ML18092A306
| ML18092A306 | |
| Person / Time | |
|---|---|
| Site: | 05200045 |
| Issue date: | 03/31/2018 |
| From: | GE-Hitachi Nuclear Energy Americas |
| To: | Office of New Reactors |
| References | |
| M180068 NEDO-33878, Rev 3 | |
| Download: ML18092A306 (106) | |
Text
Enclosure 3 M180068 NED0-33878, Revision 3, ABWR ECCS Suction Strainer Evaluation of Long-Term Recirculation Capability, March 2018 Class I (Public)
IMPORTANT NOTICE REGARDING CONTENTS OF THIS DOCUMENT Please Read Carefully The information contained in this document is furnished solely for the purpose(s) stated in the transmittal letter. The only undertakings of GEH with respect to information in this document are contained in the contracts between GEH and its customers or participating utilities, and nothing contained in this document shall be construed as changing that contract. The use of this information by anyone for any purpose other than that for which it is intended is not authorized; and with respect to any unauthorized use, GEH makes no representation or warranty, and assumes no liability as to the completeness, accuracy, or usefulness of the information contained in this documenf
HITACHI GE Hitachi Nuclear Energy Non-Proprietary Information - Class I (Public)
Licensing Technical Report NED0-33878 Class I (Public)
Revision 3 March 2018 ABWR ECCS SUCTION STRAINER EVALUATION OF LONG-TERM RECIRCULATION CAPABILITY I
Copyright 2018, GE-Hitachi Nuclear Energy Americas LLC All Rights Reserved GEH Public I
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
INFORMATION NOTICE This is a non-proprietary version of the document NEDE-33878P Revision 3, which has the proprietary information removed. Portions of the document that have been removed are indicated by an open and closed bracket as shown here ((
)).
IMPORTANT NOTICE REGARDING CONTENTS OF THIS REPORT Please Read Carefully This document provides certain details of the Emergency Core Cooling System Suction Strainers for the ABWR standard design. The information contained in the document is furnished to the NRC for the purpose of conducting its review for the renewal of the ABWR standard design certification. The use of this information by anyone for any other purpose than that for which it is intended is not authorized; and with respect to any unauthorized use, GEH makes no representation or warranty, and assumes no liability as to the completeness, accuracy, or usefulness of the information contained in this document.
GEH Public I
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
TABLE OF CHANGES Rev.#
Date Revision Summary 0
02/2017 Initial Issue 1
05/2017 Revised to reduce proprietary information markings and correct 2
3 some paragraph spacing which reduced the page count by one page. There are no other changes. Revision bars not used.
08/2017 Updated the ECCS suction strainer debris downstream assessment as follows: 1) The mission time for post LOCA function of RHR and HPCF was revised from 100 days to 30 days consistent with NRC guidance; 2) ASME QME-1 was credited as reference for ECCS pump performance qualification to ensure as-built SSCs will meet post LOCA requirements including debris loading; 3) Additional detail was provided for a mitigating feature to prevent settling of debris in instrument lines; 4) Clarification of RHR heat exchanger flow path and assessment of heat exchanger I
performance under post LOCA debris loading was provided.
03/2018 In the proprietary NEDE, changed a reference in Section 2.1.3.2 from "2.1.3.2" to "2.1.3".
GEH Public Updated References 18 and 34.
Appendix A.4.1, first bullet, added Reference 27.
Updated the ECCS suction strainer debris downstream assessment description as follows:
- 1) Revised Appendix A.4.1, Auxiliary Equipment Evaluation, to reflect the assessment for instrument line plugging and wear is based on instrumentation line configuration and orientation and not system flow and materials settling velocities as is the criteria for process piping.
- 2) Revised Appendix A.4.1, Auxiliary Equipment Evaluation, to reflect that this report is incorporated by reference in the I
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Rev.#
Date GEH Public NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Revision Summary ABWR DCD Tier 2. This report imposes requirements on ABWR design.
- 3) Updated the Auxiliary Equipment Evaluation presented in Tables A-4 through A-8 to reflect that ECCS pump design is based on ECCS suction strainer sizing to prevent clogging of pump internal passages including mechanical seal assemblies. The ECCS pump manufacturer will specify cyclone separator performance and seal cooling line orifice hole size to prevent debris plugging.
- 4) Updated Tables A-4, A-5, and A-6 to correct subscripts for Iron Oxide.
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
TABLE OF CONTENTS TABLE OF CHANGES.................................................................................................... 3 TABLE OF CONTENTS.................................................................................................. 5 LIST OF ILLUSTRATIONS.............................................................................................. 6 LIST OF TABLES............................................................................................................ 6
1.0 INTRODUCTION
.................................................................................................. 7 1.1 Background................................................................................................ 7 1.2 Purpose..................................................................................................... 9 1.3 Acronyms................................................................................................. 10 1.4 Definitions................................................................................................ 11 1.5.
Assumptions............................................................................................ 13 2.0 DESIGN METHODS........................................................................................... 15 2.1 Discussion............................................................................................... 15 2.1.1 Debris Types / Quantities..................................................................... 15 2.1.2 Selection of Bounding Strainer Design................................................. 19 2.1.3 Head Loss Evaluation.......................................................................... 20 3.0 DESIGN RESULTS 1& ACCEPTANCE CRITERIA..................................... /........ 28 3.1 Design Results......................................................................................... 28 3.1.1 RHR Acceptance Criteria.......................................................................... 29 3.1.2 HPCF Acceptance Criteria........................................................................ 29 3.1.3 RCIC Acceptance Criteria......................................................................... 30
4.0 CONCLUSION
S................................................................................................. 31
5.0 REFERENCES
................................................................................................... 32 APPENDIX A DOWNSTREAM EFFECTS EVALUATION............................................. 35 A.1 OVERVIEW....................................................................................................... 35 A.2 ECCS SYSTEM DESCRIPTIONS AND MISSION TIMES.................................. 36 A.3 DEBRIS INGESTION.......................................................................................... 39 A.4 WEAR RATE AND COMPONENT EVALUATION.............................................. 41 A.4.1 Auxiliary Equipment Evaluation................................................................ 41 A.5 REACTOR INTERNALS AND FUEL BLOCKAGE EVALUATION............. T...... 46 GEH Public I
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LIST OF ILLUSTRATIONS FIGURE A-1, ABWR ECCS FLOW PATHS.................................................................. 37 FIGURE A-2, LAYOUT OF ECCS COMPONENTS FOR DOWNSTREAM ASSESSMENT
........................................................................................................................... 44 FIGURE A-3, NORMAL FUEL CHANNEL COOLING FLOW PATHS........................... 48 LIST OF TABLES Table 1: RMI Surface Area to Volume Ratio............................................................... 14 Table 2: ((
0 0 0 0 0 0 0 0 0 0 0
)) Pipe Insulation Debris Load.................................................... 16 Table 3: ABWR Debris Load Fractions........................................................................ 17 Table 4: ABWR Pipe Insulation Debris Load............................................................... 18 Table 5: ABWR Other Debris Sources........................................................................ 18 Table 6: System Flow Conditions................................................................................ 19 Table 7: Total Clean Strainer Head Loss.................................................................... 23 Table 8: Non-Fibrous Debris Bump-Up Factor............................................................ 25 Table 9: RMI Head Lo~s................................................................................J............. 27 Table 10: Summary of Data........................................................................................ 28 Table A-1: ECCS Mode, Mission Time and Description............................................... 38 Table A-2: ABWR Debris Source Term........................................................................ 40 Table A-3: ABWR Debris Downstream Concentration................................................. 45 Table A-4: ECCS Suction Strainer Downstream Effects-RHR Core Cooling Mode A 1 49 Table A-5: ECCS Suction Strainer Downstream Effects-RHR Suppression Pool Cooling Mode 81....................................................................................................................... 62 Table A-6: ECCS Suction Strainer Downstream Effects-Containment Spray with Heat Removal Mode E.......................................................................................................... 73 Table A-7: ECCS Suction Strainer Downstream Effects-High Pressure Core Flooder Mode 81................................................................................................................................. 85 Table A-8: ECCS Suction Strainer Downstream Effects-Reactor Core Isolation Cooling System Mode C............................................................................................................ 95 GEH Public I
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
1.0 INTRODUCTION
1.1 Background
The Advanced Boiling Water Reactor (ABWR) design was certified as 10 CFR Part 52, Appendix A, in a final rulemaking published May 12, 1997, effective June 11, 1997. In the certified design, emergency core cooling system (ECCS) suction strainers were included to address concerns with debris that could block the suction of the ECCS pumps when recirculating from the suppression pool.
On December 7, 2010, GEH applied to the U.S. Nuclear Regulatory Commission (NRG) for the renewal of the ABWR standard plant design certification (DC), which the NRG had issued on June 11, 1997. Because of lessons learned from BWR operating experience and from the review of Generic Safety lssue-191, Assessment of [Effect of] Debris Accumulation on PWR Sump Performance, the staff determined that additional information was required to evaluate compliance of the Emergency Core Cooling System (ECCS) design with 10 CFR 50.46(b)(5). Lessons learned included recognition of the inadequacy of the criterion to allow 50 percent blockage of the strainer surface area and recognition of chemical precipitates as a potential debris source. The staff incorporated these and other lessons learned into revisions of Regulatory Guide (RG) 1.82, Water Sources for Long-Term Recirculation Cooling Following a Loss-of-Coolant Accident.
In a July 20, 2012 response to GEH's application for certification renewal, the NRG communicated the list of design changes that the NRG considered to be regulatory improvement or changes that could meet the 10 CFR 52.59(b) criteria. Item 9 requested that GEH confirm that the emergency core cooling system suction strainer design complies with 10 CFR 50.46(b)(5), including providing net positive suction head (NPSH) margins using RG 1.82, Revision 4, addressing chemical, in-vessel, and ex-vessel downstream effects, providing a structural analysis, and updating the IT AAC as necessary consistent with the new guidance.
ECCS Suction Strainer Debris Issue Boiling Water Reactor (BWR) strainer performance issues were evaluated in the mid-1990s after some incidents at foreign and domestic BWRs led to concerns about strainer performance. Evaluation of these issues led to enlargement of strainer size, and the N RC's conclusion almost a decade ago that the questions regarding BWR strainer performance had been resolved. In 2007, the NRG did a preliminary area-by-area comparison of regulatory and technical treatment of BWRs vs. PWRs. The NRC's initial conclusion was that there were disparities in treatment, but there is not enough information to validate the GEH Public I
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public) issues or their significance. The NRC concluded additional evaluations were needed to determine the safety significance of these issues.
The NRC's Office of Nuclear Regulatory Research and the BWR Owners' Group (BWROG) have begun new work on BWR strainer performance. The NRC and the BWR Owners Group have met on several occasions to discuss a path forward. The NRC staff has provided perspective to the BWROG on some of the subject areas related to strainer performance based on lessons learned from evaluations of PWR Sump Performance.
Currently operating BWR strainer designs are based on guidance from sources such as the BWR Owners Group Utility Resolution Guidance, the accompanying safety evaluation (SE) and NUREG/CR-6224, Parametric Study of the Potential for BWR ECCS Strainer Blockage Due to LOCA Generated Debris. In future evaluations, BWR strainer designs consider subsequent guidance developed during the resolution of GSl-191 and GL 2004-02 including chemical and downstream effects and strainer head loss and vortexing.
ABWR Solution The ABWR ECCS strainers are sized to conform with the guidelines provided in Reg Guide 1.82 Rev. 4, for the most severe of all postulated breaks.
The debris generation model was developed in accordance with the Utility Resolution Guidance, NED0-326~6-A (Reference 1 ).
The design debris load transported to the suppression pool is based on the Utility Resolution Guidance, NED0-32686-A (Reference 1 ).
The ECCS Strainer design is based on the Debris Load Fraction that accumulates on a given strainer for the Loss of Coolant Accident (LOCA) case considered. For conservatism, the worst-case load fraction for each system was applied even if it resulted from a different type of LOCA (RHR vs. MS break).
Suction strainer sizing criteria is based on meeting NPSH requirements at runout system flow.
The ABWR design provides reasonable assurance that downstream effects as a result of debris bypassing the strainers will not have a deleterious effect on critical components such as fuel rods, valves and pumps downstream of the suction strainers.
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
The ABWR design incorporated improvements from the currently operating boiling water reactor (BWR) design:
ABWR design eliminates recirculation piping external to the reactor pressure vessel (RPV), which removes a significant source of insulation debris and reduces the likelihood of a large high energy pipe break leading to the introduction of debris.
ABWR main steam and feedwater piping connects to the RPV above the core, thus eliminating a large break loss of coolant accident (LOCA) below the top of active fuel.
ABWR uses a stainless-steel liner for the submerged portion of the ABWR suppression pool as opposed to carbon steel used in earlier designs of BWR suppression pools, significantly lowering the amount of corrosion products which can accumulate in the suppression pool.
The use of several materials in the primary containment are prohibited or minimized (e.g., aluminum, zinc), mitigating many of the chemical effects from debris.
The ABWR has diversification of ECCS delivery points, which helps to reduce the consequences of downstream blockage. Two High Pressure Core Flooder (HPCF) loops deliver coolant to the region above the core (i.e., at the outlet of the fuel assemblies). One of three LPCF loops provide coolant through one of the feed water lines. The Reactor Core Isolation Cooling (RCIC) system delivers coolant to the other feedwater line. Two LPCF systems deliver coolant through separate spargers into the outer annulus region. Should any blockage occur in the lower core region (such as the fuel inlet) which could limit the effectiveness of systems like Residual Heat Removal (RHR)), the HPCF system will still be effective at providing cooling water because it delivers water through spargers located above the core.
1.2 Purpose The purpose of this technical report is to provide certain supporting technical information regarding the new design of the ECCS suction strainers for the ABWR.
This technical report provides supporting information to show conformance with RG 1.82, Water Sources for Long-Term Recirculation Cooling Following a Loss-of-Coolant Accident, Revision 4.
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1.3 Acronyms I Acronym ABWR OBA DCD ECCS ESBWR FAPCS GPM HPCF IOZ LOCA MSL NPSH RCIC RHR RMI GEH Public NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
I Explanation Advanced Boiling Water Reactor Design Basis Accident Design Control Document Emergency Core Cooling System Economic Simplified Boiling Water Reactor Fuel and Auxiliary Pools Cooling System Gallons per Minute High Pressure Core Flooder Inorganic Zinc Loss of Coolant Accident Main Steam Line Net Positive Suction Head Reactor Core Isolation Cooling Residual Heat Removal Reflective Metal Insulation I
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public) 1.4 Definitions To understand certain design terms or supporting information, definitions are provided below.
Term D
L Ac AFoiI Q
T
µ V
Ah L.\\hTotal L.\\hc1ean L.\\hRMI Kc1ean Kh Kbu Kp Kt I
K2 GEH Public Descri~tion Units Outside strainer diameter ft Strainer length ft Circumscribed strainer area ft2 Foil Area on Strainer ft2 Flow rate gpm water temperature F
Dynamic viscosity lbm-sec/ft2 Kinematic viscosity ft2/sec I
Head loss ftH20 Total strainer head loss ftH20 Losses through a clean strainer ftH20 Losses due to Reflective Metal Insulation ftH20 (RMI) on strainer Clean strainer head loss coefficient ftH20 Debris head loss coefficient Bump up factor for non-fibrous debris Proportionality Constant Thickness constant for RMI material I
Strainer flange resistance coefficient I
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Term u
U1 Us V
MF Mc Mz Mpc MRF Meo d
dr t
ta tp tmax GEH Public NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Descri12tion Units Circumscribed approach velocity ft/sec Approach velocity corrected for strainer ft/sec surface area Average RMI settling velocity ft/sec Flow velocity in suction line ft/sec Mass of fibrous debris lbm Mass of sludge I corrosion products lbm Mass of inorganic zinc (IOZ) lbm Mass of epoxy coated IOZ (paint chips) lbm Mass of rust flakes lbm Mass of dust I dirt lbm I Interfiber distance ft Fiber diameter ft Debris bed thickness ft Theoretical RMI Bed Thickness ft Projected RMI Bed Thickness ft Max RMI Bed Thickness ft I
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public) 1.5.
Assumptions 1.5.1 Some design details from ((
)) which are used as inputs to this evaluation, are considered representative of the ABWR standard plant.
Examples include:
The pipe insulation debris load calculation (Reference 7).
The NPSH calculations given in References 17, 18, and 19.
1.5.2 For the purpose of estimating viscosity for head loss through the strainer, the suppression pool temperature is assumed to be ([
))
1.5.3 ((
)) the best estimate head loss predictions obtained with the methodology described in Reference 5 will provide reasonable assurance of producing a bounding head loss estimate.
1.5.4 It is assumed that a design basis sludge load of 200 lbm per cycle bounds the generation rate for a typical ABWR.
Section 3.2.4.3.2 of the URG (Reference 1 ), describes a survey of operating BWRs that measured the rate lof sludge generation. The data, collected from 12 plants with Mark I, II, and Ill containment designs, indicated a median sludge generation rate of 88 lbm per year. The URG recommends a value of 150 lbm per year to bound these results unless a lower plant-specific value can be justified.
The ABWR design features many improvements over the conventional BWRs that will help to minimize the generation of sludge. Specifically, the suppression pool is equipped with a stainless steel liner, and many interfacing systems utilize stainless steel pipe, which reduces the generation of carbon steel corrosion products. The ABWR suppression pool is enclosed in a concrete compartment and protected from the drywell environment, unlike some containment designs (from the BWROG survey), which are subject to dirt and debris falling through grating into the pool.
The above considerations suggest the ABWR sludge generation rate would be less than the typical operating BWR. Therefore, the assumed ABWR sludge load of 200 lbm ( 100 lbm per year with a two-year operating cycle) is considered a reasonable assumption. Furthermore, there is a COL Item in Section 6.2.7.3 of the ABWR Design Control Document (DCD) (Reference 21) that requires the applicant to establish a method for maintaining a level of cleanliness that supports this assumption.
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1.5.5 It is assumed that a surface-area-to-volume ratio of ((
debris. ((
)), Table 1 below, ((
))
Table 1: RMI Surface Area to Volume Ratio
)) for RMI Values Taken Explicitly from Table 3 of Derived to support this Reference 15 assumption RMI Surface Volume of RMI Area ((
Pipe Radial RMI RMI
((
Surface Area to OD Thickness OD Volume Ratio
))
))
in in in in2 in3
((
I
))
RMIOD
((
))
This assumption is used.in Section 2.1.3.5 for the purpose of estimating the contributions of RMI debris to the strainer head loss.
1.5.6 The suppression pool, at its minimum drawdown level, provides a static head of
((
)) above the pump inlet nozzle. This amount of static head is consistent with the static head used in ((
)) calculation 31113-0E11-2113 I
(Reference 17).
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public) 2.0 DESIGN METHODS The methodology for sizing and qualifying a stacked disk ECCS Suction Strainer was initially developed in Reference 2. After this guidance was issued, it was determined that the methodology contained certain flaws, which are addressed in Reference 3. An updated method was documented in Reference 5, and was implemented for the Economic Simplified Boiling Water Reactor (ESBWR) Fuel and Auxiliary Pools Cooling System (FAPCS) strainer in Reference 12. These references are used as the model for this ABWR evaluation.
For simplicity, an existing strainer design will be selected from those evaluated in Reference 5. The ABWR-specific debris load, flow rate, and pool conditions will then be applied using the methods described in Reference 5 to demonstrate that a qualified strainer design exists to support ABWR certification.
Note that this evaluation demonstrates a single bounding design for the ABWR standard design to ensure compliance to 1 OCFR50.46(b)(5).
Future COLA applicants or COL licensees that elect to develop a more optimal sizing for each of the three ECCS strainers would need to seek NRC approval of a departure to the ABWR standard design for the strainers, which would require review and approval by the NRC as part of the COLA or in a post-COL license amendment request.
I 2.1 Discussion This section describes the strainer qualification process, and the reasoning for each step.
2.1.1 Debris Types / Quantities This subsection discusses the types and quantities of debris in the ABWR standard design.
2.1.1.1 Piping Insulation The debris generated from pipe insulation for ((
31113-0A51-2104 Rev. 0, which can be found in ((
)) was calculated in
)).
This calculation is based on Method 3 of Reference 1, which uses spherical zones of influence with a volume based on destruction pressure specific to the type of insulation.
This calculation evaluates Nukon fiber debris and reflective metal insulation (RMI) debris under two scenarios: (1) a Main Steam Line (MSL) break, and (2) a break in the Residual Heat Removal System (RHR). These two cases were selected because:
A MSL break has the largest ZOI and generates the most debris of any break.
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Although an RHR break generates less debris than a MSL break, there is no personnel grating separating the RHR break from the drywell to wetwell connecting vents. Therefore, a larger fraction of generated debris could make its way to the wetwell, whereas some higher-elevation MSL-generated debris would be intercepted by the grating. Until these transport factors are considered, the RHR break should not be ruled out.
