenge frequency and the failure rate for the valves. 2) What are those conditional probabilities of the discs coming apart for each of the overspeed conditions, design and intermediate overspeeds.
-Ray, Brown, Stetkar open 7/23 Chapter 10 W
W Westinghouse to revise DCD to correct mis-characterization about speed control, independence. Discussed at Feb meeting. Open questions on intercept valve test frequency and method of testing for overspeed 3 months -->6 months. Questions on turbine missile analyses diversity.
Updated in Feb.
AP1000 Design Safety Evaluation Report Meeting ACRS Subcommittee Action Items (DRAFT)
July 23 - 24, 2009, October 6-7, 2009, November 5, 2009, February 2-3, 2010, and April 22, 2010 Revised 4-27-10 3
ID No.
Action Item Status Source (Chapter/
Discussion)
Westinghouse/
Bellefonte application Who has action Comment/Disposition 10 Elbow Taps for RCS Flow Measurement.
Need further information, discuss uniformity of flow. Provide ACRS background information for Westinghouse change for monitoring RCS flow to reflect an alternate testing method to the precision heat balance.
The alternate testing method includes using elbow taps. OI-SRP-16-CTSB-25.
-Banerjee Additional questions was raised during the April 22 meeting:
How are various measurement indications reconciled, at operating plants?
For AP1000 Design, What is the uncertainty in core flow; How is the uncertainty estimated; What is the measurement used for; and how accurate does it have to be?
-Said open 7/24 Chapter 16 W
W/DN RL DNRL to provide relevant Westinghouse submittals to ACRS.
Need submittals from Westinghouse. Communicated to Westinghouse on 1/15/2010.
The action item was updated in the April, 2010 meeting.
11 Aircraft Impact Assessment staff evaluation.
Subcommittee wants briefing.
-Ray, Banerjee open 7/24 Chapter 19 W
DNRL NWE1/NWE2 to arrange closed ACRS subcommittee briefing.
19F revision.
TEMS FROM OCTOBER SC MEETINGS 26 Waste management forecast (by category and volume if available)
-Ryan open 11 COL COL to provide.
AP1000 Design Safety Evaluation Report Meeting ACRS Subcommittee Action Items (DRAFT)
July 23 - 24, 2009, October 6-7, 2009, November 5, 2009, February 2-3, 2010, and April 22, 2010 Revised 4-27-10 4
ID No.
Action Item Status Source (Chapter/
Discussion)
Westinghouse/
Bellefonte application Who has action Comment/Disposition 27 PRA audit results. COL PRA?
open 19 W
NWE2 DNRL has provided documents on 3/30/2010- under review.
31 Chapter 2 geotech information open W
W/NW E2 Include when discussing related chapter 3 (seismic) 31.
5 ITEMS FROM NOV 5 FC MEETING open 32 I&C Architecture(major changes)
-Brown open 11/5 W
NRC Addressed on November 19 and Feb 2-3. May be future questions.
33 In addition to design/hardware changes, Committee wants changes to methods
-Abdel-Khalik open 11/5 W
NRC ASTRUM was discussed in Feb. New action item 49 has more questions about TH methods, seismic analyses (future meeting).
Pg 76 of Nov 5 Transcripts. Future changes to be highlighted.
Updated in Feb.
AP1000 Design Safety Evaluation Report Meeting ACRS Subcommittee Action Items (DRAFT)
July 23 - 24, 2009, October 6-7, 2009, November 5, 2009, February 2-3, 2010, and April 22, 2010 Revised 4-27-10 5
ID No.
Action Item Status Source (Chapter/
Discussion)
Westinghouse/
Bellefonte application Who has action Comment/Disposition 34 HFE DAC closure a) For I&C and HEF, Rev 15 DAC that have been deleted in Rev 17, Show the subcommittee details of how those DAC were satisfied, Two or three examples might be sufficient. (Dennis C. Bley) b) I&C DAC - Westinghouse indentified in the Nov 09 meeting that DAC close out was divided into 3 phases:
Phase 1 DAC 1, Phase 2 DAC 2, Phase 3 DAC 3 What each DAC was intended to include and how each item was closed in each phase should be provided. (Charles Brown) open 11/5 W
NRC Final SER should document DAC closure including acceptance criteria.
Updated in Feb. 2010 ITEMS FROM NOVEMBER SC MEETINGS AP1000 Design Safety Evaluation Report Meeting ACRS Subcommittee Action Items (DRAFT)
July 23 - 24, 2009, October 6-7, 2009, November 5, 2009, February 2-3, 2010, and April 22, 2010 Revised 4-27-10 6
ID No.
