ML22027A808

Enclosure 3: Callaway, Unit 1, Methodology for a Risk-Informed Approach to Address Generic Letter 2004-02

ML22027A808
Person / Time
Site:	Callaway
Issue date:	01/27/2022
From:	Ameren Missouri, Union Electric Co
To:	Office of Nuclear Reactor Regulation
Shared Package
ML22027A804	List: ML22027A805 ML22027A806 ML22027A807 ML22027A808 ML22027A809 ULNRC-06690, Enclosure 5: Callaway, Unit 1, LAR Supplement to Address Audit Discussion Points Summarized in NRC Letter Dated September 14, 2021 (ML21238A138)
References
ULNRC-06690
Download: ML22027A808 (208)

Text

ULNRC-06690 Enclosure 3 Callaway Methodology for a Risk-Informed Approach to Address Generic Letter 2004-02 ATTACHMENTS:

3-1 Introduction 3-2 Deterministic Basis 3-3 Risk-Informed Basis 3-4 Defense-in-Depth and Safety Margin

ULNRC-06690 Enclosure 3, Attachment 3-1 Page 1 of 2 -1 Introduction

ULNRC-06690 Enclosure 3, Attachment 3-1 Page 2 of 2 This enclosure provides the Callaway methodology for a risk-informed approach to respond to Generic Letter (GL) 2004-02, as discussed in Staff Requirements Memorandum (SRM)-SECY-12-0093, "Closure Options for Generic Safety Issue - 191, Assessment of Debris Accumulation on Pressurized-Water Reactor Sump Performance". The risk-informed approach is intended to be applied to Callaway Nuclear Plant Unit 1.

In the Risk over Deterministic (RoverD) methodology, the effects of debris that are bounded by plant-specific testing are mitigated in accordance with NRC-accepted methodology for resolution of GL 2004-02. Breaks that are not bounded by plant-specific testing are conservatively assumed to result in core damage. RoverD addresses the effects on long-term cooling due to debris accumulation on the emergency core cooling system (ECCS) and containment spray system (CSS) sump strainers in recirculation mode as well as core flow blockage due to in-vessel effects of debris that penetrates the strainers. A full spectrum of postulated loss-of-coolant accidents (LOCA) is analyzed, including double-ended guillotine breaks for all pipe sizes up to the largest pipe in the reactor coolant system. The changes to core damage frequency and large early release frequency associated with GL 2004-02 concerns are quantified by applying the LOCA frequencies published in NUREG-1829, and then compared to Regulatory Guide (RG) 1.174 acceptance guidelines. The results quantified in Section 7 of Enclosure 3-3, in combination with the defense-in-depth and safety margin described in Enclosure 3-4, meet the criteria of RG 1.174 for considering the risk from effects of LOCA debris to be in Region III (very small) and that no additional plant modification is required to close GL 2004-02 for Callaway. A detailed description of the RoverD methodology is presented in Enclosure 3-3 of this submittal.

The licensing basis with regard to effects of debris is that there is a high probability that the effects of LOCA debris will be mitigated based on successful plant-specific prototypical testing, and analyses that show that the risk from breaks that could generate debris that is not bounded by the testing is very small and acceptable in accordance with the criteria of RG 1.174.

The regulations require a deterministic analysis. Implementation of the licensing basis requires justification in accordance with 10 CFR 50.12 of exemptions to the relevant regulations; i.e. 10 CFR 50.46(a)(1), General Design Criteria (GDC) 35, GDC 38 and GDC 41. The exemptions are complemented by an amendment to the Callaway Unit 1 Operating License to allow for the change in analysis methodology per 10 CFR 50.59 and to change ECCS and CSS Technical Specifications.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 1 of 126 Attachment 3-2 Deterministic Basis -

Generic Letter 2004-02 Supplemental Response

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 2 of 126 Deterministic Basis - Generic Letter 2004-02 Supplemental Response

Subject:

Union Electric Companys (d.b.a. Ameren Missouri) approach to resolving issues described in Generic Letter (GL) 2004-02 is to use the guidance and requirements of NEI 04-07 (Reference [1]), industry guidance, industry and plant-specific tests, and the South Texas Project Pilot Plants use of Risk over Deterministic (RoverD) methodology to perform a comprehensive set of evaluations of the effects of design-basis accident conditions on the ability of structures, systems, and components, including the containment emergency sump strainers, to mitigate the consequences of the analyzed accidents and maintain long-term core cooling in a manner consistent with governing regulatory requirements listed in GL 2004-02. This Enclosure 3 provides the Callaway methodology for risk-informed approach and responds to GL 2004-02. All responses provided within this document supersede any responses that were previously submitted unless otherwise denoted.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 3 of 126 1 Overall Compliance Provide information requested in GL 2004-02 Requested Information Item 2(a) regarding compliance with regulations.

GL 2004-02 Requested Information Item 2(a)

Confirmation that the ECCS and CSS recirculation functions under debris loading conditions are or will be in compliance with the regulatory requirements listed in the Applicable Regulatory Requirements section of this GL. This submittal should address the configuration of the plant that will exist once all modifications required for regulatory compliance have been made and this licensing basis has been updated to reflect the results of the analysis described above.

Response

This submittal by Ameren Missouri proposes a change associated in methodology to use a risk-informed approach to determine the design requirements to address the effects of loss-of-coolant accident (LOCA) debris instead of a traditional deterministic approach. The details of the risk-informed approach are provided in Attachment 3-3.

The debris analysis (which includes coatings, insulation and other debris) covers a full spectrum of postulated LOCAs, including double-ended guillotine breaks (DEGB), for all pipe sizes up to and including the design basis accident (DBA) LOCA to provide assurance that the most severe postulated LOCAs are evaluated. While a deterministic licensing basis will continue to apply to LOCA break sizes that generate debris that is bounded by Callaway plant-specific testing, Callaway conservatively relegates to failure the LOCA break sizes that can generate and transport debris not bounded by the Callaway plant-specific testing and applies the risk-informed methodology. Callaway's RoverD methodology applies NUREG-1829 to determine the break frequency for the smallest breaks that fail to obtain the highest frequency, and uses that frequency as the change in core damage frequency (CDF) for comparison to the criteria in Regulatory Guide (RG) 1.174. The results of the evaluation show that the risk from the proposed change is "very small" in that it is in Region III of RG 1.174. The methodology includes conservatisms in the plant-specific testing and in the assumption that all the unbounded breaks are relegated to failure.

Callaway's risk-informed approach to the effects of LOCA debris replaces the existing deterministic approach described in Callaways licensing basis and consequently requires an amendment to the Callaway Unit 1 Operating License to incorporate the revised methodology per the requirements of 10 CFR 50.90. This proposed amendment to the Operating License is described in Enclosure 2. The proposed methodology changes to implement and replace the current deterministic methodology with a risk-informed methodology also require changes to the descriptions of how

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 4 of 126 Callaway meets 10 CFR 50.46(a)(1), GDC 35, GDC 38 and GDC 41. Those changes require exemptions to certain requirements of 10 CFR 50.46(a)(1), GDC 35, GDC 38 and GDC 41, and the requests for the exemptions are provided in Attachments 1-1 through 1-4 of this submittal.

In addition, Ameren Missouri proposes to amend the Callaway Unit 1 Operating License to revise the Technical Specifications (TS) for the ECCS and containment spray system (CSS). The changes proposed for these TS would delete Surveillance Requirement (SR) 3.5.2.8 in TS 3.5.2, "ECCS - Operating," and delete its mention from SR 3.5.3.1 in TS 3.5.3, "ECCS - Shutdown," add TS 3.6.8, "Containment Recirculation Sumps," and clarify TS 5.5.15, "Safety Function Determination Program." The proposed TS changes will align the TS with the risk-informed methodology change and follow the TSTF-567 Model. The proposed actions are based on the amount of debris tested in the Callaway plant-specific testing so that the determination of operability is performed without needing a risk assessment, which makes the process consistent with NRC guidance on operability determinations. The License Amendment Request (LAR) for the changes to the TS is provided in Enclosure 2.

Ameren Missouri previously replaced the sump screens in Callaway Unit 1 with substantially larger and physically more robust strainers; therefore, there are no physical modifications needed or planned in support of this application.

When implemented, the licensing basis with regard to effects of debris is that there is an acceptably high probability that the effects of LOCA debris will be mitigated based on successful plant-specific prototypical testing using deterministic assumptions, and analyses that show that the risk from breaks that could generate debris that is not bounded by the testing is very small and acceptable in accordance with the criteria of RG 1.174.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 5 of 126 2 General Description of and Schedule for Corrective Actions Provide a general description of actions taken or planned, and dates for each. For actions planned beyond December 31, 2007, reference approved extension requests or explain how regulatory requirements will be met as per Requested Information Item 2(b). (Note: All requests for extension should be submitted to the NRC as soon as the need becomes clear, preferably not later than October 1, 2007.)

GL 2004-02 Requested Information Item 2(b)

A general description of and implementation schedule for all corrective actions, including any plant modifications, that you identified while responding to this GL.

Efforts to implement the identified actions should be initiated no later than the first refueling outage starting after April 1, 2006. All actions should be completed by December 31, 2007. Provide justification for not implementing the identified actions during the first refueling outage starting after April 1, 2006. If all corrective actions will not be completed by December 31, 2007, describe how the regulatory requirements discussed in the Applicable Regulatory Requirements section will be met until the corrective actions are completed.

The information in this section supplements information previously provided by Ameren Missouri in response to GL 2004-02, section 2, Requested Information Item 2(b)

(Reference [2]). This response now introduces testing completed in 2016 which replaces 2008 testing meant to support assumptions and corresponding conclusions contained in the earlier GL 2004-02 response.

Response

Other than the implementation of the proposed changes to the TS and Final Safety Analysis Report (FSAR) associated with the LAR included in this application, Ameren Missouri does not anticipate implementation of any additional modifications to Callaway Unit 1 in response to GL 2004-02 based on the data collected and analysis performed to date.

This response supplements the plant modifications described in this response in the previous submittal (Reference [2]).

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 6 of 126 3 Specific Information Regarding Methodology for Demonstrating Compliance Specific information regarding methodology is necessarily two-fold: deterministic and risk-informed. Compliance is demonstrated using 2016 deterministic testing results with further risk-informed RoverD analysis.

3.a. Break Selection The objective of the break selection process is to identify the break size and location that present the greatest challenge to post-accident sump performance.

1. Describe and provide the basis for the break selection criteria used in the evaluation.

2. State whether secondary line breaks were considered in the evaluation (e.g.,

main steam and feedwater lines) and briefly explain why or why not.

3. Discuss the basis for reaching the conclusion that the break size(s) and locations chosen present the greatest challenge to post-accident sump performance.

Response to 3.a.1. Describe and provide the basis for the break selection criteria used in the evaluation:

A wide range of hypothetical pipe break (location and size) cases at Callaway were evaluated. The risk assessment utilized Containment Accident Stochastic Analysis GSI Resolution and Evaluation (CASA Grande) software over a wide range of potential break sizes and break locations in conjunction with the Callaway CAD model to determine bounding accident scenarios that may pose a threat to plant operation in the event of a DBA. Debris sources that are not break-dependent, such as latent debris and unqualified coatings debris, were also evaluated.

CASA Grande automates zone of influence (ZOI) debris generation and analyzes each weld location for DEGB spherical ZOI destruction, as well as partial-break hemispherical ZOI destruction. Fiber debris generation at each location and for each break size is found with the convergence criteria discussed in Attachment 3-3.

Since all Class 1 weld locations are analyzed for various break sizes there is no need for break selection criteria. Note that secondary line breaks, spurious and stuck-open pilot-operated relief valves, and pump seal LOCAs were also assessed.

Response to 3.a.2. State whether secondary line breaks were considered in the evaluation (e.g., main steam and feedwater lines) and briefly explain why or why not:

Secondary line breaks (large main steam and feedwater line breaks) were considered as secondary risk contributors. Refer to the responses to Questions 34 and 35 in Enclosure 5 for additional information regarding secondary risk contributor screening.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 7 of 126 Based on the screening results, there is no contribution to CDF/LERF associated with GL 2004-02 phenomena from secondary line breaks Response to 3.a.3. Discuss the basis for reaching the conclusion that the break size(s) and locations chosen present the greatest challenge to post-accident sump performance:

Because the CASA Grande computational debris generation modules analyze each Class 1 weld location for varying break sizes, all locations that present a challenge to post-accident sump performance are evaluated. Discussion of the CASA Grande results is provided in Attachment 3-3.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 8 of 126 3.b. Debris Generation/Zone of Influence (ZOI) (Excluding Coatings)

The objective of the debris generation/ZOI process is to determine, for each postulated break location: (1) the zone within which the break jet forces would be sufficient to damage materials and create debris; and (2) the amount of debris generated by the break jet forces.

1. Describe the methodology used to determine the ZOIs for generating debris.

Identify which debris analyses used approved methodology default values. For debris with ZOIs not defined in the guidance report/SE, or if using other than default values, discuss method(s) used to determine ZOI and the basis for each.

2. Provide destruction ZOIs and the basis for the ZOIs for each applicable debris constituent.

3. Identify if destruction testing was conducted to determine ZOIs. If such testing has not been previously submitted to the NRC for review or information, describe the test procedure and results with reference to the test report(s).

4. Provide the quantity of each debris type generated for each break location evaluated. If more than four break locations were evaluated, provide data only for the four most limiting locations.

5. Provide total surface area of all signs, placards, tags, tape, and similar miscellaneous materials in containment.

The information in this section revises information previously provided by Ameren Missouri to GL 2004-02, section 3.b. (Reference [2]).

Response to 3.b.1. Describe the methodology used to determine the ZOIs for generating debris. Identify which debris analyses used approved methodology default values. For debris with ZOIs not defined in the guidance report/SE, or if using other than default values, discuss method(s) used to determine ZOI and the basis for each:

The methodologies used by Callaway to determine debris generation ZOls are:

1. For NUKON and Thermal-Wrap, Callaway implemented ZOIs consistent with the risk-informed, pilot plant. Proprietary report ALION-REP-ALION-2806-01, Insulation Debris Size Distribution for use in GSI-191 Resolution, (Reference

[4]) provides a refined methodology to NEI 04-07 for calculating the distribution of NUKON and Thermal-Wrap debris sizes within the ranges of spherical ZOI volumes. Pressure values within an expanding jet decrease as the fluid travels away from the break point. The debris size distribution of destroyed insulation resulting from jet impingement is dependent on jet pressure and is therefore different at increased distances from the break location. The distances are classified in sub-zones that were determined using air jet impact test data (Reference [4]), with conservatism added to account for the potentially higher

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 9 of 126 level of destruction from a two-phase jet. Alion report 2806-01 (Reference [4])

shows that within the overall ZOI, the size distribution would vary based on the distance of the insulation from the break, and insulation debris generated near the break location would consist of more small pieces than would insulation debris generated near the edge of the ZOI.

2. Min-K insulation installed within the reactor cavity at Callaway cannot be destroyed from a HELB. The location of the Min-K panels is such that it cannot be impacted by HELB jets. As stated in staff comments (Reference [5]), The NRC staff agrees that the test results only apply to Callaway and Wolf Creek Nuclear Plants and that these plants have performed plant-specific evaluations to determine that the Min-K panels cannot be impacted by the jet based on the insulation panel locations in the plant.

3. Alphamat D blankets are installed at Callaway on the top of the reactor vessel similar to the location of Min-K insulation. These blankets are employed for high heat thermal protection within Callaway and a total quantity of 43.84 ft3 was measured from plant drawings. Since Alphamat D is in a similar location to Min-K, Alphamat D cannot be destroyed from a HELB. Therefore, failure of Alphamat D blankets is not considered.

4. FOAMGLAS is located on the steam generator blowdown system and Residual Heat Removal (RHR) system. FOAMGLAS was discovered in containment in the summer of 2019 and is not evaluated for debris generation. Approximately 146 ft3 or 1167 lbm of FOAMGLAS are in containment. In the analysis documented in this LAR, low density fiber glass (LDFG) is modeled at the location of FOAMGLAS. This results in an over prediction of destroyed LDFG and risk, but an under prediction of destroyed particulate at break locations that have the potential to destroy FOAMGLAS.

5. Transco RMI is used in containment as equipment insulation on the steam generators. Mirror RMI is used on the reactor pressure vessel head and reactor coolant system (RCS) on both the hot leg and cold leg piping. Both types of RMI are composed of stainless steel. ZOIs implemented for these types of RMI adhere to guidance in the NEI 04-07 Volume 2.

Response to 3.b.2. Provide destruction ZOIs and the basis for the ZOIs for each applicable debris constituent:

Destruction ZOI is defined as the volume about the break in which the jet pressure is greater than or equal to the destruction damage pressure of the insulation, coatings, and other materials impacted by the break jet. The size of the ZOI is defined in terms of pipe diameters of the piping assumed to break. The ZOI is defined as a

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 10 of 126 spherical volume centered at the assumed piping break. Table 3.b-1 describes the destruction pressures and associated ZOI radii used in the evaluation of impacted Callaway materials.

Table 3.b-1: Destruction Pressure and ZOI Radii for Potential Debris Sources Destruction Material Pressure ZOI Reference (psig)

NEI 04-07, Vol. 2 SE RMI-Mirror (with std. bands) 2.4 28.6 Table 3.2 NEI 04-07, Vol. 2 SE Transco RMI 114 2.0 Table 3.2 Jacketed NUKON ALION-REP-ALION-6 17.0 (with std. bands)* 2806-01 [4]

ALION-REP-ALION-Thermal-Wrap* 6 17.0 2806-01 [4]

Min-K N/A** N/A** Site-specific testing [6, 5]

AlphaMat D N/A** N/A** Site-specific testing [6, 5]

• Debris constituents and subshell ZOIs are not provided because this is proprietary information

• • Encapsulated Min-K insulation is located near the reactor vessel and cannot be impacted by a ZOI (Reference [6, 5]). The same reactor vessel geometry that prevents Min-K insulation from being hit by HELB jet also applies to the Alpha D blankets installed in the same location.

Response to 3.b.3. Identify if destruction testing was conducted to determine ZOIs. If such testing has not been previously submitted to the NRC for review or information, describe the test procedure and results with reference to the test report(s):

Plant-specific destruction testing was conducted for Min-K. Min-K insulation installed within the reactor cavity at Callaway cannot be destroyed from a HELB.

The location of the Min-K panels is such that it cannot be impacted by HELB jets.

As stated in staff comments (Reference [5]), The NRC staff agrees that the test results only apply to Callaway and Wolf Creek Nuclear Plants and that these plants have performed plant-specific evaluations to determine that the Min-K panels cannot be impacted by the jet based on the insulation panel locations in the plant.

Plant-specific destruction tests that had been performed for jacketed NUKON blankets as described in the previous submittal (Reference [2]) were not used to determine ZOIs. Destruction tests were not conducted for any other insulation to

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 11 of 126 determine ZOIs. All ZOIs implemented, including Min-K, were previously reviewed by the NRC.

Response to 3.b.4. Provide the quantity of each debris type generated for each break location evaluated. If more than four break locations were evaluated, provide data only for the four most limiting locations:

CASA Grande postulates DEGB and multiple partial breaks at all ASME Class 1 and ISI weld locations, while also accounting for the weld break frequencies. DEGB and partial breaks are postulated at 704 locations. Table 3.b-2 shows the quantity of each debris type generated for the four most limiting locations.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 12 of 126 Table 3.b-2: Maximum Insulation Debris Generated within the ZOI Weld Weld 2-BB- EBB01D- Weld 2-BB-01-3065D- RSG- 01-3065A-WC-001- INLET- Weld 2-BB- WDC-001-Insulation FW1 SC010 01-S402-2 FW1 LDFG - Fine Pieces, lbm 243 243 241 241 LDFG - Small Pieces, lbm 811 809 809 843 LDFG - Large Pieces, lbm 374 374 374 325 LDFG - Intact Blankets, lbm 401 401 400 347 RMI - Small Pieces, lbm 48 49 28 49 RMI - Large Pieces, lbm 16 16 10 16 Min-K, lbm 0 0 0 0 Qualified Epoxy, lbm 23 21 53 6 Qualified IOZ, lbm 992 991 989 1000 Degraded Qualified, Fine, lbm 129 129 129 129 Degraded Qualified, Small Chip, lbm 25 25 25 25 Degraded Qualified, Large Chip, lbm 53 53 53 53 Degrade Qualified, Curled Chip, lbm 53 53 53 53 Rust, lbm 0 0 0 0 Unqualified Acrylic, lbm 31 31 31 31 Unqualified Alkyd, lbm 95 95 95 95 Unqualified Epoxy, lbm 2016 2016 2016 2016 Unqualified IOZ, lbm 2024 2024 2024 2024 Unqualified Varnish, lbm 18 18 18 18 Latent Particulate, lbm 170 170 170 170 Latent Fiber, lbm 30 30 30 30 Physical Fiber Margin, lbm 50 50 50 50 Response to 3.b.5. Provide total surface area of all signs, placards, tags, tape, and similar miscellaneous materials in containment:

As shown in Table 3.b-3, the surface area for miscellaneous debris, consisting of signs / placards or equipment identification tags, labels and tape that remain in containment during power operation is 330.2 ft2. To provide assurance that these miscellaneous debris quantities are not exceeded, walkdowns are conducted prior to the end of each refuel outage to ensure that unqualified temporary signs / placards

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 13 of 126 are removed, and plant procedures require that new or replacement equipment identification tags or labels installed in containment to approved types that have been qualified as not contributing to transportable debris in the containment postaccident environment.

In addition to the metal equipment tags listed in Table 3b-3, a limited quantity of 3-in by 6-in EPRI radiological stainless steel tags are also in containment. These metal equipment and survey location tags were demonstrated to be nontransportable during 2016 testing.

Actions taken to mitigate the possibility of materials being inadvertently left behind in containment during maintenance are summarized in the responses to 3.i.1 and 3.i.2.

Table 3b-3. Miscellaneous Debris Area Debris Type Unit Area Unit Total Area (in2) Quantity (ft2)

Tape 2" x 4" 45 2.5 Tape 2" x 10" 5 0.7 Fasteners 0.5" x 2" 90 0.6 Fasteners 1" x 5" 10 0.3 Personnel Protective 2" x 2" 50 1.4 Equipment Metal Equipment Tags 3" x 5" 2363 246.1 (ZOI)

Bakelite Equipment 2.5" x 1" 225 3.9 Tags (ZOI)

Taped Equipment 2" x 7" 656 63.8 Labels (ZOI)

Bakelite Equipment 2.5" x 1" 625 10.9 Tags (outside ZOI)

Total 330.2

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 14 of 126 3.c. Debris Characteristics The objective of the debris characteristics determination process is to establish a conservative debris characteristics profile for use in determining the transportability of debris and its contribution to head loss.

1. Provide the assumed size distribution for each type of debris.

2. Provide bulk densities (i.e., including voids between the fibers/particles) and material densities (i.e., the density of the microscopic fibers/particles themselves) for fibrous and particulate debris.

3. Provide assumed specific surface areas for fibrous and particulate debris.

4. Provide the technical basis for any debris characterization assumptions that deviate from NRC-approved guidance.

The debris characteristics determination process generally conforms, with some exceptions described below, to Sections 3.4.3 of NEI 04-07, Vol. 2 SE (Reference [1]).

The debris sources for Callaway include insulation, coatings, and latent debris. The insulation debris types discussed here include Alphamat D, Min-K, NUKON, Thermal-Wrap, stainless steel RMI, and FOAMGLAS. Due to their location in containment, Min-K and Alphamat D insulation cannot be destroyed by a break jet, and are excluded from discussion. NUKON and Thermal-Wrap are located on various piping and equipment throughout containment. RMI is located on the steam generators, reactor vessel, and in the reactor bioshield penetrations on the hot and cold legs. A small quantity of FOAMGLAS is located on portions of the steam generator blowdown system and RHR system. FOAMGLAS was discovered in the summer of 2019 and was not explicitly analyzed. As noted in the response to 3.b.1, LDFG is modeled at the location of FOAMGLAS. This results in an over prediction of destroyed LDFG and risk, but an under prediction of destroyed particulate at break locations that have the potential to destroy FOAMGLAS.

Response to 3.c.1. Provide the assumed size distribution for each type of debris:

Fiber Debris A four category size distribution assigned for LDFG is used in debris generation and transport analyses. The size distributions for debris inside the ZOI or a postulated break are taken from proprietary Alion Science and Technologys internal debris size calculation (Reference [4]). These sizes are based on the air jet impact test information presented in Appendix VI of the NEI 04-07 Vol. 2 SE (Reference [1]).

Note, the Alion LDFG debris size distributions were reviewed and found acceptable by the NRC in deterministic resolutions, such as the Indian Point Energy Center

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 15 of 126 Corrective Actions for Generic Letter 2004-02 (ML082050433) document (Reference [7]) and the risk-informed pilot plant.

Due to the location in containment, Min-K insulation cannot be destroyed by a break jet, and are thus excluded from this discussion (Reference [5]). Alphamat D is in a similar location to Min-K. Therefore, Alphamat D insulation cannot be destroyed by a break jet, and are thus excluded from this discussion.

Non-Fiber Debris Based on Table 3-3 of NEI 04-07 Vol. 2 (Reference [1]), all types of RMI within a ZOI are expected to fail as 75% small pieces and 25% large pieces. Small pieces are defined as any RMI debris less than 4 inches on one side. The size of 4 inches represents a conservative upper bound of an RMI debris size that would still pass through gratings, trash racks, or radiological protection barriers by blowdown, containment sprays (CS), or post-accident pool flows (Reference [1]). A 2.0D ZOI is used for quantifying Transco RMI debris and a 28.6D ZOI is used to quantify Mirror RMI debris as no destruction testing is applicable to this insulation type.

However, RMI debris has an insignificant head loss influence in fiber and particulate mixed debris beds, which are expected for Callaway, and was found to reduce head loss under certain circumstances (Reference [8]). The assumption is, the inclusion of RMI in the debris mixture for head-loss tests could potentially result in a non-conservative head loss because RMI may disrupt the formation of a contiguous fibrous debris bed (Reference [8]).

Response to 3.c.2. Provide bulk densities (i.e., including voids between the fibers/particles) and material densities (i.e., the density of the microscopic fibers/particles themselves) for fibrous and particulate debris:

Table 3.c-1 shows the debris material, bulk densities and material densities for fibrous debris other than latent debris. The values were obtained from NEI 04-07, Vol. 1 Guidance Report (GR) Table 3-2, which has been recognized by NEI 04-07, Vol. 2 SE, section 3.4.3.6 (Reference [1]), and are discussed further below.

Table 3.c-1: Fibrous Debris Characteristics As-Fabricated Material Debris Material Density (lb/ft3) Density (lb/ft3)

NUKON 2.4 159 Thermal-Wrap 2.4 159 Table 3.c-2 shows the debris material, bulk density, material density and characteristic diameter for particulate debris (other than latent debris).

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 16 of 126 Characteristics associated with coatings particulate debris are discussed further in response to 3.h. Coatings Evaluation.

Table 3.c-2: RMI Debris Characteristics As-Fabricated Material Characteristic Debris Material Density (lb/ft3) Density (lb/ft3) Diameter (µm)

RMI 10 484 16.5 Response to 3.c.3. Provide assumed specific surface areas for fibrous and particulate debris:

Head loss across the installed recirculation strainers was determined via testing; thus, no surface area assumption was required. Therefore, these values are not provided as part of this response.

Response to 3.c.4. Provide the technical basis for any debris characterization assumptions that deviate from NRC-approved guidance:

The debris characteristics assumptions are consistent with NEI 04-07, Vol. 2 SE.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 17 of 126 3.d. Latent Debris The objective of the latent debris evaluation process is to provide a reasonable approximation of the amount and types of latent debris existing within the containment and its potential impact on sump screen head loss.

1. Provide the methodology used to estimate quantity and composition of latent debris.

2. Provide the basis for assumptions used in the evaluation.

3. Provide results of the latent debris evaluation, including amount of latent debris types and physical data for latent debris as requested for other debris under c.

above.

4. Provide amount of sacrificial strainer surface area allotted to miscellaneous latent debris.

The latent debris evaluation process described continues to conform to sections 3.5 and 4.2.2.2 of NEI 04-07, Vol. 2 SE (Reference [1]). The documented amount of latent debris in the containment building from the baseline survey was estimated to be less than 70 lb. The value of 200 lb of latent debris was used for additional conservatism.

Response to 3.d.1. Provide the methodology used to estimate quantity and composition of latent debris:

The latent debris methodology for computational failure analysis contribution to RoverD is consistent with sections 3.5 and 4.2.2.2 of NEI 04-07, Vol. 2 SE (Reference [1]): 200 lb of latent debris of which 85% was assumed to be particulate, the other 15% was assumed to be fiber. The fiber quantity used in the computational failure analysis for RoverD was 30 Ib (12.5 ft3), a bulk density of 2.4 Ib/ft3, a material density of 94 lb/ft3, and a characteristic length of 5.5 µm.

Response to 3.d.2. Provide the basis for assumptions used in the evaluation:

Representative sampling methodology, latent debris mixture, and characteristics assumptions are consistent with sections 3.5.2.2 and 3.5.2.3 of NEI 04-07, Vol. 2 SE (Reference [1]).

Response to 3.d.3. Provide results of the latent debris evaluation, including amount of latent debris types and physical data for latent debris as requested for other debris under c. above:

3.d.3a Results of Latent Debris Evaluation:

The Containment Latent Debris Sampling Plan was implemented at Callaway for the first time during Refueling Outage XIV in October 2005. Its purpose was to obtain a baseline amount of latent debris existing in the containment building. The results

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 18 of 126 indicated that approximately 60 lb of latent debris was present in the containment building.

Since Refueling Outage XIV was a steam generator (SG) replacement outage, the latent debris sampling was repeated for Refueling Outage XV in March 2007. The results indicated that approximately 44 lb of latent debris was present in the containment building.

For analysis purposes, latent debris amount in containment was increased from the results observed in Refueling Outage XIV and XV to 200 lb in the analysis to provide additional margin for the containment latent debris assessment program. A distribution of 85% dirt/dust and 15% fibers is assumed, consistent with section 3.5.2.3 NEI 04-07, Vol. 2 SE (Reference [1]). The debris distribution used for this baseline analysis, therefore, was 170 lb dirt/dust and 30 lb latent fiber.

3.d.3b Fibrous and Particulate Latent Debris Characteristics:

Table 3.d-1 shows the bulk density, material density and characteristic diameter for fibrous latent debris. These values are consistent with section 3.5.2.3 of the NEI 04-07, Vol. 2 SE (Reference [1]).

Table 3.d-1: Fibrous Material Characteristics for Latent Debris As-Fabricated Material Characteristic Debris Material Density (Ib/ft3) Density (Ib/ft3) Diameter (µm)

Latent Fiber 2.4 94 5.5 Table 3.d-2 shows the solid density and characteristic diameter for particulate.

These values are consistent with section 3.5.2.3 of the NEI 04-07, Vol. 2 SE (Reference [1]).

Table 3.d-2: Particulate Characteristics for Latent Debris Microscopic Characteristic Debris Material Density (Ib/ft3) Diameter (µm)

Latent Particulate (dirt/dust) 169 17.3 Response to 3.d.4. Provide amount of sacrificial strainer surface area allotted to miscellaneous latent debris:

For 2016 testing, a sacrificial area reduction of 150 ft2 was removed from the strainer. Applying an overlap of 25% results in 200 ft2 of miscellaneous debris in containment.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 19 of 126 3.e. Debris Transport The objective of the debris transport evaluation process is to estimate the fraction of debris that would be transported from debris sources within containment to the sump suction strainers.

1. Describe the methodology used to analyze debris transport during the blowdown, washdown, pool-fill-up, and recirculation phases of an accident.

2. Provide the technical basis for assumptions and methods used in the analysis that deviate from the approved guidance.

3. Identify any computational fluid dynamics codes used to compute debris transport fractions during recirculation and summarize the methodology, modeling assumptions, and results.

4. Provide a summary of, and supporting basis for, any credit taken for debris interceptors.

5. State whether fine debris was assumed to settle and provide basis for any settling credited.

6. Provide the calculated debris transport fractions and the total quantities of each type of debris transported to the strainers.

This content is written to support the applicability of the computational analysis done to provide generated debris quantities at each weld location to the RoverD methodology.

Response to 3.e.1. Describe the methodology used to analyze debris transport during the blowdown, washdown, pool-fill-up, and recirculation phases of an accident:

The methodology employed for the debris transport calculation is primarily based on the analyses presented in NEI 04-07 Vol. 1 GR (Reference [1]), the corresponding NEI 04-07 Vol. 2 SE (Reference [1]), and the risk-informed pilot-plant. Complete details of the debris transport analysis are presented in Ref. [9]

Blowdown Phase Transport - Implemented the methodology of the risk-informed pilot-plant where:

• Fine debris used volume fractions to estimate the mass of fine debris in upper containment and lower containment. (Degraded qualified coatings, latent debris, or unqualified coatings were not analyzed for the blowdown phase.)

• Minimum credits from the Drywell Debris Transport Study (DDTS) were applied where appropriate for fiber retention on wetted surfaces in congested flow paths.

• Three volumes identified for break locations and expansion into upper containment, including the annulus, steam generator compartments, and the pressurizer compartment.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 20 of 126 Washdown Phase Transport - Describes transport of debris carried by water flowing from higher containment elevations down to the pool; specifically by containment sprays initiated after a medium or large-break LOCA. The following assumptions apply to Washdown-Phase Transport:

• Upper containment spray is designed to be relatively uniform across the entire circular containment cross section, so spray interception by concrete and by equipment is assumed to occur in proportion to relative plan-view area.

• Cascading spill paths lead to 55% of spray flow entering the pool in the annulus, 25% of spray flow entering the pool through the refueling canal drains and the in-core tunnel, and 20% of spray flow entering the pool inside the secondary shield wall.

• Grating retention credits from the DDTS are applied consistent with guidance.

Pool Fill-Up Phase Transport - The transport of debris at the pool level due to break flow and CSS flow from the RWST. The areas below the containment floor elevation that fill up with the water/debris mixture and then remain stagnant for the remainder of the analyzed accident are referred to as inactive areas of the pool. Other areas of the pool are referred to as active areas. The following assumptions are applied to Pool Fill-Up Phase Transport:

• Small and large pieces of LDFG are not allowed to transport to inactive cavities during pool fill, leaving more debris available for transport during recirculation.

• No credit was taken for potential debris accumulation in the reactor cavity or in the in-core tunnel, leaving more debris available for transport in the pool.

• No debris transport to inactive cavities allowed until a pool height of 6 inches is reached, equivalent to the curb height circumscribing the emergency sumps.

Recirculation Phase Transport - Debris motion during active ECCS recirculation is based on Flow-3D simulations as described in response to 3.e.3 below using the following assumptions:

• Constant pool temperature held at peak of 271.74°F.

• Sprays injected at pool surface as mass sources with velocity determined by fall height.

• Settling velocity of fine particulates determined by Stokes Law, which provides very little credit for settling in a turbulent pool.

• No consideration of RMI debris, because of minimal head loss effect compared to dominant fiber and particulate and because RMI can increase bed porosity and reduce head loss.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 21 of 126

• No transport of intact fiber blankets because they cannot pass through gratings, can be captured on equipment and piping, sink when water saturated, and require very high pool velocities for transport.

• All fine fiber, coatings particulate, and latent debris in the pool at start of recirculation are assumed to be uniformly distributed.

• Transport fractions in pool determined for each debris type by identifying all computational cells that exceed the debris criteria for either tumbling velocity or TKE resuspension.

Response to 3.e.2. Provide the technical basis for assumptions and methods used in the analysis that deviate from the approved guidance:

Debris erosion of LDFG is the only area where debris transport analysis deviates from deterministic regulatory guidance. Methods implemented by the risk-informed pilot plant are applied. For debris in the containment pool 30-day erosion tests result in a 10% erosion fraction. For debris on gratings application of the DDT erosion tests result in a 1% erosion fraction.

Response to 3.e.3. Identify any computational fluid dynamics codes used to compute debris transport fractions during recirculation and summarize the methodology, modeling assumptions, and results:

Flow-3D Version 9.3 with the vendor's modified subroutine was the computational fluid dynamic (CFD) software used to compute recirculation transport fractions. The subroutine modification to the standard Flow-3D code was to enable the introduction of CS at the appropriate source locations, flow rates, and velocities. Transport of debris was determined based on local flow velocities and incipient tumbling velocities of debris types given in NEI 04-07. All fine debris (LDFG fines, all unqualified coatings, all qualified coatings, degraded qualified fines, and all latent debris) have a recirculation transport fraction of 100%. See response to 3.e.6 for transport results of other debris size distributions.

Response to 3.e.4. Provide a summary of, and supporting basis for, any credit taken for debris interceptors:

While Callaway does not have debris interceptors, debris barriers have been installed in all openings through the secondary shield wall near the emergency recirculation sumps. The barriers are made of perforated plate with 1/8th-inch-diameter holes. The capture of debris by the barriers is not considered because plant-specific test data is required for this credit.

Even though debris barriers were not credited for capture of debris, the CFD model accounts for presence of debris barriers. If debris barriers remain relatively clean

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 22 of 126 during recirculation, these doorways will provide the most direct flow path for water inside the secondary shield wall to the strainers. However, if a debris bed forms on the barriers such that flow through the perforated plate is significantly impeded, more fluid will be diverted through the doorways on the North side of the secondary shield wall, which could substantially change flow field and turbulent kinetic energy (TKE) distributions, and by extension, the recirculation transport fractions. To address this uncertainty, undocumented sensitivity cases were conducted with the door barriers modeled as fully porous and as solid barriers that are impenetrable to fluid flow. An inspection of the results for the sensitivities showed greater transport fractions for solid barriers, so the barriers were assumed to be solid in all CFD simulations. To reiterate, debris barriers were assumed to be completely blocked, which resulted in the largest transport fractions, without the debris barriers reducing the inventory of debris available to transport. These assumptions are non-physical but result in the largest transport fractions.

Response to 3.e.5. State whether fine debris was assumed to settle and provide basis for any settling credited:

Fine LDFG, fine (or all) unqualified coatings, fine (or all) qualified coatings, fine degraded qualified coatings, and fine (or all) latent debris have a recirculation transport fraction of 100% and thus do not settle.

Response to 3.e.6. Provide the calculated debris transport fractions and the total quantities of each type of debris transported to the strainers.