Although the ZOI for an RHR break is slightly smaller than that of a Feedwater break, the amount of debris generated is slightly greater - presumably because there is more insulated pipe in close proximity to RHR piping than is the case for Feedwater piping.
Also, a break in RHR piping results in a different combination of ECCS systems to mitigate the event compared to a MSL break. Thus, certain systems may have a higher debris load fraction for an RHR break than they would for a MSL break.
Additional discussion is provided in ((
)). The basis described above was used to generate the debris values found in Section 4.3.1.6.1 of the ((
)). The values were updated for Rev. 1 of that specification to those shown below:
Table 2: ((
)) Pipe Insulation Debris Load NUKON I RMI Break Type above I below grating above I below grating
((
))
The basis for the values in Table 2 is discussed in ((
)). This discussion explains that the original insulation quantities were updated based on the restrictions for Nukon to small bore piping and, also, to include transport factors have been included in the derivation of these numbers.
Because transport has already been considered, there is no longer a reason to distinguish the debris above the grating from debris below the gdting. The numbers represent the quantity of GEH Public I
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public) debris that has already made its way to the suppression pool. Therefore, the details related to the grating have been removed as they are no longer pertinent.
Because the MSL break deposits a much greater amount of debris in the suppression pool than RHR break, the only remaining reason to consider an RHR break is the difference in debris load fractions (fourth bullet from above). This evaluation can be simplified by assuming a MSL break (maximum debris) along with the maximum debris load fractions reported in Reference 9 (even though some may correspond to an RHR break).
Table 3: ABWR Debris Load Fractions Debris Load Fraction
((
))
I As shown in Table 3, the E11 and E22 load fractions of ((
)), respectively, are based on the combined flow of one HPCF and dne RHR loop at rated flow following a break in one of the three RHR loops (with no operation of RCIC). In a more realistic scenario, the two remaining RHR loops would be running in parallel and HPCF would be drawing from the CST. But because this results in no debris load on the HPCF strainer, and a load fraction of only 0.5 split between the two RHR strainers, the alignment described above is more conservative.
The E51 load fraction of ((
)) is based on the combined flow of one RHR, one HPCF, and one RCIC loop at rated flow following a break in one of the three RHR loops. In a more realistic scenario, given the large size of an RHR break, the RCIC system would not be credited in the overall ECCS performance. RCIC performance is credited in medium and small break LOCAs, which would have correspondingly less debris generated.
Therefore, the load fraction assumed above is conservative.
With this justification, the RHR debris generation values will be ignored in favor of the MSL values.
Lastly, it was recommended in Volume 1, page 59, of Reference 7, that an additional 1 ft3 of fibrous debris be added to account for miscellaneous foreign material left in GEH Public
NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public) containment. This will be factored into the calculation as if it were Nukon insulation.
Therefore, the ((
)) of Nukon resulting from a MSL break is increased by 1 ft3 (0.028 m3) to give the following finalized piping insulation values:
Table 4: ABWR Pipe Insulation Debris Load NUKON RMI
((
))
The total Nukon volume of ((
)) can be converted to a Total Fibrous Debris Mass (MF) on a density of 2.4 lbm/ft3 (per Section 6.3.3 of Reference 11 ).
MF= ((
))
2.1.1.2 Debris from Other Sources The debris generated from other sources was determined in accordance with Reference 11, making conservative assumptions where appropriate. The values below are taken from Section 4.3.1.6.2 in Revision 1 of Reference 8 and related discussion can be found in Volume 1, pages 58-59 of Reference 7. The "Mx' designations for debris type are used later in his evaluation, as are the ratios in the third column. I Table 5: ABWR Other Debris Sources Debris Type Mc= Sludge/ corrosion prod.
Mz = Inorganic Zinc (IOZ)
MPc = Epoxy Coated IOZ MRF = Rust Flakes Meo = Dust / Dirt GEH Public
((
Strainer Load 200 lbm
((
47 lbm I
85 lbm 50 lbm 150 lbm 11
))
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public) 2.1.2 Selection of Bounding Strainer Design The flow rate through the strainer is assumed to be equivalent to the runout flow for the corresponding ECCS pump. These flows are taken from Reference 9:
Table 6: System Flow Conditions
((
))
The pool water temperature is assumed to be at ((
)) per Assumption 1.5.2.
A range of qualified stacked disk strainers from the operating fleet is given in Reference 6.
To simplify this evaluation, the ((
)) strainer (Reference 16) is used to evaluate applicability to the ABWR RHR System. It is understood that the ((
)) RHR ~ystem flow ((
)) is substantially hi~her than the ABWR RHR flow rate reported above, and therefore may be oversized for the application. This is conservative for the safety function the strainer performs, but may not be the most practical or economical choice. If future COLA applicants or COL licensees elect to seek NRC approval of a departure from the standard design, future design work can be performed to qualify a more optimized strainer size, as discussed in Section 2.0 above, following the process described herein.
Because the E22 and E51 strainers have lower flow rates and lower debris load factors than the E11 strainer, it is assumed that their performance is bounded by the evaluation of the E11 system. Therefore, the head loss evaluation will be performed for only the E11.
In Section 3.0, a check is performed against the NPSH requirements for each of the three ECCS systems. As with E11, future work can determine a more optimal size for the E22 and E51 strainers.
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public) 2.1.3 Head Loss Evaluation The head loss correlation given by Reference 2 is defined as:
((
))
See Section 1.4 for a definition of these variables. Some additional factors will be added to this correlation to address considerations such as RMI insulation. The content of this section will explain the derivation of each of these parameters, and the final correlation is summarized in Section 3.
The first term from the above equation represents the losses through a clean strainer.
((
)).
The second term accounts for losses due to debris accumulation on the strainer (excluding RMI). ((
)).
2.1.3.1 Spreadsheet Instructions Reference 5 contains instructions on how to use a spreadsheet template (verified in Reference 6) to simplify many of the calculations related to strainer dimensions and debris bed thickness. The spreadsheet contains data in the "Stats All" tab for strainer designs that have already been qualified, and leaves a blank column (Column R) for a new design to be added. ((
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)) Some of these rows are not applicable to the updated method discussed in Reference 5. Others are applicable to the updated method but require more explanation and are, therefore, discussed in more detail in the following sections.
2.1.3.2 Losses through Clean Strainer and Flange The losses through the clean strainer are easily derived based on the value ((
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))
A similar method is used to determine the losses through the connecting flange. ((
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))
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Table 7: Total Clean Strainer Head Loss Clean Strainer Losses
((
((
))
))
2.1.3.3 Debris Load Head Loss Coefficient (Kh)
The definition of Kh, is based upon the method of Reference 2 with modifications described by Reference 3. The new Kh correlation makes a distinction between two strainer loading scenarios. ((
head loss coefficient is calculated to be:
((
GEH Public
)) The
))
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public) 2.1.3.4 Strainer Debris Load Bump-up Factor (Kbu)
The methodology described in Reference 2 includes (near the end of Section 3.3) a bump-up factor to account for the presence of non-fibrous components of the debris bed. The factor is defined in Appendix A of Reference 13. Table 8 summarizes the results of each step and provides a basis for the values used.
Appendix A of Reference 13 was originally intended to derive the head loss coefficient Kh.
But because this evaluation uses an alternate method to derive Kh, many of the steps below are simply marked "not required". Only the steps needed to derive K bu are used.
((
GEH Public
))
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Step 1
2 3
3 3
4-8 9
10 10 10 10 11 NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Table 8: Non-Fibrous Debris Bump-Up Factor Variable Value Units Basis Circumscribed Strainer Area ((
ft2 (Ac)
Row 19 of Ref. 6 Strainer Approach Velocity (U) ft/sec Row 52 of Ref. 6 Mass of fibrous debris (MF)*
lbm Section 2.1.1.1 Mass of corrosion products (Mc) lbm Table 5 Mc/MF Table 5 Not Required Mass ratios for other debris Table 5 l"a" coefficient for all debris Ref. ~ 3 Appendix A "b" coefficient for all debris Ref. 13 Appendix A "a" coefficient for fiber/ sludge only Ref. 13 Appendix A "b" coefficient for fiber/ sludge only Ref. 13 Appendix A K bu
)) -
Ref. 13 Appendix A
- The load factor is not applied in this table, because K bu is simply a ratio of non-fibrous to fibrous debris.
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public) 2.1.3.5 RMI Insulation Losses The contribution of RMI type insulation to the overall strainer head loss is small compared to that of other types of debris. The methodology for estimating the RMI head loss is given in Appendix B of Reference 13. Table 9 summarizes the results of each step and provides a basis for the values used.
Note that the debris table in Reference 8 specifies that RMI is stainless steel foil ((
))
For additional conservatism, this entire amount is assumed to collect entirely on one strainer (ire., the debris load factor is not applied).
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Table 9: RMI Head Loss Step Variable RMI Type RMI Thickness Strainer Length (L)
Strainer Outer Diameter (D)
Maximum Flow Rate (Q)
Foil Area on Strainer (AFoi1) 1 Circumscribed Strainer Area (Ac) 2 Strainer Approach Velocity (U) 3 Average RMI Settling Velocity (Us)
Max RMI Bed Thickness 3
(tmax) 4 Empirical Thickness Constant (Ki) 4 Theoretical Bed Thickness (ta) 5 Projected Bed Thickness (tp) 6 Proportionality Constant (Kp) 6 Head Loss (b.h) for RMI
- ((
))
GEH Public Value Units
((
in ft ft GPM ft2 ft2 ft/sec ft/sec ft ft ft ft
))
ft Basis Section 2.1.3.5 Reference 8 Row 8 of Ref. 6 Row 9 of Ref. 6 Table 6 Section 2.1.3.5 Row 19 of Ref. 6 Row 52 of Ref. 6 Table B-1 1
of Ref. 13*
Appendix B of Ref. 13 Table B-2 of Ref. 13*
Appendix B of Ref. 13 Appendix B of Ref. 13 Table B-3 of Ref. 13*
Appendix B of Ref. 13 I
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public) 3.0 DESIGN RESULTS & ACCEPTANCE CRITERIA 3.1 Design Results The head loss is calculated by compiling all the factors discussed in Section 2.1.3. The total head loss equation has been updated as shown to include various conservative factors and assumptions described in previous sections ((
))
Table 10 below summarizes each value and where in this report it was derived.
Table 10: Summary of Data Variable Value Units Basis
((
I I
The total RHR strainer head is calculated as follows ((
GEH Public
))
))
I Page 28 of 105
NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public) 3.1.1 RHR Acceptance Criteria The required NPSH for the RHR pumps is given in DCD Table 6.3-9 (Reference 21) as 2.4 m (7.9 ft). According to a ((
)) calculation ((
)), there is an available NPSH of ((
)), assuming the strainer losses do not exceed ((
)).
((
)) the strainer losses calculated in this evaluation can be adjusted based on water viscosity. ((
))
This adjustment shows that the strainer design from this evaluation can satisfy the NPSH requirements of the RHR system of a typical ABWR.
3.1.2 HPCF Acceptancb Criteria The required NPSH for the HPCF pumps is given in DCD Table 6.3-8 (Reference 21) as 2.2 m (7.2 ft). According to a ((
)) calculation ((
)), the HPCF system provides an available NPSH of ((
)), assuming that the maximum strainer losses are limited to ((
)) of head given a temperature of 100°C and a runout flow of 890 m3/hr.
The results shown in Section 3.1 meet the ((
)) of head required by ((
)).
There is significant conservatism in this method, because the NPSH margin for the
((
)) HPCF system was determined at a lower flow rate and viscosity.
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public) 3.1.3 RCIC Acceptance Criteria The required NPSH for the RCIC pumps is given in DCD Table 5.4-2 (Reference 20) as 7.3 m (24.0 ft). According to a ((
)) calculation ((
)), the RCIC system provides an available NPSH of ((
)), assuming that the maximum strainer losses are limited to ((
)) of head given a temperature of 77°C and a runout flow of 199 m3/hr.
The results shown in Section 3.1 meet the ((
)) of head required by ((
)).
There is significant conservatism in this method, because the NPSH margin for the
((
)) RCIC system was determined at a lower flow rate and viscosity.
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
4.0 CONCLUSION
S It has been shown that a strainer design exists that can be applied to the RHR System for the ABWR such that under the most limiting debris load and environmental conditions, the head losses across the debris bed, strainer, and pipe flange shall be limited to ((
)) of water under the conservative assumptions of pump runout flow and higher viscosities resulting from an assumed low temperature of ((
)). This low temperature assumption was not credited when calculating NPSH margin.
This bounding strainer design was shown to also satisfy the NPSH requirements for the HPCF and RCIC pumps.
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
5.0 REFERENCES
- 1.
NED0-32686-A Rev. 0, Utility Resolution Guidance for ECCS Suction Strainer Blockage, November 1996
- 2.
NEDC-32721 P-A Rev. 2, Licensing Topical Report: Application Methodology for the GE Stacked Disk ECCS Suction Strainer, March 2003 (GEH Proprietary)
- 3.
PLM Object 0000-0080-3041 Rev. 0, Evaluation Report (GEH Proprietary)
- 4.
PLM Object 002N1768 Rev. 1, Closure Letter (GEH Proprietary)
- 5.
PLM Object 0000-0080-3039 Rev. 2, Plant Summary Design Notes FINAL.pdf (GEH Proprietary)
- 6.
PLM Object 0000-0081-1211 Rev. 2, USBWR Strainer Stats20080520.xls (GEH Proprietary)
- 7.
PLM Object A60-00051-00, Design Record File for Suppression Pool Suction Strainers (GEH Proprietary)
I 8.
31113.62.3031, Suppression Pool Strainer f((
(GEH Proprietary)
- 9.
31113.62.3031-01600 Rev. 1, Suppression Pool Suction Strainer ((
)) (GEH Proprietary)
))
- 10.
31113-0U71-1000 Rev. 3, ((
(GEH Proprietary)
)) Reactor Building Design Specification
- 11.
NUREG/CR-6224 (SEA No. 93-554-06-A:1 ), Parametric Study of the Potential for BWR ECCS Strainer Blockage Due to LOCA Generated Debris, October 1995
- 12.
PLM Object 0000-0092-3114 Rev. 1, Preliminary Sizing of FAPCS Strainer (GEH Proprietary)
- 13.
Continuum Dynamics Report 95-09, Testing of Alternate Strainers with Insulation Fiber and Other Debris, November 1996 GEH Public I
Page 32 of 105
NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
- 14.
NEDM-20363-13-01, Hydraulics of Boiling Water Reactors, August 2006
- 15.
Continuum Dynamics Report 95-17, Structural Properties of Reflective Metal Insulation Installed in U.S. BWR's, 1996
- 16.
105E2586 Rev. 4, Assembly Drawing Suction Strainer, RHR, ((
))
- 17.
31113-0E11-2113 Rev. 1, ((
)) Residual Heat Removal System - Pump NPSH Calculation (GEH Proprietary)
- 18.
31113-0E22-2105 Rev. 1, High Pressure Core Flooder System - Pump NPSH Calculation (GEH Proprietary)
- 19.
31113-0E51-2121 Rev. 0, ((
)) Reactor Core Isolation Cooling System -
Pump NPSH Calculation (GEH Proprietary)
- 20.
25A5675AG Rev. 6, ABWR Design Control Document, Tier 2, Chapter 5
- 21.
25A5675AH Rev. 6, ABWR Design Control Document, Tier 2, Chapter 6
- 22.
25A5675BB Rev. 6, ABWR Design Control Document, Tier 2, Chapter 21
- 23.
f NED0-32686-A, Utility Resolution Guide for ECt S Suction Strainer Blockage Volume 4 Technical Support Documentation [GE-NE-T23-00700-15-21 March 1996 (Rev. 1) Evaluation of the Effects of Debris on ECCS Performance]
- 24.
31113-1 E11-M2001 through M2010, Piping and Instrument Diagram Residual Heat Removal System (GEH Proprietary)
- 25.
31113-1 E22-M2001 and M2002, Piping and Instrument Diagram HP Core Flooder System (GEH Proprietary)
- 26.
31113-1 E51-M2001 through M2003, Piping and Instrument Diagram Reactor Core Isolation Cooling System (GEH Proprietary)
- 27.
31113-1 N22-M2001, Piping and Instrument Diagram Feedwater System (GEH Proprietary)
- 28.
31113-1E11-M0100, Rev 9, Residual Heat Removal System Design List (GEH Proprietary)
GEH Public I
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
- 29.
31113-1 E22-M0100, HP Core Flooder System Design List (GEH Proprietary)
- 30.
31113-1E51-M0100, Reactor Core Isolation Cooling System Design List (GEH Proprietary)
- 31.
31113-1N22-M0100, Feedwater System Design List (GEH Proprietary)
- 32.
31113-0E11-2010, Rev.4, Residual Heat Removal (RHR) System Design Description (GEH Proprietary)
- 33.
31113-0E22-2010, Rev.5, High Pressure Core Flooder System Design Description (GEH Proprietary)
- 34.
31113-0E51-2010, Rev. 5, Reactor Core Isolation Cooling System (RCIC) Design Description (GEH Proprietary)
- 35.
NEDC-32976P, SAFER/GESTR-LOCA Loss of Coolant Accident Analysis
((
)) (GEH Proprietary)
- 36.
105E2763 R3, HPCF Sparger (GEH Proprietary)
- 37.
NEI 04i 07 Rev 0, Pressurized Water Reactor Sump Perforrriance Methodology
- 38.
NUREG/CR-6808 (LA-UR-03-0880), Knowledge Base for the Effect of Debris on Pressurized Water Reactor Emergency Core Cooling Sump Performance, February 2003
- 39.
NEDC-33302P, Fiber Insulation Effects with Defender Lower Tie Plate, March 2007 (GNF Proprietary)
- 40.
ASME QME-1-2007, Qualification of Active Mechanical Equipment Used in Nuclear Power Plants
- 41.
Regulatory Guide 1.100, Rev. 3, Seismic Qualification of Electrical and Active Mechanical Equipment and Functional Qualification of Active Mechanical Equipment for Nuclear Power Plants
- 42.
31113-0A23-1000, ((
(GEH Proprietary)
GEH Public
)) Project Design Manual, Rev 36, 6/19/2014 I
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
APPENDIX A DOWNSTREAM EFFECTS EVALUATION A.1 OVERVIEW Evaluation of the ABWR containment includes a review of the flow paths downstream of the emergency core cooling systems (ECCS). The concerns addressed for downstream effects are:
Blockage of flow paths in equipment; for example, spray nozzles or tight-clearance valves Wear and abrasion of surfaces; for example, pump running surfaces, heat exchanger tubes and orifices Blockage of flow clearances through fuel assemblies In general, the downstream review broadly considers flow blockage in the ECCS flow paths, as well as examining wear and abrasion in systems, structures, and components in the ECCS flow paths that are credited for long-term cooling functions.
The downstream review considers the flow clearance through the ECCS suction strainer.
This determines the maximum size of particulate debris that will pass through the suction strainer and enter tf e ECCS flow paths. If passages and channelsj in the ECCS downstream of the suction strainer are larger than the flow clearance thro gh the suction strainer, blockage of those passages and channels by ingested debris is not a concern. If there are passages and channels equal to or smaller than the flow clearance through the suction strainer, then the potential for blockage exists and an evaluation is made to determine if the consequences of blockage are acceptable or if additional evaluation or enhancements are warranted.
Similarly, wear and abrasion of surfaces in the ECCS is evaluated, based on the flow rates to which the surfaces will be subjected and the grittiness or abrasiveness of the ingested debris. The abrasiveness of the debris is plant-specific and depends on the insulation materials that become debris. For example, fiberglass is known to be an abrasive material.
The detailed ABWR ECCS downstream effects evaluation is documented in Appendix A, Tables A-4 through A-8.
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A.2 ECCS SYSTEM DESCRIPTIONS AND MISSION TIMES The downstream review defines both long-term and short-term system operating lineups, conditions of operation, and mission times (see Table A-1 ). Where more than one ECCS configuration is used during long-term and short-term operation, each lineup is evaluated with respect to downstream effects. The definition of the mission times form the premise from which the short-and long-term consequences are determined and evaluated.
Once conditions of operation and mission times are established, downstream process fluid conditions are defined, including assumed fiber content, hard materials, soft materials, and various sizes of material particulates. It can be shown that particles larger than the sump-screen mesh size will not pass through to downstream components. Debris may pass through because of its aspect ratio or because it is "soft" and differential pressure across the screen pulls it through the mesh. No credit is taken for thin-bed filtering effects.
See Figure A-1 below illustrating ECCS flow paths.