Action Item Status Source (Chapter/
Discussion)
Westinghouse/
Bellefonte application Who has action Comment/Disposition 35 Boric acid deposition report (Bajorek) for Armijo The thrust of these concerns relates to the lack of prototypicality of the coolant used in the downstream flow blockage tests performed by W. Banerjee requested information on the concentration of dissolved aluminum and I was interested in the complete composition of the coolant (not just boric acid).
Based on the material presented in the GSI 191 presentation, the coolant carrying the debris in these tests did not match or even approximate the composition, pH or temperature of the coolant that will exist after a LOCA. The physical state of the AlOOH will be highly dependent on chemistry and temperature, and this is the material that cements the fibrous debris. Without tests in prototypical environments, I do not see how anyone can conclude that the debris will not block the entries to the fuel assemblies.
Maybe the staff can resolve my concern. -
Armijo open GSI-191 NRC Provide copy of report.
Updated in Feb.
36 Amount of aluminum. See 35
-Banerjee and Armijo open GSI-191 W
Discuss with staff SER. Pg 1-293 of Nov 19 meeting Transcripts.
37 Statistical analysis of fuel assembly tests Banerjee, Wallis and I requested statistical analyses of the fuel assembly tests. There were a limited number of tests, and a several experimental variables. The issue here is the statistical validity of the reported findings and conclusions of these tests. - Armijo open GSI-191 W
Provide copy of report - possibly included in RAI response.
AP1000 Design Safety Evaluation Report Meeting ACRS Subcommittee Action Items (DRAFT)
July 23 - 24, 2009, October 6-7, 2009, November 5, 2009, February 2-3, 2010, and April 22, 2010 Revised 4-27-10 7
ID No.
Action Item Status Source (Chapter/
Discussion)
Westinghouse/
Bellefonte application Who has action Comment/Disposition 38 Concrete scouring
-Ray open GSI-191 W and NRC Discuss at future meeting (RAI) 39 Hot leg break - debris at top of core
-Wallis open GSI-191 W and NRC Discuss at future meeting (RAI) 41 RTCB test frequency open 7, 16 W and NRC Discuss basis for yearly (OI) 43 HSL (high speed links) topical report
-Brown open 7
W Westinghouse to provide reference. Related to SER OI? Under review. A report was sent on April 5, 2010.
ITEMS FROM FEBRUARY SC MEETINGS 46 Components MOV, POV testing, how is the risk informed and ranked. PRA is not sufficient and need to review other criteria.
-Stetkar, Shack open 3
W W to provide info on risk ranking 47 Table 15.0-5 Uncertainties table need further discussion. Were instrument drift/ other uncertainties counted in the 1-2% power changes? (Said) open 15 W/DN RL Present at future meeting 48 Confirm 1) if there are interlocks for ADS1, 2, 3, 4 actuation and what kind of failure it can occur. 2) If it occurs, what is the impact to the safety analysis?
open W
W to provide info at future meeting AP1000 Design Safety Evaluation Report Meeting ACRS Subcommittee Action Items (DRAFT)
July 23 - 24, 2009, October 6-7, 2009, November 5, 2009, February 2-3, 2010, and April 22, 2010 Revised 4-27-10 8
ID No.
Action Item Status Source (Chapter/
Discussion)
Westinghouse/
Bellefonte application Who has action Comment/Disposition 49 Sanjoy had issues on codes:
a) ASTRUM is approved for other Westinghouse PWRs, justify that it can be applied to the AP1000. What is the similarity of the AP1000 compared to the Westinghouse PWR for the LBLOCA in the initial blowdown phase?
b) W/TRAC is the best estimate code. What the conservativeness was used in the Rev. 15 compared to the best estimate approach used in the Rev. 17, which lowered the PCT significantly.
c) Since the certified design, what are the changes in the code?
Provide a summary report. WEC responded that the main changes Error of modeling in pressurizer and hot spot. (Sanjoy) open W
W to provide info at future meeting 50 What is the uncertainty of the 6 ft in water level calculation in LOCA ? (Sanjoy) open W
W to provide info at future meeting ITEMS FROM APRIL 2010 SC MEETINGS AP1000 Design Safety Evaluation Report Meeting ACRS Subcommittee Action Items (DRAFT)
July 23 - 24, 2009, October 6-7, 2009, November 5, 2009, February 2-3, 2010, and April 22, 2010 Revised 4-27-10 9
ID No.