For transported fiber debris amounts and a complete description of the RoverD methodology, see Attachment 3-3. The overall transport fractions were determined by incorporating results from all phases of transport for each break location and are presented in Table 3.e.1.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 23 of 126 Table 3.e-1: Overall Transport Fractions Debris Transport Fraction Debris Type Debris Size Upper Lower Inside the Annulus Pressurizer Pressurizer Bioshield Compartment Compartment Fines 99% 99% 99% 99%

Small Pieces 70% 60% 68% 64%

(<6)

Large Pieces LDFG 66% 64% 0% 66%

(>6)

Fines Eroded 0% 1% 0% 0%

from Smalls*

Fines Eroded 3% 4% 0% 3%

from Larges*

Unqualified Coatings Fines 100% 100% 100% 100%

Qualified Coatings Fines 99% 99% 99% 99%

Fines 100% 100% 100% 100%

Flat Small Chips 0% 6% 0% 0%

Degraded (1/8- 1/2)

Qualified Flat Large Chips Coatings 0% 4% 0% 0%

(1/2-2 )

Curled Chips 100% 96% 100% 100%

(1/2-2)

Latent Debris Fines 96% 96% 96% 96%

• Fines eroded from small and large LDFG are transport fractions that are multiplied by the amount of the constituent generated to determine the mass that transports to the strainer. All debris that is eroded to a fine transports to the strainers at 100%.

The maximum transport fraction is applied to all break locations for RoverD analyses and is highlighted in Table 3.e.1. See Attachment 3-3 for more details.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 24 of 126 3.f. Head Loss and Vortexing The objectives of the head loss and vortexing evaluations are to calculate head loss across the sump strainer and to evaluate the susceptibility of the strainer to vortex formation.

1. Provide a schematic diagram of the ECCS and CSS.

2. Provide the minimum submergence of the strainer under small-break loss-of-coolant accident (SBLOCA) and large-break loss-of-coolant accident (LBLOCA) conditions.

3. Provide a summary of the methodology, assumptions and results of the vortexing evaluation. Provide bases for key assumptions.

4. Provide a summary of the methodology, assumptions, and results of prototypical head loss testing for the strainer, including chemical effects. Provide bases for key assumptions.

5. Address the ability of the design to accommodate the maximum volume of debris that is predicted to arrive at the screen.

6. Address the ability of the screen to resist the formation of a thin bed or to accommodate partial thin bed formation.

7. Provide the basis for the strainer design maximum head loss.

8. Describe significant margins and conservatisms used in the head loss and vortexing calculations.

9. Provide a summary of the methodology, assumptions, bases for the assumptions, and results for the clean strainer head loss calculation.

10. Provide a summary of the methodology, assumptions, bases for the assumptions, and results for the debris head loss analysis.

11. State whether the sump is partially submerged or vented (i.e., lacks a complete water seal over its entire surface) for any accident scenarios and describe what failure criteria in addition to loss of net positive suction head (NPSH) margin were applied to address potential inability to pass the required flow through the strainer.

12. State whether near-field settling was credited for the head-loss testing and, if so, provide a description of the scaling analysis used to justify near-field credit.

13. State whether temperature/viscosity was used to scale the results of the head loss tests to actual plant conditions. If scaling was used, provide the basis for concluding that boreholes or other differential-pressure induced effects did not affect the morphology of the test debris bed.

14. State whether containment accident pressure was credited in evaluating whether flashing would occur across the strainer surface, and if so, summarize the methodology used to determine the available containment pressure.

The head loss and vortexing evaluations are revised due to 2016 test evaluation which replaces 2008 testing meant to support assumptions and corresponding conclusions contained in the earlier GL 2004-02 response. The computation failure analysis of

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 25 of 126 RoverD does not include head loss calculations. Instead a pass or fail criteria for break-specific head loss is implemented by comparing to the amount of fiber added in the 2016 test. See Attachment 3-3 for a complete description of the RoverD methodology.

Response to 3.f.1. Provide a schematic diagram of the emergency core cooling system (ECCS) and containment spray systems (CSS):

Schematic diagrams of the ECCS and the CSS are provided in Figures 3.f-1 and 3.f-2. The highlighted flow paths in Figure 3.f-1 depicted possible flow paths associated with containment recirculation sump ECCS operation, but do not depict specific operating conditions. For example, hot-leg and cold-leg recirculation are not aligned at the same time.

Figure 3.f-1: Callaway Unit 1 ECCS Process Flow Diagram

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 26 of 126 Figure 3.f-2: Callaway Unit 1 CSS Process Flow Diagram Response to 3.f.2. Provide the minimum submergence of the strainer under small-break loss of coolant accident (SBLOCA) and large-break loss-of-coolant accident (LBLOCA) conditions:

For the large-break LOCA condition, the containment recirculation sump strainers are submerged with greater than 8 inches of water above the top of the strainers at the time of ECCS switchover to recirculation. For the small-break LOCA condition, the recirculation sump strainers are submerged with approximately 2 inches of water above the top of the strainers at the time of ECCS switchover to recirculation. Note that the minimum submergence occurs at ECCS switchover to recirculation.

Response to 3.f.3. Provide a summary of the methodology, assumptions and results of the vortexing evaluation. Provide bases for key assumptions:

At the conclusion of the full debris load (FDL) and thin bed (TB) head-loss tests, the water level was lowered to the minimum large-break LOCA condition of 8 inches to observe low submergence conditions. During the FDL head-loss test, vortexing was not observed. During the TB head-loss test, surface swirl and small dimples were

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 27 of 126 observed, but an air core did not form. Therefore, for a LBLOCA, air ingestion due to vortex formation is unlikely to occur.

Small-break LOCA conditions were not tested. The tested large-break LOCA conditions have a flow rate and submergence 6 times larger and 4 times larger, respectively, than small-break LOCA conditions. A comparative analysis of the change in Froude number between large-break and small-break LOCA conditions yields insights to whether a vortex is more or less likely to form than the tested large-break LOCA condition, and results in a Froude number reduction for small-break LOCA conditions. Theoretically, small-break LOCA conditions are less likely to form a vortex than the tested large-break LOCA conditions. Therefore, vortexing in a manner capable of entraining air are concluded to not occur for small-break LOCA.

Response to 3.f.4. Provide a summary of the methodology, assumptions, and results of prototypical head loss testing for the strainer, including chemical effects. Provide bases for key assumptions:

Summary Callaway contracted Alden Research Laboratory (Alden) to perform testing to assess head loss development across ECCS sump strainers, identical to those installed at Callaway, after a LOCA and identify the resulting limits on debris quantities that can be tolerated without exceeding the provided head loss acceptance criteria.

The head loss test sequence included two large scale tests - a FDL test and a TB test in support of Callaway closure of GL 2004-02. The FDL test was executed the week of June 20th of 2016. The TB test was executed the week of June 27th of 2016 with the NRC witnessing testing.

The FDL test introduced incremental quantities of conventional debris (fibrous debris mixed with corresponding particulates). The debris types were distributed evenly among all batches. The TB test examined whether the quantity of particulates in the FDL test would yield acceptable head loss results under conditions where the quantity of particulates builds a debris bed with relatively small quantity of fiber. For both tests, chemical debris was added to the test tank after all of the conventional debris was added. Prior to adding chemical debris, the debris bed was characterized by allowing head loss stabilization, and performing flow and temperature sweeps.

The test facility featured two prototypically sized and flow-controlled strainer stacks arranged one behind the other with respect to the direction of the approach flow as presented in Figure 3.f-3. The head loss test strainer was situated in the pit arrangement similar to the plant, without the 6-inch curb, and featured prototypical

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 28 of 126 gaps between adjacent strainer discs. The test facility was configured to promote complete and uniform debris transport to the test strainer. The head loss testing was performed with a clearance between the wall and the strainers similar to the distance between strainers instead of half that distance, which would represent the prototypical symmetry line between the strainer stacks. Nevertheless, the test environment did not permit excessive settling and allowed the strainer disks to be loaded with debris in a relatively uniform manner.

Figure 3.f-3: Picture of the Callaway Strainer Test Tank Both tests conducted did not exceed the allowable head loss margin as defined for the FDL and TB test.

Model Description For head loss testing, two plant vertical strainer stacks were used. Two strainer stacks represent approximately 11% (0.1103 scale factor [10]) of the installed strainer area of one Callaway strainer train after a sacrificial area reduction of 150 ft2 to account for miscellaneous debris. Strainer stacks were installed in a manner that maintains the flow-controlled nature of the plant strainer configuration. Each vertical stack contained one, 7-disk module on the bottom with three, 11-disk modules situated atop. The two vertical stacks were positioned one behind another with respect to the approach flow in a pit. The pit was configured to model the plant geometry. For the tests executed, bridging to the wall did not occur since the debris bed formed predominately between the disks and the debris layer that accumulated external to the strainer stacks did not reach 2 inches beyond the stacks. The increased gap did not cause significant settling in the perimeter around the strainer and the flow patterns generated allowed the strainer stack to load relatively evenly.

Furthermore, the 6-inch curb that surrounds the sumps in the plant was not modelled in the test to ensure that all of the added debris had an opportunity to be transported to the strainer.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 29 of 126 To achieve the desired transport of debris in the test tank, a single 16-inch diameter mixing nozzle was implemented. The mixing nozzle supplied sufficient turbulence to suspend fibrous and particulate debris without disrupting debris bed development.

The main components of the test included the test tank, debris introduction hopper, and the transition tank. Debris was added to the hopper and mixed by turbulent flow within the hopper. The mixed debris was gravity drained from the hopper to the test tank. The loop was also equipped with a transition tank that effectively increased the volume of the test tank. The total flow through the test strainer, the flow to the debris introduction hopper, and the flow to the transition tank were measured by three flow meters.

The approach velocity target was conservatively increased by 15%, constant throughout the test, and was only altered for flow sweeps. The approach velocity of 0.007 ft/sec translated to a target test operating flow rate of 1094 gpm with a 2%

tolerance.

Debris Surrogates and Preparation NUKON fines were the surrogate for all LDFG sizes. Preparation began by cutting the single-sided baked NUKON blanket into pieces at a nominal 2 x 2 size. The tough outer layer of the un-burnt portion of the NUKON blanket (less than 1/8 thick) was separated from 2 x 2 debris pieces and torn into smaller pieces to help it break up consistently.

Prepared debris was initially wetted with heated test water until the base material was saturated and the high pressure spray nozzle was submerged. Preparation was considered acceptable once their composition was predominantly Class 2, consisting mainly of individual fibers with lesser quantities of fiber shards and small entanglements (Reference [10]).

PCI PWR Dirt and Dust Mixture Preparation - the procured PCI PWR Dirt and Dust did not require additional processing. PCI PWR Dirt and Dust was weighted and sprinkled into the test tank immediately upstream of the strainer configuration.

The direct introduction into the test tank was used to prevent the PCI PWR Dirt and Dust from forming large agglomerations with fiber, which ultimately could have caused the debris introduction hopper to clog.

Silica Particulates were used as surrogates for all qualified coatings, unqualified coatings, and degraded qualified coatings. Degraded qualified coatings that fail as chips were conservatively represented in the test as particulates. Particulates typically induce a greater head loss than chips. Also, unlike chips, particulates will not disrupt a contiguous debris bed that likely decreases the head loss. Also, a volume scale was applied for particulates to conserve the quantity of particulates.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 30 of 126 Min-U-Sil 5, Sil-Co-Sil 53, and Agsco 70 are the silica particulates implemented to create the desired size distribution. The size distribution was similar to the risk-informed pilot plant size distribution used in their RoverD head loss test; see Figure 3.f-4. All the silicates had the same material density of 164.6 lbm/ft3.

Figure 3.f-4: Coatings Debris Surrogate Particulate Size Distribution Chemical Debris Preparation - calcium phosphate and aluminum oxyhydroxide (AlOOH) were the chemical precipitates prescribed for the test. The chemical debris was generated under preparation outlined in WCAP-16530-NP-A. To generate chemical precipitate, deionized water was poured into a mixing tank to a verified graduation marking. The measured water volume was mixed continuously prior to any chemical addition and mixing continued until after the chemical debris in the mixing tank was added to the test. Next, the chemical salt was added to the mixing tank and the pH of the solution was monitored until it was stable for 15 minutes.

Then, the base was added. After the pH of the solution was stable for 15 minutes, the final pH value was recorded and a settling test was executed. All precipitates met the acceptance criteria provided in WCAP-16530-NP [11].

Full Debris Load Test Debris amounts that were scaled for the FDL test are given in the Table 3.f-1.

These values represent the debris amount that transports to the strainer for single-train operation.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 31 of 126 Table 3.f-1: Debris Amounts for 2016 Full Debris Load (LBLOCA) Test Debris Component Plant Qty Test Quantity1 Test Surrogate 1490 lbm 164.40 lbm Min-U-Sil 5 Particulate2 2140 lbm 236.02 lbm Agsco 70 2140 lbm 235.99 lbm Sil-Co-Sil 53 PCI PWR Dirt &

Latent Particulate 30 lbm 3.28 lbm Dust Fiber 300 lbm 33.09 lbm NUKON Fines Chemical Precipitate 25 kg 2.76 kg Calcium Phosphate Sodium Aluminum Chemical Precipitate 215 kg 23.7 kg Silicate 1 Scale factor for testing is 0.1103 2 Volume scale applied Note that the latent particulate plant quantity used in the FDL test, 30 lbm, bounds plant inventory estimates, but is less than the generic prescribed load of 170 lbm that was tested in the thin bed test, with similar resulting head loss, and used for all other analyses.

Conventional debris was introduced following an incremental batching schedule. The batching schedule allowed for the determination of head loss across the strainer at incremental debris quantities. Only NUKON fines were used as a surrogate for fibrous debris. Implementing the test using only NUKON fines will tend to produce a result with a higher head loss than a test with some of the NUKON mass introduced as smalls. The addition of conventional debris (fibrous debris and particulates) did not exceed the allowable conventional debris head loss limit.

Following the completion of conventional debris additions, flow sweeps and temperature sweeps were executed and chemical debris introduced consisted of calcium phosphate and aluminum oxyhydroxide. One calcium phosphate batch and five ALOOH batches were introduced to match the predicted plant quantity.

After all of the chemical debris was introduced the debris bed was characterized.

Head loss was first stabilized at 120°F. Then a flow sweep was conducted.

Following the flow sweep, the temperature was reduced below 100°F. The head loss was stabilized again, and a final flow sweep was conducted. Following temperature and flow sweeps, the final pH and conductivity of the test water were recorded and the test loop was drained.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 32 of 126 The maximum debris bed head loss for the FDL test is 1.45 psid at 120 °F and with a flow rate of 1102 gpm.

Thin Bed Test The debris amounts that were scaled for the 2016 TB test are given in the Table 3.f-2. These values represent the debris amount that arrives at the strainer for one-train operation.

Table 3.f-2: Debris Amounts for 2016 Thin Bed Test Debris Component Plant Test Test Surrogate Quantity Quantity Particulate 1490 lbm 164.37 lbm Min-U-Sil 5 Particulate 2140 lbm 236.18 lbm Agsco 70 Particulate 2140 lbm 236.18 lbm Sil-Co-Sil 53 Latent Particulate 170 lbm 18.72 lbm PCI PWR Dirt & Dust Fiber 150 lbm 17.43 lbm NUKON Chemical Precipitate 25 kg 2.75 kg Calcium Phosphate Chemical Precipitate 215 kg 23.68 kg Sodium Aluminum Silicate First, all of the particulate debris was introduced in one continuous fashion via the hopper. PCI PWR Dirt and Dust was added separately near the end of the particulate debris introduction directly to the test tank near the ledge of the strainer pit. After all of the particulate debris was added to the test tank, batches of NUKON fines were added to the test tank via the hopper. Fiber batches were introduced to the test with masses equivalent to 1/16-inch of coverage on the test strainer.

A total of four NUKON fines batches were introduced to the test tank. The second and third addition of fiber both had a similar head loss increase, so a fourth batch was introduced to get to the point where the head loss increase for the last fiber addition was distinctly lower than previous additions.

The debris bed flow and temperature parameters were varied after the completion of conventional debris additions. Temperature was maintained at 120°F and the head loss was stabilized. After the head loss was stabilized a temperature sweep and flow sweep were conducted.

A total of one calcium phosphate addition and six additions of ALOOH were introduced. The total quantities were the same as in the FDL test. After the completion of the chemical debris introductions, temperature and flow sweeps were

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 33 of 126 performed on the debris bed. The final pH and conductivity of the test tank was then taken, the pump was stopped and the loop was slowly drained.

The maximum debris bed head loss for the TB test is 0.9 psid at 100 °F and with a flow rate of 1102 gpm.

Clean Strainer Head Loss Clean strainer head loss (CSHL) measurements were recorded at low and high temperatures and various flow rates at the beginning of each test. The CSHL data was taken before any debris was added to the tank. The data was taken for each flow rate after the flow had been allowed to stabilize. The data was processed to develop an average loss coefficient for the clean strainer that was applied to all tests to determine the debris laden head loss.

Single Train Operation Single train operation was used for scaling debris loads to the test.

Results:

Two head loss tests were performed in support of Callaways closure of GSI-191.

Neither test exceeded the allowable head loss margin defined for the FDL test and TB test. The FDL test demonstrated that the conventional debris load was acceptably accommodated by the Callaway sump strainer configuration under the test conditions defined. The TB test showed that a particulate-dense debris bed did not exceed the head loss measured during the FDL condition or the head loss limit.

The objective of the TB test was to verify that FDL conditions are indeed limiting for strainer performance. The TB test built a filtering debris bed with the lowest possible amount of fiber to promote the formation of a particulate saturated debris bed. Since the particulate debris quantity for the executed test sequence was very high, saturation was likely to have already occurred during the FDL test. The conducted TB test confirmed that the FDL conditions are limiting.

Response to 3.f.5. Address the ability of the design to accommodate the maximum volume of debris that is predicted to arrive at the screen:

Head loss tests of the strainers showed that the strainers have acceptable performance for the design basis particulate amounts, RoverD fiber threshold mass, and design basis chemical quantity that were added to the test tank. The test tank was designed to transport all debris to the strainer, so a very small amount of debris settled and was not accommodated by the strainer. Figure 3.f.5 and Figure 3.f.6 display the upstream, debris laden strainer stacks for the FDL and TB tests, respectively. The TB and FDL test are complementary and demonstrate the robustness of the strainer.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 34 of 126 Figure 3.f-5: Post FDL Test, Front Side of Upstream Strainer Stack, Top (Left) and Bottom (Right)

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 35 of 126 Figure 3.f-6: Post TB Test Upstream Strainer Stack

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 36 of 126 Response to 3.f.6. Address the ability of the screen to resist the formation of a thin bed or to accommodate partial thin bed formation:

A thin debris bed with low porosity that challenges the acceptable head loss did not form. The strainer head loss was acceptable for the TB test, and head loss was less than the FDL test.

Response to 3.f.7. Provide the basis for the strainer design maximum head loss:

The basis for the strainer design maximum head loss considers the strainer performance metrics of net positive suction head margin, deaeration, potential for flashing, and structural limits.

Also, in the RoverD methodology the maximum debris loads from a successful head-loss test are implemented as deterministic acceptance criteria for strainer loading during risk-informed simulations. A deterministic fiber threshold of 300 Ibm that was tested with bounding particulate loads is the strainer loading acceptance criteria.

See Attachment 3-3 for a complete description of the RoverD methodology.

Response to 3.f.8. Describe significant margins and conservatisms used in the head loss and vortexing calculations:

Head loss is based on laboratory testing rather than a calculation. Numerous conservatisms were implemented during testing as outlined in the following list.

• LDFG fines were used as a surrogate for LDFG smalls and larges.

• The approach velocity was conservatively increased by 15% (beyond the approach velocity increase due to miscellaneous debris).

• The scaling factor applied was for single train operation.

• Test procedures were designed to promote uniform debris distribution on the strainer to maximize head loss.

• The test tank did not have the 6-inch curb around the strainers to maximize debris transport.

• Debris material that demonstrated reductions in strainer head loss, such as reflective metallic insulation (Reference [8]), was excluded from the test.

Evaluation of the potential for vortexing was predominantly based on laboratory testing rather than a calculation. At the conclusion of head-loss tests, vortexing tests were conducted at the maximum large-break LOCA flow rate and minimum large-break LOCA submergence. For small-break LOCA, a comparative analysis was

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 37 of 126 performed using the Froude equation to conclude vortices with a solid air core would not form. See the response for 3.f.3 for more details.

Additional discussions of margin for Callaway 2016 head loss testing are available in the Defense-in-Depth and Safety Margin discussions of Attachment 3-4.

Response to 3.f.9. Provide a summary of the methodology, assumptions, bases for the assumptions, and results for the clean strainer head loss calculation:

The calculation (Reference [12]) utilized two distinct methodologies based on the entire strainer assembly configuration in determining the CSHL: (1) strainer and (2) structural support plenum and discharge. The first methodology for strainer only head loss employed an equation that was experimentally derived and which was used to determine the strainer head loss contribution. The second methodology utilized classical standard hydraulic head loss coefficients for the plenum and discharge to the sump. The individual head loss results from the strainer and plenum were added together to obtain the head loss for the entire strainer assembly configuration.

The strainer surface areas utilized in the calculation are based on initially calculated values using a minimum surface area of 3279.5 ft2. The actual strainer area was increased, due to design enhancements and structural revisions, to 3311.5 ft2, which is an increase of less than 1%.

A flow rate of 8830 gpm is used to determine the CSHL, while the maximum flow rate is 8750 gpm.

The CSHL is increased by 6% to account for measurement uncertainty during testing.

The results of CSHL including uncertainty are presented in Table 3.f-3.

Table 3.f-3: Temperature Dependent CSHL Clean Strainer Head Loss at 140°F, ft Clean Strainer Head Loss at 212°F, ft 0.7 0.6 Response to 3.f.10. Provide a summary of the methodology, assumptions, bases for the assumptions, and results for the debris head loss analysis:

The total strainer head loss consists of a CSHL in addition to a debris laden head loss that includes chemical precipitates. As discussed in response to Issue 3.f.9, the

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 38 of 126 CSHL is determined from an experimentally derived equation and classical, standard hydraulic head loss coefficients. The debris laden head loss is based on laboratory testing of the strainer module (Reference [10]).

Debris laden head loss is determined during testing that occurred at 120 °F and at a flow rate 15% greater than large-break LOCA conditions. For all large-break LOCA strainer performance metrics, the debris laden head loss was not scaled for temperature or flow rate, which would reduce the head loss. The maximum debris laden head loss from testing is 1.5 psi at 120 °F (or 3.5 ft at 120 °F). Table 3.f-3 displays the CSHL. Table 3.f-4 displays the total strainer head loss.

Table 3.f-4: Temperature Dependent Total Strainer Head Loss Total Head Loss at 140°F, ft Total Head Loss at 212°F, ft 4.2 4.1 Response to 3.f.11. State whether the sump is partially submerged or vented (i.e., lacks a complete water seal over its entire surface) for any accident scenarios and describe what failure criteria in addition to loss of net positive suction head (NPSH) margin were applied to address potential inability to pass the required flow through the strainer:

The sumps are fully submerged for SBLOCA and LBLOCA conditions. The sumps are not vented.

Response to 3.f.12. State whether near-field settling was credited for the head-loss testing and, if so, provide a description of the scaling analysis used to justify near-field credit:

Strainer head loss testing did not credit near-field settling. The test tank was designed to maximize transport to the strainers. With the exception of latent particulate which was poured in just upstream of the strainers, only fine debris was used. Also, adverse agglomeration of debris did not occur.

Response to 3.f.13. State whether temperature/viscosity was used to scale the results of the head loss tests to actual plant conditions. If scaling was used, provide the basis for concluding that boreholes or other differential-pressure induced effects did not affect the morphology of the test debris bed:

Temperature/viscosity was not used to scale the results of the head loss test to actual plant conditions. Therefore, head losses at the test temperature of 120 °F are assumed to represent head losses at higher plant temperatures.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 39 of 126 Response to 3.f.14. State whether containment accident pressure was credited in evaluating whether flashing would occur across the strainer surface, and if so, summarize the methodology used to determine the available containment pressure:

Containment accident pressure was credited in evaluating potential for flashing across the strainer surface. A containment accident pressure of 1.7 psi is credited for temperatures 212 °F and above which equates to approximately 10% of the available accident pressure. RG 1.82 states, The calculation of available containment pressure and sump/pool water temperature as a function of time should underestimate the expected containment pressures and overestimate the sump/pool water temperatures. Since containment pressure and sump/pool water temperature are dependent, the stated requirements are achieved by post-processing a design basis containment response analysis (Reference [13]) where containment pressure is reduced by the saturation pressure and 1.8 psig. Saturation pressure is required to maintain the fluid as a liquid and thus is not available containment pressure. The reduction of 1.8 psig is determined by reducing the initial containment pressure of the design basis analysis from a technical specification maximum of 1.5 psig (Reference [13, 14]) to the technical specification minimum of -0.3 psig (Reference

[14]). These conditions result in the maximum sump/pool water temperatures and minimum containment pressure.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 40 of 126 3.g. Net Positive Suction Head (NPSH)

The objective of the NPSH section is to calculate the NPSH margin for the ECCS and CSS pumps that would exist during a loss-of-coolant accident (LOCA) considering a spectrum of break sizes.

1. Provide applicable pump flow rates, the total recirculation sump flow rate, sump temperature(s), and minimum containment water level.

2. Describe the assumptions used in the calculations for the above parameters and the sources/bases of the assumptions.

3. Provide the basis for the required NPSH values, e.g., three percent head drop or other criterion.

4. Describe how friction and other flow losses are accounted for.

5. Describe the system response scenarios for LBLOCA and SBLOCAs.

6. Describe the operational status for each ECCS and CSS pump before and after the initiation of recirculation.

7. Describe the single failure assumptions relevant to pump operation and sump performance.

8. Describe how the containment sump water level is determined.

9. Provide assumptions that are included in the analysis to ensure a minimum (conservative) water level is used in determining NPSH margin.

10. Describe whether and how the following volumes have been accounted for in pool level calculations: empty spray pipe, water droplets, condensation and holdup on horizontal and vertical surfaces. If any are not accounted for, explain why.

11. Provide assumptions (and their bases) as to what equipment will displace water resulting in higher pool level.

12. Provide assumptions (and their bases) as to what water sources provide pool volume and how much volume is from each source.

13. If credit is taken for containment accident pressure in determining available.

NPSH, provide description of the calculation of containment accident pressure used in determining the available NPSH.

14. Provide assumptions made which minimize the containment accident pressure and maximize the sump water temperature.

15. Specify whether the containment accident pressure is set at the vapor pressure corresponding to the sump liquid temperature.

16. Provide the NPSH margin results for pumps taking suction from the sump in recirculation mode.

The information in this section revises information previously provided by Ameren Missouri to GL 2004-02, section 3.g. (Reference [2]). The NPSH calculation is revised due to 2016 test evaluation which replaces 2008 testing meant to support assumptions and corresponding conclusions contained in the earlier GL 2004-02 response. The

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 41 of 126 NPSH margin evaluation process described below conforms to sections 3.7 and 4.2.5 of NEI 04-07, Vol. 2 SE (Reference [1]).

Response to 3.g.1. Provide applicable pump flow rates, the total recirculation sump flow rate, sump temperature(s), and minimum containment water level:

RHR Pump flow rate during recirculation is 4800 gpm for each pump. CS pump flow rate during recirculation is 3950 gpm for each pump. The total strainer flow rate is 8750 gpm for each strainer.

The maximum and minimum large-break LOCA pool temperature is approximately 265 °F and 140 °F. NPSH analysis is evaluated at 212 °F.

Large-break LOCA minimum water level is elevation 2001' 10" and occurs at ECCS switchover. Small-break LOCA minimum water level elevation is 2001' 3.5".

Response to 3.g.2. Describe the assumptions used in the calculations for the above parameters and the sources/bases of the assumptions:

The flow rates implemented in the NPSH analysis are maximums derived from pre-operational tests.

NPSH analysis is determined at 212 °F because this temperature provides the limiting NPSH margin. Below 212 °F atmospheric pressure (or subcooling of the fluid) is in direct competition with increasing system head losses which are a function of fluid properties. Subcooling margin increases with decreasing temperature at a rate greater than the increasing system head losses. Therefore, NPSH margin is gained as temperature decrease below 212 °F. At temperatures greater than 212

°F, containment pressure is equal to vapor pressure because containment accident pressure is not credited for NPSH analysis. Therefore, NPSH available is only a function of static head and head loss. For this analysis static head is constant and is selected based on a minimum large-break LOCA. Head loss increases as temperature decreases. Therefore, the minimum temperature within the temperature range, 212 °F, is analyzed. To recap, 212 °F is the lowest temperature which produces the highest head loss when subcooling does not provide an additional net head. Also, a CSHL of 0.7 ft at 140 °F and debris bed head loss of 3.5 ft at 120 °F were conservatively applied to the NPSH calculation at 212 °F without a correction for temperature, which would reduce the head losses.

For large-break LOCA NPSH analysis, the minimum large-break LOCA water level occurs at ECCS switchover and was applied in the NPSH margin evaluation.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 42 of 126 Response to 3.g.3. Provide the basis for the required NPSH values, e.g., three percent head drop or other criterion:

NPSH required was determined by the pump vendors and applied in NPSH margin analyses as specified. NPSH required was not corrected for temperature. NPSH required was increased for air in the fluid at the pump suction inlet per RG 1.82.

Response to 3.g.4. Describe how friction and other flow losses are accounted for:

The friction and flow loss values are based on standard industry accepted estimates of piping friction and fitting head losses at maximum flow rates. Equations used to determine head losses are displayed below.

2 2 2

= ( )

2 2 2 where HL is the head loss attributed to friction, ft f is the friction factor, unitless L is the pipe length, ft D is the inside pipe diameter, ft (L/D)equiv is the fitting head loss coefficient K is the fittings head loss coefficient v is the fluid velocity, ft/s g is the acceleration caused by gravity, ft/s2 Friction factors are determined with a Moody chart or an empirical derivation of a Moody chart.

Response to 3.g.5. Describe the system response scenarios for LBLOCA and SBLOCAs:

For LOCAs, there are two modes of operation: the injection mode and the recirculation mode of operation.

Large-Break LOCA During a large-break LOCA, depressurization of the RCS results in a pressure decrease in the pressurizer. The reactor trip signal subsequently occurs when the pressurizer low pressure trip setpoint is reached. Once RCS pressure is less than approximately 600 psig, the four accumulator tanks will inject into the RCS. A safety injection signal (SIS) is generated when the low pressurizer pressure SI setpoint is reached. A containment spray actuation signal (CSAS) is generated when the

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 43 of 126 containment pressure setpoint is reached. Upon receipt of an SIS and CSAS, the ECCS and CSS are activated, commencing the injection mode of ECCS and CSS operation. This mode of operation consists of both trains of the ECCS pumps running (two charging pumps, two SI pumps, and two RHR pumps) and both CS pumps taking suction from the RWST and delivering water to the RCS.

Continued operation of the RHR pumps supplies water during long-term cooling.

After the water level of the RWST reaches a minimum allowable value, coolant for long-term cooling of the core is obtained by automatically switching to the cold-leg recirculation mode of operation in which borated water is drawn from the containment recirculation sumps and returned to the RCS cold legs (CLs) by the RHR pumps. The CS pumps, SI pumps, and CCP pumps are manually aligned to the containment recirculation sumps with a timed operator action and continue to operate in recirculation mode.

Approximately 13 hours1.50463e-4 days <br />0.00361 hours <br />2.149471e-5 weeks <br />4.9465e-6 months <br /> after initiation of the LOCA, the SI pumps are realigned to supply water to the RCS hot legs to mitigate the boric acid concentration in the reactor vessel, while RHR pumps and CCP pumps continue to inject into CLs.

Small-Break LOCA For a small-break LOCA, information provided by Westinghouse indicates that for "a typical Westinghouse 4-loop PWR with a larger dry containment, such as Wolf Creek or Callaway, an equivalent 3-inch diameter break or smaller may result in the RCS pressure equilibrating at 1000 psi to about 1200 psi. At this pressure, the SI accumulators will not discharge. For breaks of greater than about an equivalent 3-inch diameter, the plant would undergo a sufficiently rapid depressurization that the SI accumulators would discharge".

During a small-break LOCA scenario, a SIS will start both trains of charging, SI and RHR pumps in the injection mode from the RWST to the RCS (cold-leg injection).

The charging pumps will inject water immediately. If RCS pressure continues to decrease below the shut-off head of the SI pumps (~1550 psig), they will also start injecting into the RCS. As the control room operators progress through their emergency procedures, they may shut-off the RHR pumps based on RCS pressure (stable or increasing). The SI accumulators are also aligned to inject into the RCS when the RCS pressure drops below the accumulator pressure. The RHR pumps will not start injecting until RCS pressure drops below the shutoff head of the RHR pumps (~ 325 psig). If the combination of the charging pumps and SI pumps does not equal the break flow, RCS pressure will continue to decrease. If RCS pressure stabilizes somewhere above the shut-off head of the RHR pumps, they may be turned off. For a small-break LOCA pressure in the containment building is not expected to exceed the pressure required for CSAS. Therefore, CS is not expected to actuate during a small-break LOCA.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 44 of 126 The objective of the control room operators is to cool down and depressurize the RCS so that the RHR pumps may be aligned from the RCS hot legs and recirculated back to the cold legs. But, if the RWST injects enough fluid to where two of the four normal sump level indicators read greater than 6 1, the RHR pumps will be aligned to take suction from the containment emergency recirculation sumps and supply suction to the SI and charging pumps. If RCS pressure is below the shut off head of the RHR pumps, the RHR pumps will also inject into the RCS. The recirculating water will be cooled as it is pumped through the RHR heat exchangers.

Response to 3.g.6. Describe the operational status for each ECCS and CSS pump before and after the initiation of recirculation:

For a large-break LOCA, prior to the recirculation phase of the analyzed postulated accident, both safety trains of ECCS pumps are running, which includes two charging pumps, two SI pumps, and two RHR pumps. In addition, both CS pumps are running. Following initiation of the recirculation phase, the status remains as described above.

Response to 3.g.7. Describe the single failure assumptions relevant to pump operation and sump performance:

For GSI-191 the single worst failure is loss of a strainer because all of the debris is loaded on a single strainer, which induces failures at smaller break sizes. RoverD implemented the loss of a train for all analysis.

Response to 3.g.8. Describe how the containment sump water level is determined:

Given the net mass of water added to the containment floor, determined by the difference between water sources and holdup volumes, the post-LOCA containment building water level is calculated by an accumulation rate correlation that is a function of elevation.

Sources that add water to containment include:

1. RWST,

2. RCS,

3. Accumulators,

4. Initial atmosphere water vapor.

Features that remove water from the containment sump include:

1. Water vapor in the containment atmosphere,

2. Water volume remaining in the RCS,

3. Water film on surfaces,

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 45 of 126

4. Water volume in ECCS and CS piping,

5. HVAC duct and piping,

6. Water in transit from the CS nozzles and the break to the containment sump,

7. Water in the refueling pool and other holdup,

8. Water below the 2000 ft elevation,

9. Water in other miscellaneous holdup such as trenches, pits, etc.

Response to 3.g.9. Provide assumptions that are included in the analysis to ensure a minimum (conservative) water level is used in determining NPSH margin:

The RWST, RCS and the SI accumulator inventories were assumed to be the same density as pure water. This assumption is reasonable since the boric acid concentrations are small (i.e. less than or equal to 2500 ppm).

The total RHR and CS piping hold-up volume calculated was increased by a conservative 5% to account for additional volume that was not considered (such as higher cross-sectional area for valves, other fittings, and drain lines).

An assumption of 5% SG tube plugging is assumed in the water level calculation.

Following installation of replacement SGs in October 2005, a combined total of one tube in the four SGs was plugged; therefore the use of 5% plugging is a conservative assumption.

The temperature of the water within the SI accumulators is assumed to be equal to the maximum initial containment air temperature consistent with the accident analysis of 120 °F. This approach is conservative because the density of water decreases with increasing temperature, limiting the mass of water that could spill into containment.

The water density at the sump temperature is used to calculate the post-LOCA RCS volume since it would be difficult to accurately quantify the average RCS water inventory temperature following the break. This is conservative because the RCS temperature will be higher than the sump temperature due to decay heat and residual RCS piping and component heat.

To account for miscellaneous holdup volumes not specifically quantified, a miscellaneous holdup quantity of 250 ft3 is included.

The initial RCS volume is minimized by assuming a minimum pressurizer volume of 38%. This assumption is based on the nominal pressurizer span at 100% power and Tavg = 570.7 °F.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 46 of 126 Also, the minimum volume for the water sources was applied with the maximum volume of the water holdup.

Response to 3.g.10. Describe whether and how the following volumes have been accounted for in pool level calculations: empty spray pipe, water droplets, condensation and holdup on horizontal and vertical surfaces. If any are not accounted for, explain why:

All volume questioned were accounted for in the pool level calculation as holdup volumes. Further description is provided below.

1. Empty spray pipe: Water volume required to fill initially empty CS pipes (and RHR pipes) is 578 ft3 and is removed from the active volume that contributes to pool height.

2. Water droplets: Water droplets are held up in the air as steam and have a volume of 4126 ft3. Water droplets are removed from the active volume that contributes to pool height.

3. Holdup on horizontal and vertical surfaces: A film thickness of 1/32 is assumed to form on wetted surfaces and has a volume of 1164 ft3. This volume is removed from the active volume that contributes to pool height.

Also, to account for uncertainties, an additional miscellaneous holdup of 250 ft3 is removed from the active volume that contributes to pool height as stated in the Response to 3.g.9.