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GEH Public NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
FIGURE A-1, ABWR ECCS FLOW PATHS Steam Feedwater I
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Emergency Cool Cooling System RHR CORE COOLING RHR NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Table A-1: ECCS Mode, Mission Time and Description Mode of Mission Time I
Description Operation
((
30 days
((
30 days SUPPRESSION POOL COOLING RHR WElWELL SPRAY HIGH PRESSURE CORE FLOODER REACTOR CORE ISOLATION COOLING SYSTEM RHR Alternate Flow path (not credited)
GEH Public
))
30 days I
DI 12 hrs Based on fire water tank I diesel fire pump fuel capacity I
I I
))
I I
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
A.3 DEBRIS INGESTION A summary of the debris ingestion model used to assess the equipment in the ECCS systems is provided below in Table A-2, ABWR Debris Source Term. The debris considered includes fibrous insulation debris and particulate debris consisting of paint chips, concrete dust, and reflective metallic insulation shards small enough to pass through the holes of the ECCS suction strainer perforated plates.
For passive screens the amount of debris, both fibrous and particulate, that passes through the screen is dependent upon the size of the flow passages in the suction strainer and the ratio of the open area of the screen to the closed area of the screen. There are other factors affecting debris bypass through the suction strainer, such as the fluid approach velocity to the screen, and the screen geometry.
The ABWR suction strainer perforated discs are fabricated from 11 gauge (0.12 in.) thick stainless steel plate with 0.125 in. diameter holes with 0.188 in. staggered spacing (Reference 16).
A series of assumptions has been applied in determining the make-up of the post-LOCA fluid:
- 1. No credit is provided for filtering of material due to a thin bed of material on the suction strainer
- 2. The dimensions of particulates p1ssing through a suction strainer are assumed as follows:
The maximum length (I) of deformable particulates that may pass through the penetrations (holes) in passive suction strainers is equal to ((
))
The maximum width (w) of deformable particulates that may pass through the penetrations (holes) in passive suction strainers is equal to ((
))
The maximum thickness (t) of deformable particulates that may pass through the penetrations (holes) in a passive suction strainers is equal to ((
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))
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The maximum cross-sectional area (a) of deformable particulates that may pass through the penetrations (holes) in a passive suction strainer is equal to ((
))
The maximum dimension (length, width, and/or thickness) of non-deformable particulates that may pass through a suction strainer is limited to the cross-sectional flow area of the penetration (hole) in the suction strainer.
Table A-2: ABWR Debris Source Term Debris Type Sludge / corrosion prod.
Inorganic Zinc (IOZ)
Epoxy Coated IOZ Rust Flakes Dust/ Dirt NUKON Reflective Metal Insulation
((
GEH Public Strainer Load 200 lbm 47 lbm 85 lbm 50 lbm 150 lbm 51.6 lbm 38,500 lbm Debris Downstream Strainer 200 lbm 47 lbm 85 lbm 50 lbm 150 lbm 51.6 lbm Note1 38,500 lbm Nole 2
))
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
A.4 WEAR RATE AND COMPONENT EVALUATION A.4.1 Auxiliary Equipment Evaluation The methodology presented in NEI 04-07, Pressurized Water Reactor Sump Performance Evaluation Methodology (Reference 37), was applied to assess auxiliary components subject to debris-laden post LOCA fluid. The following EGGS modes of operation were assessed for downstream effects. EGGS component sizing was developed from
((
TABLE A-4, RHR CORE COOLING MODE A1 (Ref: 31113-1E11-M2001 through M2010, Piping and Instrument Diagram Residual Heat Removal System (Reference 24) and 31113-1N22-M2001, Piping and Instrument Diagram Feedwater System (GEH Proprietary) (Reference 27))
TABLE A-5, RHR SUPPRESSION POOL COOLING MODE B1 (Ref: 31113-1E11 -
M2001 through M2010, Piping and Instrument Diagram Residual Heat Removal System) (Reference 24)
TABLE A-6, RHR CONTAINMENT SPRAY with HEAT REMOVAL MODE E (Ref:
r 1113-1 E11-M2001 through M2010, Piping and lnstrpment Diagram Residual Heat Removal System) (Reference 24)
TABLEA-7, HIGH PRESSURE CORE FLOODER MODE B1(Ref: 31113-1E22-M2001 and M2002, Piping and Instrument Diagram HP Core Flooder System)
(Reference 25)
TABLE A-8, REACTOR CORE ISOLATION COOLING SYSTEM MODE C
{Ref:31113-1 E51-M2001 through M2003, Piping and Instrument Diagram Reactor Core Isolation Cooling System (Reference 26) and 31113-1 N22-M2001, Piping and Instrument Diagram Feedwater System (GEH Proprietary) (Reference 27)
NED0-32686-A, Utility Resolution Guide for EGGS Suction Strainer Blockage, Volume 4, Technical Support Documentation [Evaluation of the Effects of Debris on EGGS Performance GE-NE-T23-00700-15-21 March 1996 (Rev. 1 )] (Reference 23), provides a generic 1 safety evaluation for EGGS auxiliary components that bounds the EGGS components for ABWR.
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This assessment addresses auxiliary components including ECCS pumps required to operate during recovery from LOCA and containment steam line break accidents. This report is incorporated by reference in the ABWR DCD Tier 2. This report imposes requirements on ABWR design.
The ECCS pumps are assumed to operate for the required mission time of 30 days following a LOCA. The evaluations consider ECCS pump hydraulic performance, mechanical shaft seal assembly performance, and pump mechanical performance (vibration).
NED0-32686-A, Utility Resolution Guide for ECCS Suction Strainer Blockage, Volume 4, Technical Support Documentation [Evaluation of the Effects of Debris on ECCS Performance GE-NE-T23-00700-15-21 March 1996 (Rev. 1 )] (Reference 23), provides a generic safety evaluation for ECCS auxiliary components including pumps that bounds the ECCS systems for ABWR.
ECCS pump performance for the specific plant as-built configuration will require demonstration of acceptable performance under design conditions including design debris loading. Demonstration of acceptable performance for as-built ECCS pumps is validated under ASME QME-1-2007, Qualification of Active Mechanical Equipment Used in Nuclear Power Plants (Reference 40), as endorsed by RG 1.100, "Seismic Qualification of Electrical and jActive Mechanical Equipment and Functional Q~alification of Active Mechanical Equipment for Nuclear Power Plants," Revision 3, September 2009 (Reference 41 ).
This assessment addresses the effect of wear on ECCS heat exchangers and evaluate the consequences of wall thinning on heat exchanger performance. A tube plugging evaluation would be required if the heat exchanger tube inner diameter is smaller than the largest expected particle.
This assessment addresses the effect of wear on orifice and spray nozzles in the credited ECCS. An orifice/ nozzle plugging evaluation would be required if the inner diameter is smaller than the largest expected particle.
This assessment addresses the plugging and wear on instrumentation tubing based on instrumentation line configuration and orientation. While debris will tend to tend to settle out in low flow areas in ECCS process piping, guidelines for locating process instrument connections (taps) on main process pipelines with fittings installed above the horizontal plane of the process piping ensures that no settling of debris in an instrument line will occur. Also, pressure instruments measure through impulse piping. There is no flow with this configuration to pull debris into the measuring devices.
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In the Safety Evaluation for WCAP-16406P (ML073520295), the NRC concluded that no settling of debris will occur in an instrument line installed above the horizontal plane of the process piping. The ((
)) ABWR Project Design Manual (31113-0A23-1000, Reference 42) provides guidelines for locating process instrument connections (taps) on main process pipelines to ensure that fittings on the bottom of piping where they can collect crud are avoided.
Therefore, ECCS instrument lines in service during post-LOCA operation are installed above the horizontal plane of the process piping. No settling of debris in an instrument line in this orientation is expected.
This assessment addresses the effect of wear and plugging on system piping and components based on system flow and material settling velocities. The evaluation reviews areas of localized high velocity and high turbulence.
This assessment addresses the effect of wear and plugging in reactor vessel internals or reactor fuel. See Figure A-2 for the layout of ECCS components.
RG 1.82 Revision 4 states downstream blockage is a concern for tight-clearance valves (such as throttle and check valves) that are not in the fully open position during post-LOCA operation. ECCS components in the flow path in service during post LOCA modes of operation are evaluated from failure due to blockage under design debris loading. Tight clearance valves such as throttle and check valves were reviewed under this evaluation.
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ABWR ECCS Piping RHR HPCF RCIC Containment Spray FIGURE A-2, LAYOUT OF ECCS COMPONENTS FOR DOWNSTREAM ASSESSMENT GEH Public I
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Table A-3: ABWR Debris Downstream Concentration Debris Type Concentration In SP ppm by Assessment from NED0 -32686 Vol 4 weight [% by vol]
Sludge I corrosion prod.
Dust I Dirt Inorganic Zinc (IOZ)
Rust Flakes Epoxy Coated IOZ NUKON Reflective Metal Insulation Total Non-Fiber Debris Concentration GEH Public
((
))
Sludge is a generic term for rust particles from the carbon steel piping connected to the suppression pool. Sludge is generated during normal operation when the suppression pool is inaccessible. The sand will not melt or form a large enough agglomeration to significantly block flow.
Dirt/ Dust is generated during normal operation when the suppression pool is inaccessible.
The failure mode for the IOZ could include some small flakes that would very rapidly break up into particles or very small pieces. The size of the very small pieces would probably be much less than 0.060 inches across. The small chips or flakes would result only where the IOZ was disbanded, if such areas existed. A tightly bonded IOZ would erode by powdering and would not flake or chip off the surface.
Rust particles are generated during normal operation when the suppression pool is inaccessible. The rust chips are of low strength and will fracture into even smaller pieces upon interaction with other components.
Failed epoxy coating would be expected to produce chips or small sheets because epoxies have good tensile strength and are somewhat flexible during a LOCA event. The epoxy paint is also relatively brittle an1 will breakup into smaller pieces upon interaction with other cor ponents.
(1) Assume all NUKON passes through strainer (2) Assume 23% NUKON (fines) pass through strainer The glass fibers are so fragile that they have virtually no mechanical strength. The rust, paint, and fiberglass debris that pass through the suppression pool strainers will be subjected to the ECCS flow rates and turbulence that will cause disintegration into particles of even smaller sizes.
(1) Assume all RMI passes through strainer (2)
Assume 4.3% RMI small pieces pass through strainer (1)
Assume non-fiber debris contributes to wear/erosion with all RMI passing through strainer (2) Assume non-fiber debris contributes to wear/erosion with 4.3% RMI passing through strainer Experimental data on effects of particulates on pump hydraulic performance applied to ECCS type pumps show that pump performance degradation is negligible for particulate concentrations less than 1% by volume. [Ref NUREG / CR 2792]
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
A.5 REACTOR INTERNALS AND FUEL BLOCKAGE EVALUATION Flow blockage, such as that associated with core grid supports, mixing vanes, and debris filters are considered. Flow paths between upper downcomer and upper plenum/upper head are evaluated for long term cooling degradation resulting from flow interruption from plugging. All internal flow paths that influence long-term cooling are addressed for the potential for plugging these paths. The flow blockage associated with core grid supports, mixing vanes, and debris filter, and its effect on fuel rod temperature are considered.
The flow paths through the ABWR are illustrated in Figure A-1. ECCS flow with debris is injected inside the shroud (HPCF) and travels to the fuel inlet through the holes in the Lower Tie Plate, getting collected in the Lower Tie Plate grid/filter. Once the in-shroud level reaches the normal water level in the steam separators and spills into the RPV annulus, the debris will be mixed in the lower plenum and enter through the inlet orifice. Should the debris block most of the bundle inlet flow (over 95%) the coolant inside the bundle would form a level and flow would reverse at the channel top and enter the bundle from the upper plenum flow path for RHR and RCIC). The debris would then collect inside the bundle on the upper tie plate and spacers, to a much lower degree, but adequate long term cooling would still be achieved.
This bypass debris was assessed for !the potential blockage of coolant flow at the entrance I to the fuel assemblies as described in NEDC-33302P, Fiber Insulation Effects with Defender Lower Tie Plate (Reference 39). Tests have been performed to simulate clogging of the Defender Lower Tie Plate (DL TP) with a small concentration of fiber insulation material.
This evaluation concludes that significant BWR fuel bundle inlet clogging does not result in GNF2 fuel heat-up after the LOCA re-fill from ECCS injection. These conclusions apply to other BWR fuel bundles (e.g., ABWR GE P8x8R) with equivalent degree of inlet resistance as used in this evaluation.
NED0-32686-A, Utility Resolution Guide for ECCS Suction Strainer Blockage, Volume 4, Technical Support Documentation [Evaluation of the Effects of Debris on ECCS Performance GE-NE-T23-00700-15-21 March 1996 (Rev. 1 )], provides a generic safety evaluation for GE11 and GE 13 fuel that bounds the ECCS components for ABWR.
Even if the fibrous insulation would plug the debris filter on the fuel, the consequences of plugging, considered from an ECCS cooling standpoint, would not impede adequate core cooling during a LOCA. With normal core spray distribution, complete flow blockage of the GEH Public I
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public) fuel lower tie plate debris filter would allow adequate core cooling to be maintained.
Consequently, it is very unlikely that excessive flow blockage of the lower tie plate debris filter would jeopardize adequate post-LOCA core cooling. It is considered inconceivable for debris to plug all channels so that flooding could not occur from below. However, if the inlet to one or more fuel channels is totally blocked from below by debris, these bundles would receive radiation cooling to the channel walls as the bypass refills, then direct cooling from water spill-over from above once the water level is restored above the top of the fuel channels. Due to the expected core reflooding rate, it is a best-estimate basis, the fuel in any blocked channels would remain well below the peak cladding temperature (PCT) limit of 2200°F.
The maximum particle sizes of the expected rust, iron oxide, epoxy paint, and sand are smaller than the fuel debris filter hole sizes and are likely to pass through without plugging.
Therefore, there is no safety concern for fuel bundle flow blockage and consequent fuel damage due to all the non-fibrous debris.
See Figure A-3 for a depiction of normal fuel channel cooling flow paths.
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FLOW 14-----IFUELAS::. r.,lllY
- fOUR-LOBEO (ONE L061: SHOWN)
NOOMAL BUNOLE LOW!;fi TIE PLATE ~Ol.ES IFU~L suJIMfiT PIFC~
c;;ORt SUPPORT ~Et,llll V ORIFICE CO~TROI. RQO GUIDE TUO FIGURE A-3, NORMAL FUEL CHANNEL COOLING FLOW PATHS GEH Public I
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Component ID ECCS PIO ID Component ECC5 components in flow pilth to be assessed
((
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Table A-4: ECCS Suction Strainer Downstream Effects-RHR Core Cooling Mode A1 System/ Component Flowrate
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Determine flowrate at points in system and use the flow / velocity to evaluate ~ttlin& and wear.
Fluid Vek>clty thN Component It is assumed that settling will occur when the flow velocity in the process piping Is less than the settling velocity for the debris type.
If settling is not present, debris will remain in soluUon ilnd not dog lines and components.
In the Safety Evaluiltion for WCAP-16406P (ML073520295), the NRC concluded that no settling of debris will occur in an instrument linl!
installed above the horizontal plane of the process piping. Reference 42 provides guidelines for toe.ting process instrument connections {taps) on main process pipelines to ensure that fittings on the bottom of piping when! they can collect crud are avoided (Section 5.3.3.1.8.3).
Therefore, ECCS instrument lines in service during post-LOCA operation are instillled above the horizontal plane of the process piping. No settlin& of debris in iln instrument line in this orientiltion is expected.
The settlin1 velocity for 2.5 mil SS RMI is assumed to be 0.4 ft/sec (ref NEOO 32686 (URG)J.
A settlin& velocity of0.2 ft/swu usicned for paint chips. Finally, a settlin1 velocity of0.4 ft/s was assicned to concrete dust and other dryweU particulates. (ref NUREG CR 6224].
A settlin1 velocity for NUCON fibers used for preliminary assessment is 0.25 ft/sec based on having 1eometry of particles that would bypus the suction strainer. {ref boundin1 NU REG CR 6224 Table 8,-3 and NEI 04-07 Table 4-2).
System OeKrtptions and Miuk>n Time
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The ABWR ECCS mission time for RHR post-LOCA performance is 30 days (720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br />), consistent with NRC 1uidi1nce. Guidance in NUREG/CR*
6988, *final Report-Evilluiltion of Chemkat Effects Phenomena in Post*
LOCA Coolant," indic.ates that, although the regulations in 10 CFR 50.46{bl(5) require that long-term cooling be maintained indefinitely
("for an extended period of time"),
30-days is typically considered to be an appropriate time period to demonstrate ECCS functionality and that, beyond this time, the decay heat loadin1 is small, makin& alternative coolin& possible should ECCS functionality be lost.
Debris ln,estlon Model The quantity of debris and makeup downstream of the strainer needs to be determined to assess wear rate of pfpinc and components.
Debris considered indudes fibrous insulation debris and particulate debris consisting of paint chips, concrete dust.
and reflective metallic insulation shards small enough to pass throu1h the holes of the ECCS suction stf'iliner perforilted plates (1/8-inch diameter).
In general, the assumptions account for particles larger than the screen opening size and assume all transportable milterial with the above dimensions or smaller passes through the suction strainer unimpeded thus maximizing the calculated particulate and fibrous debris concentrations in the posHOCA process fluid.
The maximum length of deformable particuliltes that mily pass through the penetrations {holes) in pusive suction strainers is equal to two times (2X) the maximum linear dimension of the penetrilllHon (hole) in the suction strainer.
The maximum wKlth of deformable partkulates thilt may pass throu1h the penetrations {holes) in passive suction strainer is equal to the maximum linear dimension of the penetration (hole) in the suction strainer, plus 10 percent (10%).
The maximum thickness of deformable particulates that may pass through the penetrations {holes) in a passive suction strainer is equal to one*ha1f (1/2) the maximum linear dimension of the penetration {hole) in the suction strainer.
The maximum cross-sectional area of deformable particulates that may pass through the penetrations (holes) in a passive suction strainer is equal to the maximum cross-sectional How area of the penetration (hole) in the suction strainer, plus 10 percent (l°"l-The maximum dimension {length, width and/ or thickness) of non-deformable particulates that mily pass throu1h a suction strainer is limited to the cross-Wear Rate and Component Evaluation There are two types of wear of close running clearances within the pump; 1) free-Howin& abrasive wear and 2) packin&*type abrilsfVe wear. Wear within dos1Holerance, high-speed components is a complex analysis. The actual abrasive wear phenomena will likely not be either a cl.usic free-ffowin& or packin1 wear case, but a combination of the two. Both should be considered in the evaluation of their components.
Consider how wear of internal surfaces of pump components will affect pump hydraulic performance {total dynamic head ilnd flow), the mechanic.I performance (vibration), and pressure boundary inte1rity (shaft seals).
Valve and heat exchanger wetted materials should be evaluated for susceptibility to wear, surface abrasion, and ptu11in1. Wear may alter the system flow distribution by increasin1 How down a path (decreasin1 resistance caused by wear), thus starvin1 another critic.al path. Or conversely, inaeased resistance from plu11in1 of a valve openin&, orifice, or heat exchanger tube may c.ause wear to occur in another path that experiences increased flow.
Sludge / corrosion prod. 200 lbm
!density 324 lb/ft1 per NEI 04-07 Table4-2]
Inorganic Zinc (IOZ) 47 lbm (0.2516 ft1 per URGJ Epoxy Coated IOZ 85 1bm (0.65 ftl per URG]
Rust Flakes SO lbm (324 lb/ ft3 per NEI 04-07 Table 4-2)
Oust/ Dirt SO lbm (156 lb/ ft3 per NEI 04*07 Table 4-2]
Supp. Pool (SP) Initial Vol. (min.)::
3455 m3 (Ref OCO T6.2-2) = 3.455 x 106 liters.
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Au,cll &.ry Equipment Evaluation Evilluation of Oownstreilm Effects on Major Components The effects of debris passing through the strainers on downstream components such as pumps. valves. and heat exchan1ers has been evaluated as requir~ under Re1 GuKte 1.82 Rev 4.
This evaluation indudes assessin& wear on surfaces exposed to the fluid stream due to various types of debris: e.1.
paint chips or RMI shards. Evaluating the potential for blockage of small clearances due to downstream debris are also Included. The materials and cleilrances for the valves. pumps. and heat exchangers downstream of the ABWR ECCS suction strainers are essentially the same as the milterials and dearances for the valves. pumps.
and heilt exchangers downstream of the PWR containment sump suction strainers. Therefore. utilizing aspects applied to PWR methodology for the ABWR is appropriate. (ref STP OCD 6(.3.21 Page 49 of 105 1
C.omponent 10 U71 Component Containment Orywell Connecting Vents GEH Public Mode of Opention System/ Component Flowrate NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Flukf Velocity thru CDmponent System Oeseriptions and Mission Time I-Debris ln,estion Model sectional flow area of the penetration (hole) in the suction strainl!r. ( WCAP*
016406]
The materials involved are relatively stiff and incompressible and account for long, thin strands, of insulation being able to pass through tight openings.
It is assumed no settling of material once in solution. The material will tend to settle out in low flow areas in piping, the reactor vessel, the containment floor, or hold-up volumes.