Action Item Status Source (Chapter/
Discussion)
Westinghouse/
Bellefonte application Who has action Comment/Disposition 51 Details of the plate-to-plate welds for the SC wall steel plates and how the quality of welds are assured.
- Boza and Sam.
open Chapter 3 Shield Building Design W
52 Details of the roof beam to tension ring connection.
- Boza open Chapter 3 Shield Building Design W
53 Explanation of the pushover analysis methodology: how were the lateral and vertical forces selected, combined and applied, and how are the results of this nonlinear analysis interpreted.
- Boza open Chapter 3 Shield Building Design W
CLOSED ITEMS 1
GSI and Generic Issue Process. How is it addressed since Rev. 15? (example GSI-191) closed 7/23 Summary discussion Chapter 1 W
DNRL Provided additional presentation in Feb meeting 3
RTD Relocation. Is there an impact on the dead-band for rod control. Are they at upper half or at top of the hot leg?
-Abdel-Khalik, Ray closed 7/23 Summary discussion Chapter 5 W
W Closed at October meeting. Westinghouse to provide presentation in future ACRS meeting AP1000 Design Safety Evaluation Report Meeting ACRS Subcommittee Action Items (DRAFT)
July 23 - 24, 2009, October 6-7, 2009, November 5, 2009, February 2-3, 2010, and April 22, 2010 Revised 4-27-10 10 ID No.
Action Item Status Source (Chapter/
Discussion)
Westinghouse/
Bellefonte application Who has action Comment/Disposition 5
Pressurizer. Does the shape change affect chugging behavior with ADS discharge?
What is the effect on level control setpoints?
closed 7/24 Summary discussion Chapter 5 W
W Westinghouse provided presentation at Nov ACRS meeting.
DNRL has provided documents on safety analyses 7
Zinc Injection (information on operating experience (14 foot core). Is there exothermic reaction; how much zinc coats on fuel.
closed 7/24 Chapter 19 meeting Chapter 5 W
W Westinghouse to provide presentation in future ACRS meeting.
Discussed at Oct meeting. DNRL to provide documents. Also was discussed during Nov meeting on chapter 9. Closed 8
PTLR Process. Need to clarify how this is captured in TS, other examples (COLR).
closed 7/24 Chapter 5 W
Closed at Oct meeting 12 Turbine missile generation. ACRS would like more information about assumptions in analysis
-Sketkar questions closed 7/24 Summary discussion Chapter 10 W
TVA/D NRL/N WE1 Issue to be discussed during chapter 3 review where missile generation from one unit s impact on a second unit is discussed.
Also missile hazards analysis for existing units on the site should be addressed in presentation to ACRS Discussed at Oct and Feb meeting. Issue of Dual unit sites is adequately addressed. New questions were raised and they are added to Item 9.
13 BLN Hydrology Issue and QA aspects. Staff to provide inspection report and public meeting accession numbers.
closed 7/24 Summary discussion Chapter 19 TVA DNRL 8-10-09 update - action complete information provided to Mike Lee in a 7/28 email from Joe Sebrosky Discussion topic to be deferred to RCOLA site specific review 14 Concerned about ad-hoc basis of the staffs review of design changes to determine if a particular design change impacts other areas of the FSAR.
closed 7/23 Summary Discussion Chapter 5, Chapter 10 W
DNRL Closed by focus on design changes not just DCD changes AP1000 Design Safety Evaluation Report Meeting ACRS Subcommittee Action Items (DRAFT)
July 23 - 24, 2009, October 6-7, 2009, November 5, 2009, February 2-3, 2010, and April 22, 2010 Revised 4-27-10 11 ID No.
Action Item Status Source (Chapter/
Discussion)
Westinghouse/
Bellefonte application Who has action Comment/Disposition 15 Would like a better understanding of how GSI 199 (eastern Tennessee seismic zone) affects the seismic margins bounding approach.
-Ray closed Chapter 19 both DNRL/
NWE1 Issue to be discussed during chapter 2 bellefonte presentation or during other SC on GSI-199. Closed in Feb.
-site specific 16 Does the recent flood in France shed any In sights with regard to PRA?
-Banerjee closed Chapter 19 both DNRL/
NWE1 Issue to be discussed during chapter 2 bellefonte presentation.
Closed in Feb
-site specific 17 Present information on testing. Present testing done to support Rev 15 and 17 design certifications. Present testing done to demonstrate as-built - i.e. the initial test program. Present testing that is done throughout the life of the plant.