Response to 3.g.11. Provide assumptions (and their bases) as to what equipment will displace water resulting in higher pool level:

Water below the 2000 elevation does not contribute to the pool height because these locations are below the reactor containment building floor, consists of the reactor cavity and incore tunnel, and have a volume of 17915 ft3. Equipment and structures that displace water below the 2000 elevation include incore tubes, incore tunnel beams, and the reactor vessel. Above the 2000 elevation level the pool level is affected by pressurizer relief tank (PRT) supports, reactor coolant drain tank (RCDT) supports, recirculation sump curbs, incore sump curbs, and the incore tunnel. Concrete walls and raised floors also affect the minimum pool level in containment. Below is a summary of the equipment and structures that displace water volume. Note that pipes and hangers are assumed to displace 0.5% of water volume. This displacement is accounted for in the accumulation rates, but is not shown below.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 47 of 126 Equipment below 2000' elevation that displaces water:

Volume Profile (that consists of the reactor cavity and incore tunnel): 17915 ft3

1. Incore tubes - 30.05 ft3

2. Reactor vessel - 2078 ft3

3. Incore tunnel beams - 21.9 ft3 Equipment between elevation 2000'-0" and 2000'-6" that displaces water:

Volume Profile: 7,698.5 ft3

1. Concrete walls - 1535.5 ft3

2. Floor at 2001'-4" - 2355 ft3

3. PRT supports - 18.4 ft3

4. RCDT supports - 2.78 ft3

5. Recirculation sump curbs - 16.9 ft3

6. Incore sump curbs - 9.45 ft3

7. Area of incore tunnel - 94.3 ft3

8. Accumulator Base Plates - 36.8ft3 Equipment between elevation 2000'-6" and 2001'-4" that displaces water:

Volume Profile: 12,777 ft3

1. Concrete walls - 2549 ft3

2. Floor @ 2001'-4" - 3909 ft3

3. PRT supports - 30.4 ft3

4. RCDT supports - 24.6 ft3

5. Incore sump curbs - 15.7 ft3

6. Area of incore tunnel - 156.5 ft3 Accumulation Rate:

Equipment between elevation 2001'-4" and 2001'-10" that displaces water:

Volume Profile: 7,698.5 ft3

1. Concrete walls - 1535.5 ft3

2. SG and RCP Base Plates - 84 ft3

3. PRT supports - 18.4 ft3

4. Incore sump curbs - 9.45 ft3

5. Area of incore tunnel - 94.3 ft3 Above 2001'-10", the water level will only be displaced by concrete walls. The area profile will increase by 92 ft2 with the additional space of the reactor annulus. This along with the 0.5% volume displacement of pipes and hangers will result in an accumulation rate of 12,353 ft3/ft above this level.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 48 of 126 Response to 3.g.12. Provide assumptions (and their bases) as to what water sources provide pool volume and how much volume is from each source:

The initial RCS volume is minimized by assuming a minimum pressurizer volume of 38%. This assumption is based on the nominal pressurizer span at 100% power and Tavg = 570.7°F.

The RWST, RCS and the SI accumulator inventory was assumed to be the same density.as pure water. This assumption is reasonable since the boric acid concentrations are small.

To conservatively minimize the mass of water contained in the SI accumulators that could flow into the containment building, the temperature is assumed to be equal to the maximum initial containment air temperature of 120°F, consistent with the accident analysis. This approach is conservative because the density of water decreases with increasing temperature.

Mass input to sump from the containment water level calculation at ECCS switchover (or RHR swapover) accident scenario is:

• RCS blowdown 551,068 Ibm

• SI accumulators 199,996 Ibm

• Initial containment vapor 732 Ibm

• RWST input 1,882,666 Ibm Response to 3.g.13. If credit is taken for containment accident pressure in determining available NPSH, provide description of the calculation of containment accident pressure used in determining the available NPSH:

Credit is not taken for containment accident pressure in determining available NPSH. (Containment accident pressure corresponding to the vapor pressure at the sump liquid temperature was credited for potential for flashing evaluations as stated in the response to Issue 3.f.14, but not for available NPSH.)

Response to 3.g.14. Provide assumptions made which minimize the containment accident pressure and maximize the sump water temperature:

Credit is not taken for containment accident pressure in determining available NPSH. (Containment accident pressure corresponding to the vapor pressure at the sump liquid temperature was credited for potential for flashing evaluations as stated in the response to Issue 3.f.14, but not for available NPSH.)

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 49 of 126 Response to 3.g.15. Specify whether the containment accident pressure is set at the vapor pressure corresponding to the sump liquid temperature:

For temperature above 212 °F the containment accident pressure is set equal to the vapor pressure corresponding to the sump liquid temperature. For temperatures below 212 °F containment accident pressure is not credited, and containment pressure is set equal to 14.7 psia.

Response to 3.g.16. Provide the NPSH margin results for pumps taking suction from the sump in recirculation mode:

NPSH margins for pumps taking suction from the sump in recirculation mode at the limiting instance, 212 °F (see the response to Issue 3.g.2 for more details), are presented in Table 3.g-1.

Table 3.g-1: NPSH Margin Results at 212 °F Pump NPSH Margin (ft)

RHR 2.8 CS 2.1

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 50 of 126 3.h. Coatings Evaluation The objective of the coatings evaluation section is to determine the plant-specific ZOI and debris characteristics for coatings for use in determining the eventual contribution of coatings to overall head loss at the sump screen.

1. Provide a summary of type(s) of coating systems used in containment, e.g.,

Carboline CZ 11 Inorganic Zinc primer, Ameron 90 epoxy finish coat.

2. Describe and provide bases for assumptions made in post-LOCA paint debris transport analysis.

3. Discuss suction strainer head loss testing performed as it relates to both qualified and unqualified coatings and what surrogate material was used to simulate coatings debris.

4. Provide bases for the choice of surrogates.

5. Describe and provide bases for coatings debris generation assumptions. For example, describe how the quantity of paint debris was determined based on ZOI size for qualified and unqualified coatings.

6. Describe what debris characteristics were assumed, i.e., chips, particulate, size distribution and provide bases for the assumptions.

7. Describe any ongoing containment coating condition assessment program.

The information in this section revises information previously provided by Ameren Missouri to GL 2004-02, section 3.h. (Reference [2]). The coatings evaluation described below conform to sections 3.4.2.1 and 3.4.3 of NEI 04-07, Vol. 2 SE (Reference [1]).

Response to 3.h.1. Provide a summary of type(s) of coating systems used in containment, e.g., Carboline CZ 11 Inorganic Zinc primer, Ameron 90 epoxy finish coat:

The definition of a DBA qualified coating used at Callaway is:

A coating system used inside reactor containment that can be attested to having passed the required laboratory testing, including irradiation and simulated DBA, and has adequate quality documentation to support its use as DBA qualified. This applies to all coating systems, epoxy or otherwise, that are used inside the reactor containment building.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 51 of 126 The qualified coatings inside the reactor containment are detailed in Callaway calculations and specifications. There are various types of qualified coatings used in the containment including epoxy and IOZ systems.

• Carboline 195 primer with Carboline 191 HB finish is an epoxy system used to coat concrete walls, ceilings, and floors as well as accumulators, RCP, and HXR.

• Ameron Dimetcote 6 or Carboline CZ-11 SG as a primer with Ameron 90 finish are IOZ systems used to coat containment liner plates or structural steel respectively.

Any coating that does not satisfy the above definition is classified as an unqualified coating.

The unqualified coatings inside the reactor containment are detailed in Callaway calculations. There are various types of unqualified coatings used in the containment including acrylic, alkyd, epoxy systems, IOZ, and varnish.

• Carboline 890 and Carboline 193 LF are epoxy coatings used in containment on steel surfaces. Also, Carboline 890 is used as a service level 1 coating inside containment.

• Alkyd coatings are oil based paints used on various components such as valves, actuators and equipment. Benjamin Moore Ironclad is a coating on pipe elbows specified as an alkyd within Callaway.

• Dimetcote is an IOZ silicate coating on the exterior of the reactor coolant pump (RCP) motors.

• Varnish is found throughout containment on several cooling fan motors as an original equipment manufacturer (OEM) primer coat for epoxy.

Response to 3.h.2. Describe and provide bases for assumptions made in post-LOCA paint debris transport analysis:

Debris transport is determined at four break locations. The maximum transport fraction for each materials constituent is applied for analysis and is presented below.

Unqualified coatings are assumed to fail as 10 micron particulate and have a transport fraction of 100%.

Qualified coatings are assumed to fail as 10 micron particulate and have a transport fraction of 99%. The only credit applied is pool fill transport.

Degraded qualified coatings vary in size and transport as displayed in Table 3.h-1.

The amount of mass for each size is also presented in Table 3.h-1. Blowdown, washdown, and pool fill transport do not influence degraded qualified coatings. For damaged coatings, holdup is not credited during blowdown, washdown, or recirculation. The transport fraction for these stages is 100%. During pool fill, a

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 52 of 126 portion of qualified coatings debris are expected to be pushed by sheet flow to inactive cavities and the emergency sump strainers. One percent of destroyed qualified coatings are estimated to transport to inactive cavities. The overall transport fraction accounts for all transport stages but is finally equivalent to the pool-fill transport fraction, 1 x 1 x 1 x 0.99 = 0.99.

Table 3.h-1: Degraded Qualified Coatings Sizes, Percent Mass, and Transport Fractions.

Description Size  % by Mass Transport Fraction Fines < 1/8 49.51 100%

1/8 to 1/4 5.02 Flat Small Chips 6%

1/4 to 1/2 4.41 Flat Large Chips 1/2 to 2 20.53 4%

Curled Chips 1/2 to 2 20.53 100%

Response to 3.h.3. Discuss suction strainer head loss testing performed as it relates to both qualified and unqualified coatings and what surrogate material was used to simulate coatings debris:

Strainer head loss testing was conducted in 2016 to demonstrate acceptable performance with the design basis particulate debris loading. Quantities for strainer head loss testing were based on a scaling factor derived from the test module size relative to the total strainer size less miscellaneous debris. To conserve the number of particulates, the scaling factor was applied to the volumes of debris predicted to be transported to the strainer. Silica sand (AGSCO 70) and ground silica (Sil-Co-Sil 53 and Min-U-Sil 5) were used as surrogate materials for the containment qualified, unqualified, and degraded qualified coatings. For degraded qualified coatings a particulate surrogate was used in lieu of chips because typically, particulates induce a greater head loss and, unlike chips, particulates will not disrupt a contiguous debris bed, which would reduce the head loss.

Response to 3.h.4. Provide bases for the choice of surrogates:

The basis for surrogate selection was to have a similar size distribution to the risk-informed pilot plant, which was accomplished by using 26% Min-U-Sil 5, 37%

Sil-Co-Sil 53, and 37% AGSCO 70. Figure 3.h.1 compares the size distributions of Callaway and the risk-informed pilot plant with a cumulative distribution function.

Since all three surrogates have identical material densities, the volume fraction distribution is identical to the mass distribution.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 53 of 126 Figure 3.h.1: Comparison of Particle Size Distribution for Callaway and the Risk-Informed Pilot Plant Response to 3.h.5. Describe and provide bases for coatings debris generation assumptions. For example, describe how the quantity of paint debris was determined based on ZOI size for qualified and unqualified coatings:

The following attributes provide the basis for coatings debris generation assumptions and the determination of the quantities of coatings generated during an event, while adhering to regulatory guidance.

Qualified Coatings ZOI sizes for qualified coating systems are based on WCAP-16568-P jet impingement testing data and staff guidance regarding coatings evaluation (Reference [7]). Qualified coating systems with an epoxy topcoat are analyzed with a 4D ZOI. Qualified coating systems that have exposed IOZ are analyzed with a 10D ZOI [5]. All qualified coatings are assumed to fail as 10 micron particulate.

Per NEI 04-07, qualified coatings within the ZOI are assumed to fail as a result of impingement and post-accident environmental conditions. Qualified coatings outside the ZOI are assumed to remain intact. To determine the amount of qualified coatings that fail, a three-dimensional model of the containment was constructed to model the geometric orientation of all qualified coatings in relation to possible LOCA

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 54 of 126 initiating welds. CASA Grande was used to simulate all potential breaks and to calculate the areas of specific surfaces (i.e. floors, walls, equipment, etc.) within each ZOI. Plant documentation identifying coating types and applications (i.e.

coating dry film thickness) were also incorporated to CASA Grande to calculate the associated volume of qualified coatings. The qualified coating volumes and dry film densities were used to determine the qualified coating masses.

Coating systems applied in the model for concrete are the systems that generated the most debris based on mass per surface area. The coating system containing Dimetcote is used on the steel liner plate, while the system containing Carboline CZ-11SG is used for structural steel. Also, the amount of qualified coatings in the model matches the qualified coatings schedule. Table 3.h.2 displays details of the qualified coating systems.

Table 3.h.2: Coating Systems Assumed for Debris Generation Coating Dry Film Dry Film System Coating Density Thickness Number Surface Type Coating Name Type (lbm/ft3) (mils)

Concrete Walls Carboline 195 107.97 20 100, 102 Epoxy and Ceilings Carboline 191 HB 104.6 6 Carboline 195 107.97 20 103 Concrete Floors Epoxy Carboline 191 HB 104.6 12 Ameron D6 (Liner Plate) 300 4 IOZ Ameron 90 117.3 6 104 Steel Carboline CZ-11SG 214.3 4 (Structural Steel) IOZ 117.3 6 Ameron 90 During a plant inspection, rust formation was discovered on the GN-050 HBC pipes that are part of the HVAC system. Since this rust is located under jacketed fiberglass insulation, it is not considered to contribute to debris generation or chemical effects post-LOCA unless the insulation covering it also breaks. Therefore, the rust uses a 17D ZOI size, like the LDFG covering it. The thickness of this rust was ultrasonically measured in six different locations and the average thickness of 0.1 inch was used in quantifying the rust. The density of rust is 320 lbm/ft3. Also, rust was assumed to be destroyed as 10 micron particulate.

Unqualified Coatings Per NEI 04-07 all unqualified coatings inside and outside a ZOI are assumed to fail as a result of impingement and post-accident environmental conditions. Amounts of unqualified coatings that fail were determined in a similar manner to qualified coatings. Plant unqualified coatings document describe location, coating, dry film

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 55 of 126 thickness, and surface area. The dry film densities are determined by theoretical coating spread rates (sq. ft. per gallon at 1-mil thickness) that require liquid density, shipping weight, and percent solids instead of specific vendor coating spread rates.

Specific coatings are unknown from some alkyds and epoxies. Unknown alkyds implemented properties from NEI guidance. Unknown epoxies were assumed to be unqualified Carboline 890, which was commonly used at Callaway.

The total unqualified coatings mass of acrylic, alkyd, epoxy and IOZ fail as 10 µm particulate, contribute to every break scenario, and transport to the strainer at 100%.

This follows the NRC guidance. The total mass of unqualified coatings is approximately 4190 lbm; see Table 3.h-3 for more details regarding unqualified coatings quantities.

Table 3.h-3: Unqualified Coatings Quantities Coating Type Mass (lb) Volume (ft3)

Acrylic (Carboline 3359) 31.392 0.463 Alkyd (Generic) 95.158 0.971 Alkyd (Benj. Moore Ironclad) 0.128 0.001 Epoxy (Generic) 910.752 7.160 Epoxy (Carboline 193 LF) 514.934 4.210 Epoxy (Carboline 191 HB) 590.362 5.644 IOZ (Carbozinc 11) 673.545 3.143 IOZ (Dimetcote) 780.000 2.600 IOZ (Generic) 570.468 2.662 Varnish (FD Heat Resistant) 17.72 0.215 Total in the Recirculation Pool 4184 27 Degraded Qualified Coating A degraded qualified coating is a qualified coating that degraded over time and has test data to support failure characteristics. Tests performed for Comanche Peak Steam Electric Station by Keeler & Long (Reference [15]) has been reviewed and found applicable to the degraded DBA-qualified epoxy and inorganic zinc coatings applied at Callaway. In the test, an epoxy topcoat and inorganic zinc primer coating system that degraded was removed from the Comanche Peak Unit 1 containment after 15 years of nuclear service. The removed coating was subjected to DBA conditions in accordance with ASTM D 3911 03. In addition to the standard test protocol contained in ASTM D 3911 03, 10 ppm filters were installed to capture debris generated during the test.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 56 of 126 Data in this report shows that inorganic zinc predominantly fails in a size range from 9 to 89 microns with the majority being between 14 and 40 microns. Therefore, a conservative size of 10 microns was assumed for transport and head loss tests of inorganic zinc. Data in this report also showed that DBA-qualified epoxy (Carboline Phenoline 305) that has failed as chips by delamination tend to remain as chips in a LOCA environment. Almost all of the chips remained larger than 1/32-inch diameter.

Consistent with manufacturer's published data sheets and material safety data sheets, Carboline Phenoline 305 is representative of the other DBA qualified epoxy coatings found in U.S. nuclear power plants (Reference [15]). This includes Carboline 890 epoxy coating in Callaways containment.

Degraded qualified coatings contribute debris to every break scenario. Carboline 890 is the only degraded qualified coating in Callaway. The size and mass distribution of the degraded qualified Carboline 890 epoxy is provided in Table 3.h-4 and follows NRC guidance (Reference [16]). If the degraded qualified epoxy has an IOZ primer, the IOZ primer is assumed to fail as 10 micron particulate based on Keeler & Long Report 06-0413 (Reference [15]).

Table 3.h-4: Degraded Qualified Coating Carboline 890 Epoxy Debris Details Description Size  % by Mass Mass, lbm Fines < 1/8 49.51 128.57 1/8 to 1/4 5.02 13.039 Flat Small Chips 1/4 to 1/2 4.41 11.455 Flat Large Chips 1/2 to 2 20.53 53.351 Curled Chips 1/2 to 2 20.53 53.351 Response to 3.h.6. Describe what debris characteristics were assumed, i.e.,

chips, particulate, size distribution and provide bases for the assumptions:

Per NRC guidance all qualified and unqualified coatings were assumed to fail as 10 micron particulate, and degraded qualified epoxy coatings were assumed to fail with the size distribution presented in Table 3.h-4.

Response to 3.h.7. Describe any ongoing containment coating condition assessment program:

Coating condition assessments are conducted as part of the structures monitoring program and conducted, at a minimum, once each fuel cycle in accordance with plant procedures and preventative maintenance documents. Monitoring involves conducting a general visual examination of all accessible coated surfaces within the

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 57 of 126 containment building and is intended to characterize the condition of the coating systems. If determined to be necessary, additional nondestructive and destructive examinations of degraded coating areas will be conducted as specified by the plant Protective Coatings Specialist. If localized areas of degraded coatings are identified, those areas are evaluated and scheduled for repair/replacement as necessary.

Examinations of degraded coating areas are conducted by qualified personnel as defined in plant procedures as recommended by ASTM D 5163 05a. Detailed instructions on conducting coating examinations, including deficiency reporting criteria and documentation requirements are delineated in plant procedures and preventative maintenance documents.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 58 of 126 3.i. Debris Source Term The objective of the debris source term section is to identify any significant design and operational measures taken to control or reduce the plant debris source term to prevent potential adverse effects on the ECCS and CSS recirculation functions.

Provide the information requested in GL 04-02 Requested Information Item 2.(f) regarding programmatic controls taken to limit debris sources in containment.

GL 2004-02 Requested Information Item 2(f)

A description of the existing or planned programmatic controls that will ensure that potential sources of debris introduced into containment (e.g., insulations, signs, coatings, and foreign materials) will be assessed for potential adverse effects on the ECCS and CSS recirculation functions. Addressees may reference their responses to GL 98-04, Potential for Degradation of the Emergency Core Cooling System and the Containment Spray System after a Loss-of-Coolant Accident Because of Construction and Protective Coating Deficiencies and Foreign Material in Containment, to the extent that their responses address these specific foreign material control issues.

In responding to GL 2004 Requested Information Item 2(f), provide the following:

1) A summary of the containment housekeeping programmatic controls in place to control or reduce the latent debris burden. Specifically for RMI/low-fiber plants, provide a description of programmatic controls to maintain the latent debris fiber source term into the future to ensure assumptions and conclusions regarding inability to form a thin bed of fiber debris remain valid.

2) A summary of the foreign material exclusion programmatic controls in place to control the introduction of foreign material into the containment.

3) A description of how permanent plant changes inside containment are programmatically controlled so as to not change the analytical assumptions and numerical inputs of the licensee analyses supporting the conclusion that the reactor plant remains in compliance with 10 CFR 50.46 and related regulatory requirements.

4) A description of how maintenance activities including associated temporary changes are assessed and managed in accordance with the Maintenance Rule, 10 CFR 50.65.

If any of the following suggested design and operational refinements given in the guidance report (guidance report, section 5) and SE (SE, section 5.1) were used, summarize the application of the refinements.

5) Recent or planned insulation change-outs in the containment which will reduce the debris burden at the sump strainers

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 59 of 126

6) Any actions taken to modify existing insulation (e.g., jacketing or banding) to reduce the debris burden at the sump strainers

7) Modifications to equipment or systems conducted to reduce the debris burden at the sump strainers

8) Actions taken to modify or improve the containment coatings program Response to 3.i.1. A summary of the containment housekeeping programmatic controls in place to control or reduce the latent debris burden.

Specifically for RMI/low-fiber plants, provide a description of programmatic controls to maintain the latent debris fiber source term into the future to ensure assumptions and conclusions regarding inability to form a thin bed of fiber debris remain valid:

Housekeeping and foreign material exclusion program procedures have been revised to target the containment cleaning effort from the results of the swipe sampling survey and to enhance the containment cleanliness requirements in Modes 1 through 4.

Response to 3.i.2. A summary of the foreign material exclusion programmatic controls in place to control the introduction of foreign material into the containment:

Callaway procedurally tracks all transient materials taken inside containment during modes 1 through 4. Prior to entry into mode 4, containment cleanliness is established by performing and documenting a visual inspection of the containment for loose debris. During normal operations, all items taken into containment are logged. At the completion of the containment entry the items are accounted for. At the completion of work activities inside containment during normal operations, the work area is thoroughly cleaned and inspected (including the area below the work activity, if the work was performed on grating), prior to leaving containment.

Response to 3.i.3. A description of how permanent plant changes inside containment are programmatically controlled so as to not change the analytical assumptions and numerical inputs of the licensee analyses supporting the conclusion that the reactor plant remains in compliance with 10 CFR 50.46 and related regulatory requirements:

Engineering Design Guide ME-012 provides guidance for containment sump blockage concerns for design changes inside containment. New components or replacement components must have a qualified coating. Any material that is to be added to containment must be evaluated to determine if the potential exists to create debris that could end up at the strainers. Deviations from the guidance are permitted but must be evaluated by an engineer cognizant of GSI-191 and be explained in the change package.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 60 of 126 In addition to the design change controls, Callaway procedurally tracks all transient materials taken inside containment during modes 1 through 4. During normal operations, all items taken into containment are logged. At the completion of the containment entry the items are accounted for. At the completion of work activities inside containment during normal operations, the work area is thoroughly cleaned and inspected (including the area below the work activity, if the work was performed on grating), prior to leaving containment.

Response to 3.i.4. A description of how maintenance activities including associated temporary changes are assessed and managed in accordance with the Maintenance Rule, 10 CFR 50.65:

Procedures are in place to control maintenance activities and evaluate temporary changes that have the potential to affect the debris source term.

The containment entry procedures contain requirements for control of materials during work activities conducted in the containment building during modes 1 through

4. Following maintenance activities in the containment building, procedures that control the containment cleanliness verification process specifically require both general area and target area cleaning.

Changes implemented as temporary alterations in support of maintenance that impact plant design are required to be developed in accordance with the same design change procedures that are used for all plant modifications. As described in section 2, the plant modification procedures contain administrative controls that specifically address potential impacts of debris on the ECCS performance.

Response to 3.i.5. Recent or planned insulation change-outs in the containment which will reduce the debris burden at the sump strainers:

During Refueling Outage XIV, replacement SGs were installed. The replacement SGs were furnished with RMI, which replaced the jacketed NUKON insulation that had been previously installed. The installation of RMI on the replacement SGs is presently accounted for in the debris source term. There are no forthcoming planned insulation change-outs that would reduce the debris burden at the sump strainers.

Response to 3.i.6. Any actions taken to modify existing insulation (e.g.,

jacketing or banding) to reduce the debris burden at the sump strainers:

There are no planned actions to modify existing insulation (e.g., jacketing or banding) to reduce the debris burden at the sump strainers.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 61 of 126 Response to 3.i.7. Modifications to equipment or systems conducted to reduce the debris burden at the sump strainers:

There are no planned modifications to equipment or systems to reduce the debris burden at the sump strainers.

Response to 3.i.8. Actions taken to modify or improve the containment coatings program:

There are no planned actions to modify the existing containment coatings to reduce the debris burden at the sump strainers.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 62 of 126 3.j. Screen Modification Package The objective of the screen modification package section is to provide a basic description of the sump screen modification.

1. Provide a description of the major features of the sump screen design modification.

2. Provide a list of any modifications, such as reroute of piping and other components, relocation of supports, addition of whip restraints and missile shields, etc., necessitated by the sump strainer modifications.

Response to 3.j.1. Provide a description of the major features of the sump screen design modification:

New sump strainers were installed in the two containment Recirculation Sumps during Callaway Refueling Outage XV. The PCI Sure-FlowTM Strainers were installed in the sump pits to accommodate the post-accident containment water levels. Figure 3.j-1 shows an isometric view of the location of the sumps in the containment building below two SI accumulator tanks located in the lower left portion of the figure. Figure 3.j-2 shows a closer view of the sump pits.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 63 of 126 Figure 3.j-1: Isometric View of Lower Containment

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 64 of 126 Figure 3.j-2: Close-Up View of Lower Containment Each new sump strainer is made up of 72 modules. Eight modules are seven plate/disks high and 64 modules are eleven plates/disks high (Refer to Figure 3.j-3).

The modules are arranged in a square matrix of 16 modules on each level, except for the bottom level that has only eight modules (Refer to Figures 3.j-4 and 3.j-5).

Each stack of modules (see Figure 3.j-5) is an integrated unit that equalizes the flow rate and corresponding pressure drop across the perforated plate at each level and allows for a distributed pressure drop across the column. The strainers are installed on a strainer substructure assembly, which is installed at the bottom of the containment recirculation sump pit. The strainers superstructure consists of four vertical supports on the 2000' elevation concrete pad. These supports are inside the sumps 6-inch concrete curb. A series of horizontal channels connect to the four vertical supports and provide lateral restraint for the module stacks. The strainers are robust so as to also serve as the trash racks, as described in the license amendment application (Reference 23 and 30). The strainers have 0.045-inch holes in the perforated stainless-steel plate surfaces. The materials for the strainer supports, both the lower support platform and the superstructure, are also stainless steel.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 65 of 126 Figure 3.j-3: 11 Disk Sump Strainer Module Detail

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 66 of 126 Figure 3.j-4: 11 Sump Strainer Plan View

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 67 of 126 Figure 3.j-5: 11 Disk Sump Strainer Section Detail The original containment recirculation sump screens and trash racks had approximately 200 ft2 of effective surface area per sump. The new replacement sump strainers have approximately 3300 ft2 of effective surface area per sump that can handle the amount of debris generated and carried to the sumps. A significant design feature of the new PCI Sure-Flow strainers ensures uniform flow rate through all sections of the modules. This ensures that during post-accident operation, debris is not preferentially distributed to certain areas of the strainer.

Additionally, as a result of the increased surface area, the approach velocity of the recirculation coolant flow at the sump strainer face will be less than 0.01 ft/s.

Response to 3.j.2. Provide a list of any modifications, such as reroute of piping and other components, relocation of supports, addition of whip restraints and missile shields, etc., necessitated by the sump strainer modifications:

As mentioned in section 3.e.4 above, debris barriers have been installed in all openings through the secondary shield wall near the emergency recirculation

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 68 of 126 sumps. The barriers prevent the flow of debris-laden fluid directly to the sumps and force the fluid to take a "long path" through shield wall openings farther away from the sumps. Using perforated plates with a hole size of 1/8 inch, the debris barriers are designed to restrict passage of debris while allowing water to pass through the barrier. While not specifically credited in the debris transport analysis, the effect of any water flow through the "A" and "D" debris will lower pool velocity out the "B" and "C" loop openings. This is conservative compared to the current transport analysis which assumes all water flows out the "B" and "C" loop openings. Debris barriers have been installed in the Loop A and Loop D passageway entrances through the secondary shield wall, as well as in drain trenches and other openings in the secondary shield wall near the sumps. Blockage of small and large piece debris through Loop A and Loop D passageways and other openings was included in the transport modeling.

Based on the interference with the new containment recirculation sump strainers, two additional changes were necessary. These changes were relocation of the trisodium phosphate dodecahydrate (TSP) baskets and modification of the containment recirculation level indication.

During the spring of 1995, Callaway replaced the original active spray additive system, which used sodium hydroxide contained in a spray additive tank as the neutralizing agent, with TSP. The TSP baskets were originally installed inside the original containment sump recirculation screens and placed over the containment sump pit. As a result of the installation of the new containment recirculation sump strainers, these baskets were relocated several feet because their current locations would cause a physical interference with the strainers.

As a result of the new strainer design, the recirculation sump level indication, which resides inside the 6-inch curb surrounding the containment recirculation sump strainers, was relocated and modified. The previous sump level instrumentation was modified by removing the portion of each level instrument that was located inside the containment recirculation sump. This change was considered acceptable since 1) the containment normal sumps provide indication to satisfy post-accident containment sump level indication and 2) the presence of the 6-inch curb surrounding the containment recirculation sumps would not allow indication of containment flooding until at least 6 inches of water was on the containment floor.

Note that there is no curb surrounding the two containment normal sumps.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 69 of 126 3.k. Sump Structural Analysis The objective of the sump structural analysis section is to verify the structural adequacy of the sump strainer including seismic loads and loads due to differential pressure, missiles, and jet forces.

Provide the information requested in GL 2004-02 Requested Information Item 2(d)(vii).

GL 2004-02 Requested Information Item 2(d)(vii)

Verification that the strength of the trash racks is adequate to protect the debris screens from missiles and other large debris. The submittal should also provide verification that the trash racks and sump screens are capable of withstanding the loads imposed by expanding jets, missiles, the accumulation of debris, and pressure differentials caused by post-LOCA blockage under flow conditions

1. Summarize the design inputs, design codes, loads, and load combinations utilized for the sump strainer structural analysis.

2. Summarize the structural qualification results and design margins for the various components of the sump strainer structural assembly.

3. Summarize the evaluations performed for dynamic effects such as pipe whip, jet impingement, and missile impacts associated with high-energy line breaks (as applicable).

4. If a backflushing strategy is credited, provide a summary statement regarding the sump strainer structural analysis considering reverse flow.

Response to 3.k., Item 2(d)(vii). Verification that the strength of the trash racks is adequate to protect the debris screens from missiles and other large debris. The submittal should also provide verification that the trash racks and sump screens are capable of withstanding the loads imposed by expanding jets, missiles, the accumulation of debris, and pressure differentials caused by post-LOCA blockage under flow conditions:

The structural evaluation for the replacement strainers, provided by EC-PCI-WC-CAL-6002-6003-1001, concluded that the strainers meet the acceptance criteria for all applicable loadings (i.e. seismic, assumed debris laden operation, and assumed strainer differential pressure). The assumed structural loads were verified to bound the predicted GSI-191 strainer conditions. Also, Callaway does not have trash racks.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 70 of 126 Response to 3.k.1. Summarize the design inputs, design codes, loads, and load combinations utilized for the sump strainer structural analysis:

The sump strainer structural qualification analysis evaluated the strainer modules as well as the supporting structures associated with the strainers. The governing code for qualification of the strainer is the Callaway code of record, the American Institute of Steel Construction (AISC), 7th edition. In circumstances where the AISC code does not provide adequate guidance for the particular component, other codes or standards are used for guidance. The evaluations were performed using a combination of manual calculations and finite element analysis using the GTSTRUDL software and the ANSYS software.

The strainers are designed for the following load combinations:

Seismic loads - The strainers are designed to meet Category I Seismic Criteria.

Both the Operating Basis Earthquake (OBE) and the Safe Shutdown Earthquake (SSE) loads are developed from response spectra curves that envelope the response spectra curves for Callaway. The structures are considered "Bolted steel structures" and the damping values for seismic loads are taken from RG 1.61, Rev.

0 as 4% for the OBE and 7% for the SSE.

Live Loads - Live loads include the weight of the debris accumulated on the strainer and the differential pressure across the strainer perforated plates in the operating condition.

Thermal Loads - Thermal expansion is considered in the design and layout of the structures. The strainers are free to expand in the vertical direction as the superstructure is designed with a sliding connection allowing the strainer modules to expand upward without constraint. In the lateral direction, seismic supports are gapped leaving enough space to accommodate the thermal growth of the strainers and their supports without restraint. The design temperature for the strainers is 268°F, which is the maximum calculated containment sump water temperature during a large-break LOCA. The maximum air temperature inside containment can reach as high as 320°F, however this is a very short term spike and the structure would not have time to heat up to this temperature before the containment air temperature would fall back down to lower levels. Therefore, use of the maximum water temperature for material properties and thermal expansion is appropriate.

Hydrodynamic loads - Hydrodynamic loads on the strainers from the motion of the water surrounding the strainer during a seismic event were also considered.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 71 of 126 Response to 3.k.2. Summarize the structural qualification results and design margins for the various components of the sump strainer structural assembly:

The structural qualification design margins for the various components of the sump strainer structural assembly are listed in Table 3.k-1. At all locations of the structure, the computed stress is less than the associated allowable stress.

Table 3.k-1: Sump Strainer Structural Assembly Components Design Margins Strainer Component Interaction Ratio1 External Radial Stiffener (including Collar and Plates) 0.15 / 0.79 Tension Rods 0.43 / 0.51 Spacers 0.71 / 0.79 Edge Channels 0.10 / 0.96 Cross Bracing Cables 0.08 / 0.41 Hex Couplings 0.17 / 0.69 Core Tube 0.03 / 0.11 Substructure Angle Iron Support Legs 0.57 / 0.71 Substructure Angle Iron Framing (including coped sections and 0.98 / 0.91 angle braces)

Substructure Channels (including coped sections) 0.92 / 0.94 Cover Plates 0.33 / 0.46 Superstructure Square Tubing Support Legs 0.19 / 0.74 Superstructure Channels 0.13 / 0.60 Perforated Plate (DP Case) 0.80 / 0.66 Perforated Plate (Seismic Case) 0.31 / 0.29 Perforated Plate (Inner Gap) 0.972 / 0.9996 Wire Stiffener2 0.70 Perforated Plate (Core Tube End Cover DP Case) 0.70 / 0.60 Perforated Plate (Core Tube End Cover Seismic Case) 0.07 / 0.08 Radial Stiffening Spokes of the End Cover Stiffener 0.12 / 0.11 Core Tube End Cover Sleeve 0.08 / 0.05 Weld of Radial Stiffener to Core Tube 0.07 / 0.31

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 72 of 126 Strainer Component Interaction Ratio1 Weld of mounting tabs to End Cover Stiffener 0.02 / 0.01 Weld of End Cover Stiffener to End Cover Sleeve 0.07 / 0.05 Edge Channel Rivets 0.05 / 0.67 Inner Gap Hoop Rivets 0.09 / 0.08 End Cover Rivets 0.03 / 0.02 Connecting Bolts and Pins 0.50 / 0.63 Mounting Pin Weld 0.43 / 0.80 Substructure Sealing Plates 0.99 Substructure Bolted Connections 0.76 / 0.93 Substructure Welded Connections 0.46 / 0.77 Substructure Post Jack Bolt and Baseplate 0.63 / 0.71 Substructure Wall Jack Bolts 0.39 / 0.39 Superstructure Bolted Connections 0.08 / 0.79 Superstructure Welded Connections 0.22 / 0.82 Superstructure Expansion Anchors3 0.15 / 0.88 / 0.64 Superstructure Anchor Base Plate3 0.16 / 0.64 I 0.76 Superstructure Anchor Base Plate Stiffener Welds3 0.18 / 0.76 I 0.40 1 Interaction Ratio, i.e., the calculated stress divided by the allowable stress. Listed as OBE/SSE cases unless noted otherwise.

2 DP loads only 3 Worst case OBE/SSE for ShearX, ShearY, and Tension The assumed GSI-191 inputs to the structural evaluation are compared to ensure the assumed loads bound the predicted results. Table 3.k-2 contains a comparison of the implemented differential pressure for structural evaluations of the strainer versus the maximum differential pressure measured during head loss tests. The comparison shows that the maximum measured differential pressure is less than the implemented differential pressure for structural evaluations at both indicated temperatures.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 73 of 126 Table 3.k-2: Sump Strainer Head Loss Margin Structural Head Tested Head Loss, Head Loss Margin, Condition Loss Limit, ft-water ft-water ft-water Hot, 268 oF 4.2 4.1 0.1 Cold, 185 oF 5.6 4.2 1.4 Also, the mass of debris implemented in the structural evaluation is compared to the mass of debris predicted to reach the strainers assuming 100% filtrations (all debris is captured by the strainer). Total debris mass implemented as a boundary condition on a single train in the structural analyses is 4330.8 lbm. The maximum amount of debris transported to the strainer for a single LOCA among all examined cases that do not exceed the tested RoverD fiber limit is 5408.3 lbm, which consists of masses displayed in Table 3.k-3. Fiber and qualified coatings are break-dependent debris sources, and 344.5 lbm is the largest amount of break-dependent debris that is transported to a strainer for any individual successful break. Unqualified coatings, latent fiber, latent particulate, and fiber margin masses contribute to every break regardless of size. Chemical load with Largest LDFG Debris Generated with Intact Blankets for RoverD Success Cases is the chemical load with the maximum quantity of LDFG debris generated for successful RoverD cases.

Table 3.k-3: Sump Strainer Debris Loadings Debris Type Mass, lbm Break Dependent Debris (Fiber + Qualified 344.5 Coatings)

Unqualified Coatings 4,370.0 Latent Fiber 28.8 Latent Particulate 163.2 Fiber Margin 50.0 Chemical Load with Largest LDFG Debris Generated with Intact Blankets for RoverD 451.8 Success Cases Initial comparison of the maximum transported debris mass associated with all LOCA that pass the tested RoverD fiber limit to the assumed structural mass limit suggests that the analyzed structural load can be exceeded by a maximum of 5408.3 lbm - 4330.8 lbm = 1,077.5 lbm. Recall that all cases exceeding the tested RoverD fiber limit are already relegated to core damage. Thus, any incremental risk caused by seismic-induced LOCA can only be caused by cases having debris beds with less fiber than the RoverD limit, and more total mass than assumed in the mechanical load evaluation. The difficulty is that unqualified coatings present in

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 74 of 126 every break cause the excess load. This initial assessment is mitigated by the following considerations.

If two trains are active, a maximum debris mass of 5408.3/2 = 2704.2 lbm is distributed to each train, and the debris mass on each strainer is bounded by the boundary condition of the structural analysis. Therefore, two-train operation, the dominant system response scenario, is certified by the structural analysis with significant margin.

For single-train operation, the maximum amount of debris possible on the strainer exceeds the debris mass boundary condition without credit for coatings pull tests of Carboline 193LF primer and 191HB topcoat (Reference [17]). Prior to a discussion of pull test results, the history of this coatings system needs to be understood.