It is assumed the debris forms a homogeneous solution at the start of the event.
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hperimental data on the effects of particulates on pump hydraulic performance applied to ECCS type pumps show that pump performance degradation is negligible for particulate concentrations less than 1% by volume. [Ref: NU REG/CR 2792J NU REG/CR 2792 notes conservative estimates of the nature and quantities of debris show that fine abrasives may be present in concentrations of about 0.1% by volume (about400 ppm by weight). and that very conservative estimates of fibrous material yield concentrations of less than 1% by volume. Published data on the effects of partiC\\llates on pumps generally deal with particulate concentrations at many times these values.
Auxlllary Equipment Evaluation Page 50 of 105 1
Component ID Ell*Ol Component RHR System
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Fluid Vekldty thn, Component System Descriptions and Mlssk>n Time The Emergency Core Cooling (ECC)
Systems are designed to withstand a hostile environment and still perform their function for 30 days followin1 an uddent.
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Wear Rate and Compone:nt Evaluatlon Materials of construction fOf' ECCS system components are listed in DCO Table 6.1*1 Engineered Safety Features Component Materials.
Considerinc an ECCS misstOn time of 30 days (720 hrs.}, the wear of components subjected to the debris particles in solution {0.083 " SP volume) Is considered insignificant.
(ref: An Assessment of Residual Heat Removal.ind Containment Spray Pump Perform.ance Under Air and Debris lneestin& Conditions, NUREG/
CR-2792)
Auxlllary Equlpm~t Evaluation Evaluation of Downstream Effects on Major Components The effects of debris passin& through the strainers on downstream components such as pumps. valves. and heat uchan1ers has been evaluated as riequired under Re& Gutde 1.82 Rev 4, This evaluatk>n indudes assessin& wur on surfaces exposed to the fluid stream due to various types of debris: e.g.
paint chips or RMI shards. Eva1uatin&
the potential for blockage of small clearances due to downstream debris are also Included. The materials and clearances for the valves. pumps. and heat e)(changers downstream of the ABWR ECCS suctk>n strainers are essentii1lly the same as the materials and clearances for the valves. pumps.
and heat exchangers downstream of the PWR containment sump suctk>n strainers. Therefore. Utilizing aspects applied to PWR methodology for the ABWR is appropriate. [ref STP DCD 6C.3.2]
The RHR system has no ti&ht clearance valves throttled durine post LOCA operation that would be susceptible to blockace or binding, AU RHR valves 1n the post LOCA lineup will be dosed {i.e.
isolate CST suction flow path) or fully open. As renected on Table 1, Valve Position Chart, on Figure 5.4-11, Resktual Heat Removal System PFC (Shel!t 2 of 2), no RHR valvl!s arl!
throttled durine post LOCA modes of operation. RHR minimum flow is maintained by a pipin& orificl! rathl!r than throttlinc of the minimum flow valve.
RHR system check valves installed in thl! main RHR pump discharee line, minimum flow line and jockey pump dischar&I! linl! have active safety functions to open. These RHR valves are not susceptible to doeeine, settling or wear. The dearances of these check valves prevl!nt debris from adversely impacting the function of thesl!
components. The check valve material is carbon steel. Erosion or wear during the post LOCA credited 30-day mission Page 51 of 105 1
Component 10 0001 B X-202 Component Suction Strainer Penetration
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Fluid Velocity thru Component System Descriptions
- nd Mission Time
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The sizin& of the RH R suction strainers conforms to the guidance of Reg Guide 1.82. The sizing is based on s;1tisfyin& the NPSH requirements at runout flow, plus margin, with postulated piping insulation debris in the SP accumulated on the pump suction strainers. The sizing of the strillners is based on 30 days of post-LOCA operation.
RHR desicn has ii provision for installiltion of a temporary strainer in Heh loop durinc pre-operational and stilrtup testinc.
Strainers are located to ilvoid air entrainment during a LOCA blowdown or from vortexing action and away from the safety relief valve quencher discharee zones.
Stuiners shiltl be sized to prevent do11in1 of pump internal passages.
(Ref: 31113-0E11*2010 (Ref. 321].
Debris ln,nOon Model
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The ECCS piping/ component flow area exceeds the ma1dmum dimension of the debris particles. Therefore, clo11in1 is not considened credible.
WHr Rate
- nd Component Evaluation Au>tlliaryEqulpment Evaluation time writ not impact system performance.
RHR ~tern orifice plates.ind SP and dryweU sp;ugers installed in the RHR process piplng have safety functions to maintain flow. These RHR components are not susceptible to doulng, settling or wcear. The clearances of these components prevent debris from adversely impacting the function of these components. The orifice and sparser material is stiinless steel.
Erosion or wear durin& thll! post LOCA credited 30-day m ission time will not impact system performance.
Page 52 of 1051
Component 10 FOOlB (0018 Component Motor Operated Block Valve RHR Pump B
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Fluid Velocity thru c.omponent
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System Descriptions and M tsslon Time
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Debris Ingestion Model The ECCS piping / component flow area exceeds the maximum dimension of the debris particles. Therefore, clogging is not considered credible.
Wear Rate and Component Evaluation Auxlllary Equipment Evaluation The ECCS piping / component flow area As described in NU REG / CR 2792, An NED0-32686 (URG) Vol 4 Evaluation of exceeds the maximum dimension of the Assessment of Residual Heat Removal the Effects of Debris on ECCS debris particles. Therefore, clogging is not and Containment Spray Performance Performance (GE*NE-T23-00700-1S.21),
considered credible.
Under Air and Debris Ingesting Conditions, concludes that under LOCA conditions with generated debris at the pump, pump performance degradation is expected to be negligible. In the event of shaft seal failure due to wear or loss of cooling fluid, seal safety bushings limit leakage rates. This is based on a debris concentration less than 0.5% by volume.
When considering long-term pump operation and performance, it is necessary to consider how wear of internal pump components will affect the pump hydraulic performance (total dynamic head and flow), the mechanical performance (vibration),
and pressure boundary integrity (shaft seals). The wear of the dose running clearances may affect the hydraulic performance because of increased internal or bypass leakage. Multistage pumps, designed for high head service, usually operate at speeds above the first natural frequency of the rotating assembly. The running clearances of the suction side and discharge side of each impeller stage are designed and manufactured to provide hydrostatic support and damping for the rotating assembly, thus allowing operation at super-critical speeds without dynamic instability. Increasing the close running clearances due to wear may reduce the overall shaft support stiffness at each impeller location, addresses safety and operational concerns for failure of ECCS pumps associated with particles that pass through the ECCS suction strainers.
The ECCS pump design is coordinated with the ECCS suction strainer sizing to prevent clogging of pump internal passages including mechanical seal assemblies. The consequence of a plugged pump seal line would be high seal temperature and poor seal life.
The ECCS pump includes a mechanical seal assembly with cyclone particle separator and seal*cooling heat exchanger. A cyclone separator type of filtration is provided to maintain a clean cooling water supply to the seal.
The size of orifices used to control the flow to ECCS pump seals is specified by the pump manufacturer to ensure the pump seal cooling lines are not susceptible to plugging by debris not filtered by the cyclone separator type filter or debris larger than the seal cooling line orifice hole diameter.
Wear rings and bushings are specifically designed (hard materials) to resist wear due to hard particulates in the process fluid. tf the concentration of hard particulates is unusually excessive, the effect could be a long*term deterioration in the pump performance, in the form of low pump head. The requirement of 30 days of Page 53 of 105 1
Component ID Component GEH Public Mode of Operation System/ Componfflt Fk>wrate NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Fluid Velocity thru Component System Descriptions and Mlssk>n Time Debris ln,Htion Model Wear Rete and Component Evaluatlon Au,clllary Equipment Evaluation thus affectin& the dynamic stability of post LOCA operation is not considerl!d the pump. Debris in the pumped fluid lonr:-term.
may affect the sealing capability of mechanical shaft seals. These seals are dependent on seal injection flow to cool the primary seal components.
Debris in the pumped flow has the potential of blodc.in& the seal injection now path or oflimitine the performance of the seal componenu due to debris buildup in bellows and sprin1s. These effecu may lead to primary sul failure. Graphite safety bushin1s {disaster bushings) milly fail if e>Cposed to high pressure fluid with debris followin& a prima ry seal failure thus, providin& an outside containment path for post-LOCA fluid.
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It is expected that ECCS pumps opented for 30 days (720 hrs.) under modes of operation assessed and pumpin& liquid at maximum suspended solids will not wear to a point where vibntion will affect opera bility.
Seal Faces New seal faces are tapped to very flat and smooth surfaces. The workin& gap between the faces is a fracttOn of a micron. This means that larie particulates would pass over the seal faces, and would not enter the interface to destroy the smoothness of the face and cause leakage.
For the passive strainer with the holes sized at 0.12S in., little fiber is expected to pass throuch after the Initial filter bed is formed. Little of the other debris (except for minimum sized iron oxide sludce) is expected to pass after the initial filter bed precoat is formed.
Therefore, all materials would most likely pass throuch the orifice if 1% by volume of fiber does not cause a hiehly unlikely *blitz" which plugs the orifice.
Because all particles are larger than a fraction of a micron, they would not enter the pump seal face. For shafts and bushincs, debris in quantities of one percent or less of the pump fluid is likely to not constitute a major threat to the bushinc integrity.
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Page 54 of 105 1
Component 10 F0028 Component Check Valve
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GEH Public Mode of Operation System/ Component Flowrate
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Flukl Velocity thru Component System Descriptions and M ission Time Debris ln,estion Model The ECCS piping / component flow area exceeds the maximum dimension of the debris particles. Therefore, cloning is not consid@red credible.
Wear Rate and Component Evaluation Auxlllary Equipment Evaluation
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ECCS pump performance for the specific plant as-built configuration will rll!:quire demonstriltion of acceptable performance under design conditions including design debris loading.
Demonstration of acceptable performance for as-built ECCS pumps is validated under QME-1 2007, Qualification of Active Mechanical Equipment Used in Nuclear Power Plants as endorsed by RG 1.100, "Seismic Qualification of Electrical and Active Mechanical Equipment and Functional Qualification of Active Mtchanical Equipment for Nuclear Power Ptants/ Revis'ion 3, September 2009.
Page 55 of 105 1
Component 10 F003B 80018 Component Manual Block Valve Heat Exchanger
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Fluid Velocity thru Component System Descriptions 1nd Mission Time Debris Ingestion Model
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The ECCS piping/ component flow area exceeds the maximum dimension of the debris particles. Therefore, clogging is not considered credible.
The RHR heat exchanger tube ID is 17.22 mm. The ECCS strainer will restrict debris to less than 3.18 mm. Therefore, the RHR heat exchanger will not become clogged from debris passing downstream of the ECCS suction strainer.
Wear Rat e and Component Evaluation Auxlllary Equlpment Evaluation NED0-32686 (URG) Vol 4 includes evaluation of ECCS heat exchangers.
This assessment was adjusted for the ABWR RHR heat exchanger with suppression pool water flowing though the tubes of the ~eat exchanger. As described in ABWR DCD section 5.4.7.1, the ABWR RHR heat exchanger has taken advantage of a design change that was made with respect to prior BWRs. ABWR has the reactor water flowing through the tube side of the heat exchanger, whereas, prior BWRs had the reactor water flowing through the shell side. The primary purpose for the change was to reduce radiation buildup in the heat exchanger by providing a more open geometry flow path through the center of the tubes, as opposed to the shell side construction of spacers, baffles, and low flow velocity locations, which can provide places for radioactive sludge to accumulate.
Heat Exchangers Significant effect on RHR heat exchanger performance can occur if a large quantity of debris is retained inside the heat exchangers causing blockage of the flow and/or fouling of the tubes. Flow from the suppression pool is channeled through the tubes of the RHR heat exchangers. The tube side flow velocity of a RHR heat exchanger is approximately 2 ft/ sec. At this velocity, the flow will entrain the small particles without allowing them to settle in the Page 56 of 105 1
Component ID Component GEH Public Mode of Operation System/ Component Flowrate NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Hukt Velocity thru Component System Descriptions *nd Mfssk>n Time Debris ln,estion Model Wear Rate and Component Evaluation Au,clllary Equipment Evaluation heat exchanger. Thi! tube size is 0.68" diameter. The results of the size distribution analyses are evaluated as follows:
- 1. The rust chips are the largest, but are very likely to break into smaller pieces.
Considering the possibility that the largest chips get through the strainer holes and through the pumps without being broken up, (not considered credible), they w ill pass through the heat exchanger tubes. Iron oxide (Fe20 1 or Fe]O. ) will not promote oxidation and corrosion on the inside diameter of the stainless steel tubes. Therefore, rust debris particles will not contribute to fouling and/ or thinning of the tubes.
- 2. EPOlCY paint chips are small and light enough that they will be swept through the heat exchanger-5, and are of no concern.
- 3. The size of the sand grains are small enough that it is unlikely that they will be captured along the flow path, but may be heavy enough to settle in pockets of low velocity near the tube sheets of the heat uchanger.
Because they will not settle on the inner surface of the tubes, they will not affect the heat exchanger performance.
- 4. Of the samples evaluated in Reference 1, only 0.1% of the fiber population had a length of0.39" or greater. With this length, it is unlikely they could attach to the inner diameter of the RHR heat exchanger tubes.
Moreover, the fibers were so fragile that any attempt to disperse the clumps caused extensive brtakage of the longer fibers. These fiber-5 also will be easily swept away and carried out of the heat exchanger without affecting heat exchanger performance. In summary, a review of heat exchanger performance concludes that nonsotuble insulation material will not deteriorate the performance of the as-built heat exchanger. The rust chips could present some potential effect to RHR heat exchanger performance. However, this concern is minimized by the fact that a large fraction of the bigger chips are so thin that they will flow through the heat exchangers while others will be broken into still smaller pieces by the rapid flow and therefore easily pass Page 57 of 105 1
Component 10 f0048 FE-0068 00038 Component Motor Operated Control Valve Flow Element flow Restrictin1 Orifice
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System DncripUons *nd Mlssk>n Time
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Debris tncestlon Model The ECCS pipin& / component flow area exceeds the maximum dimension of the debris particles. Therefore, clogging is not considered credible.
The ECCS piping / component flow areil exceeds the maximum dimension of the debris partkles. Therefore, clo11in1 is not considered cr~ible.
Wear Rate and Component Evaluation AuxlllaryEquipment Evaluation throuah the heat l!xch.inger. Thi!: key factors in heat exchanger performance ue the routine maintenance, insp@ction, and deaning of the: heat excho1n1@r, Debris that pass through the ECCS suction straincm do not affect heat exchan1er perform.1nce The:refore, there is no abnormal operational or ufety concern with the identified debns on RHR hut uchancer performance, assuming they are properly maintained.
Page 58 of 105 1
Component 10 FOOSB f006 f007 Reactor Internals
[Reactor Pressure Vessel 811]
Component Motor Operated Block Valve Penetration Check Valve (N2 Testable)
Manual Block Valve Mode of Operation
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Flu kt Velodty thru Component
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System Descriptions and Mlssk>n Time Debris ln,estlon Model The ECCS piping / component flow area exceeds the maximum dimension of the debris particles. Therefore, clogging is not considered credible.
The ECCS piping / component flow area exceeds the maximum dimension of the debris particles. Therefore, clogging is not considered credible.
The ECCS piping / component flow area exceeds the maximum dimension of the debris particles. Therefore, clogging ts not considered credible.
The ECCS piping / component flow area exceeds the maximum dimension of the debris particles. Therefore, clogging is not considered credible.
The ECCS piping/ component flow area exceeds the maximum dimension of the debris particles. Therefore, clogging is not considered credible.
Wear Rllte and Component Evaluation AuxlllaryEquipm~t Evaluation As described in NED0-32686 (URG) Vol 4, containment spray nozzles were found to have orifices or openings sized from 0.125" to 1.5". It is highly unlikely that any of the identified debris which would be expected to be much smaller Page 59 of 105 1
Component 10 Reactor Internals
[Reactor Pressure Vessel 811}
Jll Fuel Assembly Component Reactor Assembly
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Fluid Velocity thru Component
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System Descriptions and Mlssk>n Time Debris ln1esUon Model RHR injection is through the spargers The reactor vessel flow area orifices above the core outside the core exceed the maximum dimension of the shroud in the annulus. Flow is directed debris particles. Therefore, clogging is not through the inlet orifice / lower tie considered credible.
plate to the fuel assembly from lower plenum flooding.
Flow from spray is also available through the bypass hole / lower tie plate.
- Flow is also available to the fuel as"semblies through the upper tie plates.
The ABWR evaluation examines the effects of bundle inlet clogging that reduces the available inlet flow from natural circulation phenomena following initial core refill when the core region is covered by a two-phase mixture. ([
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Once the bundle decay heat has decreased and insufficient voids exist to maintain the level in the bundle above the top of the fuel channel, adequate cooling from the upper plenum spillover will exist. Thus, the evaluation concludes that for significant bundle inlet clogging following initial core refill, BWR fuel bundle cooling is assured.
Wear Rate and Component Evaluation AuxlllaryEqulpment Evaluation by the time it reached the orifices, would be able to block the orifice. A very few longer particles would be expected to pass through the passivl!:
suction strainers.
There is no safety significance due to the small number of particles versus the large number of containment spray nozzles and orifices. Therefore, the expected debris will be of no sa fety concern for the containment spray operation.
As described in NED0*32686 {URG) Vol 4, a safety evaluation by the GEF has addressed the fiberglass debris as it might affect the new GEll and GE13.
This document states that even though the fibrous insulation would not be expected to plug the debris filter, the consequences of plugging were considered from an ECCS cooling standpoint. As a result of these considerations, it was concluded that adequate core cooling would be provided during a LOCA. With normal core spray distribution, complete flow blockage of the fuel lower tie plate debris filter would allow adequate core cooling to be maintained.
Consequently, it is very unlikely that excessive flow blockage of the lower tie plate debris filter would jeopardize adequate post*LOCA core cooling. It is considered inconceivable for debris to plug all channels so that flooding could not occur from below. However, if the inlet to one or more fuel channels is totally blocked from below by debris, these bundles would receive radiation cooling to the channel walls as the bypass refills, then direct cooling from water spill*over from above once the water level is restored above the top of Page 60 of 105 1
Component ID CompoMnt GEH Public Mode of Oper9Uon System/ Component Flowrate NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Flukl Velocity thru Component System Oescrtpt6ons *nd Mission Time Debris tncestion Model Wur Rate and C.Omponent Evaluation Auidllairy Equipment Evaluation the fuel channels. The fuel in any blocked channels would remain well below the peak dadding temperature (PCT) limit of 22cxrF.
Thi! maximum particle sizes of the expected rust, iron oxide, epoxy paint, and Hnd are smilller thiln the fuel debris tilter ho~ sizes and ue liker, to pass throuch without plugainc.
Therefore, there is no s.ifety concern for fuel bundle now blocka&e and cons~uent fuel damage due to all the debris Identified.
Page 61 of 105 1
Component 10 ECCS PIDID Component ECCS components in flow path to be assessed
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Table A-5: ECCS Suction Strainer Downstream Effects-RHR Suppression Pool Cooling Mode 81 System/ Component Flowrate
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Determine flowrate at points in system and use the flow / velocity to evaluate settling and wear fluid Velocity thn, Component It is assumed that settling will occur when the flow velocity in the process piping is less than the settling velocity for the debris type.
If settling is not present, debris will remain in solution and not clog lines and components.
The settling velocity for 2.5 mil SS RMI is assumed to be 0.4 ft/sec (ref NEOO 32686 (URG)]
In the Safety Evaluation for WCAP*
16406P (ML073520295}, the NRC concluded that no settling of debris will occur in an instrument 1ine installed above the horizontal plane of the process piping. Reference 42 provides guidelines for locating process instrument connections (taps) on main process pipelines to ensure that fittings on the bottom of piping where they can collect crud are avoided (Section 5.3.3.1.8.3).
Therefore, ECCS instrument lines in service during post-LOCA operation are installed above the horizontal plane of the process piping. No settling of debris in an instrument line in this orientation is expected.
A settling velocity of0.2 ft/ s was assigned for paint chips. Finally, a settling velocity of 0.4 ft/s was assigned to concrete dust and other drywell particulates. [ref NUREG CR System Descriptions and Mission Time
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The ABWR ECCS mission time for RHR post-LOCA performance is 30 days (720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br />), consistent with NRC guidance. Guidance in NUREG/CR-6988, "Final Report-Evaluation of Chemical Effects Phenomena in Post-LOCA Coolant," indicates that, although the regulations in 10 CFR 50.46(b)(5) require that long-term cooling be maintained indefinitely
("for an extended period of time"),
30-days is typically considered to be an appropriate time period to demonstrate ECCS functionality and that, beyond th is time, the decay heat loading is small, making alternative cooling possible should ECCS functionality be lost.