-Abdel-Khalik closed Chapter 14 Both W,
- TVA, DNRL See item #2 18 Concerned about workload and what can be done to help ACRS (suggested that alternatives can be explored like thermal hydraulic issues being discussed for all design centers during one set of ACRS meetings).
closed 7/24 Summary Discussion DNRL DNRL to discuss issue with upper management and determine if there are alternatives. Closed 19 Staff to provide information regarding what is meant by rad significant closed Chapter 12 8/10- update added based on comment from Mike Lee. Need to review transcripts when available to better understand item Relates to July 22 ACRS letter on NEI-08-08. Generic to all COLs - closed with respect to AP1000 SC AP1000 Design Safety Evaluation Report Meeting ACRS Subcommittee Action Items (DRAFT)
July 23 - 24, 2009, October 6-7, 2009, November 5, 2009, February 2-3, 2010, and April 22, 2010 Revised 4-27-10 12 ID No.
Action Item Status Source (Chapter/
Discussion)
Westinghouse/
Bellefonte application Who has action Comment/Disposition 20 Provide information regarding how digital I&C failure rates were addressed in the PRA and whether there were improvements made in the design as a result of insights from the PRA.
-Kress?
closed Chapter 19 8/10- update added based on comment from Mike Lee. Need to review transcripts when available to better understand item.
Discussed at Feb meeting 21 In several areas, the Committee sought figures or other visuals to understand the design changes (flow skirt, flywheel),
functional block diagram on turbine controls.
The Committee will be looking for this in future chapters.
closed NA Both W/TVA
/DNRL Chapter 7 presentation includes several figures. Westinghouse will provide more figures in future presentations (1/15/2010).
Closed in Feb 22 In most cases, the Committee was not particularly interested in process issues, such as handling of COL holder items. For future meetings, suggest not presenting COL and open items where this is the primary consideration.
closed NA Both W/TVA
/DRNL discussed in February meeting 23 The Committee was interested in how the staff ensures that overall impacts are considered, such as: could something about COL impact upon the IBR usage, and are all effects of a particular design change evaluated. (relates to item 14 above) closed NA Both DNRL DNRL to consider if additional information in this area should be presented to the ACRS. Westinghouse will discuss their process during Nov meeting. Closed 24 The Committee indicated that there is still confusion about RCOL transition process.
closed NA TVA NWE1 Provide additional discussion in future ACRS meeting - included during Nov 5 FC meeting. Closed in Feb 25 Human Factors Engineering, including Computer-Based procedures audit
. Task analyses closed 18 W
NWE2 DNRL provided documents. GA wants information on integration of HRA into HFE (from 11/5) -documents provided AP1000 Design Safety Evaluation Report Meeting ACRS Subcommittee Action Items (DRAFT)
July 23 - 24, 2009, October 6-7, 2009, November 5, 2009, February 2-3, 2010, and April 22, 2010 Revised 4-27-10 13 ID No.
Action Item Status Source (Chapter/
Discussion)
Westinghouse/
Bellefonte application Who has action Comment/Disposition 28 Pipe break hazard analyses (DAC)
-Banerjee, Ray closed 3.6 W
W/NW E2 Provide report when completed (2010)). Closed in Feb 29 Screening criteria for striping (thermal fatigue)
-Banerjee closed 3.12 W
W Discuss at future meeting. Westinghouse is targeting April.
Closed at 4/22 meeting 30 WESTEMS code and J-weld
-Shack closed 3.9.1 W
NWE2 Open items in SER - will discuss with AFSER 40 Underground piping (fluids) and conduit (electrical) and how they perform with regard to groundwater intrusion and surface water infiltration. The concern includes the pipe, connections and material performance at the connections (joint adhesives welding materials, etc.). A related question are any of the tritium task force results and recent experiences reported for Vermont Yankee and Indian Point raising issues for such piping. (Mike Ryan) closed 9
W and NRC Discuss at future meeting. March/April pg 2-187 of Nov 20 meeting Transcripts. Closed at 4/22 meeting 42 Cyber Security closed 7
NRC NWE2 provided copy of TR. Closed in Feb 44 RTNSS tutorial
-Ray closed DNRL At Feb meeting 45 Multiple spurious actuation report
-Ray,Maynard closed 9
DNRL W
Westinghouse to provide copy of report. Proprietary concerns?
Feb discussion --> closed.
51 Get a NRC consultant report on ASTRUM applicability evaluation (NRO provided the report after the meeting).
closed DNRL DNRL provided report following Feb meeting. Closed