Carboline 193LF primer and 191HB topcoat were applied with an SP-3 surface preparation method to unprimed structural steel, touch-up of damaged coatings, and small-bore pipes. At the time of application, the coating system and application method were considered qualified. However, tests performed on this coating system by an independent lab showed poor adhesion, and Callaway revised this coating systems classification to unqualified. In 2018, Callaway performed pull tests at twelve locations with three replicates each for a total of thirty six tests of Carboline 193LF primer and 191HB topcoat to measure adhesion to a substrate. Conclusions from the pull tests are quoted below (Reference [17]).

All test locations exhibited average adhesion strength in excess of 200 psi, which is the original design requirement stated in ANSI N5.12-1974, Protective Coatings (paints) for the Nuclear Industry. Coating system adhesion strength of greater than 200 psi has, in the past, been correlated to acceptable visual inspection by industry experts as documented in EPRI TR-1019157. This past EPRI research provides the basis for NRC accepted visual coatings inspection of safety-related coatings systems in lieu of containment wide physical testing. Similarly, based on the successful (>200 psi) adhesion test results documented in this evaluation for all tested locations including those acceptable by visual inspection, all steel surfaces coated with the 193LF/191HB coating system and having an acceptable visual inspection per PM16505768 can be assumed to have an adhesion strength greater than 200 psi.

Further the 193LF/191HB system utilized in containment has been shown in past Oak Ridge National Laboratory testing to stay attached during DBA immersion testing, and was only downgraded from a qualified to a non-qualified system based on Bechtel reporting of blistering and poor adhesion during testing at an independent laboratory. The 193LF/191HB system did pass an independent laboratory tensile adhesion test. The

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 75 of 126 plant-specific results in this report prove adhesion for the Callaway inspection, which combined with the results of Oak Ridge National Lab testing prove DBA LOCA performance. The Carboline 193LF/191HB system applied over a SP-3 cleaned surface will remain on the unqualified coatings log but may be evaluated with improved DBA performance in future evaluations based on this plant-specific testing.

Reclassifications of visually acceptable Carboline 193LF and Carboline 191HB from unqualified coatings to qualified coatings result in a reduction of 1105.3 lbm. Therefore, the total mass predicted to reach a single strainer from the largest inventory LOCA passing the RoverD threshold is 4303.0 lbm, which does not exceed the rated performance of the strainer based on a structural analysis load of 4330.8 lbm. Based on Callaway coatings reclassification, seismic induced loads do not add incremental risk to estimated CDF.

Also, during head-loss tests at Alden Research Laboratories, Callaway strainers withstood 4.2 ft of head loss and total debris introduction of 6339.4 lbm (at plant scale) without any visually observed mechanical defects. Masses introduced to the head-loss test exceed the structural analysis boundary condition by approximately 50%. Since the objective of the head-loss tests was to determine hydraulic success for ECCS pump performance, the plenum holding up the strainers was not modeled and the strainers were not accelerated (shaken) during hydraulic testing.

Based on the preceding justifications, the mass implemented in the structural analysis is deemed bounding to the masses predicted to reach the strainers.

Response to 3.k.3. Summarize the evaluations performed for dynamic effects such as pipe whip, jet impingement, and missile impacts associated with high-energy line breaks (as applicable):

Locations of the strainers provide significant protection from dynamic effects such as pipe whip, jet impingement, and missile impacts associated with a high-energy line break. The recirculation sump strainers are outside the secondary shield wall and are located inside a pit where approximately 1 ft of the strainers are above the reactor containment building floor. A concrete structure is also approximately 7 ft above the strainers and a concrete wall divides the strainer trains. Structural steel that stabilizes the top of the strainer stacks would also provide protection. Figures 3.k-1, 3.k-2, and 3.k-3 illustrate many of the described features.

Also, high-energy pipes are not located in this region. Therefore, the strainers are not susceptible to damage from pipe whip, jet impingement, or missiles associated with high-energy line breaks.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 76 of 126 Figure 3.k-1: Picture of Emergency Sump Strainer A

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 77 of 126 Figure 3.k-2: CAD Picture of Strainer

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 78 of 126 Figure 3.k-3: Drawing with Cross-Sectional of Strainer Response to 3.k.4. If a back flushing strategy is credited, provide a summary statement regarding the sump strainer structural analysis considering reverse flow:

A back flushing strategy is not used for mitigating an excessive strainer head loss condition.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 79 of 126 3.l. Upstream Effects The objective of the upstream effects assessment is to evaluate the flowpaths upstream of the containment sump for holdup of inventory which could reduce flow to and possibly starve the sump.

Provide a summary of the upstream effects evaluation including the information requested in GL 2004-02 Requested Information Item 2(d)(iv).

GL 2004-02 Requested Information Item 2(d)(iv)

The basis for concluding that the water inventory required to ensure adequate ECCS or CSS recirculation would not be held up or diverted by debris blockage at choke-points in containment recirculation sump return flowpaths.

1) Summarize the evaluation of the flow paths from the postulated break locations and containment spray washdown to identify potential choke points in the flow field upstream of the sump.

2) Summarize measures taken to mitigate potential choke points.

3) Summarize the evaluation of water holdup at installed curbs and/or debris interceptors.

4) Describe how potential blockage of reactor cavity and refueling cavity drains has been evaluated, including likelihood of blockage and amount of expected holdup.

The information previously provided by Ameren Missouri to GL 2004-02, of upstream effects evaluation and Requested Information Item 2(d)(iv) (Reference [2]) continues to apply.

Response to 3.l., Item 2(d)(iv). The basis for concluding that the water inventory required to ensure adequate ECCS or CSS recirculation would not be held up or diverted by debris blockage at choke-points in containment recirculation sump return flowpaths The discussion that follows provides a basis for concluding that water inventory required to ensure adequate ECCS and CSS recirculation would not be held up or diverted by debris blockage at choke-points in containment recirculation sump return flowpaths.

The upstream effects evaluation process described below conforms to section 7.2 of NEI 04-07, Vol. 2 SE (Reference [1]).

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 80 of 126 Response to 3.l.1. Summarize the evaluation of the flow paths from the postulated break locations and containment spray washdown to identify potential choke points in the flow field upstream of the sump:

The Callaway upstream effects evaluation includes an assessment of the Callaway containment geometry and transport pathways that CS flow and ECCS leakage from the RCS will follow to the lower elevations of the containment building. The evaluation is based upon a review of Callaway design drawings and photographs of inside the containment building.

Each elevation of the containment building was reviewed to identify the physical and structural features that affect the flow of debris and water to the lower elevations of the containment building. The containment building was divided into seven general compartments for individual evaluation separated by grating, concrete walls, and concrete floors.

1. Upper containment including lay down area (elevation 2068'-8" to dome elevation 2205'-0"): Overall the area at this elevation is open with numerous areas of floor grating, which would allow water to pass through to the lower elevations unencumbered. There is one small area of concrete flooring near the pressurizer valve rooms, but water in this location will flow to the grated or open areas surrounding it. This area is open inside and outside the secondary shield walls down to the operating floor at elevation 2047'-6". No potential choke points or hold-up points were identified in this area.

2. Operating floor (elevation 2047'-6"): Overall the area is open inside and outside the SG secondary shield walls to allow water flow to the lower elevations. The area is open inside these secondary shield walls down to elevation 2001'-4" and outside the secondary shield walls down to the operating floor at elevation 2047'-

6". No potential choke points were identified at this elevation.

A hold-up point in this area of the containment building is the reactor head storage and decontamination area. Water collected on the head stand will drain to the surrounding floor but water will be retained by a curb surrounding the head stand. The area inside the curb has a 4-inch floor drain that directs water to a common drain header and then to the drain trenches at the ground floor elevation. However, the drain could become plugged with debris and is not considered functional for this evaluation.

3. Annulus and inside secondary shield (elevation 2026'-0"): Major equipment and features in this area include the main steam and feedwater lines, the tops of the A and D SI accumulators, several HVAC openings, and a compartment for the letdown orifices, the top of which is located at elevation 2036'-0". The northern,

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 81 of 126 northwestern, and southwestern sides of the annulus have mostly concrete floors while the rest of the elevation outside the secondary shield is grated. There are no curbs associated with the concrete floors, so water inventory will flow to the lower elevations without holdup. No potential choke points or hold-up points were identified at this elevation.

4. Refueling pool (elevation 2009'-9" and elevation 2007'-2"): The refueling pool floor (elevation 2009'-9") contains two 10" drains that are sealed with flanges during refueling operations and are completely open during power operations.

There are debris exclusion devices (trash rack cages) installed during power operations to prevent the drain from becoming a choke point. Each debris exclusion device, described in more detail below, is welded to a flange which is bolted to the drain. The flange is approximately 2 inches thick which creates a 2-inch hold-up volume below the flange elevation.

There is an upending pit below the refueling pool floor elevation at elevation 2007'-2". The drain in the upending pit is a 4-inch line which is normally isolated with a normally closed valve. This area is a hold-up point that would retain water inventory following a postulated design-basis accident (post-DBA). No potential choke points were identified at either of these elevations.

5. Ground floor inside secondary shield (elevation 2001'-4"): There are only four significant openings through which post-DBA recirculation water may pass through the secondary shield wall. These passageways provide personnel and equipment access through the secondary shield wall in an area near each of the four RCPs, and include steps to transition from the 2001'-4" floor elevation inside the secondary shield wall to the 2000'-0" floor elevation outside the wall. Three of the four openings are approximately six feet wide. The fourth opening, entering under the pressurizer near the "D" loop RCP, is approximately 3-feet wide. In Figure 3.l-1, the opening near the "A" loop RCP is shown to the left of the sump pits and the opening near the "D" loop RCP is shown to the right of the sump pits.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 82 of 126 Figure 3.l-1: Isometric View of Sump Pit Area Additionally, there is a system of small drain trenches, approximately one-foot wide by one-foot deep that surround the primary shield wall and transfer drain water to outside the secondary shield wall. Trenches and drain piping outside the secondary shield walls direct drainage to the normal containment sumps (which are not part of the ECCS) located in the containment ground floor annulus at elevation 2000'-0". Since the containment flood level will exceed the floor elevation inside the secondary shield wall, the trench system is expected to transport water to the containment annulus.

Debris barriers have been installed in the Loop A and Loop D passageway entrances through the secondary shield wall, which are near the containment recirculation sumps. Debris barriers have also been installed in the portions of the drain trenches and other openings in the secondary shield wall that are near the recirculation sumps. The debris barriers at the Loop A and Loop D entrances and the drain trenches are fabricated using perforated plate with 1/8-inch holes to restrict passage of debris while allowing water to pass through the barrier. The barriers prevent the flow of debris laden fluid directly to the sumps and force the fluid to take a "long path" through shield wall openings farther away from the sumps. A portion of the drain trench in the containment annulus region can be seen in Figure 3.l-1, with a trench opening through the secondary shield wall just to the right of the Loop D passageway.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 83 of 126 The remaining two open six foot wide passageways through the secondary shield wall will transport the ECCS break flow and CSS flow from inside the secondary shield to the containment annulus without restriction. In addition, the remaining trenches penetrating the secondary shield wall will also pass a significant quantity of water from inside the secondary shield wall to the containment annulus. Given these large passageways and large total trench length, large debris or mounds of debris would not create a choke point or hold-up point preventing the recirculation fluid from transporting to the sump. For added conservatism and ease of analysis, no water flow through the drain trenches is accounted for in the CFD model.

6. Ground floor, annulus (elevation 2000'-0"): The containment building emergency recirculation sumps are also located in this annular region between the secondary shield wall and the containment wall, as shown in Figure 3.l-1. A 6-inch curb surrounds each sump pit, creating a 6-inch deep hold-up volume above the 2000'-0" floor elevation. As discussed above, the normal containment sumps receive water flow from the drain trenches and piping in this area. This represents an additional hold-up volume below the 2000'-0" floor elevation.

Given the large flow passages in the annulus region, significant mounds of debris would not create a choke point preventing the recirculation fluid from transporting to the sump.

7. Reactor cavity basement and incore instrumentation tunnel and sump (elevation 1970'-6"): This area of evaluation encompasses the area under the reactor vessel in the reactor cavity as well as the incore instrumentation tunnel. Post-DBA water inventory flow to this area will come from the elevation 2001'-4" hatch north of the primary shield wall when the flood height exceeds 2001'-10" due to the protective 6-inch curb. In addition, flow to this area will also come from the permanent cavity seal ring access covers. This tunnel and area under the reactor cavity will retain water inventory during post-DBA recirculation mode operations. No potential choke points were identified in this area.

Response to 3.l.2. Summarize measures taken to mitigate potential choke points:

Administrative controls ensure the drains from the refueling cavity to lower containment are not obstructed during power operations.

Response to 3.l.3. Summarize the evaluation of water holdup at installed curbs and/or debris interceptors:

As discussed above, a 6-inch curb surrounds each containment recirculation sump pit, creating a 6-inch deep hold-up volume above the 2000'-0" floor elevation. Debris barriers installed in the Loop A and Loop D passageway entrances through the

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 84 of 126 secondary shield wall do not impact water hold-up since Loop B and Loop C passageways allow debris laden fluid to flow into the containment building annulus area and to the recirculation sumps.

Response to 3.l.4. Describe how potential blockage of reactor cavity and refueling cavity drains has been evaluated, including likelihood of blockage and amount of expected holdup:

The refueling pool floor (elevation 2009'-9") contains two 10-inch diameter drains that are open during power operations. There are debris exclusion devices (trash-rack cages) installed during power operations over each of the 10-inch drains to prevent large pieces of debris from plugging the drains. The trash rack cages measure 33.5" x 33.5" x 15" with 5-inch openings. Figure 3.l-2 shows a trash rack cage installed over one of the 10-inch drains.

The 10-inch drains go straight through the refueling cavity floor slab and discharge into the open area below; thus, the drain pipes themselves would not become plugged with debris. Administrative controls ensure the drains from the refueling cavity to lower containment are not obstructed during power operations.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 85 of 126 Figure 3.l-2: Refueling Pool Trash Rack Cage

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 86 of 126 3.m. Downstream Effects - Components and Systems The objective of the downstream effects, components and systems section is to evaluate the effects of debris carried downstream of the containment sump screen on the function of the ECCS and CSS in terms of potential wear of components and blockage of flow streams. Provide the information requested in GL 04-02 Requested Information Item 2(d)(v) and 2(d)(vi) regarding blockage, plugging, and wear at restrictions and close tolerance locations in the ECCS and CSS downstream of the sump.

GL 2004-02 Requested Information Item 2(d)(v)

The basis for concluding that inadequate core or containment cooling would not result due to debris blockage at flow restrictions in the ECCS and CSS flowpaths downstream of the sump screen, (e.g., a HPSI throttle valve, pump bearings and seals, fuel assembly inlet debris screen, or containment spray nozzles). The discussion should consider the adequacy of the sump screens mesh spacing and state the basis for concluding that adverse gaps or breaches are not present on the screen surface.

GL 2004-02 Requested Information Item 2(d)(vi)

Verification that the close-tolerance subcomponents in pumps, valves and other ECCS and CSS components are not susceptible to plugging or excessive wear due to extended post-accident operation with debris-laden fluids.

1. If NRC-approved methods were used (e.g., WCAP-16406-P with accompanying NRC SE)1, briefly summarize the application of the methods. Indicate where the approved methods were not used or exceptions were taken, and summarize the evaluation of those areas.

2. Provide a summary and conclusions of downstream evaluations.

3. Provide a summary of design or operational changes made as a result of downstream evaluations.

1The draft NRC SE for this document was issued to the applicant in November 2007.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 87 of 126 Response to 3.m., Item 2(d)(v). The basis for concluding that inadequate core or containment cooling would not result due to debris blockage at flow restrictions in the ECCS and CSS flowpaths downstream of the sump screen, (e.g., a HPSI throttle valve, pump bearings and seals, fuel assembly inlet debris screen, or containment spray nozzles). The discussion should consider the adequacy of the sump screens mesh spacing and state the basis for concluding that adverse gaps or breaches are not present on the screen surface.

The discussion that follows provides a basis for concluding that inadequate containment cooling will not occur due to debris blockage at flow restrictions in ECCS and CSS flow paths downstream of the sump strainer, such as HPSI throttle valves, pump bearings and seals and CS nozzles.

Analysis was performed using the methodology outlined in WCAP-16406-P (Reference [18]). No exceptions were taken to the WCAP-16406-P-A methodology.

The analysis concluded that no modifications to components or instrumentation were necessary.

The following methodology was used:

a. The safety function of the containment heat removal systems and the ECCS that use the containment recirculation sump as the source for system cooling water was reviewed.

b. The systems for supporting the safety functions of the containment heat removal systems and the ECCS were identified.

c. The flow paths for each system used during recirculation mode were identified.

d. Flow diagrams, piping and instrumentation drawings, operating procedures, vendor manuals, etc., were reviewed to determine valve position(s) and the size of the flow passages in each component in the flow path.

e. The flow passageway for components in which there is a potential plugging concern was compared to the debris size.

Dimensions of particulates passing through a passive sump screen were determined as:

a. The width of deformable particulates that may pass through the sump screen is limited to the size of the flow passage hole in the sump screen, plus 10 percent.

b. The thickness of deformable particulates that may pass through the sump screen is limited to one-half the size of the flow passage hole.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 88 of 126

c. The maximum length of deformable particulates that may pass through the flow passage hole in the sump screen is equal to two times the diameter of the flow passage hole.

d. The thickness and/or width and maximum length of non-deformable particulates that may pass through the sump screen is limited to the size of the flow passage hole in the sump screen.

The strainer area for Callaway is 6623 ft2 (Reference [19]) assuming two operable trains to all allow the maximum about of debris to bypass and come into contact with downstream components and instrumentation. The debris load at Callaway includes fiber, coatings (unqualified and qualified), particulates, and chemicals.

Callaway has evaluated the downstream impact of sump debris on the performance of the ECCS and CSS following a LOCA. The analysis includes erosive wear, abrasion, and potential blockage of flow paths induced by debris ingested through the containment sump screen during the recirculation mode of the ECCS and CSS for an allotted mission time of 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br />. Wear evaluations take into account the concentration of debris in the recirculation water as well as the size of the debris.

This information is given in [20].

Table 3.m-1: Initial Mass Concentration for the Debris Load Mass Concentration, Debris Type Size ppm Penetrating Fiber

>100 m 25 (Includes Latent Fiber)

Qualified Coatings 10 m 115 Depleting Coating Chips (large) >400 m 244 Non-Depleting Coatings (medium) 100 m to 400 m 16 Non-Depleting Coatings (small) 10 m 224 Latent Particulate 10 m 18 Chemical Debris 10 m 64 Components evaluated for erosive wear include valves, spray nozzles and orifice plates in the recirculation flow path, the tube side of RHR heat exchangers, as well as, RHR, CS, CC and SI pumps for both suction and discharge sides. The analysis showed that for a constant debris concentration over the mission time of 30 days, erosive wear on these components is determined to be insufficient to affect the system performance. All pumps were evaluated for abrasive wear on suction and discharge sides, no pumps showed limited operation over the 30 day mission time.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 89 of 126 Blockage analysis was conducted for components, based on maximum deformable debris size of 0.094 and non-deformable debris size of 0.047 (Reference [21]).

Debris ingestion sizes are in relation to the containment sump strainers comprised of perforated plate with 0.045 +/- 0.002 holes and assuming that deformable debris may bypass at two times the diameter of the hole. Based on the determined debris size each recirculation-critical flow channel, valve and nozzle at Callaway will not fail due to the recirculation of debris laden fluid according to acceptance criterial stated in WCAP-16406-P that when a flow passage is greater than 1 inch diameter and fluid velocity remains above 0.42 ft/s plugging will not occur.

The instrumentation tubing is also evaluated for potential blockage of the sensing lines. There are static flow instrument lines to various pressure or differential pressure transmitters connected to the system piping. The lines are nominally 0.75" in size. There is no flow from the main process line into these static instrument lines that would cause fiber or particulate matter to enter the lines. The instrumentation lines in the main process lines of the RHR system are all attached above the piping centerline, this placement eliminates the concern for debris settlement that could adversely affect the associated instruments.

Response to 3.m., Item 2(d)(vi). Verification that the close-tolerance subcomponents in pumps, valves and other ECCS and CSS components are not susceptible to plugging or excessive wear due to extended post-accident operation with debris-laden fluids.

The discussion that follows provides a basis for concluding that ECCS and CSS components are not susceptible to excessive plugging or excessive wear due to extended post-accident operation with debris-laden fluids.

Callaway pump bearings and seals were evaluated for plugging and determined to not be susceptible to deformable or non-deformable debris obstructing flow. The bearings, seals, and impellers were evaluated for wear and it was determined that for a 720 hour0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> mission time, any wear imparted by debris laden fluid would be within acceptable limits. The evaluation was consistent with the methodology presented in WCAP-16406-P (Reference [18]).

Response to 3.m.1. If NRC-approved methods were used (e.g., WCAP-16406-P with accompanying NRC SE)1, briefly summarize the application of the methods. Indicate where the approved methods were not used or exceptions were taken, and summarize the evaluation of those areas:

The evaluations that provide the bases for conclusions presented in this section were developed using WCAP-16406-P-A, Evaluation of Downstream Sump Debris Effects in Support of GSI-191 Revision 1 and the accompanying NRC SER

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 90 of 126 (Reference [18]). No exceptions were taken but there are items to note in the following categories;

1. Debris Size Distribution GSI-191 head loss evaluations commonly assume unqualified coatings failure is biased to a 10-µm particulate size, providing a higher fraction of debris that is transported to the strainer and a higher head loss response. However, this does not pose a challenging load for downstream effect analysis. Although generally used to describe degraded qualified coatings, the Alion-Comanche Peak failure fractions and size distribution, based on autoclave testing of degraded qualified coatings, is used to create a more reasonably challenging debris load for the Callaway wear evaluations. Furthermore, the fraction of failed fine coatings (49.51%) from the Alion-Comanche Peak distribution does not provide more specific size data for chips smaller than 1/8, which account for 12.4% of the 49.51% fines. Thus, 12.4% of 49.51%, or 6.14% of all failed coatings are assumed to be particulate in the range of 100 µm to 400 µm. Table 3.m-2 shows the failure fractions used in the Callaway downstream effects analysis.

Table 3.m-2: Modified Alion-Comanche Peak Epoxy Failure Mass Fractions Total Debris Load Debris Classification Fractions Fine (Assumes 12% of the 49.51% is 100 µm to 400 6.14%

µm)

Fine (Assumes other 88% of 49.51% is >400 µm) 43.36%

Flat small chips 5.02%

Flat small chips 4.41%

Flat large chips 20.54%

Curled chips 20.54%

2. Particulate Penetration Particulate penetration fraction of 24% was determined from a thin-bed test.

Based on multiple industry strainer head loss tests, an estimate of 76% strainer capture of chemical debris is reasonable, and the actual value would be greater.

Chemicals are assumed to form 10-m particles, but are likely much smaller, and while small debris is not the highest contributor to wear, ultimately assuming more debris bypassing the strainer will cause greater wear on downstream components

3. Debris Depletion Callaway downstream wear evaluation takes into account debris depletion for pump evaluations. Fibrous debris, transportable RMI, particulate debris 100 m

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 91 of 126 (except coatings), and coatings 400 m are assumed to deplete over time. A debris depletion coefficient () of 0.07 hr-1 is assumed corresponds to a depletion half-life of 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> in accordance with WCAP-16406-P methodology.

4. Unqualified Coatings.

Due to the high transportability of small particulate, all unqualified coatings are assumed to fail as 10-m spheres with 100% transportability to the sump strainer, effectively increasing the debris load that bypasses the strainer.

5. Fluid Velocity The Callaway downstream wear calculation models the fluid velocity to be equal to the velocity at time zero (t=0). This modeling assumption is based on the principle that velocity is inversely proportional to the flow area of the component that the fluid is moving through for a constant volumetric flow rate. As a component begins to wear, the velocity will decrease slightly and potentially decelerate the wear rate.

The items above do not deviate from the WCAP-16046-P methodology and their implementation increases the conservatism built in to the Callaway downstream effects evaluation.

Response to 3.m.2. Provide a summary and conclusions of downstream evaluations:

The evaluations summarized in this section show that, using NRC-approved analysis methodologies and plant-specific equipment properties, inadequate containment cooling will not occur due to debris blockage at flow restrictions in ECCS and CSS flowpaths downstream of the sump strainer, such as HPSI throttle valves, pump bearings and seals and CS nozzles.

The RHR, CS, CC and SI pumps at Callaway were evaluated for downstream wear using maximum WCAP-16406-P methodology and were found not to be compromised by wear imparted by debris ingested in recirculating coolant during an accident. Table 3.m-3 shows the wear-to-design clearance factors for each category of pump.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 92 of 126 Table 3.m-3: Wear-to-Design Clearance Factors for Pumps Clearance Factor Performance Component (wear-to-design) Evaluation Determination RHR Pumps 1.2X Hydraulic Acceptable CS Pumps 1.1X Hydraulic Acceptable Mechanical SI Pumps >2.5X* Acceptable Vibration Mechanical CC Pumps >2.5X* Acceptable Vibration

• Predicted post-wear stiffness is compared to that of the same pump considering symmetric 2.5X wear to both sides of the pump. If the combined asymmetric stiffness is greater than the combined symmetric stiffness, then pump performance is determined to be acceptable.

Valve performance acceptability maintains a design flow area increase of less than 3% at the completion of the mission time. Table 3.m-4 shows the Callaway valves evaluated and the associated flow increase percentage. No valves have an increase of greater than 3% of the original design flow area and thus will not be compromised over the 720 hour0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> mission time.

Table 3.m-4: Valve Flow Increase Over 720 Hour Mission Time Customer ID A/A, %

EMV0089 0.06 EMV0090 0.06 EMV0091 0.06 EMV0092 0.06 EMV0095 0.70 EMV0096 0.41 EMV0097 0.41 EMV0098 0.53 EMV0107 2.18 EMV0108 2.18 EMV0109 2.18 EMV0110 2.18 The acceptance criterion for RHR heat exchangers is that the minimum acceptable tube wall thickness is 0.0173 in. Wear evaluations determined that the eroded

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 93 of 126 thickness of the tube wall would be 0.0489 in, which is considerably more robust than the minimum required thickness. The evaluation shows that the RHR heat exchanger will not be compromised due to debris laden fluid flow over the 720 hour0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> mission time.

A list of orifices evaluated for Callaway is available in Table 3.m-5. According to WCAP-16406-P (Reference [18]) orifices must maintain a change in flow rate of less than the 3% over the 720 hour0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> mission time. The results in Table 3.m-5 show that no orifices at Callaway are expected to fail because of wear imparted by debris ingested in a LOCA.

Table 3.m-5: Orifice Evaluation for Flow Increase over Mission Time Location ID Q/Q (%)

EJFO-2, 3 RHR accumulator 0.119 EPFO-3,4 RHR system EJFO-5,6 0.0101 CS pump discharge ENFE-5,11 0.013 RHR pump discharge EJFE-610, 611 0.020 RHR cold leg injection EJFE-618 0.012 RHR hot leg injection EJFE-988 0.047 CC pump discharge EMFE-917A, B 0.076 CC cold leg injection EMFE-924, 925, 926, 927 1.930 SI pump discharge EMFE-918, 922 0.048 SI cold leg injection EMFE-980, 981, 982, 983 0.744 SI hot leg injection EMFE-984, 985, 986, 987 0.691 The CSS sprays at Callaway are expected to have an increase in flow rate of 0.31%,

over the course of the mission time. This result is well below the allowed 10%

increase acceptance criteria given in WCAP-16406-P (Reference [18]) showing that spray nozzles at Callaway will not fail the mission time due to the recirculation of debris laden fluid.

The instrumentation tubing is also evaluated for potential blockage of the sensing lines. There are static flow instrument lines to various pressure or differential pressure transmitters connected to the system piping. The lines are nominally 0.75" in size. There is no flow from the main process line into these static instrument lines that would cause fiber or particulate matter to enter the lines. The instrumentation lines in the main process lines of the RHR system are all attached above the piping

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 94 of 126 centerline, this placement eliminates the concern for debris settlement that could adversely affect the associated instruments.

Potential for blockage of the reactor vessel level instrumentation system (RVLIS) is not evaluated since Callaway has a Westinghouse designed RVLIS, and according to WCAP-16406-P-A (Reference [18]), the debris ingested through the sump strainers will not affect the reactor vessel water level measurements.

Response to 3.m.3. Provide a summary of design or operational changes made as a result of downstream evaluations:

At this time, no design or operational changes are being implemented to deal with downstream effects.

Plugging of Close-Tolerance Subcomponents:

Close-tolerance subcomponents in pumps, valves and other ECCS and CSS components were evaluated for potential plugging or excessive wear due to extended post-accident operation with debris-laden fluids. The evaluations were developed in accordance with WCAP-16406-P-A, Evaluation of Downstream Sump Debris Effects in Support of GSI-191 Revision 1 and the accompanying NRC SER (Reference [18]). No exceptions were taken to the WCAP-16406-P-A methodology.

The ECCS and CSS included in an evaluation of potential for plugging in downstream components are the CSS, chemical and volume control system (CVCS), high pressure coolant injection system (HPCIS), and the RHR (Reference

[21]).

The potential for plugging of equipment in the ECCS and CSS recirculation flow paths (other than RHR pumps, centrifugal charging pumps, HPCIS pumps, and CSS Pumps) is analyzed in WES004-PR-01, Revision 2 (Reference [21]).

The following methodology was used in WES004-PR-01:

a. The safety function of the containment heat removal systems and the ECCS that use the containment recirculation sump as the source for system cooling water was reviewed.

b. The systems for supporting the safety functions of the containment heat removal systems and the ECCS were identified.

c. The flow paths for each system used during recirculation mode were identified.

d. Flow diagrams, piping and instrumentation drawings, operating procedures, vendor manuals, etc., were reviewed to determine valve position(s) and the size of the flow passages in each component in the flow path.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 95 of 126

e. The flow passageway for components in which there is a potential plugging concern was compared to the debris size.

Dimensions of particulates passing through a passive sump screen were determined as:

a. The width of deformable particulates that may pass through the sump screen is limited to the size of the flow passage hole in the sump screen, plus 10 percent.

b. The thickness of deformable particulates that may pass through the sump screen is limited to one-half the size of the flow passage hole.

c. The maximum length of deformable particulates that may pass through the flow passage hole in the sump screen is equal to two times the diameter of the flow passage hole.

d. The thickness and/or width and maximum length of non-deformable particulates that may pass through the sump screen is limited to the size of the flow passage hole in the sump screen.

Accordingly, the maximum debris size used in the evaluation was 0.094 inch for deformable debris and 0.047 inch for non-deformable debris.

With regard to flow area evaluation for plugging of check valves, section 7.3.3.3 of WCAP-16406-P-A (Reference [18]) states that "in accordance with Westinghouse WCAP-11534 (Reference [22]), a minimum velocity of 0.42 ft/sec is needed to flush the debris in a system. If the minimum velocity is met, the valve will pass the debris, provided the valves are larger than 1 inch. In the event the minimum velocity is not met or the valve is 1 inch or less, vendor input is required. For lift check valves of sizes 1-1/2 inch or greater, the clearance dimension between the plug and the seat is generally greater than 11/32 inch." These criteria were used to assess plugging of check valves.

The results of the assessment performed in WES004-PR-01 (Reference [21]) pertain to four systems that are critical to recirculation. The RHR, volume control, HPCIS and CSS were analyzed and it was found that all valves, piping, flow instruments, heat exchangers and spray nozzles that are involved in recirculation meet the same plugging assessment criteria. Based on deformable particulate size of 0.094 inch and non-deformable particulate size of 0.047 inch, each recirculation-critical flow channel, valve and nozzle was found to be greater than 1 inch diameter and fluid velocity remains above 0.42 ft/s in each case. These results confirm that each component involved in recirculation can accommodate sump bypass particles without plugging.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 96 of 126 Wear and Abrasion:

Assessment of erosive wear and abrasion of equipment wear of ECCS and CSS equipment is based on results of analysis in CN-CSA-05-20, Revision 2 (Reference

[23]).

The mass of debris in recirculating fluid that passes through the sump is characterized in terms of concentration in parts per million (ppm). For downstream effects, the total initial debris comprised of the individual debris concentrations is defined as the ratio of the solid mass of the debris in the pumped fluid to the total mass of water that is being recirculated by the ECCS and CSS. The individual mass concentrations, computed in CN-CSA-05-49, Revision 2 (Reference [24]), rounded up to the nearest whole number for reporting purposes are displayed in Table 3.m.6.

Table 3.m-6: Mass Concentrations Debris Type Concentration (ppm)

Fibrous 33 Particulate 7 Coatings 248 Chemical 8 TOTAL 296 Based on the results in CN-CSA-05-20 (Reference [23]), with no consideration of debris depletion, the erosive wear on heat exchangers, orifices, and spray nozzles due to fluid with 296 ppm debris concentration over a mission time of 30 days is insufficient to affect the system performance.

Pump Performance:

For pumps, three aspects of the effect of debris ingestion through the sump strainers were addressed: (1) hydraulic performance, (2) mechanical shaft seal assembly performance, and (3) mechanical performance (vibration).

Based on the analysis documented in CN-CSA-05-20 (Reference [23]), the hydraulic and mechanical performance of ECCS and CSS pump were determined to be unaffected by recirculating sump debris.

Mechanical shaft seal assembly performance evaluation resulted in two action items:

(1) evaluation of cyclone separators and the impact on their function, and (2) the evaluation of the pumps carbon/graphite backup seal bushings due to the plant-specific debris mix.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 97 of 126 Analysis documented in LTR-SEE-I-08-138 (Reference [25]) showed that the cyclone separators will not become blocked by recirculation debris. Analysis documented in CN-SEE-I-08-67 (Reference [26]) demonstrated that the primary seals are not expected to fail as a function of debris.

Callaway centrifugal charging and safety injection pumps are multi-stage and had to be evaluated for mechanical vibration. Based on the evaluation documented in CN-CSA-05-20 (Reference [23]), using the methodology in Appendix R of WCAP-16406-P-A (Reference [18]), it is shown for both the centrifugal charging and safety injection pumps that the stiffness provided by the worn suction side wear ring is larger than the combined stiffness provided by the suction and discharge wear rings at a symmetric clearance of two times the design clearance. On that basis, the centrifugal charging and safety injection pumps pass the vibration evaluation.

Heat Exchanger Wear:

Tube failure for heat exchangers will occur when the resultant wall thickness after erosion is less than the required wall thickness to retain internal and external pressures.

The analysis in CN-CSA-05-20 (Reference [23]) shows that without consideration of debris depletion, the actual tube wall thickness minus the eroded wall thickness is greater than the wall thickness required to retain pressure. Therefore, failure of the tube wall will not occur. In addition, because erosion of the tube wall due to fluid-borne debris is less than 1% of the actual wall thickness, any pre-existing wear of the heat exchanger tube wall with normal (debris-free) fluid is considered negligible.

Orifice Wear:

To evaluate failure of orifices, the increase in the orifice inner diameter due to erosive wear must be proven to not affect the system performance. Based on section 8.4 of WCAP-16406-P-A (Reference [18]), an insignificant amount of wear occurs when the system flow through the orifice is changed by less than 3%, where 2% is the standard orifice tolerance and 1% is repeatability.

The analysis in CN-CSA-05-20 (Reference [23]) shows that without consideration of debris depletion the change in the system flow from erosive wear through the orifices is less than 3%. Therefore erosive wear will not affect the system performance.

Spray Nozzle Wear:

For spray nozzles, failure due to erosive wear is considered to occur when the flow from the nozzle increases by 10% due to the increase in the nozzle inner diameter.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 98 of 126 The analysis in CN-CSA-05-20 (Reference [23]) shows that without consideration of debris depletion, the change in spray nozzle flow is less than 1%, which is under the 10% criterion. Therefore erosive wear will not affect the spray nozzle performance.

Instrumentation Blockage:

Potential for blockage of the RVLIS is not evaluated since Callaway has a Westinghouse designed RVLIS, and according to WCAP-16406-P-A (Reference

[18]), the debris ingested through the sump strainers will not affect the reactor vessel water level measurements.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 99 of 126 3.n. Downstream Effects - Fuel and Vessel The objective of the downstream effects, fuel and vessel section is to evaluate the effects that debris carried downstream of the containment sump screen and into the reactor vessel has on core cooling.

1. Show that the in-vessel effects evaluation is consistent with, or bounded by, the industry generic guidance (WCAP-16793)2, as modified by NRC staff comments on that document. Briefly summarize the application of the methods. Indicate where the WCAP methods were not used or exceptions were taken, and summarize the evaluation of those areas.

2Because this document is still under NRC review, licensees should be aware of any NRC RAIs on it. The draft NRC SE for WCAP-16793 is expected to be issued in December 2007. After resolution of any open items from the staffs evaluation of this document, the staff will determine whether additional information is needed from licensees. Licensees should not delay their GL responses pending this information.

Callaway assessed downstream in-vessel debris effects using WCAP-17788 methodology [27], debris penetration results obtained from 2016 strainer testing that yielded a 4-parameter correlation for fiber penetration and shedding as a function of strainer load, and pool/vessel recirculation equations implemented for STP risk-informed pilot evaluations. In-vessel analyses were performed assuming 300 lbm of fiber impinging on two operating ECCS strainers, allowing significantly more fiber to pass through the thinner debris beds. Previous WCAP testing determined that in-vessel chemical products will not form prior to 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

There are 193 fuel assemblies in the Callaway reactor core, which has a Westinghouse reactor design with an upflow barrel/baffle region. The reactor core may contain any combination of Westinghouse fuel assemblies, and a limited number lead test assemblies that have not completed representative testing may be placed in nonlimiting core regions as provided in Technical Specification 4.2.1. Switchover to hot leg injection occurs at approximately 13 hours1.50463e-4 days <br />0.00361 hours <br />2.149471e-5 weeks <br />4.9465e-6 months <br /> after nearly all fiber debris is deposited on the strainer or in the fuel, so the WCAP analysis is not sensitive to this parameter.