62241
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A settling velocity for NUCON fiber-5 used for preliminary assessment is 0.25 ft/sec based on having geometry of particles that would bypass the suction strainer. [ref bounding NUREG CR 6224 Table B-3 and NEI 04-07 Table 4-2]
Debris ln1t'fllon Model
[The quantity of debris and makeup downstream of the strainer needs to be determined to assess wear rate of piping and components)
Debris considered includes fibrous insulation debris and particulate debris consisting of paint chips, concrete dust, and reflective metallic insulation shards small enough to pass through the holes of the ECCS suctio n stra ine r perforated plates (1/8-inch diameter)
In general, the assumptions account for particles larger than the screen opening size and assume all transportable material with the above dimensions or smaller passes through the suction strainer unimpeded thus maximizing the calculated particulate and fibrous debris concentrations in the post-LOCA process fluid.
The maximum length of deformable particulates that may pass through the penetrations (holes) in passive suction strainers is equal to two times (2X) the maximum linear dimension of the penetration (hole) in the suction strainer.
The maximum width of deformable particulates that may pass through the penetrations (holes) in passive suction strainers is equal to the maximum linear dimension of the penetration (hole) in the suction strainer, plus 10 percent (10%).
The maximum thickness of deformable particulates that may pass through the penetrations (holes) in a passive suction strainer is equal to one-half (1/2) the maximum linear dimension of the penetration (hole) in the suction strainer.
The maximum cross-sectional area of deformable particulates that may pass through the penetrations (holes) in a passive suction strainer is equal to the maximum cross*sectional now area of the Wear Rate and Component AuxllfaryEquipment Evaluation Evaluation There are two types of wear of dose Evaluation of Downstream Effects on running dearances within the Major Components pump; 1) free-flowing abrasive wear and 2) packing-type abrasive wear.
Wear within close-tolerance, high-speed components is a complex.
analysis. The actual abrasive wear phenomena will likely not be either a classic free-flowing or packing wear case, but a combination of the two.
Both should be considered in the evaluation of their components.
Consider how wear of internal s urfa ces of pump components will affect pump hydraulic performance (total dynamic head and flow), the mechanical performance (vibration),
and pressure boundary integrity (shaft seals).
Valve and heat exchanger wetted materials should be evaluated for susceptibility to wear, surface abrasion, and plugging. Wear may alter the system flow distribution by increasing flow down a path (decreasing resistance caused by wear), thus starving another critical path. Or conversely, increased resistance from plugging of a valve opening, orifice, or heat exchanger tube may cause wear to occur in another path that e11.periences increased flow.
Sludge/ corrosion prod. 200 lbm
[density 324 lb/ftl per NEI 04-07 Table4-2]
Inorganic Zinc (IOZ) 47 lbm
[0.2516 ftl per URG]
Epoxy Coated IOZ 85 lbm
[D.65 ft1 per URG]
Rust Flakes SO lbm 1324 lb/ftl per NEI 04-07 Table 4-2]
Oust / Dirt 150 1bm (156 lb/ ft1 per NEI 04-07 Table 4-21 Supp. Pool (SP} Initial Vol. (min.) =
3455 m3 (Ref DCO T6.2-2) = 3.455 11.
10' liters.
The effects of debris passing through the strainers on downstream components such as pumps. valves. and heat exchanger-5 has been evaluated as required under Reg Guide 1.82 Rev 4.
This evaluation includes assessing wear on surfaces ex.posed to the fluid stream due to various types of debris: e.g. paint chips or RMI shards. Evaluating the potential for blockage of small clearances due to downstream debris are also included. The materials and clearances for the valves. pumps. and heat exchangers downstream of the ABWR ECCS suction strainers are essentially the same as the materials and clearances for the valves. pumps. and heat exchangers downstream of the*PWR containment sump suction strainers. Therefore.
Utilizing aspects applied to PWR methodology for the ABWR is appropriate. [ref STP DCD 6C.3.2]
Page 62 of 105 1
Component 10 U71 Component Containment Orywell Connecting Vents GEH Public Mode of Operation System/ Component Ftowrate NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Fluid Velocity thn, Component System DescrlpUons and M ission Time Wear R*te and Component Evaluation penetration (hole) in the suction strainer,
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plus 10 percent (10%).
The maximum dimension {length, width and/ or thickness) of non-deformable particulates that may pass through a suction strainer is limited to the cross-sectional flow area of the penetration (hole) in the suction strainer. [ WCAP-016406-PJ The materials involved are relatively stiff and incompressible and account for long, thin strands, of insulation being able to pass through tight openings.
It is assumed no settling of material once in solution. The material will tend to settle out in low flow areas in piping, the reactor vessel, the containment floor, or hold-up volumes.
It is assumed the debris forms a homogeneous solution at the start of the event.
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E,cperimental data on the effects of particulates on pump hydraulic performance applied to ECCS type pumps show that pump performance degradation is negligible for particulate concentrations less than 1% by volume. [Ref: NU REG/CR 2792]
NU REG/CR 2792 notes conservative estimates of the nature and quantities of debris show that fine abrasives may be present in concentrations of about 0.1% by volume (about 400 ppm by weight).
and that very conservative estimates of fibrous material yield concentrations of less than 1% by volume. Published data on the effects of particulates on pumps generally deal with particulate concentrations at many times these values.
Auxlllary Equipment Evaluation Page 63 of 105 1
Component 10 Ell-01 Component RHR System
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Fluid Velocity thru Component System DestripUons and Miuk>n Time f-----
O.bris ln1estion Model
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We.r Rate and CompoMnt Evaluation AuxlllaryEqulpment Evaluation The Emergency Core Cooling (EC()
DCD 531.3.2.3 Water Quality and Materials of construction for ECCS Evaluation of Downstream Effects on Major Components Systems ue designed to withstand a Submergence, provides reactor water system components are listed in OCD hostile environment and still perform quality characteristics for the design basis Table 6.1-1 Engineered Safety The effects of debris passing through the strainers on downstream components their function for 30 days following LOCAs inside primary containment.
Features Component Materials.
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an ilccident.
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Considering an ECCS mission time of 30 days (720 hrs.), the wear of components subjected to the debris partides in solution (0.083 % SP volume) is considered insignificant.
such as pumps. valves. and heat exchangers has been evaluated as required under Reg Guide 1.82 Rev 4.
This evaluation includes assessing wear on surfaces exposed to the flu id stream due to various types of debris: e.g. paint chips or RMI shards. Evaluating the potential for blockage of small clearances (ref: An Assessment of Residual Heat due to downstream debris are also Removal and Containment Spray included. The materials and clearances Pump Performance Under Air and for the valves. pumps. and heat Debris Ingesting Conditions, NU REG/
exchangers downstream of the ABWR CR-2792)
ECCS suction strainers are essentially the same as the materials and clearances for the valves. pumps. ilnd heilt exchilngers downstream of the PWR containment sump suction strainers. Therefore.
Utilizing aspects applied to PWR mdhodology for the ABWR is appropriate. (ref STP DCD 6C.3.2]
The RHR system has no tight clearance valves throttled during post LOCA operation that would be susceptible to blockage or binding. All RHR valves in the post LOCA lineup will be closed (i.e.
isolate CST suction flow path} or fully open. As reflected on Table 1, Valve Position Chart, on Figure S.4-11, Residual Heat Removal System PFD (Sheet 2 of 2),
no RHR valves are throttled during post LOCA modes of operation. RHR minimum flow is maintained by a piping orifice rather than throttling of the minimum nowvatve.
RHR system check valves installed in the main RHR pump discharge line, minimum flow line and jockey pump discharge line have active safety functions to open.
These RHR valves are not susceptible to clogging, settling or wear. The clearilnces of these check Vil Ives prevent debris from adversely impacting the function of these Page 64 of 105 1
Component 10 0001 B Component Suction Strainer
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GEH Public Mode of Operatkm System / Component Flownte
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Fluid Velod ty thru Component System Ot!scripUons and Missk>n Time
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The sizin1 of the RHR suction strainers conforms to the 1uldance of Reg Guide 1.82. The sizin1 is based on Ytisfying the NPSH requirements at runout flow, plus ma11in, with postulated pipinc insulat10n debris in the SP accumu~ted on the pump suction strainers. The sizinc of the strainers Is based on 30 days of post*
LOCA operation.
RH R desifn has a provision for installation of a temporary strainer in each loop durinc pre-operational and startup testinc.
Strainers are louted to avoid air entrainment durinc a LOCA blowdown or from vortexln& action and away from the safety relief valve quencher discharge zones.
Strainers shall be sized to prevent douinc of pump internal passages.
(Ref: 31113-0£11-2010 {Ref. 32)1
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Debris ln1ntk>n Model
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Wear Rate and Component Evaluatlon Auxlllary Equipment Evaluation components. The check valve material is carbon steel. Erosion or weu during the post LOCA credited 30-day mission time will not impact system perform ance.
RHR system orir1ee plates ilnd SP and drywell spar1ers installed in the RHR process piping have safety functtOns to maintain flow, These RHR components are not susceptible to clo&ein&, settling or wear. The clearances of these components prevent debris from adversely impacting the functtOn of these components. The orifice and sparger material is stainless steel. Erosion or wear during the post LOCA credited 30-day mission time will not impact system performance.
Page 65 of 105 1
Component ID X*202 F001B (0018 Component Penetration Motor Operated Block Valve RHR Pump 8
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Fluid V<<!lodty thru Component
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Debris lngntion Model The ECCS piping / component flow area e,cceeds the ma)(imum dimension of the debris particles. Therefore, clogging is not considered credible.
The ECCS piping / component flow area exceeds the maximum dimension of the debris particles. Therefore, clogging is not considered credible.
Wear Rate and Component Evaluation Auxiliary Equipment Evaluation The ECCS piping / component flow area As described in NU REG /CR 2792, An NED0-32686 (URG) Vol 4 Evaluation of exceeds the maximum dimension of the Assessment of Residual Heat Removal the Effects of Debris on ECCS debris particles. Therefore, clogging is not and Containment Spray Performance Performance (GE-NE-TB-00700-15-21),
considered credible.
Under Air and Debris Ingesting addresses safety and operational Conditions, concludes that under LOCA conditions with generated debris at the pump, pump performance degradation is expected to be negligible. In the event of shaft seal failure due to wear or loss of cooling fluid, seal safety bushings limit leakage rates. This is based on a debris concentration less than 0.5%
by volume.
When considering long-term pump operation and performance, it is necessary to consider how wear of internal pump components will affect the pump hydraulic performance (total dynamic head and flow), the mechanical performance (vibration),
and pressure boundary integrity concerns for failure of ECCS pumps associated with particles that pass through the ECCS suction strainers.
The ECCS pump design is coordinated with the ECCS suction strainer sizing to prevent clogging of pump internal passages induding mechanical seal assemblies. The consequence of a plugged pump seal line would be high seal temperature and poor seal life.
The ECCS pump includes a mechanical seal assembly with cyclone particle separator and seal-cooling heat exchanger. A cyclone separator type of filtration is provided to maintain a clean cooling water supply to the seal.
(shaft seals). The wear of the close The size of orifices used to control the running clearances may affect the flow to ECCS pump seals is specified by hydraulic performance because of the pump manufacturer to ensure the increased internal or bypass leakage.
pump seal cooling lines are not Multistage pumps, designed for high susceptible to plugging by debris not head service, usually operate at filtered by the cyclone separator type speeds above the first natural filter or debris larger than the seal cooling frequency of the rotating assembly.
line orifice hole diameter.
The running clearances of the suction Page 66 of 105 1
Component ID Component GEH Public Mode of Operation System/ Component Fk>wnte NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Fluid Velocity thru Component System OescrlpUons and Mission Time 04ebris ln1~ion Model WNr Rate and Component Evaluation side and discharge side of each impeller stage are designed and manufactured to provide hydrostatic support and damping for the rotating assembly, thus allowing operation at sup@r*critical speeds without dynamic instability. Increasing the closl!!:
running clearances due to wear may reduce the overall shaft support stiffness at each impeller location, thus affecting the dynamic stability of the pump. Debris in the pumped fluid may affect the seating capability of Auxiliary Equipment Evaluation Wear rings and bushings are specifically designed (hard materials) to resist wear due to hard particulates in the process fluid. If the concentration of hard particulates is unusually excessive, the effect could be a long-term deterioration in the pump performance, in the form of low pump head. The requirement of 30 days of post LOCA operation is not considered long-term.
mechanical shaft seats. These seals Seal Faces are dependent on seal injection flow New seal faces are lapped to very flat and to cool the primary seal components.
smooth surfaces. The working gap Debris in the pumped flow has the between the faces is a traction of a potential of blocking the seal micron. This means that large injection flow path or of limiting the particulates would pass over the seal performance of the seal components faces, and would not enter the interface due to debris buildup in bellows and to destroy the smoothness of the face springs. These effects may lead to and cause leakage.
primary seal failure. Graphite safety bushings (disaster bushings) may fail if exposed to high pressure fluid with debris following a primary seal failure thus, providing an outside containment path for post-LOCA fluid.
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For the passive strainer with the holes sized at 0.125 in., little fiber is expected to pass through after the initial filter bed is formed, and also tittle of the other debris (except for minimum sized iron oxide sludge) is expected t o pass after the initial filter bed precoat is formed.
Therefore, alt materials would most likely pass through the orifice if 1% by volume of fiber does not cause a highly unlikely "blitz" which plugs the orifice. Because all particles are larger than a fraction of a micron, they would not enter the pump seal face. For shafts and bushings, debris in quantities of one percent or less of the pump fluid is likely to not constitute a
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major threat to the bushing integrity.
It is expected that ECCS pumps
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operated for 30 days (720 hrs.) under modes of operation assessed and pumping liquid at maximum suspended solids will not wear to a point where vibration will affect operability.
Page 67 of 105 1
Component ID Component GEH Public Mode of Operatton System/ Component Flowrate NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Ftuid Velocity thru Component System De$crlptlons and Mission Time
~bris Ingestion Model Wear Rate and Component Evaluation AuxllJary Equipment Evaluation
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ECCS pump performance for the specific plant as-built configuration will require demonstration of acceptable performance under design conditions including design debris loading.
Demonstration of acceptable performance for as-built ECCS pumps is validated under QME-12007, Qualification of Active Mechanical Equipment Used in Nuclear Power Plants as endorsed by RG 1.100, "Seismic Qualification of Electrical and Active Mechanical Equipment and Functional Qualification of Active Mechanical Equipment for Nuclear Power Plants/
Revision 3, September 2009 Page 68 of 105 1
Component 10 F002B F0038 BOOIB Component Check Valve Manua1Slock Valve Heat Exchanger
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Fluld Velocity thN Component
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~bris ln1estion Model The ECCS piping/ component flow area e1Cceeds the maximum dimension of the debris particles. Therefore, clogging is not considered credible.
The ECCS piping / component flow are.i exceeds the ma,dmum dimension of the debris particles. Therefore, clogging is not considered credible.
The RHR heat exchanger tube ID is 17.22 mm. The ECCS strainer will restrict debris to less than 3.18 mm. Therefore, the RHR heat e,cchanger will not become clogged from debris passing downstream of the ECCS suction strainer.
Wear Rate and Component Evaluation Auxlll~ry Equipment Evaluatlon NED0-32686 (URG) Vol 4 includes evaluation of ECCS heat exchangers:
This assessment was adjusted for the ABWR RHR heat exchanger wrth suppression pool water flowing though the tubes of the heat exchanger. As described in ABWR DCO section 5.4.7.1, the ABWR RHR heat exchanger has taken advantage of a design change that was made with respect to prior BWRs. ABWR has the reactor water flowing through the tube side of the heat eKchanger, whereas, prior BWRs had the reactor water flowing through the shell side. The primuv purpose for the change was to reduce radiation buildup in the heat exchanger by providing a more open geometry flow path through the center of the tubes, as opposed to the shell side construction of spacers, baffles, and low flow velocity locations, which can provide places for radioactive sludge to accumulate.
Heat Exchangers Significant effect on RHR heat exchanger performance can occur if a large quantity of debris Is retained inside the heat exchangers causing blockage of the flow and/or fouling of the tubes. Flow from the suppression pool is channeled through the tubes of the RHR heat exchangers. The tube side flow velocity of Page 69 of 105 1
Component ID Component GEH Public Mode of Operatton System/ Component Flownite NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public) fluid Velocity thru Component System Descrfptfons and Missfon Time
~bris ln1estk,n Model Wear Rate and Component Evaluation Auxiliary Equipment Evaluatlon a RHR heat @xchanger is approximately 2 ft/ SM. At this velocity, the flow will entrain the small particles without allowing them to settle in the heat t!:XChanger. The tube size is 0.68 inch diameter. The results of the size distribution analyses are evaluated as follows:
- 1. The rust chips are the largest, but are very likely to break into smaller pieces.
Considering the possibility that the largest chips &et through the strainer holes and through the pumps without being broken up, (not considerll!:d credible), they will pass through the heat exchanger tubes. Iron oxide (Fe10 i or F~O,) will not promote oxidation and corrosion on the inside diameter of the stainless steel tubes. Therefore rust debris particles wilt not contribute to fouling and/ or thinning of the tubll!:s.
- 2. Epoxy paint chips arll!: small and light 11!:nough that thll!:y wilt bll!: swll!:pt through thll!: hll!:at e>cchangers, and arll!: of no concll!:m.
- 3. The sizll!: of the sand grains arll!: small 11!:nough that it is unlikely that thll!:V will be capturll!:d along the flow path, but may bll!:
hll!:avy 11!:nough to settle in pod:11!:tS of low velocity near the tubll!: shell!:ts of the heat e>cchanger.
Becausll!: thll!:y will not settlll!: on the innll!:r surface of the tubes, they will not affect the heat 11!:xchangll!:r performance.
- 4. Of the samples 11!:valuated in Rll!:ference 1, only 0.1% of thll!: fiber population had a length of 0.39" or &rll!:ater. With this length, it is unlikely they could attach to thll!: innll!:r diamll!:tll!:r of RHR hll!:at e>cchaneer tubes. Moreover, the fibers werll!: so fra&ile that any attempt to dispersll!: thll!: clumps causll!:d e>ctensive brll!:akage of thll!: longll!:r fibll!:r-5. Thesll!:
fiben also will bll!: easily swept away and carried out of the heat 11!:xchanger without affectin& heat Hchan1ll!:r pll!:rformancll!:. In summary, a rll!:vill!:w of heat exchanger performance concludll!:s that nonsolublll!:
insulation matll!:rial will not deteriorate the pll!:rformance of the as-built heat exchanger. Thi!: rust chips could present some potll!:ntiat effect to RHR heat exchanger performance. However, this concll!:m is minimized by the fact that a large fraction of the bi1&ll!:r chips are so thin that they will flow through the heat Page 70 of 105 1
Component ID f0048 FE-006B D0048 Motor Operated Control Valve Flow Element Flow Restricting Orifice
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~bri, ln1estion Model The ECC5 piping / component flow area exceeds the maximum dimension of the debris particles. Therefore, clouina: is not considered credible.
The ECCS piping / component flow area exceeds the maximum dimension of the debris particles. Therefore, cloning is not constdered credible.
The ECC5 piping / component flow area exceeds the maximum dimension of the debris particles. Therefore, clogging is not considered credible.
Wear Rate and Component Evaluation Auxlllilry Equipment Evaklatlon exchangers w hilll!: others will be broken into still smaller piecM by the rapid flow and therefore easily pass through the heat exchanger. The key factors in heat exchanger performance an~ the routine maintenance, inspection, and cll~aning of the heat 11!:)(Changer. D@bris that pass through the ECCS suction strainers do not affect heat exchanger performance Therefore, there is no abnormal operiltional or safety concern with the identified debris on RHR heat exchanger performance, assuming they are property maintained.
Page 71 of 105 1
Component ID FOOSB fOOSSB X-205 Component Motor Operated Control Valve Manual Block Valve Penetration
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~bris ln1estion Modet The ECCS piping / component flow area exceeds the maximum dimension of the d@brls particles. Therdore, clogging is not considered credible.
The ECCS pipin1 / component flow area e,cceeds the maximum dimension of the debris particles. Therefore, clogging is not consid@red cr@dible.
The ECCS piping / component flow are;i Hceeds the maximum dimension of the debris partides. Therefore, clogging is not considered credible.
Wear Rate and Component Evaluation Auxiliary Equipment Evaluatlon Page 72 of 105 1
Component 10 ECCS PIO ID Component ECCS components in flow p;ath to be assessed
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Table A-6: ECCS Suction Strainer Downstream Effects-Containment Spray with Heat Removal Mode E System / Component Flowrate
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Determine flowrate at points in system and use the flow/ velocity to evaluate settling ilnd wear.
FluJd Velocity thru Component It is assumed that settling will occur when the flow velocity in the process piping is less than the settling veloclty for the debris type.
If settlin1 is not present, debris will remain in solution and not dog lines ilnd components.