WCAP-17788 analysis results pass all performance criteria for both hot and cold leg breaks. For cold-leg breaks, fiber inventory at the core inlet and in the core volume are determined to be 5.46 g/FA (i.e., below the WCAP-17788-P, Rev. 0, Volume 1, Section 9.2.1 in-core limit). Based on the results of this analysis, fiber accumulation in the reactor vessel would not preclude adequate core cooling in an accident scenario that generates and transports 300 lbm of fibrous debris with both ECCS strainers running.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 100 of 126

Background

Ameren Missouri addresses GL 2004-02 questions regarding in-vessel debris accumulation and blockage by performing analyses (References [28], [29]) consistent with WCAP-17788-P (Reference [30]). The only material differences compared to the WCAP-17788-P formalism are that Callaway pool circulation equations include a time-dependent strainer filtration function calibrated to test data rather than applying a constant filtration efficiency, and the Callaway strainer filtration function allows fiber shedding to occur from an established debris bed, even when filtration efficiency nears 100%. The Callaway analysis includes calculation of total fiber accumulating in the core and total fiber accumulating at fuel channel inlets for the tested 300-lbm fiber debris load (Reference [19]). All results from the WCAP-17788-P calculation are found to be favorable for the Westinghouse fuel type used at Callaway. Although WCAP-17788-P has not been endorsed by the Nuclear Regulatory Commission (NRC) as official guidance, it does provide an industry benchmark against which to compare plant-specific arguments needed to satisfy GL 2004-02.

The important finding of WCAP-17788-P is that core cooling can be maintained with some tolerable amount of fiber accumulation in every fuel assembly, because the sum of impeded direct flow and alternate-path flow is sufficient to avoid maximum fuel-temperature limits, under some conditions. Core cooling can be maintained with alternate-path flow provided that maximum allowed fuel channel blockage does not occur before post-LOCA time tblock that is tied to a conservative decay heat history and depends on core design and fuel type. This conclusion is based on: 1) fuel channel testing performed to determine flow-loss coefficients under a range of fiber loads for several fuel types, and 2) thermal hydraulic calculations performed to verify acceptable fuel temperatures given a maximum tolerable fiber load in every fuel channel. The WCAP-17788-P study assumes a nominal sump switchover (SSO) time of 20 minutes when Emergency Core Cooling System (ECCS) injection is drawn from the sump rather than from the Refueling Water Storage Tank (RWST). Sump switchover time determines the post-LOCA time when debris begins to arrive at the strainer and in the fuel, and the decay heat load at the time of maximum allowed blockage.

The minimum SSO for Callaway is approximately 12 minutes (11.87 min) for a Large-Break Loss of Coolant Accident (LBLOCA) (Reference [31]), and the corresponding decay heat is higher at 12 minutes than the 20-minute decay heat used for WCAP-17788-P thermal hydraulic verification of adequate cooling. Several arguments presented here support adequacy of the Callaway in-vessel blockage analysis with a 12-minute SSO time, including a comparison of decay-heat reference points between Callaway and the WCAP-17788-P analysis, and an examination of core-fiber accumulation histories. A Callaway SSO time of approximately 15 minutes (14.82 min) occurs under the FSAR licensing basis Maximum Safeguards configuration where only one containment spray pump is assumed to operate (Reference [32]), and this configuration leads to higher, but still acceptable, in-vessel fiber loads.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 101 of 126 It is recognized that downstream fiber diversion through spray systems reduces the amount of fiber reaching the vessel (WCAP-17788-P), so in-vessel blockage analyses are reported here for the Maximum Safeguards configuration where one spray pump is unavailable and both ECCS trains function normally. Although dual-train spray actuation is the most likely plant LOCA response, loss of one spray pump is consistent with the Callaway licensing basis that requires operation of at least one spray train to meet radiological dose and Environmental Qualification (EQ) concerns. By Callaway Emergency-Operating Procedures (EOPs), at least one spray continues to operate until a relatively low differential containment pressure of 4.5 psi is reached, at which point, operators have the discretion to terminate spray. In many simulations, even two-train spray operation requires multiple days to achieve depressurization. Depressurization time is longer for single-train spray operation. Therefore, the Maximum Safeguards configuration provides the most conservative flow condition with respect to in-vessel effects that is consistent with the licensing basis and with existing EOPs. Conversely, full dual-train spray and dual-train ECCS was assumed and tested for the purpose of recirculation strainer performance characterization.

Decay-Heat Comparison WCAP-17788-P Volume 1 Section 5.3.3.5 "Conservative Assumptions" documents the decay heat standard used in the WCAP analyses. Decay heat is modeled similar to the requirements in 10 CFR Part 50, Appendix K. The analyses use the 1971 American Nuclear Society (ANS) Proposed Standard, Decay Energy Release Rates Following Shutdown of Uranium Fueled Thermal Reactors with a 1.2 multiplier applied for conservatism.

For the reference plant modeled in the WCAP analysis, decay heat at the assumed SSO time of 20 minutes is 87.4 MWth (including the 20% conservatism). For Callaway's conservatively calculated minimum SSO time of 11.87 minutes, decay heat is approximately 10% higher at 96.7 MWth using the same decay methodology described in the WCAP (see Figure 3.n-1).

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 102 of 126 Figure 3.n-1. Callaway and WCAP-17788 Decay Heat Comparison.

The 1971 ANSI methodology with 20% increase factor introduces a large conservatism in the calculated decay heat. By comparison, the Callaway FSAR references ANSI/ANS-5.1-1979, "American National Standard for Decay Heat Power in Light Water Reactors", August 1979 for multiple Design Basis Accidents including Steam Generator Tube Rupture and Main Feedline Break. The 1979 decay heat standard is accepted as a conservative methodology and results in a calculated decay heat of approximately 83.2 MWth at the 11.87-minute SSO time, which is approximately 14% lower than calculated for Callaway using the Appendix K / WCAP-17788 methodology (96.7 MWth) and 5% lower than the decay heat modeled for the reference plant (87.4 MW th) at the WCAP assumed 20-minute SSO time.

For a LBLOCA at Callaway, sump recirculation and fiber accumulation can begin approximately 8 minutes sooner than assumed in the WCAP-17788-P analysis. Given that the minimum Callaway pool turn over time is approximately 20 minutes, assuming minimum water volume and dual train ECCS injection flow, the 8 minute difference means that less than 1/2 of the pool volume has passed through the strainer while decay heat is dropping. If the higher Callaway Appendix K decay heat point in Figure 3.n-1 is chosen as the starting point, 8 minutes of decay reduce the heat load to be approximately equal to the WCAP-17788-P 20-min SSO heat load (a reduction of approximately 10%). This observation assumes a similar rate of decay between the

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 103 of 126 1979 ANSI/ANS decay heat methodology (blue history in Figure 3.n-1) and the 1971 ANSI decay heat methodology with added conservatism (curve not shown in Figure 3.n-1).

To summarize, WCAP-17788-P introduces a large conservatism by using the 1971 ANS decay heat standard with a 1.2 multiplier. Comparing the reference plant decay heat at the assumed 20-minute SSO time to the Callaway-specific value calculated using the ANSI/ANS-5.1-1979 standard at an 11.87-minute SSO time shows that the decay heat modeled in the WCAP-17788-P analyses remains bounding for the earlier Callaway SSO time and for all recirculation times thereafter.

Core-Fiber Accumulation Histories Examination of core fiber histories calculated for dual train ECCS and dual train CS under the assumption of maximum flow split to alternate flow paths (Figure 3.n-2) shows that after 8 minutes of Callaway sump recirculation, the amount of fiber present at the core inlet (black dot) is approximately 91% of its final equilibrium maximum, and the equilibrium maximum never approaches more than 63% of the WCAP-17788-P recommended limit of 50.6 g/FA*. (After 8 minutes of recirculation, the core inlet inventory is only 57% of the recommended limit). Note that the time tblock represents the time after which total fuel-inlet blockage can be tolerated without incurring fuel damage, concurrent with the WCAP 20-minute decay heat history. Similarly, the total reactor vessel fiber inventory (upper bold red history in Figure 3.n-2) never reaches the WCAP-17788-P (Volume 1, Section 6.5.5.10.c) recommended limit. Total fiber accumulating in the heated core region through alternate flow paths (dashed history) is higher than the core-inlet fiber total inventory, indicating that sufficient resistance builds on the fuel inlets to divert flow to alternate flow paths. Fiber histories presented in Figure 3.n-2 are calculated assuming minimum flow, two-train core spray diversion after a post-SSO delay of 7.75 min to achieve full realignment. All fiber arriving in the core is retained permanently.

A similar examination of core fiber histories calculated for dual train ECCS and dual train CS under the assumption of minimum flow split to alternate flow paths (Figure 3.n-

3) shows that after 8 minutes of Callaway sump recirculation, the amount of fiber present at the core inlet (black dot) is approximately 78% of its final equilibrium maximum, and the equilibrium maximum never approaches more than 89% of the WCAP-17788-P recommended limit of 50.6 g/FA*. (After 8 minutes of recirculation, the core inlet inventory is only 69% of the recommended limit). The change in assumed AFP flow split does not change total fiber inventory accumulating in the reactor vessel, but total fiber accumulating in the heated core region through alternate flow paths (dashed history) is now lower than the core-inlet fiber inventory because of the applied WCAP-17788-P correlation for minimum AFP flow split. All other parameters remain the same as for Figure 3.n-2.

• As shown in WCAP-17788-NP, Volume 4, Rev. 1, December 2019, Figure RAI-4.7-20, this value is non-proprietary.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 104 of 126 Figure 3.n-2. Callaway LBLOCA fiber histories for 11.87-min SSO time and dual-train operation with maximum AFP flow split.

Figure 3.n-3. Callaway LBLOCA fiber histories for 11.87-min SSO time and dual-train operation with minimum AFP flow split.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 105 of 126 Under the Callaway Maximum Safeguards configuration, one containment spray pump is assumed to fail, delaying SSO to 14.82 minutes and allowing more fiber transport directly to the reactor vessel. Figure 3.n-4 illustrates core fiber histories for the Maximum Safeguards configuration under the assumption of maximum AFP flow split.

Maximum fuel inlet fiber is the same as in Figure 3.n-2, but AFP fiber increases significantly, raising the total core inventory by 10 g/FA. Again, all WCAP-17788-P reactor vessel fiber limits are satisfied. Figure 3.n-5 illustrates core fiber accumulation for under the assumption of minimum AFP flow split. Fuel inlet fiber is higher than shown in Figure 3.n-4, but does not exceed the recommended early blockage limit.

Figure 3.n-4. Callaway LBLOCA fiber histories for 14.82-min SSO and Maximum Safeguards operation (one CS pump failed) with maximum AFP flow split.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 106 of 126 Figure 3.n-5. Callaway LBLOCA fiber histories for 14.82-min SSO and Maximum Safeguards operation (one CS pump failed) with minimum AFP flow split In summary, although Callaway begins sump recirculation approximately 8 minutes earlier than assumed in the WCAP-17788-P analysis, the Callaway in-vessel fiber analysis remains valid for the following reasons:

1) The WCAP 20-minute heat load bounds the Callaway heat load at the earlier 11.87-minute SSO time that is used for FSAR accident analyses, and therefore, bounds decay heat at all later recirculation times.

2) Callaway App-K heat loads at the earlier 11.87-minute SSO time decay by 10%

within 8 minutes to be approximately equal to the WCAP 20-minute heat load, while 91% of the final equilibrium fuel-channel fiber inventory has accumulated (equals only 63% of the recommended limit).

3) Total fuel-channel fiber inventory never reaches more than 90% of the WCAP-17788-P recommended maximum limit (Maximum Safeguards configuration),

leaving adequate flow capacity to compensate for 8 minutes of higher heat load assumed under the WCAP-17788-P decay heat methodology.

4) These conclusions hold for two-train (all pumps running) and Maximum Safeguards (one CS failed) plant-response configurations. While the Maximum Safeguards configuration indicates higher reactor vessel fiber loads, expected dual train response provides defense in depth assurance of adequate cooling.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 107 of 126 3.o. Chemical Effects3 The objective of the chemical effects section is to evaluate the effect that chemical precipitates have on head loss and core cooling.

1. Provide a summary of evaluation results that show that chemical precipitates formed in the post-LOCA containment environment, either by themselves or combined with debris, do not deposit at the sump screen to the extent that an unacceptable head loss results, or deposit downstream of the sump screen to the extent that long-term core cooling is unacceptably impeded.

2. Content guidance for chemical effects is provided in Enclosure 3 to a letter from the NRC to NEI dated September 27, 2007 (ADAMS Accession Nos.

ML072600425, ML072600372).

3The NRC staff expects to issue a draft SE on WCAP-16530, "Evaluation of Post-Accident Chemical Effects in Containment Sump Fluids to Support GSI-191," in November 2007.

The information in this section revises information previously provided by Ameren Missouri to GL 2004-02, section 3.o. (Reference [2]). Evaluation of the effects of chemical precipitate on head loss relies on completion of the actions associated with vendor testing completed in 2016 meant to support assumptions and corresponding conclusions contained in this GL 2004-02 response.

Response to 3.o.1. Provide a summary of evaluation results that show that chemical precipitates formed in the post-LOCA containment environment, either by themselves or combined with debris, do not deposit at the sump screen to the extent that an unacceptable head loss results, or deposit downstream of the sump screen to the extent that long-term core cooling is unacceptably impeded.

Debris and other containment sources which could contribute to the formation of chemical precipitates in the sump pool were evaluated using the WCAP-16530-NP Spreadsheet.

Strainer head loss test was conducted in 2016. The head loss testing showed acceptable head loss for the conditions tested.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 108 of 126 Response to 3.o.2. Content guidance for chemical effects is provided in to a letter from the NRC to NEI dated September 27, 2007 (ADAMS Accession Nos. ML072600425, ML072600372).

3.o.2.1 Sufficient Clean Strainer Area: Those licensees performing a simplified chemical effects analysis should justify the use of this simplified approach by providing the amount of debris determined to reach the strainer, the amount of bare strainer area and how it was determined, and any additional information that is needed to show why a more detailed chemical effects analysis is not needed.

Ameren Missouri is not crediting a simplified chemical effects testing. The chemical effects evaluation process flow chart provided in the NRC guidance document has been modified, as shown in Figure 3.o-1, to highlight the process approach taken for testing and evaluation.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 109 of 126 Figure 3.o-1: Chemical Effects Evaluation Process Flow Chart 3.o.2.2 Debris Bed Formation: Licensees should discuss why the debris from the break location selected for plant-specific head loss testing with chemical precipitate yields the maximum head loss. For example, plant X has break location 1 that would produce maximum head loss without consideration of chemical effects. However, break location 2, with chemical effects considered, produces greater head loss than break location 1. Therefore, the debris for head loss testing with chemical effects was based on break location 2.

The maximum chemical and particulate loads were paired with the RoverD fiber threshold. Therefore, the debris bed with most amount of chemical and particulates was tested, which is expected to yield maximum head losses.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 110 of 126 3.o.2.3 Plant-Specific Materials and Buffers: Licensees should provide their assumptions (and basis for the assumptions) used to determine chemical effects loading: pH range, temperature profile, duration of containment spray, and materials expected to contribute to chemical effects.

The following major assumptions were made in calculating the post-accident chemical effects analysis for Callaway.

• The initial sump pH was assumed to be pH (4.6) from the maximum Boron concentration in pool (2500ppm).

• The initial spray pH (4.8) was assumed to be the pH of the spray additive solution.

• The spray pH values from the time of recirculation were assumed to equal the sump pH values.

• The temperature profile implemented was the LOCA DBA temperature profile.

• The sprays are on for 30-days.

• Undamaged insulation is covered by stainless steel jacketing that minimizes insulation exposure to CS. Jackets act as a protective barrier for underlying insulation and minimizes internal wetting of the insulation. Even if the interior is dampened, the solution likely remains inside the jacket secluded from the containment pool. Therefore, undamaged, jacketed insulation is not included in the sprayed insulation inventory for WCAP-16530 predictions.

• The "intact blanket" portion of the NUKON debris is not considered as a reactant source, and is not included in the inventory for WCAP-16530 predictions.

The Callaway CSS uses TSP as a buffer solution. The TSP is mixed by the containment sump recirculation pool water prior to being sprayed into the containment building.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 111 of 126 Table 3.o-1: Input for Chemical Effects Evaluation Parameter Value Aluminum (submerged) surface area 458 ft2 Aluminum (submerged) mass 1,145 lbm Aluminum (unsubmerged) surface area 273 ft2(2)

Aluminum (unsubmerged) mass 851 lbm NUKON 410 ft3 NUKON density 2.4 lbm/ft3 Concrete 2,623.5 ft2 Maximum recirculation water volume 63,656.7 ft3(3)

Buffering agent TSP Sump temperature, minimum 170.9 °F Sump temperature, maximum 262.2 °F Sump pH post-LOCA, min / max 4.6 / 7.6 Spray pH post-LOCA, min / max 4.8 / 7.6 Spray duration 30 days 3.o.2.4 Approach to Determine Chemical Source Term (Decision Point): Licensees should identify the vendor who performed plant-specific chemical effects testing.

The strainer performance testing was conducted at the Alden facility in Holden, Massachusetts and performed by ALDEN personnel.

3.o.2.5 Separate Effects Decision (Decision Point): State which method of addressing plant-specific chemical effects is used.

The methods of WCAP-16530 were used to access the plant-specific chemical effects precipitate loading and testing chemical precipitates were produced using the methods in WCAP-16530.

3.o.2.6 Since the NRC USNRC is not currently aware of the testing approach, the NRC USNRC expects licensees using it to provide a detailed discussion of the chemical effects evaluation process along with head loss test results.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 112 of 126 Ameren Missouri did not use an AECL Model.

3.o.2.7 AECL Model: Licensees should provide the chemical identities and amounts of predicted plant-specific precipitates.

Ameren Missouri did not use an AECL Model.

3.o.2.8 WCAP Base Model: For licensees proceeding from block 7 to diamond 10 in the Figure 1 flow chart [in Enclosure 3 to a letter from the NRC to NEI dated September 27, 2007 (ADAMS Accession No. ML0726007425)], justify any deviations from the WCAP base model spreadsheet (i.e., any plant-specific refinements) and describe how any exceptions to the base model spreadsheet affected the amount of chemical precipitate predicted.

Ameren Missouri did not take credit for any exceptions to the base model of WCAP-16530 spreadsheet.

3.o.2.9 WCAP Base Model: List the type (e.g., AlOOH) and amount of predicted plant-specific precipitates.

The WCAP-16530-NP base model spreadsheet was used. The results of the analysis are shown in Table 3.o-2 below.

Table 3.o-2: Predicted Chemical Precipitate Formation for Ameren Missouri Baseline Methodology Type of precipitate Pounds (lbm)

AlOOH 0 NaAlSi3O8 474 Ca3(PO4)2 55 Calcium phosphate precipitate was a chemical precipitate shown to be formed using the chemical effects spreadsheet. Calcium phosphate was used in the testing for the quantities of calcium phosphate required.

Although sodium aluminum silicate (NaAISi3O8) was a chemical precipitate shown to be formed using the chemical effects spreadsheet, AIOOH was used as a surrogate.

This substitution was used because the production of NaAISi3O8 is considered hazardous. The justification is from section 7.3.2 of WCAP-16530-NP, which stated

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 113 of 126 that the characteristics of NaAISi3O8 are sufficiently similar to AIOOH, thus AIOOH may be used in lieu of NaAISi3O8.

3.o.2.10 WCAP Refinements: State whether refinements to WCAP-16530-NP were utilized in the chemical effects analysis.

No refinements to WCAP-16530 were utilized in the chemical effects analysis.

3.o.2.11 Solubility of Phosphates, Silicates and Al Alloys: Licensees should clearly identify any refinements (plant-specific inputs) to the base WCAP-16530 model and justify why the plant-specific refinement is valid.

No plant-specific refinements were utilized.

3.o.2.12 Solubility of Phosphates, Silicates and Al Alloys: For crediting inhibition of aluminum that is not submerged, licensees should provide the substantiation for the following: (1) the threshold concentration of silica or phosphate needed to passivate aluminum, (2) the time needed to reach a phosphate or silicate level in the pool that would result in aluminum passivation, and (3) the amount of containment spray time (following the achieved threshold of chemicals) before aluminum that is sprayed is assumed to be passivated.

Inhibition or passivation of aluminum was not used in determining the aluminum corrosion and the resultant chemical precipitates.

3.o.2.13 Solubility of Phosphates, Silicates and Al Alloys: For any attempts to credit solubility (including performing integrated testing), licensees should provide the technical basis that supports extrapolating solubility test data to plant-specific conditions. In addition, licensees should indicate why the overall chemical effects evaluation remains conservative when crediting solubility given that small amount of chemical precipitate can produce significant increases in head loss.

No reduction of chemical precipitate was achieved by crediting solubility.

3.o.2.14 Solubility of Phosphates, Silicates and Al Alloys: Licensees should list the type (e.g., AlOOH) and amount of predicted plant-specific precipitates.

The amount and type of precipitate predicted is discussed in response 3.o.2.9.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 114 of 126 3.o.2.15 Precipitate Generation (Decision Point): State whether precipitates are formed by chemical injection into a flowing test loop or whether the precipitates are formed in a separate mixing tank.

Precipitates are formed in a separate mixing tank.

3.o.2.16 Chemical Injection into the Loop: Licensees should provide the one-hour settled volume (e.g., 80 ml of 100 ml solution remained cloudy) for precipitate prepared with the same sequence as with the plant-specific, in-situ chemical injection.

Precipitates were not formed by injection into the test loop.

3.o.2.17 Chemical Injection into the Loop: For plant-specific testing, the licensee should provide the amount of injected chemicals (e.g., aluminum),

the percentage that precipitates, and the percentage that remains dissolved during testing.

Precipitates were not formed by injection into the test loop.

3.o.2.18 Chemical Injection into the Loop: Licensees should indicate the amount of precipitate that was added to the test for the head loss of record (i.e., 100%, 140%).

Precipitates were not formed by injection into the test loop.

3.o.2.19 Pre-Mix in Tank: Licensees should discuss any exceptions taken to the procedure recommended for surrogate precipitate formation in WCAP-16530.

No exceptions to the procedure in WCAP-16530 were taken for the surrogate precipitate formation.

3.o.2.20 Technical Approach to Debris Transport (Decision Point): State whether near field settlement is credited or not.

Ameren Missouri chemical effects head loss testing did not credit for near field settling.

3.o.2.21 Integrated Head Loss Test with Near-Field Settlement Credit:

Licensees should provide the one-hour or two-hour precipitate settlement values measured within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of head loss testing.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 115 of 126 Ameren Missouri chemical effects head loss testing did not credit near field settling.

3.o.2.22 Integrated Head Loss Test with Near-Field Settlement Credit:

Licensees should provide a best estimate of the amount of surrogate chemical debris that settles away from the strainer during the test.

Ameren Missouri chemical effects head loss testing did not credit near field settling.

3.o.2.23 Head Loss Testing Without Near Field Settlement Credit:

Licensees should provide an estimate of the amount of debris and precipitate that remains on the tank/flume floor at the conclusion of the test and justify why the settlement is acceptable.

Settled particulate was collected and weighted. For the FDL and TB tests 2.4 kg and 2.1 kg settle, which is less than 1% of the particulate mass tested.

Particulate that was collected and weighted at the end of the tests had multiple opportunities at transport by being re-suspended from agitation before settling at the bottom of the mixing region between the mixing nozzle and the strainer pit. A photograph of the deposition pattern at the end of the TB test is provided in Figure 3.o-2. A similar pattern was observed at the conclusion of the FDL test. The makeup of the settled debris is difficult to determine (i.e., it isnt appropriate to assume equal distribution among the batches).

Figure 3.o-2: Settled Particulate at the Conclusion of the Thin Bed Test

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 116 of 126 3.o.2.24 Head Loss Testing Without Near Field Settlement Credit: Licensees should provide the one-hour or two-hour precipitate settlement values measured and the timing of the measurement relative to the start of head loss testing (e.g., within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />).

All chemical product used in head loss testing was confirmed by test procedure to meet the settling criteria established in WCAP-16530-NP, and all chemical product was introduced to the head loss test loop within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after passing a settling test. Repeat settling tests were performed in the rare case that chemical product was prepared more than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> before it was needed for introduction to the head loss test loop.

3.o.2.25 Test Termination Criteria: Provide the test termination criteria The test termination criteria is less than a 1% change in head-loss per hour.

3.o.2.26 Data Analysis: Licensees should provide a copy of the pressure drop curve(s) as a function of time for the testing of record.

Pressure curve as a function of time for the FDL and TB head loss tests are presented in Figures 3.o-3 to 3.o-6.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 117 of 126 Figure 3.o-3: Full Debris Load Test Conventional Debris Timeline

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 118 of 126 Figure 3.o-4: Full Debris Load Test Chemical Debris Timeline

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 119 of 126 Figure 3.o-5: Thin Bed Test Conventional Debris Timeline

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 120 of 126 Figure 3.o-6: Thin Bed Test Chemical Debris Timeline 3.o.2.27 Data Analysis: Licensees should explain any extrapolation methods used for data analysis.

Data was not extrapolated.

3.o.2.28 Integral Generation (Alion):

Ameren Missouri did not perform Alion-style Integral Generation Testing.

3.o.2.29 Tank Scaling / Bed Formation: Explain how scaling factors for the test facilities are representative or conservative relative to plant-specific values.

Ameren Missouri did not perform Alion-style Integral Generation Testing.

3.o.2.30 Tank Scaling / Bed Formation: Explain how bed formation is representative of that expected for the size of materials and debris that is formed in the plant-specific evaluation.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 121 of 126 Ameren Missouri did not perform Alion-style Integral Generation Testing.

3.o.2.31 Tank Transport: Explain how the transport of chemicals and debris in the testing facility is representative or conservative with regard to the expected flow and transport in the plant-specific conditions Ameren Missouri did not perform Alion-style Integral Generation Testing.

3.o.2.32 30-Day Integrated Head Loss Test: Licensees should provide the plant-specific test conditions and the basis for why these test conditions and test results provide for a conservative chemical effects evaluation.

Ameren Missouri did not perform Alion-style Integral Generation Testing.

3.o.2.33 30-Day Integrated Head Loss Test: Licensees should provide a copy of the pressure drop curve(s) as a function of time for the testing of record.

Ameren Missouri did not perform Alion-style Integral Generation Testing.

3.o.3.34 Data Analysis Bump Up Factor: Licensees should provide the details and the technical basis that show why the bump-up factor from the particular debris bed in the test is appropriate for application to other debris beds.

Ameren Missouri did not perform Alion-style Integral Generation Testing.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 122 of 126 3.p. Licensing Basis The objective of the licensing basis section is to provide information regarding any changes to the plant licensing basis due to the sump evaluation or plant modifications.

Provide the information requested in GL 04-02 Requested Information Item 2(e) regarding changes to the plant licensing basis. The effective date for changes to the licensing basis should be specified. This date should correspond to that specified in the 10 CFR 50.59 evaluation for the change to the licensing basis.

GL 2004-02 Requested Information Item 2(e)

A general description of and planned schedule for any changes to the plant licensing bases resulting from any analysis or plant modifications made to ensure compliance with the regulatory requirements listed in the Applicable Regulatory Requirements section of this GL. Any licensing actions or exemption requests needed to support changes to the plant licensing basis should be included.

The information in this section revises information previously provided by Ameren Missouri to GL 2004-02 Requested Information Item 2(e) (Reference [2]).

Response to 3.p., Item 2(e). A general description of and planned schedule for any changes to the plant licensing bases resulting from any analysis or plant modifications made to ensure compliance with the regulatory requirements listed in the Applicable Regulatory Requirements section of this GL. Any licensing actions or exemption requests needed to support changes to the plant licensing basis should be included.

Ameren Missouri is in the process of implementing licensing basis changes to support overall resolution of GSI-191 and GL 2004-02. These licensing basis changes include those associated with procedures and physical plant modifications, with changes to TS, with exemptions to certain regulations, and with analyses and evaluations.

The plant licensing basis changes due to procedures and plant modifications were evaluated against the current licensing basis, as well as the future licensing basis that will be in effect following implementation of the actions in the GL 2004-02 corrective action package. Procedure and plant modifications that have been implemented are described in section 2.

In Reference 23, Ameren Missouri requested a license amendment to revise TS 3.5.2, "ECCS - Operating," to support replacement of the containment recirculation sumps inlet trash racks and screens with the PCI Sure-Flow replacement strainers described in section 3.j above. The approved amendment (Reference 24) revises

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 123 of 126 Surveillance Requirement 3.5.2.8 by replacing the phrase "trash racks and screens" with the word "strainers."

The analyses and evaluations supporting the GL 2004-02 corrective actions will become part of the plant licensing basis upon complete implementation of the GL 2004-02 corrective action package. See Enclosure 2 for the amendment request, TS changes, and FSAR changes.

All changes to the current licensing basis will be described in the Callaway FSAR in accordance with the requirements of 10 CFR 50.71(e).

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 124 of 126 4 References

[1] NEI 04-07 Rev. 0, "Vol. 1 Pressurized Water Reactor Sump Performance Evaluation Methodology, Vol. 2 Safety Evaluation by the Office of Nuclear Reactor Regulation Related to NRC Generic Letter 2004-02, Revision 0, December 6, 2004," U.S. Nuclear Regulatory Commission, December 2004.

[2] AmerenUE Letter ULNRC-05481, "Response to Request for Additional Information Re: Response for NRC Generic Letter 2004-02, 'Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors'," (ADAMS Accession No. ML080810491) dated February 29, 2008.

[3] MEMO-9143-WMC-2K17-01, Rev 0, "MSLB MFLB Conditional Sump Failure Probabilities," April 2017.

[4] ALION-REP-ALION-2806-01, Rev. 4, "Insulation Debris Distribution for use in GSI-191 Resolution," Alion Science and Technology, May 2009.

[5] ML100570364, "Nuclear Regulatory Commission Conclusions Regarding Pressurized Water Reactor Owners Group Rsponse to Request for Additional Information Dated January 25, 2010 Regarding Licensee Debris Generation Assumptions for GSI-191," Nuclear Regulatory Commission, February 2010.

[6] WCAP-16710-P Rev 0, "Jet Impingement Testing to Determine the Zone of Influence (ZOI) of Min-K and NUKON Insulation for Wolf Creek and Callaway Nuclear Operating Plants," October 2007.

[7] ML082050433, "Indian Point Energy Center Corrective Actions for Generic Letter 2004-02".

[8] NUREG/CR-6808, "Knowledge Base for the Effect of Debris on Pressurized Water Reactor Emergency Core Cooling Sump Performance," Los Alamos National Laboratory, February 2003.

[9] ALION-CAL-CEC-9143-017, "Callaway Risk-Informed Debris Transport Calculation," Alion Science and Technology, November 2016.

[10] 1162CECGSI-R2-00, Rev. 0, "Callaway Energy Center Head Loss Technical Report," March 2018.

[11] WCAP-16530-NP, "Evaluation of Post-Accident Chemical Effects in Containment Sump FLuids to SUpport GSI-191," Westinghouse, March 2008.

[12] TDI-6002-05 / TDI-6003-05, Rev. 4, "Clean Head Loss - Wolf Creek / Callaway,"

Performance Contracting Inc (PCI), April 2008.

[13] ZZ-525 Rev 001 Addendum 5, "Containment Temperature-Pressure Sensitivities During Main Steam Line Break and Large Break Loss of Coolant Accident for Containment Cooler Energy Removal Capability (CAR #20128648)," October 2013.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 125 of 126

[14] Technical Specification 3.6.4, "Containment Pressure," Amendment No. 202.

[15] 06-0413, "Design Basis Accident Testing of Coating Samples from Unit 1 Containment TXU Comanche Peak SES," April 2006.

[16] ML080230462, "NRC Staff Review Guidance Regarding Generic Letter 2004-02 Closure in the Area of Coatings Evaluations," Mach 2008.

[17] 01252178, "Unqualified Containment Coating Testing Carboline 193LF/191HB Applied to SP-3 Cleaned Bare Carbon Steel RF22," January 2018.

[18] WCAP-16406-P-A, Rev. 1 (Proprietary), "Evaluation of Downstream Sump Debris Effects in Support of GSI-191," Westinghouse Electric Company LLC, March 2008.

[19] ALION-CAL-CEC-9345-003 R0, "Strainer Penetration Test Report," Alion Science and Technology, 2018.

[20] ALION-CAL-CEC-9143-020 R0, "Callaway Energy Center Dowstream Ex-Vessel Effects Evaluation for ECCS Components," Alion Science and Technology, October 2018.

[21] WES004-PR-01, Rev. 2, "Evaluation of Containment Recirculation Sump Downstream Effects for the Wolf Creek Electric Generating Station and the Callaway Nuclear Plant," Enercon Services Inc., May 2006.

[22] WCAP-11534 (Proprietary), "Evaluation of Containment Coatings for Sequoyah Unit 2," Westinghouse Electric Corporation, September 1987.

[23] CN-CSA-05-20 Rev. 2 (Proprietary), "Wolf Creek/Callaway Sump Debris Downstream Effects Evaluation for ECCS Equipment," Westinghouse Electric Company LLC, September 2008.

[24] CN-CSA-05-49 Rev. 2 (Proprietary), "Callaway/Wolf Creek GSI 191 Down Stream Effects Debris Ingestion Evaluation," Westinghouse Electric Company LLC, August 2008.

[25] LTR-SEE-I-08-138, Rev. 0 (Proprietary), "Evaluation of Potential for Fibrous Debris to Clog Cyclone Separator Ports at Callaway and Wolf Creek Nuclear Plants,"

Westinghouse Electric Company LLC, September 2008.

[26] CN-SEE-I-08-67 Rev. 0 (Proprietary), "Wolf Creek/Callaway Mechanical Seal Evaluation for ECCS Pumps," Westinghouse Electric Company LLC, September 2008.

[27] WCAP-17788-NP R0, "Comprehensive Analysis and Test Program for GSI-191 Closure," Westinghouse, July 2015.

[28] ALION-CAL-CEC-9143-019, Rev. 0, "WCAP-17788 In-Vessel Debris Effects Evaluation," 2018.

[29] SERCO-CAL-CEC-9143-024, Rev. 0, "Strainer Penetration Fiber Time History Calculation," May 2020.

[30] WCAP-17788-P, Volume 1, Rev. 0 (Proprietary), "Comprehensive Analysis and Test Program for GSI-191 Closure (PA-SEE-1090)," July 2015.

ULNRC-06690 Enclosure 3, Attachment 3-2 Page 126 of 126

[31] BN-16, Rev.1, "RWST Drain-down during Transfer to Cold Leg Recirculation,"

Ameren Missouri Calculation, August 2006.

[32] CN-SEE-02-11, "SCP Minimum Switchover Times," Westinghouse Electric Company Calculation.

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 1 of 60 Attachment 3-3 Risk-Informed Basis

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 2 of 60 1 Introduction Risk over Deterministic (RoverD) is a method that follows the guidance of Regulatory Guide (RG) 1.174 (NRC, 2018) to assess the risk associated with concerns raised in Generic Letter (GL) 2004-02. RoverD requires a head-loss test that successfully achieves all deterministic strainer performance metrics, while the quantity of low-density fiber glass (LDFG) tested is a risk-based metric. CASA Grande is used to evaluate the magnitude of loss of coolant accidents (LOCAs) required to exceed the risk-based metric, referred to as the fiber threshold. The fiber threshold is set low to underestimate the true level where functionality may be lost, so that risk for strainer failure is overestimated. Even when adopting a low threshold for failure, the risk is shown to be very small (Reference [1]).

The risk-based metric is used to classify scenarios as deterministic or risk informed as illustrated in Figure 1-1. Deterministic scenarios are those in which LDFG estimated to arrive on the emergency strainers by CASA Grande do not exceed the fiber, or risk-based, threshold. Risk-informed scenarios occur when LDFG estimated to arrive at the ECCS strainers exceeds the amount of LDFG used in strainer testing, and the risk contribution of these breaks is evaluated by CASA Grande against RG 1.174 quantitative criteria for core-damage frequency {CFD, CFD} and large early-release frequency {LERF, LERF}.

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 3 of 60 Figure 1-1: RoverD separates those scenarios that go to success deterministically from those that are assumed to go to failure and require risk-informed analysis Scenarios are the result of exhaustive sampling for break sizes and orientations at weld locations to identify the smallest break size that would exceed the fiber threshold.

Although some scenarios at a weld location with one or more scenarios in the risk-informed category may be successful, in RoverD, the frequency assigned at any risk-informed weld is the frequency associated with the smallest break size for that weld. As a consequence, some scenarios at weld locations may have break sizes larger than the smallest size, but do not produce more fines than the tested amount. That is, some scenarios for any particular non-double-ended guillotine break (DEGB) risk-informed weld may be successful (in fact, many may be successful). The nature of this kind of behavior is shown in Figure 1-2.

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 4 of 60 (a) Conceptual illustration of a break with (b) Depiction on the {angle of orientation, break diameter where robust barriers truncate the size} phase plane of the smallest break size and the ZOI such that breaks larger than the smallest resulting amount of LDFG. Some areas on the break exceeding the tested amount of LDFG phase plane at break sizes larger than the smallest result in less amounts of LDFG. have less than the tested amount of LDFG.

Figure 1-2: Hypothetical break and the LDFG production for different break sizes and orientations showing how some break sizes larger than the smallest break size in a risk-informed weld location can have less LDFG produced.

The term deterministic refers to any scenario that is bounded by tests and do not contribute to risk. Using test data that includes breaks that are not bounded by test data results in scenarios that would fall outside the bounding envelope of the tests. The risk for any such scenarios is required to meet a very small threshold as shown in Figure 1-3.

In the following, the various analyses required to complete a RoverD assessment are summarized. The steps required to complete a RoverD analysis are summarized in Section 2.

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 5 of 60 Figure 1-3: Flow chart showing the RoverD evaluation process following categorization of scenarios to determine risk acceptability. In this description, the frequency, , of break at any location is evaluated based on its diameter using NUREG-1829.

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 6 of 60 2 RoverD Methodology Summary RoverD involves the following steps to assess the risk associated with the concerns raised in GL 2004-02:

1. Perform a deterministic head-loss test where the quantity of LDFG tested is implemented as a risk-based metric. Also, the head-loss test must be successful for all strainer performance metrics such as net positive suction head (NPSH),

deaeration, potential to flash, vortex formation, and structural requirements.

2. Simulate CASA Grande to:

a. Equally distribute NUREG-1829 break frequencies to all break locations. This method is known as the top-down approach.

b. Determine the smallest break, known as the critical break size, at each location that generates and transports LDFG in excess of the fiber threshold and assume core damage at these locations.

i. If a DEGB at a specified location does not generate and transport LDFG to the strainer in excess of the fiber threshold, the break is counted as a success, does not contribute to risk, and is classified as deterministic or non-critical. Note, if a DEGB is counted as a success, all partial breaks would be successful as well. Partial breaks generate less debris than a DEGB.

ii. If a DEGB break at a specified location generates and transports LDFG to the strainer in excess of the fiber threshold, the welds are classified as risk-informed or critical. The critical break size at this location is determined by searching partial breaks at 0.1 inch break size increments and 1° angular increments. The contribution to risk is determined by the difference in exceedance frequency between the critical break size and the inner weld diameter (scaled by the number of welds in this size range).

c. Aggregate the exceedance frequencies for all risk-informed breaks.