In the Safety Evilluation for WCAP*
16406P (ML07352029S), the NRC concluded thilt no settlin& of debris will occur in an instrument line installed above the horizontal pl;;ine of the process pipin1. Reference 42 provides 1uidelines for locating process instrument connections (tilps) on main process pipelines to ensure thilt fittin1s on the bottom of pipin& where th~ can collect crud ue avoided (Section S.3.3.LS.3). Therefore, ECCS instrument lines ln servke during post*LOCA operation are installed above the horlzontill plane of the process pipinc. No settlinc of debris in an instrument line in this orientation is expected.
The settlin& velocity for 2.S mil 55 RMI is assumed to be 0.4 ft/sec [ref NEDO 32686 (URG)J A settlin1 velocity of 0.2 ft/ s was assicned for pamt chips. Finally, ii settlin& velocity of 0.4 ft/s was assigned to concrete dust and other drywe ll puticulates. (ref NUREG CR 6224]
A settlin& velocity for NUCON fibers used for preliminary assessment is 0.2S ft/sec based on havin&
ceometry of partides that would bypns the suction stniner. (ref boundin& NU REG CR 6224 Table B-3 ilnd NEI 04*07 Tilble 4*2]
System Dttcriptlons and Mission Time
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The ABWR ECCS mission time for RH R post LOCA performance is 30 dil'(S {720 houn). consistent with NRC auidance. Guidance in NUREG/CR-6988, "'Finill Report -
Evaluation of Chemical Effects Phenomena in Post-LOCA Coolant,"
indicates that, although the regulations in 10 CFR 50.46(bl(S) require that Iona-term coolina be maintained indefinitely ("for an extended period of time"), 30-days is typkally considered to be an appropriate time period to demonstrate ECCS functionality and that, beyond this time, the decay heat loading is small, making alternative coolin& possible should ECCS functionality be lost.
Debris lncestlon Model
[The quantity of debris and makeup downstream of the striliner needs to be determined to assess wear rate of pipina and components.)
Debris considered indudes fibrous insulation debris and particulate debris consisting of paint chips, concrete dust, and reflectrle metilllic insulation shards smilll enough to pass throuch the holes of the ECCS suction strainer perforated plates (1/8-inch diameter).
In general, the assumptions ilccount for particles larger than the screen opening size and assume iltl transportable material with the above dimensions or Smi111er passes through the suction stniner unimpeded thus malCimizin&
the calculated particulilte and fibrous debris concentrations in the post-LOCA process fluid.
The milXimum length of deformable particulates that mily pass throuah the penetrations (holes) in passive suction strainers is equal to two times (2X) the maximum linear dimension of the penetntion (hole) in the suction strainer.
The maximum width of deformable pilrticulates that may pass throu1h the penetntions {holes) in pilssive suction strainers is equal to the maximum linear dimension of the penetration (hole) in the suction stniner, plus 10 percent (10%).
The malCimum thickness of deformable puticulates that may pass throuah the penetrations (holes) in a passive suction strainer is equill to one-half {1/2) the maximum linear dimension of the penetration {hole) in the suction stniner.
The maximum cross-sectional area of deformable puticutates thilt may pass through the penetrations (holes) in a passive suction strainer is equal to the maximum cross-sectional now area of the penetration {hole) in the suction strainer, plus 10 percent {l°").
The maximum dimension {lenath, width and/or thickness) of non-deformable particulates that mily pilSs throu&h ii suction strainer is limited to the cross*
Wear Rate and Component Evaluation There are two types of wear of close runnin& cleilrilnces within the pump; 1) free-flowing abrasive wear and 2) paddna-type abrasive wear. Wear within close-tolerance, hich-speed components is ii complex ilnalysis. The actual ilbnsive wear phenomenil will likely not be either a classk free-flowing or pildtina wear case, but ii combination of the two. Both should be considered in the evilluation of their components.
Consider how wear of internal suffices of pump components will affect pump hydrilulic performance (total dynamic head and flow), the mechanical performance (vibrationl, ilnd pressure boundary intearity (shaftseills).
Valve and heilt exchilnaer wetted materials should be evaluated for susceptibility to weilr, surface abrasion, and plugging. Weilr may alter the system flow distribution by increilsin& How down a path (decreasina resistance caused by wear), thus starvina ilnother critical pilth. Ot conversely, inaeased resistance from pluuina of a valve openin&, orifice, or heat eKchanger tube mily cause weilr to occur in ilnother path that experiences increased flow.
Sludge/ corrosion prod. 200 lbm (density 324 lb/ ft3 per NEI 04*07 Ti1ble4-2) lnorcanicZinc (IOZ) 47 lbm (0.2516 ft3 per URG]
Epoxy Coated IOZ 85 lbm 0.65 fr.3 per URG)
Rust Flakes 50 lbm (324 lb/ ft3 per NEI 04-07 Table 4-2)
Oust/ Dirt 150 lbm
[156 lb/ ft3 per NEI 04-07 Table 4-2)
Supp. Pool (SP) Initial Vol. (min.)=
34SS m3 {Ref OCD T6.2* 2):: 3.4SS x 1061iters.
Assumin& the minimum SP volume and worst case debris volume, the concentriltion of suspended solids Auxlllary Equipment Evaluatlon
£valuation of Downstream Effects on Major Components The effects of debris passin1 through the strainers on downstream components such as pumps.
valves. ilnd heat exchilnaers hilS been evaluated as required under Rea Guide 1.82 Rev 4. This evaluation includes assessina wear on surfaces exposed to the fluid stream due to various types of debris: e.a. pilint chips or RMI shards.
Evaluatina the potential for blockilge of smilH clearances due to downstream debris ilre also included. The milterials and cleannces for the valves. pumps. and heat exchangers downstream of the ABWR ECCS suction strainers are essentially the same as the materials and cleuilnces for the valves. pumps. and heat exchilngers downstream of the PWR containment sump suction stniners.
Therefore. Utilizing npects applied to PWR methodology for the ABWR is appropriate. (ref STPOCD6C.3.2)
Page 73 of 105 1
Component 10 U71 Component Containment Orywetl Connecting Vents GEH Public Mode of Operat ktn System / Component Bow rate NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Fluid Velocity thru Com porwnt System Descriptions and Mission Time Debris lncestlon Model sectional flow area of the penetration (hole) in the suction strainer. ( WCAP*
016406}
The materials involved are relatively stiff and incompressible and account for long, thin strands, of insulation being able to pass through tight openings.
It is assumed no settling of material once in solution. The material wilt tend to settle out in low flow areas in piping, the reactor vessel, the containment floor, or hold-up volumes.
It is assumed the debris forms a homogeneous solution at the start of the event.
((
Wear Rate and Component Evaluatlon in the SP water is estimated at 5130 ppm by weight [0.07% vol.] for non*
fiber debris and 6.8 ppm by weight (0.018% vol.) fiber debris.
Under a realistic assumption of 4.3% of RMI passing through the ECC5 suction strainer, 218 ppm by weight [0.003% vol.] would exist in the SP volume.
Under a realistic assumption of 23%
of NUKON fibers passing through the ECCS suction strainer, 1.6 ppm by weight [0.004% vol.) would exist in the SP volume. Experimental data on the effects of particulates on pump hydraulic performance applied to ECC5 type pumps show that pump performance degradation is negligible for particulate concentrations less than 1% by volume. [Ref: NU REG/CR 2792]
NUREG/CR 2792 notes conservative estimates of the nature and quantities of debris show that fine abrasives may be present in concentrations of about 0.1% by volume (about 400 ppm by weight).
and that very conservative @stimat@s of fibrous material yield concentrations of less than 1% by volume. Published data on the effects of particulates on pumps generally deal with particulate concentrations at many times these values.
Auxiliary Equipment Evaluatlon Page 74 of 105 1
Comporwnt ID Ell-01 Component RHR System
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public) fluid Velocity thru Component System Descriptions and Mission Time Debris lncestion Model
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The Emercency Core Cooling (ECC)
DCD 531.3.2.3 Wiiter Quality and Systems are designed to withstand Submergence, provides rHctor water a hostile environment and still quality chuacteristics for the desian perform their function for 30 davs bHk LOCAs inside prffflary followinc an accident.
contilinment..
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Wear Rate and CompoMnt Evaluation Materials of construction for ECCS system components are listed in DCO Table 6.1-1 Encineered Safety Features Component M,1terials.
ConsidMing an ECCS mission time of 30 days (720 hrs.), the wear of components subjected to the debris particles in solution (0.083 % SP volume) is considered insienificant.
(ref: An Assessment of Residuill Heilt Removal ilnd Containment Spray Pump Performance Under Air and Debris tn1estin1 Conditions, NUREG/
CR-2792)
Auxllluy Equipment Evaluation Evaluiltion of Downstream EffKts on Miljor Components The effects of debns passinc through the strainen on downstream components such as pumps.
valves. and heat exchilncers has been evaluated as required under Re1 Guide 1.82 Rev 4. This evilluation includes assessing wear on surfaces exposed to the fluid stream due to vuious types of debris: e.1. pilint chips or RMI shilrds.
Evaluating the potentlill for blockage of small clearances due to downstream debris ue also included. The materials and cleuances for the Villves. pumps. ilnd heat exchangers downstream of the ABWR ECCS suction strainers are essentiillly the same as the milteriats and deuilnces for the Villves. pumps. ilnd heat exchangers downstream of the PWR contilinment sump suction strainers.
Therefore. Utilizin& i1Spects ilpplied to PWR methodolo1y for the ABWR is appropriate. (ref STP OCD 6C.3.2)
The RHR system has no ti&ht durance Villves throttled durmg post LOCA operation thilt would be susceptible to blocka1e or bindine. All RHR valves in the post LOCA lineup will be dosed (i.e.
isolilte CST suction flow path) or fully open. As reflected on Tilble 1, Vatvi! Position Chart, on Figure S.4-11, Residual Heilt Removal System PFD (Sheet 2 of 2), no RHR valves ilre throttled during post LOCA modes of operation. RHR minimum flow is milintilined by ii piping orifice nther than throttlin& of the minimum flow valve.
RHR system check valves installed in the main RHR pump discharge tine, m inimum flow tine and jockey pump dischar1e line have active safety functions to open. These AHR valves are not susceptible to clouin&, settling or weu. The clearilnces of these check valves prevent debris from adversely impactin& the functlOn of these components. The check valve milteriat is carbon steel. Erosion or wear durin& the post LOCA credited 30-day mission time will not impact system performance.
RHR S'(1tem orifice plates ilnd SP and dryweH spu1ers installed in the RHR process pipin& have safety functions to maintain flow. These RHR components are not susceptible to clouin&,
settlinc or wear. The cleuances of these components prevent debris from adversely impacting the function of these components. The Page 75 of 105 1
Compone.,t 10 00018 X-202 FOOlB Component Suction Strainer
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Fk.l kt VeJodtythru Comf)OM'nt
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System Descriptions and Mfsslon Time
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The sizing of the RHR suction strainers conforms to the a:uidance of Reg Guide 1.82. The sizing is based on Siltisfying the NPSH requirements at runout flow, plus margin, with postulated piping insulation debris in th@ SP accumulated on the pump suction strainers. The sizing of the strainers is based on 30 days of post* LOCA operation.
RHR design has a provision for installation of a temporary strainer in each loop during pre-operational and startup testing.
Strainers are located to avoid air entrainment during a LOCA blowdown or from vortexing action and away from the safety relief valve quencher discharce zones.
Strainers shall be sized to prevent dogging of pump internal passages.
(Ret. 31113-0EU-2010 (Ref. 32})
, Debris lncestion Model Debris size downstream ECCS SuctlOn Strainer.
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The ECCS piping/ component flow area exceeds the maximum dimension of the debris particles. Therefore, clogging is not considered credible.
The ECCS piping/ component flow area exceeds the maximum dimension of the debris particles. Therefore, clogging is not considered credible.
Wear Rate and Component Evaluation Au,clllary£quipmfflt Evaluation orifice and sparger material is stainless steel.
Erosion or wear during the post LOCA credited 30*
day mission tim@ wltl not impact system perform.11nce.
Page 76 of 105 1
Component ID C0018 Component RHR Pump B
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Fluid Vefoctty thru Component
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System Descriptions a nd Missk,n Time
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Debris tncestion Model Wear Rate and Component Evaluation Auxiliary Equipmimt Evaluation The ECCS piping/ component flow area As described in NU REG /CR 2792, An NED0-32686 (URG) Vol 4 Evaluation of the Effects exceeds the maximum dimension of the Assessment of Residual Heat of Debris on ECCS Performance (GE-NE-T23*
debris particles. Therefore, clogging is Removal and Containment Spray 00700-15*21), addresses safety and operational not considered credible.
Performance Under Air and Debris concerns for failure of ECCS pumps associated Ingesting Conditions, concludes that under LOCA conditions with generated debris at the pump, pump performance degradation is expected to be negligible. In the event of shaft seal failure due to wear or loss of cooling fluid, seal safety bushings limit leakage rates.
This is based on a debris concentration less than 0.5% by volume.
When considering long-term pump operation and performance, it is necessary to consider how wear of internal pump components will affect the pump hydraulic performance (total dynamic head and flow), the mechanical performance (vibration), and pressure boundary integrity (shaft seals). The wear of the close running clearances may affect the hydraulic performance because of increased internal or bypass leakage.
Multistage pumps, designed for high head service, usually operate at speeds above the first natural frequency of the rotating assembly.
The running clearances of the suction side and discharge side of each impeller stage are designed and manufactured to provide hydrostatic support and damping for the rotating assembly, thus allowing operation at super-critical speeds without dynamic instability.
Increasing the dose running clearances due to wear may reduce the overall shaft support stiffness at each impeller location, thus affecting the dynamic stability of the pump.
Debris in the pumped fluid may affect the sealing capability of mechanical shaft seals. These seals are dependent on seal injection flow to cool the primary seal with particles that pass through the ECCS suction strainers.
The ECCS pump design is coordinated with the ECCS suction strainer sizing to prevent dogging of pump internal passages including mechanical seat assemblies. The consequence of a plugged pump seal line would be high seal temperature and poor sea11ife.
The ECCS pump includes a mechanical seal assembly with cydone particle separator and seal-cooling heat exchanger. A cyclone separator type of filtration is provided to maintain a dean cooling water supply to the seal.
The size of orifices used to control the flow to ECCS pump seals is specified by the pump manufacturer to ensure the pump seal cooling lines are not susceptible to plugging by debris not filtered by the cyclone separator type filter or debris larger than thi! seat cooling line orifice hole diameter.
Wear rings and bushings are specifically designed (hard materials) to resist Wl!ar due to hard particulates in the process fluid. If the concentration of hard particulates is unusually excessive, the effect could be a long-term deterioration in the pump performance, in the form of low pump head. The requirement of 30 days of post LOCA operation i~ not considered long-term.
Seat Faces New seal faces are lapped to very flat and smooth surfaces. The working gap between the faces is a fraction of a micron. This means that large particulates would pass over the seal faces, and would not enter the interface to destroy the smoothness of the face and cause leakage.
For the passive strainer with the holes sized at 0.125 in., little fiber is expected to pass through after the initial filter bed is formed. Little of the other debris (except for minimum sized iron O)(ide sludge) is expected to pass after the initial filter Page 77 of 105 1
Component ID Component
__ Mode of Operation GEH Public System/ Component Flowrate NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
FklidVelocitythn, CompoMnt Syttem Descriptions and Mission Time Debris lncestion Model Wear Rate and Component
£valuation components. Dl!bris in the pumped flow has the potential of blocking the seal injection flow path or of limiting the performance of the seal components due to debris buildup in bellows and springs. These effects may lead to primary seal failure.
Graphite safety bushings (disaster bushings) may fail if exposed to high pressure fluid with debris following a primary seal failure; thus, providing an outside containment path for post-LOCA fluid.
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Auxiliary Equipmn1t Evaluation bed precoat is formed. Therefore, all materials would most likl!dy pass through the orifice if 1% by volume of fiber does not cause a highly unlikely "blitz" which plugs the orifice. Because all partides arl! larger than a fraction of a micron, they would not l!nter the pump seal face. For shafts and bushings, debris in quantities of onl! percent or less of the pump fluid is likely to not constitute a major thrl!at to the bushing integrity.
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Page 78 of 105 1
Component ID F0028 F0038 B001B Component Check Valve Manual Block Valve
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Heat Exchanger
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Fluid Vetocfty thru Component
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System Descriptions and Mission Time Debris ln1estion Model The ECCS piping / component flow area exceeds the maximum dimension of the debris particles. Therefore, clogging is not considered credible.
The ECCS piping / component flow area exceeds the maximum dimension of the debris particles. Therefore, clogging is not considered credible.
The RHR heat exchanger tube ID is 17.22 mm. The ECCS strainer will restrict debris to less than 3.18 mm.
Therefore, the RHR heat exchanger will not become dogged from debris passing downstream of the ECCS suction strainer.
Wear Rate and Component Evaluation Auxllla ryEqulpment Evaluation ECCS pump performance for the specific plant as*
built configuration wit! require demonstration of acceptable performance under design conditions induding design debris loading. Demonstration of acceptable performance for as-built ECCS pumps is validated under QME*l 2007, Qualification of Active Mechanical Equipment Used in Nuclear Power Plants as endorsed by RG 1.100, ~seismic Qualification of Electrical and Active Mechanical Equipment and Functional Qualification of Activl!
Mechanical Equipment for Nuclear Power Plants,"
Revision 3, September 2009.
NED0*32686 (URG) Vol 4 includes evaluation of ECCS heat exchangers:
This assessment was adjusted for the ABWR RHR heat exchanger with suppression pool water flowing though the tubes of the heat exchanger.
As described in ABWR DCO section S.4.7.1, the ABWR RHR heat exchanger has taken advantage of a design change that was made with respect to prior BWRs. ABWR has the reactor water flowing through the tube side of the heat exchanger, whereas, prior BWRs had the reactor water flowing through the shell side. The primary purpose for the change was to reduce radiation buildup in the heat exchanger by providing a more open geometry flow path through the center of the tubes, as opposed to the shell side construction of spacers, baffles, and low flow velocity locations, which can provide places for radioactive sludge to accumulate.
Heat Exchangers Page 79 of 105 1
Component 10 Component GEH Public Mode of Operation System / Component F~rate NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public) flukl Velocity thru C'.omponent Syste m OeKtipUons and Mission Time Debris lncestion Model Wear Rate a nd Component Evaluation Auxiliary Equipment Evaluatfon Significant effect on RHR heat exchanger performance can occur if a targe quantity of debris is retained inside the hl!at elCchangers causing blockage of the flow and/or fouling of the tubes.
Flow from the suppression pool is channeled through the tubl! side of the RHR heat exchangMs.
The tube side flow velocity of a RHR heat exchanger Is approximately 2 fV sec. At this velocity, the How will entrain thl! small particles without allowing them to settle in the hl!at exchanger. The tube site is 0.68 Inch diameter.
The rHults of the size distribution analys@s ar@
evaluated as follows:
- 1. Th@ rust chips ar@ th@ largMt, but ar@ Vl!:ry lik@ly to br@ak into smaller pieces. Considering the possibility that th@ larg@st chips get through the strainer holes and through the pumps without being brok@n up, (not considered credible), will pass through th@ h@at @xchanger tubes. Iron oxide (Fe20 J or FeJO*l will not,promote oxidation and corrosion on the inside diamet@r of th@
staint@ss st@@I tubes. Therefore, rust debris particles will not contribute to fouling and/ or thinning of the tubes.
- 2. Epoxy paint chips are small and light @nough that th@y will be swept through th@ heat e)(changers, and are of no concern.
- 3. The size of the sand crains are small enouch that it is unlikety that they will be captured along the flow path, but may be h@avy @nough to settle in pockets of low velocity near the tube sheets of the heat exchanger. Because they will not settl@
on the inn@r surhce of the tubes, they will not affect the heat exchang@r performance.
- 4. Of the samples evaluated in Reference 1, only 0.1% of the fiber population had a length of 0.39" or greater. With this length, it is unlikely they could attach to the inner diameter of the RHR heat e)(changer. Moreover,.the fibers were so fragile that any attempt to disperse the clumps caused e)(tensive breakage of the longer fibers.
These fibers also will be easily swept away and carried out of the heat exchang@r without affecting heat exchanger performance. In summary, a review of heat exchanger performance concludes that nonsoluble insulation material wrll not deteriorate the performance of the as*built heat exchanger. The rust chips could present some potential effect to RHR heat
@xchanger performance. However, this concern is minimized by th@ fact that a large fraction of the bigger chips are so thin that they will flow through the heat exchangers whil@ others will be broken into sti11 smaller pieces by th@ rapid flow and th@refor@ @asily pass through the heat e)(changer.