3. Determine risk associated with secondary risk contributors (SRC), which are events with initiators other than pipe ruptures at Class-I welds between the reactor pressure vessel (RPV) and an isolation valve. SRC considered in this analysis are listed failure of isolation valves, secondary line breaks, spurious and failed-open valves, and mechanical LOCAs (pump seal LOCAs) Refer to the

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 7 of 60 responses to Questions 34 and 35 in Enclosure 5 for additional information regarding secondary risk contributor screening.

4. Determine the risk associated with additional risk contributors that challenge the successful operation of integral equipment during an event. Additional risk contributors are ex-vessel downstream wear, strainer structural analysis, and in-vessel effect.

5. Evaluate the risk contribution from all events with RG 1.174 quantitative criteria for core-damage frequency {CDF, CDF} and large early-release frequency

{LERF, LERF}.

2.1 Weld Populations and Sensitivity Studies Overview Class I welds between the RPV and first isolation valve are included for the baseline LOCA simulations where all the NUREG-1829, 25-year frequencies are distributed to this population of welds with a geometric weighting. Class I welds beyond the first isolation valve require an isolation valve failure to have a LOCA and are classified as SRC. All the NUREG-1829, 25-year frequencies are also distributed to this population of welds with a geometric weighting. Thus, NUREG-1829 frequencies are distributed in totality twice, which results in an overestimate of risk. Also, sensitivities are performed by varying the following parameters: DEGB or continuum break models, 25-year or 40-year NUREG-1829 frequencies, arithmetic or geometric weighting, and addition insulation on valves. Refer to the responses to Questions 36 and 38 in Enclosure 5 for additional information regarding sensitivity studies.

3 Head-Loss Tests Full debris load and thin bed head-loss tests were conducted at Alden Research Laboratories in 2016. The tests were conducted adhering to guidance for deterministic closure. The full debris load test targeted maximum chemical precipitate and particulate loads, while the fiber load is a risk based metric that determines the success criteria for an individual break. The full debris load test achieved successful head-loss results with 300 lbm of LDFG fines. Therefore, the RoverD limit is 300 lbm. For more details regarding the head-loss tests refer to Attachment 3-2.

4 LDFG Debris Generation LDFG is the only debris that is a risk metric. For details regarding other debris types, see Attachment 3-2, the deterministic basis. The sources for LDFG are:

• Latent Fiber

• Fiber Margin

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 8 of 60

• Break-dependent NUKON and Thermal-Wrap A latent fiber mass of 30 lbm is attributed to every break as specified by guidance (Reference [2, 3]). Plant walkdown data indicates that the actual quantity of latent fiber is less than 30 lbm. Therefore, this assumption results in larger estimates of LDFG and is conservative.

A fiber margin of 50 lbm (with 100% transport) is applied to all postulated breaks for the baseline case. This 50 lbm of fiber is in addition to ZOI-generated and latent fiber sources. This 50-lbm margin provides additional assurance (not required by regulatory guidance) that the quantified change in core damage risk is conservative and that break scenarios where the strainer is determined by analysis to be successful have unquestionably successful outcomes. Furthermore, this 50 lbm fiber margin may be used to support future discoveries of additional fiber sources in containment without invalidating the current analysis.

NUKON and Thermal-Wrap are break-dependent LDFG debris that may be generated from a LOCA. NEI (Reference [2, 3]) documented an acceptable methodology for determining the amount of debris generated in a LOCA of any particular size by defining a zone of influence (ZOI). Within the ZOI, specific size distributions of LDFG particles can be estimated (Figure 4-1).

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 9 of 60 Figure 4-1: Conceptual illustration of three zones of destruction potential within the ZOI showing how the debris distribution shifts towards larger sizes further from the break.

Each of the fiber insulation types has ZOIs based on jet testing. The maximum ZOIs used for fibrous insulations are summarized in Table 4-1 and are based on the standard deterministic approach promulgated by NEI 04-07 (Reference [2, 3]), while the debris size distributions for inner shells are based on proprietary Alion report ALION-REP-ALION-2806-01 Insulation Debris Size Distribution for use in GSI-191 Resolution (Reference [4]). Fiber ZOIs used for the Callaway analysis are equivalent to the pilot-plants fiber ZOIs.

Table 4-1: Summary of the maximum ZOI size for fiber-producing insulation Insulation Type Max ZOI ( ) Reference NEI (Reference [2, NUKON 17.0 3])

NEI (Reference [2, Thermal-Wrap 17.0 3])

As previously stated, the ZOIs for NUKON and Thermal-Wrap insulations are shells with different percentages of debris sizes created within each shell. Along with fiber

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 10 of 60 fines produced, debris sizes are calculated from each shell for small pieces, large pieces, and intact blankets.

All destroyed insulation volume was converted to mass using the manufactured densities (Reference [2]):

• NUKON 2.4 3

• Thermal-Wrap 2.4 3 5 LDFG Transport Once amounts and distributions of fiber types are known, debris transport fractions are used to estimate the amount and size of debris that accumulates on the strainer.

LDFG, latent fiber, and fiber margin overall debris transport fractions are presented in Table 5-1 because these are the debris types that contribute to the risk metric. For details regarding other debris types and the phases of debris transport, such as blowdown, pool fill, washdown, or recirculation debris transport, refer to the deterministic basis in Attachment 3-2.

Table 5-1: Overall debris transport fractions Debris Transport Fraction by Break Location Steam Upper Lower Debris Debris Generator Pressurizer Pressurizer Implemented Type Size Compartment Annulus Compartment Compartment Fraction Fines 99% 99% 99% 99% 99%

Small Pieces 70% 60% 68% 64% 70%

(<6)

Large Pieces 66% 64% 0% 66% 66%

LDFG (>6)

Fines Eroded 100% 100% 100% 100% 100%

from Smalls Fines Eroded 100% 100% 100% 100% 100%

from Larges Latent Fines 96% 96% 96% 96% 96%

Fiber Fiber Fines 100% 100% 100% 100% 100%

Margin As small and large pieces transport to the strainers or the location where they settle (for example, on grating, in a quiescent part of the containment building pool, etc.), fines

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 11 of 60 may erode or dislodge from the small and large pieces and readily transport the strainers. Table 5-2 displays the amount of fines eroded from small and large pieces.

Table 5-2: LDFG debris erosion fractions Debris Transport Fraction by Break Location Steam Upper Lower Implemented Debris Type Debris Size Generator Annulus Pressurizer Pressurizer Fraction Compartment Compartment Compartment Fines Eroded from 0% 1% 0% 0% 1%

Smalls LDFG Fines Eroded from 3% 4% 0% 3% 4%

Larges All eroded fines transport to the strainer at 100%.

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 12 of 60 6 LOCA Frequencies Break frequency data from NUREG-1829 are analyzed using both the geometric-aggregated and arithmetic-aggregated means, medians, fifth, and ninety-fifth percentiles of the elicited data. Break-size-dependent annual exceedance frequency estimates are provided for both the 25-year and 40-year fleet operation averages. Table 6-1 presents the 25-year exceedance frequencies and Table 6-2 presents the 40-year exceedance frequencies, taken respectively from Tables 7.13 and 7.19 of NUREG-1829 (Reference [5]).

Table 6-1: NUREG-1829 25-year LOCA exceedance frequencies Break Geometric (1/year) Arithmetic (1/year)

Size (in) 5th 50th Mean 95th 5th 50th Mean 95th 0.500 6.8E-05 6.3E-04 1.9E-03 7.1E-03 8.1E-04 4.8E-03 1.0E-02 3.6E-02 1.625 5.0E-06 8.9E-05 4.2E-04 1.6E-03 4.2E-05 7.0E-04 3.0E-03 1.2E-02 3.000 2.1E-07 3.4E-06 1.6E-05 6.1E-05 1.3E-06 1.9E-05 7.3E-05 2.9E-04 7.000 1.4E-08 3.1E-07 1.6E-06 6.1E-06 6.9E-08 1.3E-06 9.4E-06 3.0E-05 14.000 4.1E-10 1.2E-08 2.0E-07 5.8E-07 9.9E-09 2.6E-07 2.4E-06 7.2E-06 31.000 3.5E-11 1.2E-09 2.9E-08 8.1E-08 5.9E-09 1.5E-07 1.5E-06 5.2E-06 Table 6-2: NUREG-1829 40-year LOCA exceedance frequencies Break Geometric (1/year) Arithmetic (1/year)

Size (in) 5th 50th Mean 95th 5th 50th Mean 95th 0.500 7.0E-05 7.2E-04 2.1E-03 7.9E-03 5.2E-04 4.2E-03 9.2E-03 3.3E-02 1.625 6.1E-06 1.2E-04 5.8E-04 2.2E-03 3.9E-05 7.6E-04 3.5E-03 1.3E-02 3.000 4.8E-07 7.6E-06 3.6E-05 1.4E-04 1.4E-06 2.2E-05 1.4E-04 5.1E-04 7.000 2.8E-08 6.6E-07 3.6E-06 1.4E-05 1.0E-07 2.0E-06 2.1E-05 6.8E-05 14.000 1.0E-09 2.8E-08 4.8E-07 1.4E-06 1.4E-08 3.3E-07 4.0E-06 1.0E-05 31.000 8.7E-11 2.9E-09 7.5E-08 2.1E-07 6.1E-09 1.5E-07 1.9E-06 5.5E-06 CASA Grande uses LOCA exceedance frequencies to derive frequencies for critical breaks. Critical break frequencies are then used to aggregate per weld contributions to CDF for all breaks generating and transporting LDFG debris quantities greater than the tested RoverD failure limits.

Note that Bounded Johnson distributions have been fit to the tabulated 25-year frequency statistics to allow risk estimates to be generated for any uncertainty percentile (not just the mean, 5th, 50th, and 95th percentiles). The Bounded Johnson distributions are used to create the blue dots in Figure 7-1 and are supplemental information. The Bounded Johnson distribution has a range defined by minimum and maximum parameters and has both a shape parameter and a scale parameter. These four parameters are adjusted to attain the best possible agreement with the tabulated exceedance frequency statistics. Use of the Bounded Johnson fits provides additional insights for consideration, but does not affect the accepted RoverD methodology for total CDF risk estimation.

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 13 of 60 The maximum LDFG transported by each critical weld was determined by evaluating 360 jet directions at each critical break size, identified by searching in increments of one angular degree. The total LDFG transported for each postulated break is the sum of ZOI-generated debris, latent fiber debris, and the fiber safety margin. Finally, each critical weld contribution to CDF is calculated based on the exceedance frequency for the critical break size determined using the NUREG-1829 initiating event frequency data.

7 Baseline Results 7.1 Baseline CDF A summary of CDF estimates the change in number of core damage events per year for the continuum break model based on geometric 25-year LOCA frequencies as provided in Table 7-1 below. The CDF estimates presented in Table 7-1 correspond to the mean, 5th, 50th, and 95th percentiles of the geometric 25-year LOCA exceedance frequencies provided in Table 6-1, which provides estimates across the standard range of uncertainty.

Table 7-1: RoverD CDF results for baseline scenario Statistic 5th 50th Mean 95th CDF (# core damage events / year) 4.01E-09 9.04E-08 5.37E-07 1.95E-06 To illustrate estimated CDF for the full range of uncertainty, Bounded Johnson distributions fit to NUREG-1829 exceedance frequencies were used to calculate CDF for a discrete set of 120 percentiles that are displayed in Figure 7-1 as blue dots. The geometric method of aggregation is considered the most appropriate method for aggregating expert elicitations for LOCA exceedance frequencies. The arithmetic aggregation is implemented for several sensitivity cases in Section 9.1. Figure 7-1 shows that approximately 88% of CDF estimates are in Region III of Regulatory Guide 1.174 (Reference [1]) for the baseline case. With respect to uncertainty in the initiating event frequencies alone, these results indicate an 88% confidence that CDF is less than 1.0E-6 core damage events per year (Region III cutoff from Reg. Guide 1.174).

The black dots in Figure 7-1 indicate the 5th, 50th, mean, and 95th percentiles of CDF uncertainty propagated from LOCA initiating event frequency uncertainty.

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 14 of 60 Figure 7-1: Distribution of RoverD CDF for 25-year geometric mean frequencies 7.2 Baseline LERF The methodology for estimating LERF (change in number of large early release events per year) utilizes the ratio of conditional LERF (CLERF) to conditional CDF (CCDF).

The ratio of CLERF to CCDF is assumed to be 0.1, representing the conditional probability of large early release, given the occurrence of core-damage induced by a large break loss of coolant accident with containment sumps failed. (Approximately one in every ten core-damage events leads to large early release). Because GL 2004-02 debris-related phenomena do not directly challenge the containment building (which could lead to increased LERF), the ratio of LERF to CDF is assumed to be the same as the ratio of CLERF to CCDF. Estimates of CDF reported above are attributed exclusively to GL 2004-02 debris phenomena, so the corresponding LERF caused by GL 2004-02 phenomena can be calculated using the ratio of CLERF to CCDF. A summary of LERF estimates for the continuum break model based on geometric 25-year LOCA frequencies is provided in Table 7-2. The mean estimate of LERF is 5.37E-08 events per year and is also in Risk Region III as defined by Regulatory Guide 1.174 (Reference [1]).

Table 7-2: RoverD LERF results for baseline scenario Statistic 5th 50th Mean 95th LERF (# large early release events/year) 4.01E-10 9.04E-09 5.37E-08 1.95E-07

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 15 of 60 7.3 Baseline Weld List The critical weld list, as defined in the RoverD methodology, is a collection of welds where a postulated break generates and transports enough fibrous debris to exceed the RoverD failure threshold of 300 lbm. Table 7-3 lists the Class-I welds located between the RPV and the first isolation valve that were found to be capable of generating and transporting LDFG debris in excess of the RoverD test limit when 50 lbm of transported fiber safety margin are added to the predicted fiber inventory of every break scenario.

The table includes the weld name, the smallest break size to fail, the maximum fiber transported for the smallest break to fail, the fiber margin (the difference between the RoverD failure threshold and the amount of fiber transported), and the per weld contribution to CDF. Note, the per weld contributions to CDF in the last column sum to equal the mean CDF reported in Table 7-1.

Table 7-3: Baseline critical weld list for continuum model Fiber Smallest Transported Fiber Contribution Break Size

1. Weld Location Name at Smallest Margin to Mean to Fail Break Size (lbm) CDF(1)

(inches)

(lbm) 1 WELD EBB01B-RSG-OUTLET-SC010 11.855 300.091 -0.091 1.09E-08 2 WELD 2-BB-01-3065B-WDC-002-FW2 11.795 300.354 -0.354 1.11E-08 3 WELD 2-BB-01-F206 11.495 300.096 -0.096 1.20E-08 4 WELD 2-BB-01-S204-3 11.885 300.149 -0.149 1.08E-08 5 WELD 2-BB-01-F208 11.565 300.156 -0.156 1.18E-08 6 WELD 2-BB-01-S205-4 11.125 300.025 -0.025 1.31E-08 7 WELD 2-BB-01-F207 11.525 300.048 -0.048 1.19E-08 8 WELD 2-BB-01-S201-2 27.500 313.423 -13.423 0.00E+00(1) 9 WELD 2-BB-01-F201 10.855 300.254 -0.254 1.18E-08 10 WELD 2-BB-01-S202-2 13.275 300.183 -0.183 4.70E-09 11 WELD 2-BB-01-3065B-WDC-001-FW1 13.225 300.217 -0.217 4.86E-09 12 WELD EBB01B-RSG-INLET-SC010 13.255 300.190 -0.190 4.76E-09 13 WELD 2-EJ-04-FW9 10.500 327.631 -27.631 0.00E+00(1) 14 WELD 2-EJ-04-S018-C 10.500 329.261 -29.261 0.00E+00(1) 15 WELD 2-EJ-04-FW8 10.500 326.983 -26.983 0.00E+00(1) 16 WELD 2-EJ-04-S018-E 10.500 351.002 -51.002 0.00E+00(1) 17 WELD 2-EJ-04-F031 9.985 300.095 -0.095 1.14E-09 18 WELD EBB01A-RSG-OUTLET-SC010 10.905 300.032 -0.032 1.37E-08 19 WELD 2-BB-01-3065A-WDC-002-FW2 10.805 300.247 -0.247 1.40E-08 20 WELD 2-BB-01-F106 9.965 300.022 -0.022 1.60E-08 21 WELD 2-BB-01-S104-3 9.915 300.010 -0.010 1.61E-08 22 WELD 2-BB-01-F108 9.915 300.054 -0.054 1.61E-08 23 WELD 2-BB-01-S105-4 9.145 300.362 -0.362 1.78E-08 24 WELD 2-BB-01-F107 9.595 300.226 -0.226 1.68E-08 25 WELD 2-BB-01-S102-2 11.755 300.091 -0.091 9.45E-09 26 WELD 2-BB-01-3065A-WDC-001-FW1 11.525 300.508 -0.508 1.02E-08 27 WELD EBB01A-RSG-INLET-SC010 11.565 300.063 -0.063 1.00E-08 28 WELD 2-RV-302-121-A 27.325 300.076 -0.076 2.75E-11 29 WELD 2-BB-01-F102 26.975 300.068 -0.068 8.25E-11 30 WELD 2-BB-01-S101-2 27.500 345.081 -45.081 0.00E+00(1)

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 16 of 60 Fiber Smallest Transported Fiber Contribution Break Size

1. Weld Location Name at Smallest Margin to Mean to Fail Break Size (lbm) CDF(1)

(inches)

(lbm) 31 WELD 2-BB-01-F101 9.475 300.219 -0.219 1.50E-08 32 WELD EBB01C-RSG-OUTLET-SC010 11.615 300.129 -0.129 1.16E-08 33 WELD 2-BB-01-3065C-WDC-002-FW2 11.515 300.400 -0.400 1.20E-08 34 WELD 2-BB-01-F306 10.945 300.219 -0.219 1.36E-08 35 WELD 2-BB-01-S304-3 11.295 300.226 -0.226 1.26E-08 36 WELD 2-BB-01-F308 11.255 300.364 -0.364 1.28E-08 37 WELD 2-BB-01-S305-4 10.585 300.050 -0.050 1.46E-08 38 WELD 2-BB-01-F307 11.165 300.014 -0.014 1.30E-08 39 WELD 2-BB-01-F301 11.415 300.700 -0.700 1.02E-08 40 WELD 2-BB-01-S302-2 13.405 300.053 -0.053 4.30E-09 41 WELD 2-BB-01-3065C-WDC-001-FW1 12.995 300.271 -0.271 5.58E-09 42 WELD EBB01C-RSG-INLET-SC010 13.015 300.404 -0.404 5.51E-09 43 WELD 2-BB-01-S402-2 12.385 300.334 -0.334 7.48E-09 44 WELD 2-BB-01-3065D-WDC-001-FW1 11.825 300.020 -0.020 9.23E-09 45 WELD EBB01D-RSG-INLET-SC010 11.875 300.188 -0.188 9.08E-09 46 WELD 2-BB-01-F401 9.905 300.507 -0.507 1.41E-08 47 WELD EBB01D-RSG-OUTLET-SC010 10.745 300.278 -0.278 1.42E-08 48 WELD 2-BB-01-3065D-WDC-002-FW2 10.635 300.075 -0.075 1.45E-08 49 WELD 2-BB-01-F406 9.845 300.122 -0.122 1.63E-08 50 WELD 2-BB-01-S404-3 9.695 300.179 -0.179 1.66E-08 51 WELD 2-BB-01-F408 9.605 300.489 -0.489 1.68E-08 52 WELD 2-BB-01-S405-4 9.195 300.327 -0.327 1.77E-08 53 WELD 2-BB-01-F407 9.635 300.222 -0.222 1.68E-08 54 WELD 2-EJ-04-S016-B 10.500 310.438 -10.438 0.00E+00(1) 55 WELD 2-EJ-04-S016-C 10.500 318.508 -18.508 0.00E+00(1) 56 WELD 2-EJ-04-S016-D 10.500 316.902 -16.902 0.00E+00(1) 57 WELD 2-EJ-04-S016-E 10.330 300.053 -0.053 3.78E-10 58 WELD 2-EJ-04-S016-G 9.485 300.239 -0.239 2.26E-09 59 WELD 2-EJ-04-S016-H 10.500 403.032 -103.032 0.00E+00(1) 60 WELD 2-EJ-04-F025 10.155 300.192 -0.192 7.67E-10 5.37E-07 (1) When the interval collapses to a point (one break size), the exceedance frequency difference becomes identically equal to zero. The behavior described here is not an ad hoc or arbitrary interpretation of the NUREG-1829 exceedance frequency tables; it is a necessary attribute of the mathematical formalism.

Table 7-3 lists results for critical breaks identified using the continuum model where breaks of any size up to a full DEGB can occur on a weld. Under the continuum model, the search for a critical weld can be imagined as a systematic increase in break size on one weld beginning with a break of 0.1 inches in diameter and proceeding to larger breaks in 0.1 inch increments. Transported debris is compared to the RoverD test threshold at each step; if the transported debris exceeds the threshold, the location is judged to be a critical weld. The difference in exceedance frequency between the identified critical break size and the weld inner diameter (scaled by the number of welds in that size range) is assigned as the CDF contribution. Clearly, if one is found at a weld, then all larger breaks on that weld, up to the DEGB, are also capable of

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 17 of 60 exceeding the RoverD threshold. Thus, the difference in exceedance frequency between and the pipe inner diameter captures the full potential CDF at each critical weld.

The assignment of exceedance frequency difference, defined over an interval of minimum to maximum break size, obeys a fundamental property of exceedance functions that include all complementary cumulative distribution functions used in PRA, Monte Carlo radiation transport codes, and numerous other applications in statistics, physics, engineering, and mathematics. The total annual LOCA frequency of all break sizes cannot be conserved mathematically by any means other than assignment of exceedance frequency differences defined over intervals of break size. One result of the exceedance frequency conservation property is that when the break size interval becomes very small, so does the corresponding assignment of annual break frequency that can occur within the interval. In fact, the exceedance frequency function has no meaning at a single break size, so when the interval collapses to a point (one break size), the exceedance frequency difference becomes identically equal to zero. The behavior described here is not an ad hoc or arbitrary interpretation of the NUREG-1829 exceedance frequency tables; it is a necessary attribute of the mathematical formalism.

During the critical weld search, there are often cases where none of the postulated hemispherical ZOI arising from breaks smaller than the pipe diameter can generate and transport more debris than the RoverD threshold, no matter how small the search increment may be. However, consistent with NEI-04-07 guidance, when the break size search becomes equal to the inner pipe diameter, a spherical ZOI is assumed that suddenly forms much more debris than the previous smaller break size that is assumed to have only a hemispherical ZOI; the RoverD threshold is exceeded by the spherical ZOI and the location is declared to be a critical weld for the special case of DEGB. The discrete jump to a spherical ZOI is an artifact of current guidance. Because all hemispherical breaks evaluated up to an arbitrarily small interval close to the pipe diameter have been found to pass the RoverD threshold, the residual interval containing the DEGB is vanishingly small, and the corresponding CDF contribution of the DEGB becomes equal to zero.

Critical welds that are listed in Table 7-3 only because of their spherical ZOI DEGB failures are properly assigned zero CDF contributions under the continuum break model. While it may be non-intuitive that the traditional worst case DEGB condition can have zero risk contribution, the conclusion is validated by two essential constraints:

(1) every possible smaller break has been examined and found to be within the RoverD threshold, and (2) no breaks larger than the DEGB can form at a given weld. Because of the apparent contradiction with design-basis determinism, the NRC requested that the pilot plant also quantify CDF for an alternate DEGB-only break model as a parametric study. The results for the DEGB-only break model for Callaway are presented in Section 9.1.

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 18 of 60 8 Secondary Risk Contributors SRCs are evaluated to investigate the risk associated with initiators other than LOCAs at Class-I welds between the RPV and an isolation valve. SRCs include: (1) LOCAs at Class-I welds beyond the first isolation valve (i.e., isolable weld breaks concurrent with isolation valve failure); (2) LOCAs related to failedopen or spurious valve actuation; (3) pump seal LOCAs; and (4) secondary line breaks (concurrent with other failures that necessitate operation of the ECCS in sump recirculation mode). Refer to the responses to Questions 34 and 35 in Enclosure 5 for additional information regarding secondary risk contributor screening.

8.1 Failure of Isolation Valves This section presents CDF risk estimates for the failure of Class-I welds located both before and after the first isolation valve (refer to the response to Question 31 in for additional information regarding the definition of first isolation valves),

consistent with failure of the isolation function of these valves. Class-I welds located beyond the first isolation valve are termed isolable welds, while Class-I welds located before the first isolation valve are termed non-isolable welds. Non-isolable welds are the welds examined in baseline evaluations; see Section 7. NUREG-1829 break frequencies strictly apply only to non-isolable welds, so including isolable welds in the total weld count dilute the frequency per weld. Therefore, isolable weld breaks are treated as a secondary risk contributor, independent of and in addition to risks associated with non-isolable weld breaks.

The analysis assumes that isolable welds on the outboard side of the valve are identical to non-isolable welds on the inboard side of the valve. This assumption is reasonable so long as the operating environment is similar on both sides of the valve. It follows from this assumption that NUREG-1829 frequencies per weld per year are independently applicable to breaks at isolable welds. Treating isolable welds as a separate population increases total break frequency above the NUREG-1829 top-down conservation limit, and is conservative in terms of total LOCA initiation frequency and total CDF estimates.

A generic, conservative probability of failure for a valves isolation function is 1.11E-03 (Reference [6]). Also refer to the response to Question 31 in Enclosure 5 for additional information regarding isolation valve failure probabilities. Therefore, individual isolable weld contributions to CDF output by CASA Grande are multiplied by this factor to return the true per weld contributions to risk. The resulting values are then summed across all isolable welds and added to the total CDF computed in the baseline scenario for non-isolable welds to yield the total CDF across all isolable and non-isolable welds.

Table 8-1 provides CDF estimates for the baseline scenario and for the isolation valve sensitivity. Both scenarios are based on the continuum break size model, geometric

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 19 of 60 aggregation, and 25-year NUREG-1829 frequencies. Baseline CDF estimates from Table 7-1 are reproduced (third row), along with the CDF estimates for isolable welds both before (first row) and after (second row) multiplying by the isolation valve failure probability. Adding the values in the second and third rows provides CDF estimates that include both isolable and non-isolable welds (last row). The results show isolable welds have negligible impact on CDF. The 50-lbm fiber safety margin applied in the baseline scenario was also used in this sensitivity study.

Table 8-1: RoverD CDF results considering isolable weld SRC CDF Statistic Scenario 5th 50th Mean 95th Isolable Welds (Pre-Weighted) 1.09E-10 2.40E-09 1.13E-08 4.45E-08 Isolable Welds (Weighted) 1.22E-13 2.66E-12 1.25E-11 4.94E-11 Non-Isolable Welds (Baseline) 4.01E-09 9.04E-08 5.37E-07 1.95E-06 All Welds (Total) 4.01E-09 9.04E-08 5.37E-07 1.95E-06 Table 8-2 lists the critical isolable welds, or the welds that were found to transport an amount of LDFG debris that exceeds the 300-lbm limit derived from strainer testing. All critical isolable welds are large break LOCAs. Table 8-2 includes the critical break size to fail each critical isolable weld to within a resolution of 0.01 inches, the maximum quantity of LDFG debris transported at the critical break size, the fiber margin (the difference between the RoverD failure threshold and the amount of fiber transported),

and the per weld contributions to CDF (both before and after being weighted by the valve failure probability). Summing down the last column of the table returns the mean CDF reported for the isolable weld scenario in Table 8-1. A table of debris transport results for DEGBs at all isolable welds in containment is provided in Table 10-4.

Table 8-2: Critical isolable welds for continuum break model and 25-year LOCA frequencies Smallest Max Fiber Break Transported Fiber Contribution Contribution

1. Weld Location Name Size to at Smallest Margin to GM CDF to GM CDF Fail Break Size (lbm) (Unweighted) (Weighted)

(inches) (lbm) 1 AFIVWELD 2-EJ-04-F032 9.525 300.186 -0.186 2.17E-09 2.41E-12 2 AFIVWELD 2-EJ-04-S019-D 10.285 300.556 -0.556 4.78E-10 5.30E-13 3 AFIVWELD 2-EJ-04-FW7 9.055 300.130 -0.130 3.21E-09 3.56E-12 4 AFIVWELD 2-EJ-04-S019-F 8.765 300.124 -0.124 3.86E-09 4.28E-12 5 AFIVWELD 2-EJ-04-F033 10.500 410.195 -110.195 0.00E+00 0.00E+00 6 AFIVWELD 2-EJ-04-S015-E 10.500 372.189 -72.189 0.00E+00 0.00E+00 7 AFIVWELD 2-EJ-04-F024 9.795 300.001 -0.001 1.57E-09 1.74E-12 1.13E-08 1.25E-11

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 20 of 60 8.2 Secondary Line Breaks Secondary line breaks (large main steam and feedwater line breaks) are considered as secondary risk contributors. Refer to the responses to Questions 34 and 35 in for additional information regarding secondary risk contributor screening.

Based on the screening results, there is no contribution to CDF/LERF associated with GL 2004-02 phenomena from secondary line breaks.

8.3 Spurious and Failed-Open Relief and Safety Valves Spurious actuation and failed-open primary system relief and safety valves are considered as secondary risk contributors. In accordance with the pilot-plant submittal, relief and safety valve actuation is very similar to a small LOCA in thermodynamic response, and the smallest critical break size for Callaway is 9.145 inches (a large break). Because small or medium breaks do not lead to core damage due to GL 2004-02 phenomena, there is no significant contribution to CDF from spurious actuation and failed-open relief and safety valves. This conclusion is further supported by the observation that relief and safety valves discharge into regions with minimal to no insulated process piping. Refer to the responses to Questions 34 and 35 in Enclosure 5 for additional information regarding secondary risk contributor screening.

8.4 Mechanical LOCA (Pump Seal LOCA)

Mechanical LOCAs (pump seal LOCAs) are considered as secondary risk contributors.

In accordance with the pilot plant submittal, mechanical LOCAs would be very similar to a small LOCA in thermodynamic response, and the smallest critical break size for Callaway is 9.145 inches (a large break). Because small or medium breaks do not lead to core damage due to GL 2004-02 phenomena, there is no contribution to CDF from mechanical LOCAs. This conclusion is further supported by the observation that thermally insulated Reactor Coolant Pumps (RCP) are co-located with heavily insulated pipes in steam generator compartments that are examined extensively in all CASA debris generation calculations. Therefore, there is no possibility that RCP seal LOCA can generate an unexpectedly large amount of debris that could challenge ECCS strainers.

8.5 Additional Secondary Risk Contributors Additional secondary risk contributors, including ex-vessel downstream wear, strainer structural analysis, as well as in-vessel effects, which are analyzed with current WCAP-17788 methods, do not result in any failures and do not increase incremental risk of core damage.

The Callaway seismic PRA identifies several seismic-induced large loss of coolant accident (LLOCA) breaks that lead to core damage, so seismic-induced risk for these

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 21 of 60 events is explicitly quantified in the PRA. All seismically-induced LLOCA events, with the exception of one, are assumed to go directly to core damage, therefore, core damage due to GL 2004-02 phenomena is encompassed for these seismic events. The seismic PRA identifies one seismic-induced LLOCA, on the Pressurizer Surge Line, that does not proceed directly to core damage. However, no pressurizer surge line welds appear in the list of critical welds (Table 9.3), so debris generated by this seismically induced LLOCA does not exceed the deterministic capacity of the strainers and the event does not contribute incremental risk to the RoverD analysis.

During long-term cooling, the potential exists for boiling in the core to cause boric acid concentration to build up to a level where precipitation of boron from solution occurs.

Plate-out of boron precipitate on fuel rods could reduce heat transfer and restrict the flow of cooling water, resulting in cladding heat up. The Callaway Accident Analysis Basis Document (AABD) confirms that CL, HL, and simultaneous CL/HL minimum injection flow rates are sufficient to prevent buildup of boric acid in the core and to dilute a high concentration in the core region, if one exists, prior to reaching the boric acid solubility limit, and that the 13-hour HLSO time addresses the boric acid precipitation concern.

Refer to the responses to Questions 34 and 35 in Enclosure 5 for additional information regarding secondary risk contributor screening.

9 Sensitivities This section presents results for sensitivity studies performed to assess relative changes to RoverD CDF risk from the baseline scenario given changes to input parameters and model assumptions. These sensitivities aim to interpret or apply regulatory guidance and industry knowledge in a different manner than the baseline, consistent with sensitivity evaluations performed by the pilot plant. Two types of sensitivity studies are performed for this analysis. One set of sensitivities explores the effects of using alternative initiating event frequencies and an alternative break model, and another sensitivity study explores the effect of adding additional insulation at valve locations.

Section 9.1 provides a discussion and results for sensitivity studies that use alternative initiating event frequencies and break size models. These studies include:

1. Using a DEGB-only break model instead of the continuum break model. For this sensitivity, the only breaks that can occur in the plant are DEGBs. Partial pipe breaks are not permitted to occur.

2. Using 40-year LOCA frequencies instead of 25-year LOCA frequencies. Both sets of frequencies are provided in NUREG-1829, but the 40-year frequencies are higher with wider uncertainties to account for extended plant life.

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 22 of 60

3. Using arithmetic aggregation (arithmetic means) for the initiating event frequencies instead of geometric aggregation (geometric means). The frequency data reported in NUREG-1829 were elicited from individual experts and then aggregated to provide a standard set of frequencies across all experts.

Geometric aggregation is generally deemed the most appropriate aggregation method for this application, because it reduces the effect of outliers. Arithmetic aggregation weights all elicited values equally and is explored as a sensitivity for possible change in methodology. Refer to the response to Question 36 in Enclosure 5 for additional information regarding sensitivity analysis.

These parameter sensitivities do not affect debris destruction or transport, and so they do not influence critical welds or break sizes. Because of this simplicity, only the corresponding risk (CDF) estimates are presented for these sensitivities. Note that the 50-lbm fiber safety margin used in the baseline scenario was also used in these sensitivity studies.

Section 9.2 provides a discussion and results for a valve insulation sensitivity that applies additional insulation to select valves in containment, where more insulation may be present to conform to valve geometry, beyond the amount of insulation already applied to valve bodies in the baseline calculation. This sensitivity evaluates whether extra insulation at valve locations either causes any baseline non-critical weld to become a critical weld, or reduces the critical break size for any of the present baseline critical welds. Because this sensitivity study introduces additional LDFG debris at valve locations with the potential for destruction, an updated critical weld list is provided for the sensitivity in addition to the revised risk (CDF) estimates.

9.1 Initiating Event Frequency and Break Size Model Sensitivities This section summarizes risk results for the sensitivity studies designed to assess the effect that alternative initiating frequency aggregation methods (geometric vs. arithmetic means), break size models (continuum vs. DEGB-only), and initiating event frequency plant life (25-year vs. 40-year) have on CDF estimates for Callaway. Table 9-1 contains a summary of CDF results for each parameter sensitivity evaluated, where the first row reproduces the baseline results presented in Table 7-1.

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 23 of 60 Table 9-1: RoverD CDF results for LOCA frequency sensitivity scenarios Aggregation Break CDF Statistic

1. Plant Life Model Model 5th 50th Mean 95th 0 25-Year Geometric Continuum 4.01E-09 9.04E-08 5.37E-07 1.95E-06 1 25-Year Geometric DEGB 5.52E-09 1.23E-07 6.70E-07 2.51E-06 2 25-Year Arithmetic Continuum 2.50E-08 5.14E-07 4.07E-06 1.29E-05 3 25-Year Arithmetic DEGB 3.11E-08 6.16E-07 4.73E-06 1.52E-05 4 40-Year Geometric Continuum 8.12E-09 1.94E-07 1.22E-06 4.52E-06 5 40-Year Geometric DEGB 1.11E-08 2.62E-07 1.52E-06 5.78E-06 6 40-Year Arithmetic Continuum 3.54E-08 7.38E-07 8.08E-06 2.46E-05 7 40-Year Arithmetic DEGB 4.40E-08 9.00E-07 9.69E-06 3.06E-05 To illustrate the distribution of RoverD CDF estimates considering the full range of uncertainty, all quantiles of the continuum and DEGB-only risk calculations are plotted in Figure 7-1 (and reproduced in Figure 9-1) based on geometric aggregation of the 25-year NUREG-1829 frequencies. Continuous interpolated quantile values were derived from Bounded Johnson distributions fit to NUREG-1829 data. Considering the full range of uncertainty, approximately 88% of postulated LOCA scenarios place CDF risk in Region III of Regulatory Guide 1.174 (Reference [1]) for the continuum model, while approximately 85% fall into Region III for the DEGB-only model. Figure 9-2 compares the same CDF risk distributions based on arithmetic aggregation of the NUREG-1829 LOCA frequencies.

Figure 9-1: Distributions of RoverD CDF for 25-year geometric mean LOCA exceedance frequencies

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 24 of 60 Figure 9-2: Distributions of RoverD CDF for 25-year arithmetic mean LOCA exceedance frequencies 9.2 Valve Insulation Sensitivity Study The valve insulation sensitivity scenario applies additional insulation to valves in containment, where more insulation may be present to conform to valve geometry, beyond the valve insulation already applied in the baseline calculation. Extra LDFG insulation is applied to valves on select pipe sizes based on valve sizes defined in the CASA Grande input deck. Additional valve insulation has the potential to cause non-critical welds to become critical welds and to reduce critical break sizes for critical welds, both of which would increase CDF. This sensitivity determines whether increasing LDFG insulation around valves has a significant impact on CDF estimates.

Additional insulation was added to all valve bodies by adding collars of insulation at the valves where the collars have the same thickness as the insulation already present, effectively doubling the insulation at valve locations for the length of the collar (where the length of the collar is a function of the pipe diameters). Note that the 50-lbm fiber safety margin used in the baseline scenario was also used in this sensitivity study.

A summary of CDF results for the valve insulation sensitivity is provided in Table 9-2.

These results are based on the continuum break model and geometric aggregation of the 25-year LOCA frequencies elicited in NUREG-1829. Table 9-2 shows that the mean CDF for RoverD fiber debris increases approximately 0.56% above the baseline risk of 5.37E-07 as a result of the extra valve insulation.

Table 9-2: RoverD CDF results for valve insulation sensitivity Statistic 5th 50th Mean 95th CDF 4.05E-09 9.10E-08 5.40E-07 1.97E-06

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 25 of 60 Table 9-3 lists Class-I welds located between the RPV and the first isolation valve that were found to transport LDFG debris in excess of the tested 300-lbm RoverD fiber failure threshold for the valve insulation sensitivity scenario. Table 9-3 includes the critical break size for each critical weld determined to a resolution of 0.01 inches, the maximum quantity of LDFG debris transported at the critical break size, the fiber margin (the difference between the RoverD fiber failure threshold and the amount of fiber transported), and the per weld contribution to CDF. Note that summing the last column of the table returns the mean CDF reported in Table 9-2. Careful comparison of Table 9-3 for the valve insulation sensitivity and Table 7-3 for the baseline conditions reveals that no new critical welds are added because of the extra insulation, but critical break sizes do decrease slightly for some baseline critical welds. A table of results for DEGBs at all welds in containment is provided in Table 10-2.

Table 9-3: Critical weld list for valve insulation sensitivity scenario Smallest Max Fiber Break Transported Per Weld Fiber Margin

1. Weld Location Name Size to at Smallest Contribution (lbm)

Fail Break Size to CDF (inches) (lbm) 1 WELD EBB01B-RSG-OUTLET-SC010 11.855 300.091 -0.091 1.09E-08 2 WELD 2-BB-01-3065B-WDC-002-FW2 11.795 300.354 -0.354 1.11E-08 3 WELD 2-BB-01-F206 11.495 300.096 -0.096 1.20E-08 4 WELD 2-BB-01-S204-3 11.885 300.149 -0.149 1.08E-08 5 WELD 2-BB-01-F208 11.535 300.442 -0.442 1.19E-08 6 WELD 2-BB-01-S205-4 10.975 300.186 -0.186 1.36E-08 7 WELD 2-BB-01-F207 11.525 300.048 -0.048 1.19E-08 8 WELD 2-BB-01-S201-2 27.500 317.064 -17.064 0.00E+00 9 WELD 2-BB-01-F201 10.775 300.336 -0.336 1.20E-08 10 WELD 2-BB-01-S202-2 13.275 300.395 -0.395 4.70E-09 11 WELD 2-BB-01-3065B-WDC-001-FW1 13.225 300.217 -0.217 4.86E-09 12 WELD EBB01B-RSG-INLET-SC010 13.255 300.190 -0.190 4.76E-09 13 WELD 2-EJ-04-FW9 10.500 328.112 -28.112 0.00E+00 14 WELD 2-EJ-04-S018-C 10.500 329.742 -29.742 0.00E+00 15 WELD 2-EJ-04-FW8 10.500 327.464 -27.464 0.00E+00 16 WELD 2-EJ-04-S018-E 10.500 351.483 -51.483 0.00E+00 17 WELD 2-EJ-04-F031 9.975 300.031 -0.031 1.17E-09 18 WELD EBB01A-RSG-OUTLET-SC010 10.905 300.032 -0.032 1.37E-08 19 WELD 2-BB-01-3065A-WDC-002-FW2 10.805 300.247 -0.247 1.40E-08 20 WELD 2-BB-01-F106 9.965 300.022 -0.022 1.60E-08 21 WELD 2-BB-01-S104-3 9.915 300.010 -0.010 1.61E-08 22 WELD 2-BB-01-F108 9.915 300.054 -0.054 1.61E-08 23 WELD 2-BB-01-S105-4 9.125 300.446 -0.446 1.79E-08 24 WELD 2-BB-01-F107 9.595 300.226 -0.226 1.68E-08 25 WELD 2-BB-01-S102-2 11.755 300.411 -0.411 9.45E-09 26 WELD 2-BB-01-3065A-WDC-001-FW1 11.525 300.508 -0.508 1.02E-08 27 WELD EBB01A-RSG-INLET-SC010 11.565 300.063 -0.063 1.00E-08

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 26 of 60 Smallest Max Fiber Break Transported Per Weld Fiber Margin

1. Weld Location Name Size to at Smallest Contribution (lbm)

Fail Break Size to CDF (inches) (lbm) 28 WELD 2-RV-302-121-A 26.965 300.010 -0.010 8.41E-11 29 WELD 2-BB-01-F102 26.635 300.051 -0.051 1.36E-10 30 WELD 2-BB-01-S101-2 27.500 348.521 -48.521 0.00E+00 31 WELD 2-BB-01-F101 9.435 300.061 -0.061 1.51E-08 32 WELD EBB01C-RSG-OUTLET-SC010 11.575 300.355 -0.355 1.18E-08 33 WELD 2-BB-01-3065C-WDC-002-FW2 11.475 300.203 -0.203 1.21E-08 34 WELD 2-BB-01-F306 10.915 300.239 -0.239 1.37E-08 35 WELD 2-BB-01-S304-3 11.265 300.662 -0.662 1.27E-08 36 WELD 2-BB-01-F308 11.195 300.684 -0.684 1.30E-08 37 WELD 2-BB-01-S305-4 10.465 300.010 -0.010 1.49E-08 38 WELD 2-BB-01-F307 11.105 300.219 -0.219 1.32E-08 39 WELD 2-BB-01-F301 11.285 300.220 -0.220 1.06E-08 40 WELD 2-BB-01-S302-2 13.395 300.187 -0.187 4.33E-09 41 WELD 2-BB-01-3065C-WDC-001-FW1 12.955 300.174 -0.174 5.70E-09 42 WELD EBB01C-RSG-INLET-SC010 12.955 300.059 -0.059 5.70E-09 43 WELD 2-BB-01-S402-2 12.365 300.024 -0.024 7.55E-09 44 WELD 2-BB-01-3065D-WDC-001-FW1 11.815 300.104 -0.104 9.26E-09 45 WELD EBB01D-RSG-INLET-SC010 11.855 300.059 -0.059 9.14E-09 46 WELD 2-BB-01-F401 9.875 300.026 -0.026 1.42E-08 47 WELD EBB01D-RSG-OUTLET-SC010 10.735 300.381 -0.381 1.42E-08 48 WELD 2-BB-01-3065D-WDC-002-FW2 10.635 300.582 -0.582 1.45E-08 49 WELD 2-BB-01-F406 9.835 300.246 -0.246 1.63E-08 50 WELD 2-BB-01-S404-3 9.685 300.416 -0.416 1.66E-08 51 WELD 2-BB-01-F408 9.585 300.101 -0.101 1.69E-08 52 WELD 2-BB-01-S405-4 9.175 300.111 -0.111 1.78E-08 53 WELD 2-BB-01-F407 9.605 300.161 -0.161 1.68E-08 54 WELD 2-EJ-04-S016-B 10.500 311.199 -11.199 0.00E+00 55 WELD 2-EJ-04-S016-C 10.500 319.269 -19.269 0.00E+00 56 WELD 2-EJ-04-S016-D 10.500 317.662 -17.662 0.00E+00 57 WELD 2-EJ-04-S016-E 10.330 300.053 -0.053 3.78E-10 58 WELD 2-EJ-04-S016-G 9.485 300.287 -0.287 2.26E-09 59 WELD 2-EJ-04-S016-H 10.500 403.966 -103.966 0.00E+00 60 WELD 2-EJ-04-F025 10.135 300.624 -0.624 8.11E-10 5.40E-07 10 Full Weld Lists This section presents tabulated results for all RoverD simulations presented in the previous sections. These results include transported debris quantities and risk contributions postulated at all welds in containment.

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 27 of 60 10.1 Full Weld List for Baseline Scenario This section contains a full weld list for the baseline analysis scenario. Table 10-1 lists the weld location name, the corresponding pipe diameter (DEGB size), the amount of fiber transported by a DEGB, the fiber margin (the difference between the RoverD failure threshold and the amount of fiber transported), and the contribution of each weld to the geometric mean CDF based on 25-year NUREG-1829 frequencies at the smallest critical break size. Welds that do not exceed the RoverD limit for a DEGB are deemed non-critical welds. Non-critical welds have a positive fiber margin and do not contribute to CDF. Note that per weld contributions to CDF in the last column sum to the mean CDF reported for the baseline scenario reported in Table 7-1 and Table 9-1.

Table 10-1: Full weld list for baseline scenario DEGB Fiber Inside Fiber Contribution Transported

1. Weld Location Name Diameter Margin to Mean at DEGB Size (lbm) CDF Size (lbm)

(inches) 1 WELD 2-BB-04-F005 3.440 94.968 205.032 0.00E+00 2 WELD 2-BB-04-S003-D 3.440 96.138 203.862 0.00E+00 3 WELD 2-BB-04-S003-C 3.440 96.907 203.093 0.00E+00 4 WELD 2-BB-04-F006 3.440 103.704 196.296 0.00E+00 5 WELD 2-BB-04-S004-C 3.440 107.348 192.652 0.00E+00 6 WELD 2-BB-04-F007 3.440 105.538 194.462 0.00E+00 7 WELD 2-BB-04-S005-D 3.440 106.904 193.096 0.00E+00 8 WELD 2-BB-04-S005-C 3.440 105.307 194.693 0.00E+00 9 WELD 2-BB-04-S005-B 3.440 98.012 201.988 0.00E+00 10 WELD 2-BB-04-F008 3.440 98.011 201.989 0.00E+00 11 WELD 2-BB-04-S006-C 3.440 93.206 206.794 0.00E+00 12 WELD 2-BB-04-S006-B 3.440 91.505 208.495 0.00E+00 13 WELD 2-BB-04-F009 3.440 87.065 212.935 0.00E+00 14 WELD 2-BB-04-S007-F 3.440 87.235 212.765 0.00E+00 15 WELD 2-BB-04-S007-E 3.440 88.794 211.206 0.00E+00 16 WELD 2-BB-04-S007-D 3.440 88.661 211.339 0.00E+00 17 WELD 2-BB-04-S007-B 3.440 88.421 211.579 0.00E+00 18 WELD 2-BB-04-F010 3.440 88.433 211.567 0.00E+00 19 WELD 2-BB-04-S008-D 3.440 88.422 211.578 0.00E+00 20 WELD 2-BB-04-S008-C 3.440 88.403 211.597 0.00E+00 21 WELD 2-BB-04-S008-B 3.440 88.671 211.329 0.00E+00 22 WELD 2-BB-04-F011 3.440 88.159 211.841 0.00E+00 23 WELD 2-BB-04-S009-D 3.440 106.447 193.553 0.00E+00 24 WELD 2-BB-04-S009-C 3.440 108.635 191.365 0.00E+00 25 WELD 2-BB-04-S009-B 3.440 116.486 183.514 0.00E+00 26 WELD 2-BB-04-F012 3.440 119.125 180.875 0.00E+00 27 WELD 2-BB-01-S101-5 3.440 123.402 176.598 0.00E+00 28 WELD 2-BB-04-F015 3.440 91.238 208.762 0.00E+00 29 WELD 2-BB-04-S012-F 3.440 90.168 209.832 0.00E+00 30 WELD 2-BB-04-S012-E 3.440 90.688 209.312 0.00E+00 31 WELD 2-BB-04-S012-D 3.440 93.768 206.232 0.00E+00 32 WELD 2-BB-04-S012-C 3.440 93.125 206.875 0.00E+00 33 WELD 2-BB-04-F016 3.440 96.859 203.141 0.00E+00

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 28 of 60 DEGB Fiber Inside Fiber Contribution Transported

1. Weld Location Name Diameter Margin to Mean at DEGB Size (lbm) CDF Size (lbm)

(inches) 34 WELD 2-BB-04-S013-F 3.440 99.468 200.532 0.00E+00 35 WELD 2-BB-04-S013-H 3.440 98.851 201.149 0.00E+00 36 WELD 2-BB-04-S013-D 3.440 101.795 198.205 0.00E+00 37 WELD 2-BB-04-S013-C 3.440 102.798 197.202 0.00E+00 38 WELD 2-BB-04-S013-B 3.440 102.469 197.531 0.00E+00 39 WELD 2-BB-04-F017 3.440 102.978 197.022 0.00E+00 40 WELD 2-BB-04-S014-E 3.440 89.674 210.326 0.00E+00 41 WELD 2-BB-04-S014-D 3.440 88.802 211.198 0.00E+00 42 WELD 2-BB-04-S014-C 3.440 88.277 211.723 0.00E+00 43 WELD 2-BB-04-S014-B 3.440 88.390 211.610 0.00E+00 44 WELD 2-BB-04-F018 3.440 91.391 208.609 0.00E+00 45 WELD 2-BB-04-S015-F 3.440 91.404 208.596 0.00E+00 46 WELD 2-BB-04-S015-E 3.440 88.741 211.259 0.00E+00 47 WELD 2-BB-04-S015-D 3.440 88.717 211.283 0.00E+00 48 WELD 2-BB-04-S015-B 3.440 88.429 211.571 0.00E+00 49 WELD 2-BB-04-F019 3.440 88.425 211.575 0.00E+00 50 WELD 2-BB-04-FW2 3.440 88.383 211.617 0.00E+00 51 WELD 2-BB-04-S016-C 3.440 88.354 211.646 0.00E+00 52 WELD 2-BB-04-S016-B 3.440 84.471 215.529 0.00E+00 53 WELD 2-BB-04-F020 3.440 84.712 215.288 0.00E+00 54 WELD 2-BB-04-S017-B 3.440 85.368 214.632 0.00E+00 55 WELD 2-BB-04-F021 3.440 85.865 214.135 0.00E+00 56 WELD 2-BB-04-S018-D 3.440 114.235 185.765 0.00E+00 57 WELD 2-BB-04-S018-C 3.440 114.904 185.096 0.00E+00 58 WELD 2-BB-04-S018-B 3.440 117.401 182.599 0.00E+00 59 WELD 2-BB-04-F022 3.440 120.151 179.849 0.00E+00 60 WELD 2-EM-03-BBV059-2 1.340 81.266 218.734 0.00E+00 61 WELD 2-EM-03-FW225 1.340 81.174 218.826 0.00E+00 62 WELD 2-EM-03-FW226 1.340 80.281 219.719 0.00E+00 63 WELD 2-EM-03-FW227 1.340 83.183 216.817 0.00E+00 64 WELD 2-BB-01-S401-6 2.630 108.123 191.877 0.00E+00 65 WELD 2-BB-01-S401-10 2.630 107.102 192.898 0.00E+00 66 WELD 2-EM-03-FW259 1.340 83.669 216.331 0.00E+00 67 WELD 2-EM-03-FW258 1.340 80.368 219.632 0.00E+00 68 WELD 2-EM-03-BBV040-2 1.340 80.366 219.634 0.00E+00 69 WELD 2-BB-01-S301-5 2.630 112.110 187.890 0.00E+00 70 WELD 2-BB-01-S301-9 2.630 110.029 189.971 0.00E+00 71 WELD 2-HB-24-FW67 1.690 87.849 212.151 0.00E+00 72 WELD 2-HB-24-FW66 1.690 86.476 213.524 0.00E+00 73 WELD 2-HB-24-FW065 1.690 85.407 214.593 0.00E+00 74 WELD 2-HB-24-FW064 1.690 82.426 217.574 0.00E+00 75 WELD 2-BB-01-F004 11.190 173.660 126.340 0.00E+00 76 WELD 2-TBB03-1-W 11.190 173.660 126.340 0.00E+00 77 WELD 2-BB-01-S003-3 11.190 181.889 118.111 0.00E+00 78 WELD 2-BB-01-S003-2 11.190 200.906 99.094 0.00E+00 79 WELD 2-BB-01-S003-8 11.190 244.412 55.588 0.00E+00 80 WELD 2-BB-01-F003 11.190 187.063 112.937 0.00E+00 81 WELD 2-BB-01-F002 11.190 206.374 93.626 0.00E+00 82 WELD 2-BB-01-S001-6 11.190 191.730 108.270 0.00E+00

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 29 of 60 DEGB Fiber Inside Fiber Contribution Transported

1. Weld Location Name Diameter Margin to Mean at DEGB Size (lbm) CDF Size (lbm)

(inches) 83 WELD 2-BB-01-F001 11.190 283.298 16.702 0.00E+00 84 WELD 2-BB-01-S101-8 2.630 109.163 190.837 0.00E+00 85 WELD 2-BG-21-F014 2.630 106.172 193.828 0.00E+00 86 WELD 2-BG-21-FW-1 2.630 94.047 205.953 0.00E+00 87 WELD 2-BG-21-S010-D 2.630 87.327 212.673 0.00E+00 88 WELD 2-BG-21-S010-C 2.630 85.603 214.397 0.00E+00 89 WELD 2-BG-21-S010-B 2.630 86.262 213.738 0.00E+00 90 WELD 2-BG-21-S010-A 2.630 86.093 213.907 0.00E+00 91 WELD 2-BG-21-F013 2.630 84.796 215.204 0.00E+00 92 WELD 2-EP-02-F008 8.750 262.269 37.731 0.00E+00 93 WELD 2-EP-02-S004-E 8.750 259.170 40.830 0.00E+00 94 WELD 2-EP-02-FW2 8.750 249.745 50.255 0.00E+00 95 WELD 2-EP-02-S004-C 8.750 232.063 67.937 0.00E+00 96 WELD 2-EP-02-F007 8.750 230.776 69.224 0.00E+00 97 WELD 2-EM-03-F012 5.190 128.111 171.889 0.00E+00 98 WELD 2-EM-03-S012-D 5.190 126.707 173.293 0.00E+00 99 WELD 2-EM-03-S012-B 5.190 123.221 176.779 0.00E+00 100 WELD 2-EM-03-W237498-FW03 5.190 122.294 177.706 0.00E+00 101 WELD 2-BB-11-C600739-FW01 1.340 79.817 220.183 0.00E+00 102 WELD 2-BB-11-A600739B-FW01 1.340 79.429 220.571 0.00E+00 103 WELD 2-BB-11-FW008 1.690 78.800 221.200 0.00E+00 104 WELD 2-BB-11-FW011 1.690 78.800 221.200 0.00E+00 105 WELD 2-BB-11-FW012 1.690 78.800 221.200 0.00E+00 106 WELD 2-BB-11-FW013 1.690 78.800 221.200 0.00E+00 107 WELD 2-BB-11-FW014 1.690 80.321 219.679 0.00E+00 108 WELD 2-BB-11-FW015 1.690 80.019 219.981 0.00E+00 109 WELD 2-BB-11-FW016 1.690 79.903 220.097 0.00E+00 110 WELD 2-BB-11-V151-2 1.690 79.801 220.199 0.00E+00 111 WELD 2-EM-03-FW269 1.340 83.233 216.767 0.00E+00 112 WELD 2-EM-03-FW268 1.340 81.483 218.517 0.00E+00 113 WELD 2-EM-03-BBV022-2 1.340 81.313 218.687 0.00E+00 114 WELD 2-BB-01-S201-8 2.630 99.038 200.962 0.00E+00 115 WELD 2-BB-01-S201-15 2.630 98.619 201.381 0.00E+00 116 WELD 2-BB-06-F006 2.630 98.006 201.994 0.00E+00 117 WELD 2-BB-06-F001 2.630 101.122 198.878 0.00E+00 118 WELD 2-BB-01-S205-5 2.630 102.665 197.335 0.00E+00 119 WELD 2-BB-01-S205-6 1.690 88.213 211.787 0.00E+00 120 WELD EBB01B-RSG-OUTLET-SC010 31.000 1099.195 -799.195 1.09E-08 121 WELD 2-BB-01-3065B-WDC-002-FW2 31.000 1096.277 -796.277 1.11E-08 122 WELD 2-BB-01-F206 31.000 1081.797 -781.797 1.20E-08 123 WELD 2-BB-01-S204-3 31.000 1065.208 -765.208 1.08E-08 124 WELD 2-BB-01-F208 31.000 981.925 -681.925 1.18E-08 125 WELD 2-BB-01-S205-4 31.000 980.793 -680.793 1.31E-08 126 WELD 2-BB-01-F207 31.000 985.974 -685.974 1.19E-08 127 WELD 2-BB-01-S201-7 8.750 266.859 33.141 0.00E+00 128 WELD 2-BB-01-S201-3 1.690 89.972 210.028 0.00E+00 129 WELD 2-BB-01-S201-4 2.120 97.072 202.928 0.00E+00 130 WELD 2-BB-01-S201-5 3.440 124.006 175.994 0.00E+00 131 WELD 2-RV-302-121-B 27.500 283.530 16.470 0.00E+00

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 30 of 60 DEGB Fiber Inside Fiber Contribution Transported

1. Weld Location Name Diameter Margin to Mean at DEGB Size (lbm) CDF Size (lbm)

(inches) 132 WELD 2-BB-01-F202 27.500 286.476 13.524 0.00E+00 133 WELD 2-BB-01-S201-2 27.500 313.423 -13.423 0.00E+00 134 WELD 2-BB-01-F201 27.500 930.743 -630.743 1.18E-08 135 WELD 2-BB-01-S202-3 5.190 130.149 169.851 0.00E+00 136 WELD 2-RV-301-121-B 29.000 272.120 27.880 0.00E+00 137 WELD 2-BB-01-F203 29.000 197.316 102.684 0.00E+00 138 WELD 2-BB-01-S202-2 29.000 1102.716 -802.716 4.70E-09 139 WELD 2-BB-01-3065B-WDC-001-FW1 29.000 1112.346 -812.346 4.86E-09 140 WELD EBB01B-RSG-INLET-SC010 29.000 1110.187 -810.187 4.76E-09 141 WELD 2-EM-03-FW235 1.340 83.374 216.626 0.00E+00 142 WELD 2-EM-03-FW234 1.340 81.061 218.939 0.00E+00 143 WELD 2-EM-03-BBV001-2 1.340 81.005 218.995 0.00E+00 144 WELD 2-BB-01-S101-9 2.630 100.782 199.218 0.00E+00 145 WELD 2-BB-01-S101-13 2.630 99.992 200.008 0.00E+00 146 WELD 2-EJ-04-F030 10.500 297.911 2.089 0.00E+00 147 WELD 2-EJ-04-FW9 10.500 327.631 -27.631 0.00E+00 148 WELD 2-EJ-04-S018-C 10.500 329.261 -29.261 0.00E+00 149 WELD 2-EJ-04-FW8 10.500 326.983 -26.983 0.00E+00 150 WELD 2-EJ-04-S018-E 10.500 351.002 -51.002 0.00E+00 151 WELD 2-EJ-04-F031 10.500 407.705 -107.705 1.14E-09 152 WELD 2-BB-08-FW041-A-R-1 1.690 79.052 220.948 0.00E+00 153 WELD 2-BB-08-FW099 1.690 79.021 220.979 0.00E+00 154 WELD 2-BB-08-FW044 1.690 78.910 221.090 0.00E+00 155 WELD 2-BB-08-FW045 1.690 78.800 221.200 0.00E+00 156 WELD 2-BB-08-FW046-A 1.690 78.800 221.200 0.00E+00 157 WELD 2-BB-08-FW047 1.690 78.800 221.200 0.00E+00 158 WELD 2-BB-08-FW052-B 1.690 78.800 221.200 0.00E+00 159 WELD 2-BB-08-FW053 1.690 78.800 221.200 0.00E+00 160 WELD 2-BB-08-V121-2 1.690 78.800 221.200 0.00E+00 161 WELD 2-BB-08-FW039 1.340 79.883 220.117 0.00E+00 162 WELD 2-BB-08-FW040 1.340 78.800 221.200 0.00E+00 163 WELD 2-BB-05-F006 2.630 110.123 189.877 0.00E+00 164 WELD 2-BB-05-F001 2.630 111.485 188.515 0.00E+00 165 WELD 2-BB-01-S105-5 2.630 111.691 188.309 0.00E+00 166 WELD 2-BB-01-S105-6 1.690 88.356 211.644 0.00E+00 167 WELD EBB01A-RSG-OUTLET-SC010 31.000 1125.091 -825.091 1.37E-08 168 WELD 2-BB-01-3065A-WDC-002-FW2 31.000 1123.163 -823.163 1.40E-08 169 WELD 2-BB-01-F106 31.000 1106.701 -806.701 1.60E-08 170 WELD 2-BB-01-S104-3 31.000 1090.089 -790.089 1.61E-08 171 WELD 2-BB-01-F108 31.000 1025.453 -725.453 1.61E-08 172 WELD 2-BB-01-S105-4 31.000 1032.738 -732.738 1.78E-08 173 WELD 2-BB-01-F107 31.000 1027.755 -727.755 1.68E-08 174 WELD 2-BB-01-S102-3 10.500 285.100 14.900 0.00E+00 175 WELD 2-RV-301-121-A 29.000 291.665 8.335 0.00E+00 176 WELD 2-BB-01-F103 29.000 201.121 98.879 0.00E+00 177 WELD 2-BB-01-S102-2 29.000 1141.289 -841.289 9.45E-09 178 WELD 2-BB-01-3065A-WDC-001-FW1 29.000 1143.669 -843.669 1.02E-08 179 WELD EBB01A-RSG-INLET-SC010 29.000 1141.237 -841.237 1.00E-08 180 WELD 2-BB-01-S101-7 8.750 298.102 1.898 0.00E+00

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 31 of 60 DEGB Fiber Inside Fiber Contribution Transported

1. Weld Location Name Diameter Margin to Mean at DEGB Size (lbm) CDF Size (lbm)

(inches) 181 WELD 2-BB-01-S101-3 1.690 89.457 210.543 0.00E+00 182 WELD 2-RV-302-121-A 27.500 302.456 -2.456 2.75E-11 183 WELD 2-BB-01-F102 27.500 306.069 -6.069 8.25E-11 184 WELD 2-BB-01-S101-2 27.500 345.081 -45.081 0.00E+00 185 WELD 2-BB-01-F101 27.500 983.684 -683.684 1.50E-08 186 WELD 2-HB-24-FW001 1.690 88.017 211.983 0.00E+00 187 WELD 2-HB-24-FW002 1.690 86.761 213.239 0.00E+00 188 WELD 2-HB-24-FW078 1.690 85.640 214.360 0.00E+00 189 WELD 2-HB-24-FW079-A 1.690 80.963 219.037 0.00E+00 190 WELD 2-EP-01-F008 8.750 273.860 26.140 0.00E+00 191 WELD 2-EP-01-S004-E 8.750 268.120 31.880 0.00E+00 192 WELD 2-EP-01-S004-D 8.750 254.212 45.788 0.00E+00 193 WELD 2-EP-01-S004-C 8.750 235.325 64.675 0.00E+00 194 WELD 2-EP-01-F007 8.750 233.631 66.369 0.00E+00 195 WELD 2-EJ-04-S018-F 5.190 125.978 174.022 0.00E+00 196 WELD 2-EM-05-F007 5.190 123.837 176.163 0.00E+00 197 WELD 2-EM-05-S007-D 5.190 123.095 176.905 0.00E+00 198 WELD 2-EM-05-S007-C 5.190 122.619 177.381 0.00E+00 199 WELD 2-EM-05-W566538-F006 5.190 122.765 177.235 0.00E+00 200 WELD 2-BB-01-S102-6 2.120 98.145 201.855 0.00E+00 201 WELD 2-BB-14-F006 2.630 97.771 202.229 0.00E+00 202 WELD 2-BB-14-F001 2.630 101.155 198.845 0.00E+00 203 WELD 2-BB-01-S305-5 2.630 102.739 197.261 0.00E+00 204 WELD 2-BB-01-S305-6 2.630 104.019 195.981 0.00E+00 205 WELD EBB01C-RSG-OUTLET-SC010 31.000 1043.018 -743.018 1.16E-08 206 WELD 2-BB-01-3065C-WDC-002-FW2 31.000 1040.097 -740.097 1.20E-08 207 WELD 2-BB-01-F306 31.000 1024.979 -724.979 1.36E-08 208 WELD 2-BB-01-S304-3 31.000 1020.473 -720.473 1.26E-08 209 WELD 2-BB-01-F308 31.000 936.096 -636.096 1.28E-08 210 WELD 2-BB-01-S305-4 31.000 902.157 -602.157 1.46E-08 211 WELD 2-BB-01-F307 31.000 832.546 -532.546 1.30E-08 212 WELD 2-EP-02-F019 8.750 234.075 65.925 0.00E+00 213 WELD 2-EP-02-S009-E 8.750 227.107 72.893 0.00E+00 214 WELD 2-EP-02-S009-D 8.750 214.368 85.632 0.00E+00 215 WELD 2-EP-02-S009-C 8.750 206.341 93.659 0.00E+00 216 WELD 2-EP-02-F018 8.750 210.260 89.740 0.00E+00 217 WELD 2-BG-22-F001 2.630 101.259 198.741 0.00E+00 218 WELD 2-BG-22-S001-A 2.630 97.304 202.696 0.00E+00 219 WELD 2-BG-22-S001-B 2.630 84.554 215.446 0.00E+00 220 WELD 2-BG-22-S001-C 2.630 84.865 215.135 0.00E+00 221 WELD 2-BG-22-S001-D 2.630 85.603 214.397 0.00E+00 222 WELD 2-BG-22-S001-G 2.630 85.073 214.927 0.00E+00 223 WELD 2-BG-22-F002 2.630 85.005 214.995 0.00E+00 224 WELD 2-EM-03-F016 5.190 132.674 167.326 0.00E+00 225 WELD 2-EM-03-S015-C 5.190 117.352 182.648 0.00E+00 226 WELD 2-EM-03-S015-B 5.190 112.044 187.956 0.00E+00 227 WELD 2-EM-03-F015 5.190 113.846 186.154 0.00E+00 228 WELD 2-HB-24-FW051 1.690 82.181 217.819 0.00E+00 229 WELD 2-HB-24-FW052 1.690 83.224 216.776 0.00E+00

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 32 of 60 DEGB Fiber Inside Fiber Contribution Transported

1. Weld Location Name Diameter Margin to Mean at DEGB Size (lbm) CDF Size (lbm)

(inches) 230 WELD 2-BG-22-S001-F 1.690 83.080 216.920 0.00E+00 231 WELD 2-BB-01-S301-6 8.750 243.323 56.677 0.00E+00 232 WELD 2-BB-01-S301-3 1.690 89.223 210.777 0.00E+00 233 WELD 2-BB-01-S301-4 2.120 97.544 202.456 0.00E+00 234 WELD 2-RV-302-121-C 27.500 197.365 102.635 0.00E+00 235 WELD 2-BB-01-F302 27.500 200.530 99.470 0.00E+00 236 WELD 2-BB-01-S301-2 27.500 212.821 87.179 0.00E+00 237 WELD 2-BB-01-F301 27.500 802.507 -502.507 1.02E-08 238 WELD 2-BB-01-S302-3 5.190 134.620 165.380 0.00E+00 239 WELD 2-RV-301-121-C 29.000 290.914 9.086 0.00E+00 240 WELD 2-BB-01-F303 29.000 204.365 95.635 0.00E+00 241 WELD 2-BB-01-S302-2 29.000 1062.241 -762.241 4.30E-09 242 WELD 2-BB-01-3065C-WDC-001-FW1 29.000 1075.066 -775.066 5.58E-09 243 WELD EBB01C-RSG-INLET-SC010 29.000 1074.732 -774.732 5.51E-09 244 WELD 2-BB-09-FW152 1.690 79.879 220.121 0.00E+00 245 WELD 2-BB-09-FW151 1.690 79.281 220.719 0.00E+00 246 WELD 2-BB-09-FW148 1.690 78.817 221.183 0.00E+00 247 WELD 2-BB-09-FW147 1.690 78.800 221.200 0.00E+00 248 WELD 2-BB-09-FW142 1.690 79.117 220.883 0.00E+00 249 WELD 2-BB-09-FW141 1.690 80.391 219.609 0.00E+00 250 WELD 2-BB-09-V181-2 1.690 80.376 219.624 0.00E+00 251 WELD 2-BB-09-FW153-A 1.340 79.418 220.582 0.00E+00 252 WELD 2-BB-09-FW154-A 1.340 79.875 220.125 0.00E+00 253 WELD 2-BB-04-S002-L 1.690 86.133 213.867 0.00E+00 254 WELD 2-BG-24-FW068 1.690 85.710 214.290 0.00E+00 255 WELD 2-BG-24-FW067 1.690 81.623 218.377 0.00E+00 256 WELD 2-BG-24-BB-V084-2 1.690 81.555 218.445 0.00E+00 257 WELD 2-BG-24-FW062 1.690 81.555 218.445 0.00E+00 258 WELD 2-BB-02-F006 5.190 181.246 118.754 0.00E+00 259 WELD 2-TBB03-3-C-W 5.190 181.246 118.754 0.00E+00 260 WELD 2-BB-02-S007-B 5.190 173.744 126.256 0.00E+00 261 WELD 2-BB-02-S007-D 5.190 161.387 138.613 0.00E+00 262 WELD 2-BB-02-S007-E 5.190 151.677 148.323 0.00E+00 263 WELD 2-BB-02-S007-F 5.190 151.603 148.397 0.00E+00 264 WELD 2-BB-02-S007-G 5.190 161.811 138.189 0.00E+00 265 WELD 2-BB-02-S007-J 5.190 142.705 157.295 0.00E+00 266 WELD 2-BB-02-S001-J 5.190 138.966 161.034 0.00E+00 267 WELD 2-BB-02-S001-G 5.190 154.270 145.730 0.00E+00 268 WELD 2-BB-02-S001-F 5.190 143.175 156.825 0.00E+00 269 WELD 2-BB-02-S001-E 5.190 142.130 157.870 0.00E+00 270 WELD 2-BB-02-S001-D 5.190 148.966 151.034 0.00E+00 271 WELD 2-BB-02-S001-B 5.190 162.660 137.340 0.00E+00 272 WELD 2-TBB03-3-A-W 5.190 171.634 128.366 0.00E+00 273 WELD 2-BB-02-F001 5.190 171.634 128.366 0.00E+00 274 WELD 2-TBB03-3-B-W 5.190 176.739 123.261 0.00E+00 275 WELD 2-BB-02-F005 5.190 176.739 123.261 0.00E+00 276 WELD 2-BB-02-S006-B 5.190 167.402 132.598 0.00E+00 277 WELD 2-BB-02-S006-D 5.190 153.813 146.187 0.00E+00 278 WELD 2-BB-02-S006-E 5.190 148.017 151.983 0.00E+00

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 33 of 60 DEGB Fiber Inside Fiber Contribution Transported

1. Weld Location Name Diameter Margin to Mean at DEGB Size (lbm) CDF Size (lbm)

(inches) 279 WELD 2-BB-02-S006-F 5.190 149.480 150.520 0.00E+00 280 WELD 2-BB-02-S006-G 5.190 160.374 139.626 0.00E+00 281 WELD 2-BB-02-S006-J 5.190 146.561 153.439 0.00E+00 282 WELD 2-BB-04-F001 3.440 123.330 176.670 0.00E+00 283 WELD 2-TBB03-2-W 3.440 123.330 176.670 0.00E+00 284 WELD 2-BB-04-S001-D 3.440 104.391 195.609 0.00E+00 285 WELD 2-BB-04-S001-C 3.440 99.680 200.320 0.00E+00 286 WELD 2-BB-04-F023 3.440 98.698 201.302 0.00E+00 287 WELD 2-BB-04-F002 3.440 85.411 214.589 0.00E+00 288 WELD 2-BB-04-S002-R 3.440 85.630 214.370 0.00E+00 289 WELD 2-BB-04-S002-N 3.440 86.503 213.497 0.00E+00 290 WELD 2-BB-02-F008 5.190 179.281 120.719 0.00E+00 291 WELD 2-TBB03-4-W 5.190 179.281 120.719 0.00E+00 292 WELD 2-BB-02-S009-B 5.190 163.164 136.836 0.00E+00 293 WELD 2-BB-02-S009-C 5.190 154.260 145.740 0.00E+00 294 WELD 2-BB-02-FW1 5.190 139.009 160.991 0.00E+00 295 WELD 2-BB-02-S009-E 5.190 125.146 174.854 0.00E+00 296 WELD 2-BB-02-F009 5.190 79.140 220.860 0.00E+00 297 WELD 2-BB-02-S010-B 5.190 78.970 221.030 0.00E+00 298 WELD 2-BB-02-FW2 5.190 78.970 221.030 0.00E+00 299 WELD 2-BB-02-F016 2.630 78.800 221.200 0.00E+00 300 WELD 2-BB-02-S014-B 2.630 78.800 221.200 0.00E+00 301 WELD 2-BB-02-S014-C 2.630 78.800 221.200 0.00E+00 302 WELD 2-BB-02-F017-A 2.630 78.800 221.200 0.00E+00 303 WELD 2-BB-02-F010 2.630 78.800 221.200 0.00E+00 304 WELD 2-BB-02-S010-H 2.630 78.800 221.200 0.00E+00 305 WELD 2-BB-02-S010-G 2.630 78.800 221.200 0.00E+00 306 WELD 2-BB-02-S010-F 2.630 78.800 221.200 0.00E+00 307 WELD 2-BB-02-FW25 2.630 78.800 221.200 0.00E+00 308 WELD 2-BB-02-FW3 2.630 78.800 221.200 0.00E+00 309 WELD 2-BB-04-S002-D 3.440 93.725 206.275 0.00E+00 310 WELD 2-BB-04-FW6 3.440 92.460 207.540 0.00E+00 311 WELD 2-BB-04-S002-B 3.440 92.209 207.791 0.00E+00 312 WELD 2-BB-04-F004 3.440 92.703 207.297 0.00E+00 313 WELD 2-BB-04-S002-M 5.190 94.770 205.230 0.00E+00 314 WELD 2-BB-04-S002-K 5.190 110.293 189.707 0.00E+00 315 WELD 2-BB-04-S002-J 5.190 112.027 187.973 0.00E+00 316 WELD 2-BB-04-S002-E 5.190 112.160 187.840 0.00E+00 317 WELD 2-BB-04-F003 5.190 110.940 189.060 0.00E+00 318 WELD 2-BB-04-S011-M 5.190 110.578 189.422 0.00E+00 319 WELD 2-BB-04-S011-L 5.190 111.426 188.574 0.00E+00 320 WELD 2-BB-04-S011-J 5.190 105.472 194.528 0.00E+00 321 WELD 2-BB-04-S011-H 5.190 103.817 196.183 0.00E+00 322 WELD 2-BB-04-S011-D 5.190 104.493 195.507 0.00E+00 323 WELD 2-BB-04-S011-C 3.440 90.645 209.355 0.00E+00 324 WELD 2-BB-04-FW5 3.440 89.889 210.111 0.00E+00 325 WELD 2-BB-04-S011-A 3.440 89.855 210.145 0.00E+00 326 WELD 2-BB-04-F014 3.440 90.599 209.401 0.00E+00 327 WELD 2-BB-01-S402-4 10.500 276.991 23.009 0.00E+00