The key factors in heat exchanger performance Page 80 of 105 1
Component ID F004B FE-0068 FE-0158 Component Motor Operated Control Valve Flow Element Flow Restricting Orifice
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Ftuld Velocity thru CompoMnt
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System DescripUons and Mission Time Debris lncestion Model The ECCS piping/ component now area exceeds the maximum dimension of the debris particles. Therefore, clogging is not considered credible.
The ECCS piping / component ftow area exceeds the maximum dimension of the debris particles. Therefore, dogging is not considered credible.
The ECCS piping/ component ftow area exceeds the maximum dimension of the debris particles. Therefore, dogging is not considered credible.
Wear Rate and C.Omponent Evaluation Auxlllary Equlpm~t Evailuatfon are the routine maintenance, inspection, and cleaning of the heat e>tchanger. Debris that pass through the ECCS suction strainers do not affect heat t!xchanger performance Therefore, there is no abnormal operational or safety concern with the Identified debris on RHR heat exchanger perform,o1nce, assuming they are properly maintained.
Page 81 of 105 1
Component 10 F0198 F056B X*200A 0010 Component Motor Operated
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Block Valve Manual Block Valve Penetration WetwellSprav Spilrgers
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Fk.lMI Velodty thru Componttnt System Descriptions and M lssk>n Time Debris ln,estion Model
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The ECCS piping/ component flow area exceeds the maximum dimension of the debris particles. Therefore, dogging ls not considered credible.
The ECCS piping/ component flow area e,cceeds the maximum dimension of the debris particles. Therefore, clogging Is not considered credible.
The ECCS piping/ component flow uea exceeds the maim um dimension of the debris particles. Therefore, clogging is not considered credible.
The ECCS piping / component ftow area exceeds the maximum dimension of the debris particles. Therefore, clogging is not considered credible.
Wear Rate and Component Evaluation Auxillary Ecp.,ipmrnt Evaluation Page 82 of 105 1
Component ID F017B F0188 X30A 0009 Component Motor Openited
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Flu kt Vefodty thru Com~nt System OeacripUons and MIHion Debris ln,estion Model Time
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Wear Rate and Component Auxlllary Equ~ment Evalu.tton Evaluation Page 83 of 105 1
Component Component 10 GEH Public Mode of Oper*tion System / Component Flowrate NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Fluid Vetodty thN CompoMnt System Descriptions and Miuion Tim<
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Debris lnsestion Model We*r Rate and Component Au>elllaryEquipment Evalu.tton
£valuation Page 84 of 105 1
Component 10 ECCS PIO ID Component ECCS components in flow path to be assessed
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Table A-7: ECCS Suction Strainer Downstream Effects-High Pressure Core Flooder Mode 81 System/ Component Flowrate
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Determine flowrate at points in system ilnd use the flow/ velocity to evaluate settlin& and wear.
flukf VeJoclty thru Component It is assumed that settling will occur when the flow velocity in the process pipina: is less than the settling velocity for the debris type.
If se:ttlin1 is not present, debris will remain in solution and not do1 lines and components.
Under the Safety Evaluation for WCAP-16406P (ML07352029S), the NRC conduded that no settling of debris will occur in an instrument line installed above the horizontal plane of the process pipin1. Reference 42 provides 1uidelines for locilting process instrument connections (taps) on main process pipelines to ensure that fittin1s on the bottom of pipin& where they can collect crud are avoided [Section 5.3.3.1.8.3.
Therefore, ECCS instrument lines in service durin& post-lOCA operation are installed above the horizontal plane of the process piping. No settlln& of debris in an instrument line in this orientation is expected.
The settlln1 velocity for 2.5 mil 55 RMI is assumed to be 0.4 ft/sec [ref NEDD 32686 (URGI]
A settlin& velocity of 0.2 ft/ s WilS assi1ned for paint chips. Finalty, a settlin& velocity of 0.4 ft/s was assi&ned to concrete dust and other drywell particulatl!:s. !ref NUREG CR 6224)
A settlin1 velocity for NUCON fibers used for preliminary assessment is 0.25 ft/sec based on having 1eometry of partides that would bypass the suction strainer. !ref bounding NU REG CR6224 hble B-3 and NEI 04*
07 Table 4-2)
System Dffcriptions and Mission Time
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The ABWR ECCS mission time for HPCF post LOCA performance is 30 days (720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br />), consistent with NRC guidance. Guidance in NUREG/ CR-6988, "Final Report -
Evaluation of Chemical Effects Phenomena in Post-lOCA Coolant,"'
indicates that, although the regulations in 10 CFR S0.46(b)(5) require that long-term cooling be maintained lndefinltely ("for an extended period of time" ), 30-days is typically considered to be an appropriate time period to demonstrate ECCS functlona llty and that, beyond this time, the decay heat loading is small, making alternative cooling possible should ECC5 functionality be lost.
Debris l11Cffllon Model
[The quantity of debris and makeup downstream of the strainer needs to be determined to assess weilr nte of pipin1 and components.)
Debris considered indudes fibrous insulatton debris ilnd particulilte debris consisting of paint chips, concrete dust, ilnd reflective metilllk lnsuliltion shards smilll enough to pass throueh the holes of the ECCS suction strainer perforated plates (1/8-inch diameter).
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The maximum length of deformable particulates that may pass throu1h the penetrations (holes) in passive suction strainer is equal to two times (2X) thl!:
maximum lineu dimension of the penetratK>n (hole) in the suction strainer.
The maximum width of deformable puticulates that may pass throueh the penetrations {holes) in passive suction strainer is eqUill to the maximum linear dimension of the penetration (hole) in the suction strainer, plus 10 percent (1<)%}.
The maximum thickness of deformable particulates that may pass through the penetrations {holes) in a passive suction strainer is equal to one-half (1/2) the maximum linear diml!:nsion of the penetration {hole) in the suction strainer.
The maximum cross-sectional area of deformilble particulates that may pass through the penetrations (holes) in a passive suction strainer is equal to the milximum cross-sectionill flow area of the penetration (hole) in the suction strainer, plus 10 percent (10%).
The maxi'num dimension {1en&th, width and/or thickness) of non-deformable particulates that may pass through a suction strainer is limited to the cross*
sectional flow area of the penetration Wear Rate and Component Evaluation There ue two types of wear of dose runnin& dearances within the pump;
- 1) free-flowin1 abrasive wear and 2) packin&*type abrasive wear. Wear within dose-tolerance, high-speed components is a complex analysts.
The actual abrasive wear phenomena will likely not be either ii classic free-flowing or packin1 wear case, but a combiniltion of the two. Both should be considered in the evaluation of their components.
Consider how wear of Internal surfaces of pump components will affect pump hydraulic performance (total dynamic head and flow), the mechanical performance (vibntion),
and pressure boundary integrity (shaft seals).
Valve and heat exchan1er wetted materials should be evaluated for susceptibility to wear, surface abrasion, and pluggin&. Wear may alter the system flow distribution by increasin1 now down a path (decreasin1 resistance caused by wear), thus stilrvin1 another critical path. Or conversety, increased resfStance from pluuin& of a valve openin&, orifice, or heat exchanger tube may cause wur to occur in ilnother path that experiences increased flow.
Sludge/ corrosion prod. 200 lbm (density 324 tb/ft3 per NEI 04-07 Table4-2J lnorgank Zinc (IOZ) 47 tbm (0.2516 ft3 per URG)
Epoxy Coated IOZ 85 lbm 0.65 ft3 per URG)
Rust flakes 50 lbm (324 lb/ft3 per NEI 04-07 Table 4-21 Oust/ Dirt 150 lbm [156 lb/ft3 per NEI 04*07 Table 4-21 Supp. Pool (SP) Initial Vol. (min.)=
3455 m3 (Ref DCO T6.2-2)::: 3.455 x 106 liters.
Assumin1 the minimum SP volume and worst case debris volume, the concentration of suspended solids in the SP water is estimated at 5130 ppm by weicht ro.07% vol.) for non-Au,clllaryEquipment Evaluation
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eom,,onont 10 U71 Component Containment Drywell Connecting Vents GEH Public Mode of Operation System / Component Flowrate NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Ftuld Velocity thru Component System Descriptions and Mission Time (hole) in the suction strainer. I WCAP*
016406)
The materials involved are relatively stiff and incompressible and account for lon1, thin strands, of insulation being able to pass through tight openings.
It is assumed no settlin1 of material once in solution. The material will tend to settle out in low How are;as in pipin&, the ructor vessel, the containment floor, or hold*UP volumes.
It is.usumed the debris forms a homogeneous solution at the st.ut of the event.
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Wear Rate and Component EvatuaUon fiber debris and 6.8 ppm by weight (0.018" vol.) fiber debris.
Under a realistic assumption of 4.3%
of RMI passing through the ECCS suction strainer, 218 ppm by weight (0.003" vol.) would exist in the SP volume.
Under a realistic assumption of 23" of NUKON fibers passinc through the ECCS suction strainer, 1.6 ppm by wei&ht [0.004" vol.) would exist in the SP volume.
Experimental data on the effects of particulates on pump hydraulic performance applied to ECCS type pumps show that pump performance degradation is ne1li1ib1e for particulate concentrations less than 1% by volume. (Ref: NU REG/CR 2792)
NUREG/CR 2792 notes conservative estimates of the nature and quantities of debris show that fine abrasives may be present in concentrations of about 0.1% by volume (about 400 ppm by weight).
and that very conservative estimates of fibrous material yield concentrations of less than 1% by volume. Published data on the effects of particulates on pumps cenerally deal with particulate concentrations at many times these values.
AuxlllaryEquipment Evaluation Page 86 of 105 1
Component ID
£22-01 Component HPCF System
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Fluid Ve'oclty thru Component System Descriptions and Mfssion Time The Emergency Core Cooling (£CC)
Systems are designed to withstand a hostile environment and still perform their function for 30 dilys following an accident."
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Debris lnsestton Model DCD S31.3.2.3 Water Quality and Submergence, provides reactor water quality characteristics for the design basis LOCAs inside primary containment.
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Wear Rate and Component Evaluatktn Materials of construction for ECCS system components ilre listed in OCD Table 6.1* 1 Engineered Safety Futures Component Materials.
Considering an ECCS mission time of 30 days (720 hrs.), the wear of components subjected to the debris partkles In solution (0.083 % SP AuxlllaryEquipment Evaluation Evaluation of Downstream Effects on Major Components Both the HPCF and RCIC systems take primary suction from the CST and secondary suction from the suppression pool (SP). The CST is clean demineralized water free of debris. This assessment assumes most conservative alignment from the SP source.
volume) is considered insignificant.
The effects of debris passing through the (ref: An Assessment of Residual Heat strainers on downstream components such Removal and Containment Spray as pumps. valves. and heat exchangers has Pump Performance Under Air and Debris Ingesting Conditions, NUREG/
CR*2792) been evaluated as required under Reg Guide 1.82 Rev 4. This evaluation includes assessing wear on surfaces exposed to the fluid stream due to var'ious types of debris:
e.g. paint chips or RMI shards. Evaluating the potential for blockage of small dearances due to downstream debris are also induded.
The materials and clearances for the valves.
pumps. and heat exchana;ers downstream of the ABWR ECCS suction strainers are essentially the same as the materials and clearances for the valves. pumps. and heat exchana;ers downstream of the PWR containment sump suction strainers.
Therefore. Utilizing aspects applied to PWR methodology for the ABWR is appropriate.
(refSTP OCO 6C.3.2)
The HPCF system has no tight clearance valves throttled durin& post LOCA operation that would be susceptible to blockage or bindinc. All HPCF valves in the post LOCA lineup will be closed (i.e. isolate CST suction flow path) or fully open. As reflected on Table 1, Valve Position Chart, on Figure 6.3-1 High Pressure Core Flooder System PFO (Sheet 2 of 2), no HPCF valves are throttled during this mode of operation. HPCF minim um flow is maintained by a piping orifice rather than throttling of the minimum flow valve.
HPCF system check valves installed in the main HPCF pump suction, discharge and minimum flow line have active safety functions to open. These HPCF valves are not susceptible to clo11in1, settling or wear. The clearances of these check vatves prevent debris from adversely impacting the function of these components. The check valve material is carbon steel. Erosion or wear during the post LOCA credited 30-day mission time will not impact system performance.
Page 87 of 105 1
Component 10 0003 B X*210 F0068 Component Suction Strainer
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Fluld Vek>clty thN Component
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The sizin1 of the HPCF suction strainen; conforms to the 1uidance of Re& Guide 1.82. The sizin& is based on utisfyinc the NPSH requirements at runout flow, plus mu1in, with postulated pipin& insuliltion debris in the SP ac;comulated on the pump suctK>n stniners. The sizin& of the strainers is based on 30 days of post*
LOCA operation.
HPCF design has a provision for installation of a temporary striliner in each loop during pre*operiltional and startuptestin&,
Strainers are located to avoid air entrainment during a LOCA blowdown or from vortexing iidion.ind ilway from the safety relief valve quencher dischar1e zones.
Strainers shall be sized to prevent clo11inc of pump internal passages.
(Ref: 31113-0f22*2010 (Ref. 33)]
~bris ln,estion Model Debris size downstream ECCS Suction Strainer.
The muimum dimension {len1th, width and/or thickness) of non*deformable particulates that may pass throu1h the strainer is limited to the cross*sfflional flow area of the penetration {hole) In the strainer.
len&th = 0.24 inch Width= 0.132 in.
Thickness =0.060 in.
Cross Section Area= 0.0123 in2 The design debris source term downstream the ECC5 suction strainer is:
NUKON 51.6 lbs (assume all NUKON passes through strain@r) RMI 38,500 lbs. (Assum@ all RMI passes through strainer)
Sludge/ corrosion prod. 200 lbm lnorcanic Zinc (IOZ)
Epoxy Coated IOZ Rust Flak@.s Oust/Dirt 47 lbm 8Slbm SOlbm 1S0lbm The ECC5 piping/ component flow area
@xceeds the maximum dimension of the d@bris particles. Therefore, cloccinc Is not considered credible.
Th@ ECCS piping / component flow area exceeds the maximum dimension of the debris particles. Therefore, dogging is not considered credible.
Wear Rate and Component E~luaUon Auxiliary Equipment Evaluation Page 88 of 105 1
Component ID f0078 (0018 Component Check Valve HPCF Pump 8
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Fluid Velocity thru Component
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Debris tncestlon Model The ECCS piping/ component flow area e>cceeds the maximum dimension of the debris particles. Therefore, clogging is not considered credible.
Wear R*te and Component Evalu1t lon AuxlllaryEquipment Evaluation The ECCS piping/ component flow area As described in NU REG /CR 2792, An NED0-32686 (URG) Vol 4 Evaluation of the exceeds the ma11:imum dimension of the Assessment of Residual Heat Removal Effects of Debris on ECCS Performance (GE-debris particles. There.fore., clogging is not and Containment Spray Performance NE-T23-00700-15-21), addresses safety and considered credible.
Under Air and Debris Ingesting Conditions, concludes that under LOCA conditions with generated debris at the pump, pump performance degradation is Hpected to be negligible. In the @vent of shaft seal failure due to wear or loss of cooling fluid, seal safety bushings limit operational concerns fo r failure of ECCS pumps associated with particles that pass through the ECCS suction strainers.
The ECCS pump design is coordinated with the ECCS suction strainer sizing to prevent clogging of pump internal passages including mechanical seat assemblies. The consequence. of a plugged pump seal line teak.age rates. This is based on a would be high seal temperature and poor debris concentration less than 0.5% by seal life.
volume.
When considering long-term pump operation and performance, it is necessary to consider how wear of internal pump components will affect the pump hydraulic performance (total dynamk. head and now), the mechanical performance (vibration),
and pressure boundary integrity (shaft seals). The wear of the close running clearances may affect the hydraulic performance be.cause of increased internal or bypass leakage. Multistage pumps, designed for high head The ECCS pump includes a mechanical seal assembly with cyclone particle separator and seal-cooling heat e11:changer. A cyclone separator type of filtration is provided to maintain a clean cooling water supply to the seal The size of orifices used to control the flow to ECCS pump seals is specified by the pump manufacturer to ensure the pump seal cooling lines are not susceptible to plugging by debris not filtered by the cyclone separator type filter or debris larger than the seal cooling line orifice hole diameter.
servlCe, usually operate at speeds Wear rings and bushings are specifically above the first natural frequency of designed (hard materials) to resist wear due the rotating assembly. The running to hard particulates in the process fluid. If clearances of the suction side and the concentration of hard particulates is discharge. side of each impeller stage unusually excessr\\fe, the effect coo Id be a are designed and manufactured to long-term deterioration in the pump provide hydrostatic support and performance, in the form of low pump head.
damping for the rotating assembly, The requirement of 30 days of post LOCA thus allowing operation at super*
operation is not considered long-term.
critical speeds without dynamic instability. Increasing the close running clearances due to wear may reduce the overall shaft support stiffness at each impeller location, thus affecting the dynamic stability of the pump. Debris in the pumped fluid may affect the sealing capability of mechanical shaft seals. These seals Seal Faces New seal faces are lapped to very flat and smooth surfaces. The working gap between the faces is a fraction of a micron. This me.ans that large particulates would pass over the seal faces, and would not enter the Page 89 of 105 1
Component ID Component GEH Public Mode of Operation System / Component Flowrat e NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Flukt Veb:lty thN Component System Descriptions and Missk>n Time Debris lntfflion Model Wear Rate and Component Evaluation are dep@ndent on s@a1 injection flow to cool the primary seal components.
Debris in the pumped flow has the potential of blodc.ing the seal injection flow path or of limiting the performance of the seal components due to debris buildup in bellows and springs. These effects may lead to primary seal failure. Gr.;iphite safety bushings (disaster bushings) may fail if exposed to high pressure fluid with debris following a primary s@al failure thus, providing an outside containment path for post-LOCA fluid.
ECCS pump rotor dynamics changes and long-term effects on vibrations caused by potential wear are reviewed in the context of rotating equipment operability and reliability.
Based on AP1*6 10, a wear limit of2X as*new values is generally applied for pumps not analyzed (2X limit). It is expected that ECCS pumps operated for 30 days (720 hrs.) under modes of operation assessed and pumping liquid at maximum suspended solids will not wear to a point when!
vibration will affect operability.
Auxlllary Equipment Evaluation intl!:rface to destroy thl!!! smoothness ofthl!!!
face and cause leakage.
For the passive strainer with the holes sized at 0.125 in., little fiber is expected to pass through after thl!!! initial filter bed is formed, and also littll!!! of the other debris (except for minimum sized iron oxide sludge) is expected to pass after thl!!! initial filter bed prl!!!coat is formed. Therefore, all materials would most likely pass through the orrftce if 1% by volume of fiber does not cause a highly unlikely "blitz" which plugs the orifice.
Because all particles are larger than a fraction of a micron, they would not enter the pump seal face. For shafts and bushings, debris in quantitll!!!s of one percl!!!nt or less of thl!!! pump fluid is likl!!!ly to not constitute a major threat to the bushing integrity.
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ID F021B FE-0088 Component Check Valve Flow Element
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System Dffcriptions i nd Mfssk>n Time Debris lncestlon Model The ECCS piping/ component flow area exceeds the maximum dimension of the debris partides. Therefore, do11in1 is not considered credible.
The ECCS piping/ component now area exceeds the maximum dimension of the debris partick!-s. Therefore, do11in1 is not considered credible.
Wear Rate and Component EvaluaUon Auxiliary Equipment Evaluation
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ECCS pump performance for the specific plant as-built configuration will require demonstriltion of acceptabl@ performanc, under design conditions including design debris loadinc. Demonstration of acceptable performance for as.built ECCS pumps is validated under QME-12007, Qualific.ition of Active Mechanical Equipment Used in Nuclear Power Pl;1nts as endorsed by RG 1.100, "Seismic Qualification of Electrical and Active Mechanical Equipment and Functional Qualification of Activll! Mechanical Equipment for Nuclear Power Plants,"
Revision 3, September 2009.
Page 91 of 105 1
Component 10 00028 f0038 X* 31A f0048 FOOSB Component Flow Restricting Orifice Motor Operated Bk>ck Valve Penetration Che:ck Valve (N2 Testable)
M;rnual Block Valve
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The ECCS piping / component flow are.i exceeds the maximum dimension of the debris particles. Therefore, clogging is not considered credible.
The ECCS piping / compon@nt flow area exceeds the muimum dimension of the debris particles. Therefore, clogging is not considered credible.
The ECCS piping / component flow area
@xceeds the maximum dimension of thl!
debris particles. Ther@forll!:, clogging is not considered credible.
The ECCS piping / component flow area e11:ceeds the muimum dimension of the debris particles. Therefore, clogging is not considered credible.
The ECCS piping/ component flow area exceeds the maximum dimension of the debris particles. Therefore, clogging is not considered credible.
Wear Rate and Component EvaluaUon AUJclllaryEqulpment Evaluation Page 92 of 105 1
Component 10 Reactor Internals (Reactor Pressure Vessel 811)
Reactor Internals (Reactor Pressure Vessel Bll)
Jll Fuel Assembly Component HPCFSpar1ers
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System Descriptions and M~1ion Time The high pressure conficuration consists of two motor driven hi&h pressure core flooders (HPCF) each with tts own independent sparger dischar1in1 inside the shroud.
The ECCS flow with debris is injected inside the shroud and travels through annulus between core support plates and shroud to the fuel inlet throueh the holes in the lower tie plate, 1ettin1 collected in the lower tie plate 1rld/ filter. Also, once the in-shroud level reaches the normal water level in the steam separators and spills into the RPV annulus, the debris will be mixed in the lower plenum and enter through the inlet orifice.
Flow is also available to the fuel assemblies throueh the upper tie plates. from HPCF spray. The only way that flow will be downward from upper pl@num thru upp@r tie plate is if the lower tie plate filter becomes excessively blocked. (ABWR doesn't uncover upper core like older BWRs that can allow spray into top before inlet beCOmes fully plugeed).
Downward flow repres@nts a nearly fulty blocked inl@t filter (allowine less than S" normal flow,.an inause in inlet resistance of X400).
The ABWR ev.aluation uamines the effects of bundle inlet douine th.at reduces the availabl@ inlet flow from n.atural circulation phenomena following initi.al core r@fill when th@
core r@gion is cover@d by a two-phase mixture. Durine this post-LOCA Debris lncNUon Model The ECCS piping/ component flow area exceeds the muimum dimension of the debris partides. Therll!fore, cto11in1 is not considered credible.
The reactor vesse:I flow ue,1 orifices exceed the maximum dimension of the debrts partkles. Therefore, clogging is not considered aedibte.
Wear Rate and Component Evaluation AuxlllaryEquipment Evaluation Page 93 of 105 1
Component 10 Component GEH Public Mode of Operation System/ CompoMnt Flowrate NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Fluid VekJclty thn, Component Svstem Descriptions and MiHk>n Time period, the reduced inlet flow results in increased bundle voiding and higher velocities such that the hut transfer is sufficient to remove the decay heat. Once the bundle decay heat has decrl!ased and insufficient voids exist to maintain the level in the bundle above the top of the fuel channel, adequate cooling from the upper plenum spillover will exist.
Thus, the evaluation concludes that fouignificant bundle inlet dogging following initial core refill, BWR fuel bundle cootin&: is assured.
Debris tncestk>n Model Wear Rate and Component Evaklation AuxlllaryEquipment £valuation Page 94 of 105 1
Component 10 ECCS PIO ID CompoMnt ECCS components in flow path to be assessed
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Table A-8: ECCS Suction Strainer Downstream Effects-Reactor Core Isolation Cooling System Mode C System/ Component Ftowrate
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Determine flowrate at points in system and use the flow / velocity to evaluate settling and wear.
Fluid Velocity thru Component It is usumed that settlin& will occur when the flow velocity in the process piping is less than the settling velocity for the: debrb type.
lf settlin& is not present, debris will remilin in solution and not doc lines and components.
In the Safety Evaluation for WCAP-16406P (Ml073520295), the NRC concluded that no settling of debris will occur in an instrument line installed above the horizontal plane of the process pipinc. Reference 42 provides guidelines for locating process System Descriptions and Mission Time
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The ABWR £CC5 mission time for RCIC post LOCA performance is 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
consistent with ABWR OCO Table 3.11*
2 for environmental qualifiCiiltion.
instrument connections (taps) on main __
process pipelines to ensure that fittincs on the bottom of piping where they can collect crud are avoided (Section S.3.3.1.8.3). Therefore, ECCS instrument lines in service during post-LOCA operation are installed above the horizontal plane of the process pipinc.
No settling of debris in an instrument line in this orientation is expected.
The settling velocity for 2.5 mil 55 RMI is assumed to be 0.4 ft/sec (ref NEOO 32686 (URGII A settling velocity of0.2 ft/ s was assigned for paint chips. Finally, a settlin& velocity of0.4 ft/s was assiened to concrete dust and other drywell partk:ulates. [ref NU REG CR 6224)
A settling velocity for NUCON fibers used for preliminary assessment is 0.25 ft/sec based on having 1eometry of partides that would bypass the suction st~iner. (ref boundinc NU REG CR 6224 Table 8-3 and NEI 04-07 Table 4-2]
Debris lna:estion Model
[The quantity of debris and maket1p downstream of the strainer ne~s to be determined to assess wear rate of piping and components)
Debris considered includes fibrous insulation debris and particulate debris consisting of paint chips, concrete dust, and reflective metallic insulation shards small enough to pass throuch the holes of the ECCS suction strainer perforated plates (1/8-inch diameter)
In ceneral, the assum ptions account for partides lar1er than the screen opening size and assume an transportable material with the above dimensions or smaller passes through the suction strainers unimpeded thus maKimizing the calculated particulate and fibrous debris concentrations in the post-LOCA process fluid.
The maximum length of deformable particulates that may pass throuch the penetrations {holes) in passive suction strainer is equal to two times {2X) the maximum linear dimension of the penetration (hole) in the suction strainer.
The maximum width of deformable particulates that may pass through the penetrations {holes) in passtve suction strainers is equal to the maximum linear dimension of the penetration {hole) in the suction strainer, plus 10 percent (10%).
The maximum thickness of deformable particulates that may pass through the penetrations {holes) in a passive suction strainers is equal to one-half (1/2) the maximum linear dimension of the penetration (hole) In the suction strainer.
The maximum cross-sectional area of deformable particulates that may pass through the penetrations (holes) in a passive suction strainers ts equal to the maximum cross-sectional flow area of the penetration (hole) in the suction strainer, plus 10 percent (10%).
The maximum dimension {lencth, wtdth and/or thickness) of non-deformable particulates that may pass through a suction strainer Is limited to the cross-sectional flow area of the penetration (hole) in the suction strainer. [ WCAP-0164061 Wear Rate and CompoMnt Evaluatton There are two types of wear of close n.mninc clearances within the pump;
- 1) free-Howin& abrasive wear and 2) packin1-type abrasive wear. Wear within close-tolerance, hieh-speed components is a complex analysis.
The actual abrasive wear phenomena will likely not be either a classic free-flowinc or packin1 wear case, but a combination of the two. Both should be considered in the evaluation of their components.
Conlider how wear of internal surfues of pump components will affect pump hydraultc performance (total dynamic head and flow), the mechanical performance (vibration),
and pressure boundary intecrity {shaft seals).
Valve and heat exchancer wetted materials should be evaluated for susceptibility to wear, surface abrasion, and plu11in1. Wear may alter the system flow distribution by increasinc flow down a path (decreasing resistance caused by wear), thus starving another critical path. Or conversely, increased resistance from plu&1ing of a valve openin1, orifice, or heat exchaneer tube may cause wear to occur in another path that experiences increased flow.
Sludge/ corrosion prod. 200 lbm (density 324 lb/ft> per NEI 04-07 Table 4-21 lnorianic Zinc (102) 47 lbm
{0.2516 ftl per URGJ Epoxy Coated 102 85 lbm 0.65 ft> per URG)
Rust Flakes 50 lbm (324 lb/ft> per NEI 04-07 Table 4-2]
Oust / Dirt 150 lbm (156 lb/ ft3 per NEI 04-07 Table 4-2)
Supp. Pool {SP) Initial Vol. (min.) "'
3455 m3 (Ref oco T6.2-2) = 3.455 x 106 liters.
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AuxillaryEquipment Evaluation Evaluation of Downstream Effects on Major Components The effects of debris passinc through the strainers on downstream components such as pumps. valves. and heat exchangers has been evaluated as required under Reg Guide 1.82 Rev 4.
This evaluation includes assessin& wear on surfaces exposed to the fluid stream due to various types of debris: e.1.,
paint chips or RMI shards. Evaluating the potential for blockace of small clearances due to downstream debris are also included. The materials and clearances for the valves. pumps. and heat exchancers downstream of the ABWR ECCS suction strainers are essentially the same as the materials and clearances for the valves. pumps.
and heat exchangers downstream of the PWR containment sump suction strainers. Therefore. Uttlizin& aspects applied to PWR methodolocy for the ABWR is appropriate. [ref STP OCO 6C.3.2J Page 95 of 105 1
Component ID U71 r.omponent Containment DryweU Connecting Vents GEH Public Mode of Operation System/ Component Flowrate NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Fluid Velocity thru Component System Descriptions and M ission Time Debris tn,fftton Model The materials involved are rl!lativl!ly stiff and incomprl!ssibll! and account for long, thin strands, of insulation being able to pass through tight openings.
It is assumed no settling of material once in solution. The material will tend to settle out in low flow areas in piping, the reactor Vl!ssel, the cont.illinment floor, or hold-up volumes.
It is.illssumed the dl!bris forms a homogeneous solution.lit the start of the event.
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Experiml!ntal data on the effects of partiru1ates on pump hydraulic performancl! applied to ECCS type pumps show that pump performance degradation is negligible for partirutate concentrations less than 1% by votuml!. (Ref: NUREG/CR 2792)NUREG/CR 2792 notes conservative estimates of the nature and quantities of debris show th.lit fine abrasives may be present in concentrations of about 0.1% by voluml! {about 400 ppm by weight).
and th.lit very conservative estimates of fibrous material yield concentrations of less th.illn 1% by volume. Published dat.ill on the effects of particul.illtes on pumps gl!nerally de.ill with particulate concentrations at m.illny times these values.
Auxlllary Equlpment Evaluation Page 96 of 105 1
Component ID ESl*Ol Component RCIC System
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NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Fk.lld Veloctty thru Component System Descriptions and Mission Time The Emergency Core Cooling (ECC)
Systems are designed to withstand a hostile environment and still perform their function for 30 days following an accident.
Note: RCIC is required to operate and is environmentally qualified for 12 hrs during OBA.
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DCD S31.3.2.3 Water Quality and Submergence, provides reactor water quality characteristics for the design basis LOCAs inside primary containment.
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Wear Rate and Component Evaluation Materials of construction for ECCS system components are listed in DCD Table 6.1-1 Engineered Safety Features Component Materials.
Considering an ECCS mission time of 30 days (720 hrs.), (12 hrs credited for RCIC) the wear of components subjected to the debris particles in solution (0.083 % SP volume) is considered insignificant.
Au)(lliary Equipment Evaluation
£valuation of Downstream Effects on Major Components Both the HPCF and RCIC systems take primary suction from the CST and secondary suction from the suppression pool (SP). The CST is clean demineratized water free of debris. This assessment assumes most conservative alignment from the SP source.
The effects of debris passing through (ref: An Assessment of Residual Heat the strainers on downstream Removal and Containment Spray Pump components such as pumps. valves. and Performance Under Air and Debris heat exchangers has been evaluated as Ingesting Conditions, NU REG/ CR-required under Reg Guide 1.82 Rev 4.
2792)
This evaluation includes assessing wear on surfaces exposed to the fluid stream due to various types of debris: e.g.,
paint chips or RMI shards. £valuating the potential for blockage of small clearances due to downstream debris are also included. The materials and cleara nces for the valves. pumps. and heat exchangers downstream of the ABWR ECCS suction strainers are essentially the same as the materials and clearances for the valves. pumps.
and heat exchangers downstream of the PWR containme,:it sump suction strainers. Therefore. Utilizing aspects applied to PWR methodology for the ABWR is appropriate. [ref STP DCD 6c.3.2]
The RCIC system has no tight clearance valves throttled during post LOCA operation that would be susceptible to blockage or binding. All RCIC valves in the post LOCA lineup will be closed (i.e.
isolate CST suction flow path) or fully open. As reflected on Table 1, Valve Position Chart, on DCD Figure 5.4-9, Reactor Core Isolation Cooling System PFD (Sheet 2 of 2), no RCIC valves are throttled during this mode of operation.
RCIC minimum flow is maintained by a piping orifice rather than throttling of the minimum flow valve. RCIC flow is varied by RCIC turbine speed by positioning th"e steam governor value to maintain system flow rather than throttling RCIC process valves. RCJC is required to support post LOCA function for12 hrs.
The RCIC system check valve installed in the main RCJC pump discharge line has Page 97 of 105 1
Component 10 0002 X-214 Component Suction Strainer Penetration
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The ECCS piping / component flow area exceeds the maximum dimension of the debris particles. Therefore, clogging is not considered credible.
WHr Rate *nd Component EvaluaUon AuxlUary Equlpment Evaluation an activ@ safety function to open. This RCIC valve is not susceptible to clogging, settline or wear. The clearances of this check valve prevent debris from adversely impacting the function of these components. The chedc valve material is carbon steel. Erosion or wear during the post LOCA credited 12 hr.
mission time will not impact SV5tem performance.
Page 98 of 105 1
Component ID f006 f007 (001 Component Motor Operated Block Valve Check Valve RCIC Pump
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Debris ln1estion Model The ECCS piping / component flow area eKceeds the maximum dimension of the debris particles. Therefore, dogging is not considered credible.
The ECCS piping / component flow area exceeds the maximum dimension of the debris particles. Therefore, clogging is not considered credible.
The ECCS piping / component flow area exceeds the maximum dimension of the Wear Rate *nd Component Evaluation Auxiliary Equipment Evaluation As described in NUREG /CR 2792, An NE00-32686 (URG) Vol 4 Evaluation of Assessment of Residual Heat Removal the Effects of Debris on ECCS debris particles. Therefore, clogging is not and Containment Spray Performance Performance (GE-NE-T23-00700-1S-21},
addresses safety and operational considered credible.
Under Air and Debris Ingesting Conditions, concludes that under LOCA concerns for failure of ECCS pumps conditions with generated debris at associated with particles that pass the pump, pump performance through the ECCS suction strainers.
degradation is expected to be negligible. In the event of shaft seal failure due to wear or loss of cooling fluid, seal safety bushings limit leakage rates. This is based on a debris concentration less than 0.5% by volume.
When considering long-term pump operation and performance, it is necessary to consider how wear of internal pump components will affect the pump hydraulic performance (total dynamic head and flow), the mechanical performance (vibration ),
and pressure boundary integrity (shaft The ECCS pump design is coordinated with the ECC5 suction strainer sizing to prevent clogging of pump internal passag@s including mechanical seal ass@mbti@s. The consequence of a plugged pump seal line would be high seal temperature and poor seal life.
The ECCS pump includes a mechanical seal assembly with cyclone particle separator. A cyclone separator type of filtration is provided to maintain a clean cooling water supply to the seal.
seals). The wear of the close running The size of orifices used to control the clearances may affect the hydraulic flow to ECCS pump seals is spedfi@d by performance because of increased the pump manufacturer to ensure the internal or bypass leakage. Multistage pump seal cooling lines are not pumps, designed for high head service, susceptible to plugging by debris not usually operate at speeds above the filtered by the cyclone separator type first natural frequency of the rotating Page 99 of 105 1
Component ID Component GEH Public Mode of OpetaUon System/ Component Flowrate NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Fluid Velocity thru Component System Descriptions and Mission Time Debris lncestlon Model Wear Rate and Component Evaluation assembly. The running clearances of the suction side and discharge side of each impeller stage are designed and manufactured to provide hydrostatic support and damping for the rotating assembly, thus allowing operation at super-critical speeds without dynamic instability. Increasing the dose running clearances due to wear may reduce the overall shaft support stiffness at each impeller location, thus affecting the dynamic stability of the pump.
Debris in the pumped fluid may affect the sealing capability of mechanical AuxlllaryEqulpment Evaluation filter or debris larger than seal cooling line orifice hole diameter.
Wear rings and bushings are specifically designed (hard materials) to resist wear due to hard particulates in the process fluid. If the concentration of hard particulates is unusually excessive, the effect could bl! a long-term dl!teriotation in the pump performance, in the form of low pump head. The requirement of 30 days of post LOCA operation is not considered long-term.
shaft seals. These seals are dependent Seal Faces on seal injection flow to cool the New seal faces are lapped to very flat primary seal components. Debris in and smooth surfaces. Thi! working gap the pumped flow has the potential of between the faces is a fraction of a blocking the seal injection flow path or micron. This means that large of limiting the performance of the seal particulates would pass over the seal components due to debris buildup in faces, and would not enter the interface bellows and springs. These effects mav to destroy thi! smoothness of the face lead to primary seal failure. Graphite and cause leakage.
safety bushings (disaster bushings) may fail if exposed to high pressure fluid with debris following a primary seal failure thus providing an outside containment path for post-LOCA fluid.
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Based on APl-610, a wear limit of 2X as-new values is generally applied for pumps not analyzed (2X limit). It is i!Xpected that ECCS pumps operated for 30 days (720 hrs.) under modes of operation assl!ssed and pumping liquid at maximum suspended solids will not wear to a point where vibration will affect operability.
For the passive strainer with the holes sized at 0.125 in., little fiber is expected to pass throu~h after th!! initial filtM bed is formed, and also little of the othM debris (e11cept for minimum sized iron oxide sludge) is e11pected to pass after the initial filter bed precoat is formed. Therefor!!, all matMials would most liketv pass through the orifice if 1% by volume of fiber does not cause a highly unlikely "btitz" which plugs the orifice. Because all particles are larger than a fraction of a micron, thev would not enter the pump seal face. For shafts and bushings, debris in quantities of one percl!nt or less of the pump fluid is likely to not constitute a major threat to the bushing integrity.
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Component ID Component GEH Public Mode of Operation System / Component Fk>wrate NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public)
Flukt Vek>clty thru Component System Oncriptk>>ns and Mfsslon Ttme C>eblis ln,estlon Model Wear Rate and Component Evaluation Au,clllary Equipment Evaluation
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ECCS pump performance for the specific plant as-built configuration will require demonstration of acceptable performance under design conditions induding design debris loading.
Demonstration of acceptable performance for as-built ECCS pumps is validated undMQME-12007, Qualification of Active Mechanical Equipment Used in Nuclear Power Page 101 of 105 1
Component ID FE-007 F003 FDD4 Component Flow Element ChKkVatve Motor Operated Block\\/alve
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Fk.lld Vebclty thN Component System Descriptions and Mfss5on Time
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Debris lnt:fltion Model The ECCS pipinc / component flow uea l!Xceeds the mnimum dimension of the debris partides. Therefore, clouin& is not considered credible.
The ECCS piping/ component now area exce~s the maximum dimension of the dtbris partides. Therefore, donin& is not consider@d credible.
The ECCS piping/ component flow area exce~s the maximum dimenston of the debris partides. Therefore, clogging is not considered credible.
Wear Rate and Component E\\laluaUon Au,clllary Equipment Evaluation Plants as endorsed by RG 1.100, "Seismic Qualification of Electrical and Active Mechanical Equipment and Functional Qualification of Active Mechanical Equipment for Nudear Power Plants," Revision 3, September 2009.
Page 102 of 1051
Component ID N22 Feedwater System FOOS N22 Feedwater System F003 N22 Feedwater System X-12B N22 Feedwater System F004B Component Check Valve (Air Testable)
Check Valve !Air Testable)
Penetr;ition Ched<Valve
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Fh.dd Velocity thn, Component System OescripUons and Mittion Time
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Debris lnt:estlon Model The ECCS piping/ component flow area exceeds the maximum dimension of the debris partides. Therefore, cloning is not considered credible.
The ECCS piping/ component flow area exceeds the maximum dimension of the debris particles. Therefore, clogging is not considered credible.
The ECCS piping / component flow aru exceeds the maximum dimension of the debris particles. Therefore, clogginc is not considered credible.
The ECCS piping / component flow area exceeds the maximum dimension of the debris partides. Therefore, clogging is not considered credible.
Wear Rate and Component Evaluation AuxlllaryEquipment Evaluation Page 103 of 105 1
Component Component ID N22 Manual Block Feedwilter Valve System FOOSB Reactor Feedwater Internals Spar1ers (Reactor Pressure Vessel 811]
Ructor Reactor Assembty Internals
{Reactor Pressure Vessel 811]
JU Fuel Assembly
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Debris ln,estlon Model Wear Rate *nd Component Au,clllary Equipment Evaluation EvaluaUon The ECCS pipin& / component flow are.i exceeds the maximum dimension of the debris partides. Therefore, cloggin& is not considered credible.
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The diameter of the feedwatu sparau nozzle eKceeds the maximum dimenston (lengt h, width and/ or thickness) of non*
deformable particulates that may pass through the strainer. Therefore, fouling of this component due to debris downstream the ECC5 suction strainer is not credible.
The reactor vessel ffow area orifices u:ceeds the maximum dimension of the debris partides. Therefore, clogcing tS not considered credible.
Page 104 of 105 1
Component Component 10 GEH Public Mode of Operation Svstem / Component Flowrate NED0-33878 Revision 3 Non-Proprietary Information - Class I (Public}
Fklkt Vek>clty thru Component System Dflcriptlons and Minion Time
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Debris lna:esUon Model Wear Rate and Component Auxlllary Equipment Evaluation Evaluation Page 105 of 105 1