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 34 of 60 DEGB Fiber Inside Fiber Contribution Transported

1. Weld Location Name Diameter Margin to Mean at DEGB Size (lbm) CDF Size (lbm)

(inches) 328 WELD 2-BB-01-S402-3 11.190 285.284 14.716 0.00E+00 329 WELD 2-RV-301-121-D 29.000 282.663 17.337 0.00E+00 330 WELD 2-BB-01-F403 29.000 198.138 101.862 0.00E+00 331 WELD 2-BB-01-S402-2 29.000 1154.102 -854.102 7.48E-09 332 WELD 2-BB-01-3065D-WDC-001-FW1 29.000 1157.052 -857.052 9.23E-09 333 WELD EBB01D-RSG-INLET-SC010 29.000 1156.179 -856.179 9.08E-09 334 WELD 2-BB-01-S401-7 8.750 249.179 50.821 0.00E+00 335 WELD 2-BB-01-S401-3 1.690 89.216 210.784 0.00E+00 336 WELD 2-BB-01-S401-4 2.120 96.343 203.657 0.00E+00 337 WELD 2-RV-302-121-D 27.500 167.819 132.181 0.00E+00 338 WELD 2-BB-01-F402 27.500 171.782 128.218 0.00E+00 339 WELD 2-BB-01-S401-2 27.500 199.030 100.970 0.00E+00 340 WELD 2-BB-01-F401 27.500 931.142 -631.142 1.41E-08 341 WELD 2-BB-15-F006 2.630 108.796 191.204 0.00E+00 342 WELD 2-BB-15-F001 2.630 110.866 189.134 0.00E+00 343 WELD 2-BB-01-S405-5 2.630 111.426 188.574 0.00E+00 344 WELD 2-BB-01-S405-6 1.690 88.263 211.737 0.00E+00 345 WELD EBB01D-RSG-OUTLET-SC010 31.000 1139.034 -839.034 1.42E-08 346 WELD 2-BB-01-3065D-WDC-002-FW2 31.000 1137.556 -837.556 1.45E-08 347 WELD 2-BB-01-F406 31.000 1127.905 -827.905 1.63E-08 348 WELD 2-BB-01-S404-3 31.000 1127.648 -827.648 1.66E-08 349 WELD 2-BB-01-F408 31.000 1077.615 -777.615 1.68E-08 350 WELD 2-BB-01-S405-4 31.000 1049.937 -749.937 1.77E-08 351 WELD 2-BB-01-F407 31.000 997.012 -697.012 1.68E-08 352 WELD 2-EP-01-F019 8.750 200.131 99.869 0.00E+00 353 WELD 2-EP-01-S010-C 8.750 202.719 97.281 0.00E+00 354 WELD 2-EP-01-S010-D 8.750 220.370 79.630 0.00E+00 355 WELD 2-EP-01-S010-E 8.750 237.692 62.308 0.00E+00 356 WELD 2-EP-01-F020 8.750 245.191 54.809 0.00E+00 357 WELD 2-EJ-04-S016-F 5.190 133.818 166.182 0.00E+00 358 WELD 2-EJ-04-F029 5.190 138.986 161.014 0.00E+00 359 WELD 2-EM-05-S005-C 5.190 148.192 151.808 0.00E+00 360 WELD 2-EM-05-S005-B 5.190 149.483 150.517 0.00E+00 361 WELD 2-EM-05-F004 5.190 149.126 150.874 0.00E+00 362 WELD 2-EJ-04-F026 10.500 298.411 1.589 0.00E+00 363 WELD 2-EJ-04-S016-B 10.500 310.438 -10.438 0.00E+00 364 WELD 2-EJ-04-S016-C 10.500 318.508 -18.508 0.00E+00 365 WELD 2-EJ-04-S016-D 10.500 316.902 -16.902 0.00E+00 366 WELD 2-EJ-04-S016-E 10.500 340.531 -40.531 3.78E-10 367 WELD 2-EJ-04-S016-G 10.500 380.306 -80.306 2.26E-09 368 WELD 2-EJ-04-S016-H 10.500 403.032 -103.032 0.00E+00 369 WELD 2-EJ-04-F025 10.500 431.900 -131.900 7.67E-10 370 WELD 2-BB-07-FW004 1.340 79.316 220.684 0.00E+00 371 WELD 2-BB-07-FW003 1.340 79.501 220.499 0.00E+00 372 WELD 2-BB-07-FW002 1.340 79.602 220.398 0.00E+00 373 WELD 2-BB-07-FW001 1.340 80.046 219.954 0.00E+00 374 WELD 2-BB-07-FW005 1.690 80.000 220.000 0.00E+00 375 WELD 2-BB-07-FW006 1.690 79.683 220.317 0.00E+00 376 WELD 2-BB-07-FW007 1.690 79.252 220.748 0.00E+00

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 35 of 60 DEGB Fiber Inside Fiber Contribution Transported

1. Weld Location Name Diameter Margin to Mean at DEGB Size (lbm) CDF Size (lbm)

(inches) 377 WELD 2-BB-07-FW008 1.690 78.800 221.200 0.00E+00 378 WELD 2-BB-07-FW011 1.690 78.800 221.200 0.00E+00 379 WELD 2-BB-07-FW012 1.690 78.800 221.200 0.00E+00 380 WELD 2-BB-07-FW013 1.690 78.800 221.200 0.00E+00 381 WELD 2-BB-07-FW014 1.690 78.800 221.200 0.00E+00 382 WELD 2-BB-07-FW019 1.690 78.800 221.200 0.00E+00 383 WELD 2-BB-07-FW020 1.690 78.800 221.200 0.00E+00 384 WELD 2-BB-07-FW021 1.690 78.800 221.200 0.00E+00 385 WELD 2-BB-07-FW022 1.690 78.844 221.156 0.00E+00 386 WELD 2-BB-07-FW023 1.690 78.800 221.200 0.00E+00 387 WELD 2-BB-07-FW024 1.690 78.800 221.200 0.00E+00 388 WELD 2-BB-07-FW029 1.690 78.800 221.200 0.00E+00 389 WELD 2-BB-07-V211-2 1.690 78.800 221.200 0.00E+00 390 WELD 2-BG-21-F026 2.630 101.482 198.518 0.00E+00 391 WELD 2-BG-21-F027 2.630 105.771 194.229 0.00E+00 392 WELD 2-BB-01-S401-5 2.630 108.802 191.198 0.00E+00 393 WELD 2-BG-23-FW144 1.690 82.410 217.590 0.00E+00 394 WELD 2-BG-23-FW-3 1.690 82.535 217.465 0.00E+00 395 WELD 2-BG-23-FW-4 1.690 82.823 217.177 0.00E+00 396 WELD 2-BG-23-FW-5 1.690 82.754 217.246 0.00E+00 397 WELD 2-BG-23-FW145 1.690 81.805 218.195 0.00E+00 398 WELD 2-BG-23-FW149 1.690 82.831 217.169 0.00E+00 399 WELD 2-BG-23-FW148 1.690 82.583 217.417 0.00E+00 400 WELD 2-BG-23-FW143 1.690 82.114 217.886 0.00E+00 401 WELD 2-BG-23-A175752A-FW02 1.690 83.055 216.945 0.00E+00 402 WELD 2-BG-23-A175752A-FW01 1.690 83.653 216.347 0.00E+00 403 WELD 2-BG-23-FW138 1.690 87.995 212.005 0.00E+00 404 WELD 2-BG-22-F025 2.630 83.841 216.159 0.00E+00 405 WELD 2-BG-22-S020-A 2.630 82.407 217.593 0.00E+00 406 WELD 2-BG-22-S020-B 2.630 82.480 217.520 0.00E+00 407 WELD 2-BG-22-F026 2.630 82.558 217.442 0.00E+00 408 WELD 2-BG-23-FW150 1.690 82.563 217.437 0.00E+00 409 WELD 2-BG-23-FW151 1.690 81.904 218.096 0.00E+00 410 WELD 2-BG-23-FW152 1.690 81.580 218.420 0.00E+00 411 WELD 2-BG-23-FW153 1.690 81.534 218.466 0.00E+00 5.37E-07 10.2 Full Weld List for Valve Insulation Sensitivity Scenario This section contains a full weld list for the valve insulation sensitivity scenario. Table 10-2 lists the weld location name, the corresponding pipe diameter (DEGB size), the amount of fiber transported by a DEGB, the fiber margin (the difference between the RoverD failure threshold and the amount of fiber transported), and the contribution of each weld to the geometric mean CDF based on 25-year NUREG-1829 frequencies at the smallest critical break size. Welds that do not exceed the RoverD limit for a DEGB are deemed non-critical welds. Non-critical welds have a positive fiber margin and do

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 36 of 60 not contribute to CDF. Note that per weld contributions to CDF in the last column sum to the mean CDF reported for the baseline scenario reported in Table 9-2.

Table 10-2: Full weld list for valve insulation sensitivity scenario DEGB Fiber Inside Fiber Contribution Transported

1. Weld Location Name Diameter Margin to Mean at DEGB Size (lbm) CDF Size (lbm)

(inches) 1 WELD 2-BB-04-F005 3.440 96.193 203.807 0.00E+00 2 WELD 2-BB-04-S003-D 3.440 97.643 202.357 0.00E+00 3 WELD 2-BB-04-S003-C 3.440 98.621 201.379 0.00E+00 4 WELD 2-BB-04-F006 3.440 103.704 196.296 0.00E+00 5 WELD 2-BB-04-S004-C 3.440 107.348 192.652 0.00E+00 6 WELD 2-BB-04-F007 3.440 105.538 194.462 0.00E+00 7 WELD 2-BB-04-S005-D 3.440 107.144 192.856 0.00E+00 8 WELD 2-BB-04-S005-C 3.440 105.531 194.469 0.00E+00 9 WELD 2-BB-04-S005-B 3.440 98.012 201.988 0.00E+00 10 WELD 2-BB-04-F008 3.440 98.011 201.989 0.00E+00 11 WELD 2-BB-04-S006-C 3.440 93.206 206.794 0.00E+00 12 WELD 2-BB-04-S006-B 3.440 91.505 208.495 0.00E+00 13 WELD 2-BB-04-F009 3.440 87.065 212.935 0.00E+00 14 WELD 2-BB-04-S007-F 3.440 87.235 212.765 0.00E+00 15 WELD 2-BB-04-S007-E 3.440 88.794 211.206 0.00E+00 16 WELD 2-BB-04-S007-D 3.440 88.661 211.339 0.00E+00 17 WELD 2-BB-04-S007-B 3.440 88.421 211.579 0.00E+00 18 WELD 2-BB-04-F010 3.440 88.433 211.567 0.00E+00 19 WELD 2-BB-04-S008-D 3.440 88.422 211.578 0.00E+00 20 WELD 2-BB-04-S008-C 3.440 88.403 211.597 0.00E+00 21 WELD 2-BB-04-S008-B 3.440 88.671 211.329 0.00E+00 22 WELD 2-BB-04-F011 3.440 88.159 211.841 0.00E+00 23 WELD 2-BB-04-S009-D 3.440 106.447 193.553 0.00E+00 24 WELD 2-BB-04-S009-C 3.440 108.635 191.365 0.00E+00 25 WELD 2-BB-04-S009-B 3.440 116.486 183.514 0.00E+00 26 WELD 2-BB-04-F012 3.440 119.125 180.875 0.00E+00 27 WELD 2-BB-01-S101-5 3.440 123.402 176.598 0.00E+00 28 WELD 2-BB-04-F015 3.440 92.392 207.608 0.00E+00 29 WELD 2-BB-04-S012-F 3.440 91.321 208.679 0.00E+00 30 WELD 2-BB-04-S012-E 3.440 91.777 208.223 0.00E+00 31 WELD 2-BB-04-S012-D 3.440 94.777 205.223 0.00E+00 32 WELD 2-BB-04-S012-C 3.440 94.006 205.994 0.00E+00 33 WELD 2-BB-04-F016 3.440 96.859 203.141 0.00E+00 34 WELD 2-BB-04-S013-F 3.440 99.468 200.532 0.00E+00 35 WELD 2-BB-04-S013-H 3.440 98.851 201.149 0.00E+00 36 WELD 2-BB-04-S013-D 3.440 101.795 198.205 0.00E+00 37 WELD 2-BB-04-S013-C 3.440 102.798 197.202 0.00E+00 38 WELD 2-BB-04-S013-B 3.440 102.469 197.531 0.00E+00 39 WELD 2-BB-04-F017 3.440 102.978 197.022 0.00E+00 40 WELD 2-BB-04-S014-E 3.440 89.674 210.326 0.00E+00 41 WELD 2-BB-04-S014-D 3.440 88.802 211.198 0.00E+00 42 WELD 2-BB-04-S014-C 3.440 88.277 211.723 0.00E+00 43 WELD 2-BB-04-S014-B 3.440 88.390 211.610 0.00E+00 44 WELD 2-BB-04-F018 3.440 91.391 208.609 0.00E+00

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 37 of 60 DEGB Fiber Inside Fiber Contribution Transported

1. Weld Location Name Diameter Margin to Mean at DEGB Size (lbm) CDF Size (lbm)

(inches) 45 WELD 2-BB-04-S015-F 3.440 91.404 208.596 0.00E+00 46 WELD 2-BB-04-S015-E 3.440 88.741 211.259 0.00E+00 47 WELD 2-BB-04-S015-D 3.440 88.717 211.283 0.00E+00 48 WELD 2-BB-04-S015-B 3.440 88.429 211.571 0.00E+00 49 WELD 2-BB-04-F019 3.440 88.425 211.575 0.00E+00 50 WELD 2-BB-04-FW2 3.440 88.383 211.617 0.00E+00 51 WELD 2-BB-04-S016-C 3.440 88.354 211.646 0.00E+00 52 WELD 2-BB-04-S016-B 3.440 84.471 215.529 0.00E+00 53 WELD 2-BB-04-F020 3.440 84.712 215.288 0.00E+00 54 WELD 2-BB-04-S017-B 3.440 85.368 214.632 0.00E+00 55 WELD 2-BB-04-F021 3.440 85.865 214.135 0.00E+00 56 WELD 2-BB-04-S018-D 3.440 114.235 185.765 0.00E+00 57 WELD 2-BB-04-S018-C 3.440 114.904 185.096 0.00E+00 58 WELD 2-BB-04-S018-B 3.440 117.401 182.599 0.00E+00 59 WELD 2-BB-04-F022 3.440 120.151 179.849 0.00E+00 60 WELD 2-EM-03-BBV059-2 1.340 81.266 218.734 0.00E+00 61 WELD 2-EM-03-FW225 1.340 81.174 218.826 0.00E+00 62 WELD 2-EM-03-FW226 1.340 80.281 219.719 0.00E+00 63 WELD 2-EM-03-FW227 1.340 83.183 216.817 0.00E+00 64 WELD 2-BB-01-S401-6 2.630 108.123 191.877 0.00E+00 65 WELD 2-BB-01-S401-10 2.630 107.102 192.898 0.00E+00 66 WELD 2-EM-03-FW259 1.340 83.669 216.331 0.00E+00 67 WELD 2-EM-03-FW258 1.340 80.368 219.632 0.00E+00 68 WELD 2-EM-03-BBV040-2 1.340 80.366 219.634 0.00E+00 69 WELD 2-BB-01-S301-5 2.630 112.256 187.744 0.00E+00 70 WELD 2-BB-01-S301-9 2.630 110.184 189.816 0.00E+00 71 WELD 2-HB-24-FW67 1.690 87.849 212.151 0.00E+00 72 WELD 2-HB-24-FW66 1.690 86.476 213.524 0.00E+00 73 WELD 2-HB-24-FW065 1.690 85.407 214.593 0.00E+00 74 WELD 2-HB-24-FW064 1.690 82.426 217.574 0.00E+00 75 WELD 2-BB-01-F004 11.190 173.660 126.340 0.00E+00 76 WELD 2-TBB03-1-W 11.190 173.660 126.340 0.00E+00 77 WELD 2-BB-01-S003-3 11.190 181.889 118.111 0.00E+00 78 WELD 2-BB-01-S003-2 11.190 201.121 98.879 0.00E+00 79 WELD 2-BB-01-S003-8 11.190 245.809 54.191 0.00E+00 80 WELD 2-BB-01-F003 11.190 187.369 112.631 0.00E+00 81 WELD 2-BB-01-F002 11.190 206.374 93.626 0.00E+00 82 WELD 2-BB-01-S001-6 11.190 191.730 108.270 0.00E+00 83 WELD 2-BB-01-F001 11.190 283.721 16.279 0.00E+00 84 WELD 2-BB-01-S101-8 2.630 109.163 190.837 0.00E+00 85 WELD 2-BG-21-F014 2.630 106.172 193.828 0.00E+00 86 WELD 2-BG-21-FW-1 2.630 94.047 205.953 0.00E+00 87 WELD 2-BG-21-S010-D 2.630 87.327 212.673 0.00E+00 88 WELD 2-BG-21-S010-C 2.630 85.603 214.397 0.00E+00 89 WELD 2-BG-21-S010-B 2.630 86.262 213.738 0.00E+00 90 WELD 2-BG-21-S010-A 2.630 86.093 213.907 0.00E+00 91 WELD 2-BG-21-F013 2.630 84.796 215.204 0.00E+00 92 WELD 2-EP-02-F008 8.750 262.342 37.658 0.00E+00 93 WELD 2-EP-02-S004-E 8.750 259.279 40.721 0.00E+00

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 38 of 60 DEGB Fiber Inside Fiber Contribution Transported

1. Weld Location Name Diameter Margin to Mean at DEGB Size (lbm) CDF Size (lbm)

(inches) 94 WELD 2-EP-02-FW2 8.750 249.854 50.146 0.00E+00 95 WELD 2-EP-02-S004-C 8.750 232.209 67.791 0.00E+00 96 WELD 2-EP-02-F007 8.750 230.921 69.079 0.00E+00 97 WELD 2-EM-03-F012 5.190 128.111 171.889 0.00E+00 98 WELD 2-EM-03-S012-D 5.190 126.707 173.293 0.00E+00 99 WELD 2-EM-03-S012-B 5.190 123.221 176.779 0.00E+00 100 WELD 2-EM-03-W237498-FW03 5.190 122.294 177.706 0.00E+00 101 WELD 2-BB-11-C600739-FW01 1.340 79.817 220.183 0.00E+00 102 WELD 2-BB-11-A600739B-FW01 1.340 79.429 220.571 0.00E+00 103 WELD 2-BB-11-FW008 1.690 78.800 221.200 0.00E+00 104 WELD 2-BB-11-FW011 1.690 78.800 221.200 0.00E+00 105 WELD 2-BB-11-FW012 1.690 78.800 221.200 0.00E+00 106 WELD 2-BB-11-FW013 1.690 78.800 221.200 0.00E+00 107 WELD 2-BB-11-FW014 1.690 80.321 219.679 0.00E+00 108 WELD 2-BB-11-FW015 1.690 80.019 219.981 0.00E+00 109 WELD 2-BB-11-FW016 1.690 79.903 220.097 0.00E+00 110 WELD 2-BB-11-V151-2 1.690 79.801 220.199 0.00E+00 111 WELD 2-EM-03-FW269 1.340 83.233 216.767 0.00E+00 112 WELD 2-EM-03-FW268 1.340 81.483 218.517 0.00E+00 113 WELD 2-EM-03-BBV022-2 1.340 81.313 218.687 0.00E+00 114 WELD 2-BB-01-S201-8 2.630 99.038 200.962 0.00E+00 115 WELD 2-BB-01-S201-15 2.630 98.619 201.381 0.00E+00 116 WELD 2-BB-06-F006 2.630 98.006 201.994 0.00E+00 117 WELD 2-BB-06-F001 2.630 101.122 198.878 0.00E+00 118 WELD 2-BB-01-S205-5 2.630 102.665 197.335 0.00E+00 119 WELD 2-BB-01-S205-6 1.690 88.213 211.787 0.00E+00 120 WELD EBB01B-RSG-OUTLET-SC010 31.000 1111.688 -811.688 1.09E-08 121 WELD 2-BB-01-3065B-WDC-002-FW2 31.000 1108.769 -808.769 1.11E-08 122 WELD 2-BB-01-F206 31.000 1094.319 -794.319 1.20E-08 123 WELD 2-BB-01-S204-3 31.000 1076.967 -776.967 1.08E-08 124 WELD 2-BB-01-F208 31.000 992.323 -692.323 1.19E-08 125 WELD 2-BB-01-S205-4 31.000 991.007 -691.007 1.36E-08 126 WELD 2-BB-01-F207 31.000 996.062 -696.062 1.19E-08 127 WELD 2-BB-01-S201-7 8.750 266.859 33.141 0.00E+00 128 WELD 2-BB-01-S201-3 1.690 89.972 210.028 0.00E+00 129 WELD 2-BB-01-S201-4 2.120 97.072 202.928 0.00E+00 130 WELD 2-BB-01-S201-5 3.440 124.006 175.994 0.00E+00 131 WELD 2-RV-302-121-B 27.500 287.117 12.883 0.00E+00 132 WELD 2-BB-01-F202 27.500 290.094 9.906 0.00E+00 133 WELD 2-BB-01-S201-2 27.500 317.064 -17.064 0.00E+00 134 WELD 2-BB-01-F201 27.500 939.781 -639.781 1.20E-08 135 WELD 2-BB-01-S202-3 5.190 130.149 169.851 0.00E+00 136 WELD 2-RV-301-121-B 29.000 272.120 27.880 0.00E+00 137 WELD 2-BB-01-F203 29.000 197.316 102.684 0.00E+00 138 WELD 2-BB-01-S202-2 29.000 1115.525 -815.525 4.70E-09 139 WELD 2-BB-01-3065B-WDC-001-FW1 29.000 1124.796 -824.796 4.86E-09 140 WELD EBB01B-RSG-INLET-SC010 29.000 1122.633 -822.633 4.76E-09 141 WELD 2-EM-03-FW235 1.340 83.374 216.626 0.00E+00 142 WELD 2-EM-03-FW234 1.340 81.061 218.939 0.00E+00

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 39 of 60 DEGB Fiber Inside Fiber Contribution Transported

1. Weld Location Name Diameter Margin to Mean at DEGB Size (lbm) CDF Size (lbm)

(inches) 143 WELD 2-EM-03-BBV001-2 1.340 81.005 218.995 0.00E+00 144 WELD 2-BB-01-S101-9 2.630 100.782 199.218 0.00E+00 145 WELD 2-BB-01-S101-13 2.630 99.992 200.008 0.00E+00 146 WELD 2-EJ-04-F030 10.500 298.232 1.768 0.00E+00 147 WELD 2-EJ-04-FW9 10.500 328.112 -28.112 0.00E+00 148 WELD 2-EJ-04-S018-C 10.500 329.742 -29.742 0.00E+00 149 WELD 2-EJ-04-FW8 10.500 327.464 -27.464 0.00E+00 150 WELD 2-EJ-04-S018-E 10.500 351.483 -51.483 0.00E+00 151 WELD 2-EJ-04-F031 10.500 408.111 -108.111 1.17E-09 152 WELD 2-BB-08-FW041-A-R-1 1.690 79.052 220.948 0.00E+00 153 WELD 2-BB-08-FW099 1.690 79.021 220.979 0.00E+00 154 WELD 2-BB-08-FW044 1.690 78.910 221.090 0.00E+00 155 WELD 2-BB-08-FW045 1.690 78.800 221.200 0.00E+00 156 WELD 2-BB-08-FW046-A 1.690 78.800 221.200 0.00E+00 157 WELD 2-BB-08-FW047 1.690 78.800 221.200 0.00E+00 158 WELD 2-BB-08-FW052-B 1.690 78.800 221.200 0.00E+00 159 WELD 2-BB-08-FW053 1.690 78.800 221.200 0.00E+00 160 WELD 2-BB-08-V121-2 1.690 78.800 221.200 0.00E+00 161 WELD 2-BB-08-FW039 1.340 79.883 220.117 0.00E+00 162 WELD 2-BB-08-FW040 1.340 78.800 221.200 0.00E+00 163 WELD 2-BB-05-F006 2.630 110.123 189.877 0.00E+00 164 WELD 2-BB-05-F001 2.630 111.485 188.515 0.00E+00 165 WELD 2-BB-01-S105-5 2.630 111.691 188.309 0.00E+00 166 WELD 2-BB-01-S105-6 1.690 88.356 211.644 0.00E+00 167 WELD EBB01A-RSG-OUTLET-SC010 31.000 1131.242 -831.242 1.37E-08 168 WELD 2-BB-01-3065A-WDC-002-FW2 31.000 1129.313 -829.313 1.40E-08 169 WELD 2-BB-01-F106 31.000 1113.144 -813.144 1.60E-08 170 WELD 2-BB-01-S104-3 31.000 1096.598 -796.598 1.61E-08 171 WELD 2-BB-01-F108 31.000 1032.886 -732.886 1.61E-08 172 WELD 2-BB-01-S105-4 31.000 1039.665 -739.665 1.79E-08 173 WELD 2-BB-01-F107 31.000 1034.681 -734.681 1.68E-08 174 WELD 2-BB-01-S102-3 10.500 285.421 14.579 0.00E+00 175 WELD 2-RV-301-121-A 29.000 292.660 7.340 0.00E+00 176 WELD 2-BB-01-F103 29.000 201.121 98.879 0.00E+00 177 WELD 2-BB-01-S102-2 29.000 1147.549 -847.549 9.45E-09 178 WELD 2-BB-01-3065A-WDC-001-FW1 29.000 1149.820 -849.820 1.02E-08 179 WELD EBB01A-RSG-INLET-SC010 29.000 1147.387 -847.387 1.00E-08 180 WELD 2-BB-01-S101-7 8.750 298.102 1.898 0.00E+00 181 WELD 2-BB-01-S101-3 1.690 89.457 210.543 0.00E+00 182 WELD 2-RV-302-121-A 27.500 305.896 -5.896 8.41E-11 183 WELD 2-BB-01-F102 27.500 309.510 -9.510 1.36E-10 184 WELD 2-BB-01-S101-2 27.500 348.521 -48.521 0.00E+00 185 WELD 2-BB-01-F101 27.500 990.611 -690.611 1.51E-08 186 WELD 2-HB-24-FW001 1.690 88.017 211.983 0.00E+00 187 WELD 2-HB-24-FW002 1.690 86.761 213.239 0.00E+00 188 WELD 2-HB-24-FW078 1.690 85.640 214.360 0.00E+00 189 WELD 2-HB-24-FW079-A 1.690 80.963 219.037 0.00E+00 190 WELD 2-EP-01-F008 8.750 273.860 26.140 0.00E+00 191 WELD 2-EP-01-S004-E 8.750 268.120 31.880 0.00E+00

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 40 of 60 DEGB Fiber Inside Fiber Contribution Transported

1. Weld Location Name Diameter Margin to Mean at DEGB Size (lbm) CDF Size (lbm)

(inches) 192 WELD 2-EP-01-S004-D 8.750 254.212 45.788 0.00E+00 193 WELD 2-EP-01-S004-C 8.750 235.325 64.675 0.00E+00 194 WELD 2-EP-01-F007 8.750 233.631 66.369 0.00E+00 195 WELD 2-EJ-04-S018-F 5.190 125.978 174.022 0.00E+00 196 WELD 2-EM-05-F007 5.190 123.837 176.163 0.00E+00 197 WELD 2-EM-05-S007-D 5.190 123.095 176.905 0.00E+00 198 WELD 2-EM-05-S007-C 5.190 122.619 177.381 0.00E+00 199 WELD 2-EM-05-W566538-F006 5.190 122.765 177.235 0.00E+00 200 WELD 2-BB-01-S102-6 2.120 98.145 201.855 0.00E+00 201 WELD 2-BB-14-F006 2.630 97.771 202.229 0.00E+00 202 WELD 2-BB-14-F001 2.630 101.155 198.845 0.00E+00 203 WELD 2-BB-01-S305-5 2.630 102.739 197.261 0.00E+00 204 WELD 2-BB-01-S305-6 2.630 104.019 195.981 0.00E+00 205 WELD EBB01C-RSG-OUTLET-SC010 31.000 1058.000 -758.000 1.18E-08 206 WELD 2-BB-01-3065C-WDC-002-FW2 31.000 1055.079 -755.079 1.21E-08 207 WELD 2-BB-01-F306 31.000 1040.015 -740.015 1.37E-08 208 WELD 2-BB-01-S304-3 31.000 1035.374 -735.374 1.27E-08 209 WELD 2-BB-01-F308 31.000 951.012 -651.012 1.30E-08 210 WELD 2-BB-01-S305-4 31.000 917.044 -617.044 1.49E-08 211 WELD 2-BB-01-F307 31.000 847.433 -547.433 1.32E-08 212 WELD 2-EP-02-F019 8.750 234.525 65.475 0.00E+00 213 WELD 2-EP-02-S009-E 8.750 227.545 72.455 0.00E+00 214 WELD 2-EP-02-S009-D 8.750 214.805 85.195 0.00E+00 215 WELD 2-EP-02-S009-C 8.750 206.778 93.222 0.00E+00 216 WELD 2-EP-02-F018 8.750 211.648 88.352 0.00E+00 217 WELD 2-BG-22-F001 2.630 101.259 198.741 0.00E+00 218 WELD 2-BG-22-S001-A 2.630 97.304 202.696 0.00E+00 219 WELD 2-BG-22-S001-B 2.630 84.958 215.042 0.00E+00 220 WELD 2-BG-22-S001-C 2.630 85.595 214.405 0.00E+00 221 WELD 2-BG-22-S001-D 2.630 87.094 212.906 0.00E+00 222 WELD 2-BG-22-S001-G 2.630 86.616 213.384 0.00E+00 223 WELD 2-BG-22-F002 2.630 86.705 213.295 0.00E+00 224 WELD 2-EM-03-F016 5.190 134.476 165.524 0.00E+00 225 WELD 2-EM-03-S015-C 5.190 118.910 181.090 0.00E+00 226 WELD 2-EM-03-S015-B 5.190 113.602 186.398 0.00E+00 227 WELD 2-EM-03-F015 5.190 115.405 184.595 0.00E+00 228 WELD 2-HB-24-FW051 1.690 82.277 217.723 0.00E+00 229 WELD 2-HB-24-FW052 1.690 83.455 216.545 0.00E+00 230 WELD 2-BG-22-S001-F 1.690 83.561 216.439 0.00E+00 231 WELD 2-BB-01-S301-6 8.750 243.742 56.258 0.00E+00 232 WELD 2-BB-01-S301-3 1.690 89.223 210.777 0.00E+00 233 WELD 2-BB-01-S301-4 2.120 97.544 202.456 0.00E+00 234 WELD 2-RV-302-121-C 27.500 197.365 102.635 0.00E+00 235 WELD 2-BB-01-F302 27.500 200.530 99.470 0.00E+00 236 WELD 2-BB-01-S301-2 27.500 212.821 87.179 0.00E+00 237 WELD 2-BB-01-F301 27.500 816.971 -516.971 1.06E-08 238 WELD 2-BB-01-S302-3 5.190 136.392 163.608 0.00E+00 239 WELD 2-RV-301-121-C 29.000 294.364 5.636 0.00E+00 240 WELD 2-BB-01-F303 29.000 208.079 91.921 0.00E+00

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 41 of 60 DEGB Fiber Inside Fiber Contribution Transported

1. Weld Location Name Diameter Margin to Mean at DEGB Size (lbm) CDF Size (lbm)

(inches) 241 WELD 2-BB-01-S302-2 29.000 1076.505 -776.505 4.33E-09 242 WELD 2-BB-01-3065C-WDC-001-FW1 29.000 1089.701 -789.701 5.70E-09 243 WELD EBB01C-RSG-INLET-SC010 29.000 1089.364 -789.364 5.70E-09 244 WELD 2-BB-09-FW152 1.690 79.879 220.121 0.00E+00 245 WELD 2-BB-09-FW151 1.690 79.281 220.719 0.00E+00 246 WELD 2-BB-09-FW148 1.690 78.817 221.183 0.00E+00 247 WELD 2-BB-09-FW147 1.690 78.800 221.200 0.00E+00 248 WELD 2-BB-09-FW142 1.690 79.117 220.883 0.00E+00 249 WELD 2-BB-09-FW141 1.690 80.391 219.609 0.00E+00 250 WELD 2-BB-09-V181-2 1.690 80.376 219.624 0.00E+00 251 WELD 2-BB-09-FW153-A 1.340 79.418 220.582 0.00E+00 252 WELD 2-BB-09-FW154-A 1.340 79.875 220.125 0.00E+00 253 WELD 2-BB-04-S002-L 1.690 86.133 213.867 0.00E+00 254 WELD 2-BG-24-FW068 1.690 85.710 214.290 0.00E+00 255 WELD 2-BG-24-FW067 1.690 81.623 218.377 0.00E+00 256 WELD 2-BG-24-BB-V084-2 1.690 81.555 218.445 0.00E+00 257 WELD 2-BG-24-FW062 1.690 81.555 218.445 0.00E+00 258 WELD 2-BB-02-F006 5.190 185.924 114.076 0.00E+00 259 WELD 2-TBB03-3-C-W 5.190 185.924 114.076 0.00E+00 260 WELD 2-BB-02-S007-B 5.190 178.429 121.571 0.00E+00 261 WELD 2-BB-02-S007-D 5.190 166.355 133.645 0.00E+00 262 WELD 2-BB-02-S007-E 5.190 157.770 142.230 0.00E+00 263 WELD 2-BB-02-S007-F 5.190 158.097 141.903 0.00E+00 264 WELD 2-BB-02-S007-G 5.190 168.056 131.944 0.00E+00 265 WELD 2-BB-02-S007-J 5.190 148.931 151.069 0.00E+00 266 WELD 2-BB-02-S001-J 5.190 142.098 157.902 0.00E+00 267 WELD 2-BB-02-S001-G 5.190 157.342 142.658 0.00E+00 268 WELD 2-BB-02-S001-F 5.190 146.247 153.753 0.00E+00 269 WELD 2-BB-02-S001-E 5.190 144.827 155.173 0.00E+00 270 WELD 2-BB-02-S001-D 5.190 151.234 148.766 0.00E+00 271 WELD 2-BB-02-S001-B 5.190 164.556 135.444 0.00E+00 272 WELD 2-TBB03-3-A-W 5.190 173.530 126.470 0.00E+00 273 WELD 2-BB-02-F001 5.190 173.530 126.470 0.00E+00 274 WELD 2-TBB03-3-B-W 5.190 178.812 121.188 0.00E+00 275 WELD 2-BB-02-F005 5.190 178.812 121.188 0.00E+00 276 WELD 2-BB-02-S006-B 5.190 169.458 130.542 0.00E+00 277 WELD 2-BB-02-S006-D 5.190 156.117 143.883 0.00E+00 278 WELD 2-BB-02-S006-E 5.190 150.919 149.081 0.00E+00 279 WELD 2-BB-02-S006-F 5.190 152.860 147.140 0.00E+00 280 WELD 2-BB-02-S006-G 5.190 163.672 136.328 0.00E+00 281 WELD 2-BB-02-S006-J 5.190 150.225 149.775 0.00E+00 282 WELD 2-BB-04-F001 3.440 123.330 176.670 0.00E+00 283 WELD 2-TBB03-2-W 3.440 123.330 176.670 0.00E+00 284 WELD 2-BB-04-S001-D 3.440 104.391 195.609 0.00E+00 285 WELD 2-BB-04-S001-C 3.440 99.680 200.320 0.00E+00 286 WELD 2-BB-04-F023 3.440 98.698 201.302 0.00E+00 287 WELD 2-BB-04-F002 3.440 85.411 214.589 0.00E+00 288 WELD 2-BB-04-S002-R 3.440 85.630 214.370 0.00E+00 289 WELD 2-BB-04-S002-N 3.440 86.503 213.497 0.00E+00

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 42 of 60 DEGB Fiber Inside Fiber Contribution Transported

1. Weld Location Name Diameter Margin to Mean at DEGB Size (lbm) CDF Size (lbm)

(inches) 290 WELD 2-BB-02-F008 5.190 185.102 114.898 0.00E+00 291 WELD 2-TBB03-4-W 5.190 185.102 114.898 0.00E+00 292 WELD 2-BB-02-S009-B 5.190 169.196 130.804 0.00E+00 293 WELD 2-BB-02-S009-C 5.190 160.230 139.770 0.00E+00 294 WELD 2-BB-02-FW1 5.190 144.005 155.995 0.00E+00 295 WELD 2-BB-02-S009-E 5.190 129.324 170.676 0.00E+00 296 WELD 2-BB-02-F009 5.190 79.140 220.860 0.00E+00 297 WELD 2-BB-02-S010-B 5.190 78.970 221.030 0.00E+00 298 WELD 2-BB-02-FW2 5.190 78.970 221.030 0.00E+00 299 WELD 2-BB-02-F016 2.630 78.800 221.200 0.00E+00 300 WELD 2-BB-02-S014-B 2.630 78.800 221.200 0.00E+00 301 WELD 2-BB-02-S014-C 2.630 78.800 221.200 0.00E+00 302 WELD 2-BB-02-F017-A 2.630 78.800 221.200 0.00E+00 303 WELD 2-BB-02-F010 2.630 78.800 221.200 0.00E+00 304 WELD 2-BB-02-S010-H 2.630 78.800 221.200 0.00E+00 305 WELD 2-BB-02-S010-G 2.630 78.800 221.200 0.00E+00 306 WELD 2-BB-02-S010-F 2.630 78.800 221.200 0.00E+00 307 WELD 2-BB-02-FW25 2.630 78.800 221.200 0.00E+00 308 WELD 2-BB-02-FW3 2.630 78.800 221.200 0.00E+00 309 WELD 2-BB-04-S002-D 3.440 95.113 204.887 0.00E+00 310 WELD 2-BB-04-FW6 3.440 93.706 206.294 0.00E+00 311 WELD 2-BB-04-S002-B 3.440 93.362 206.638 0.00E+00 312 WELD 2-BB-04-F004 3.440 93.856 206.144 0.00E+00 313 WELD 2-BB-04-S002-M 5.190 94.770 205.230 0.00E+00 314 WELD 2-BB-04-S002-K 5.190 111.478 188.522 0.00E+00 315 WELD 2-BB-04-S002-J 5.190 113.678 186.322 0.00E+00 316 WELD 2-BB-04-S002-E 5.190 114.344 185.656 0.00E+00 317 WELD 2-BB-04-F003 5.190 112.317 187.683 0.00E+00 318 WELD 2-BB-04-S011-M 5.190 111.860 188.140 0.00E+00 319 WELD 2-BB-04-S011-L 5.190 113.091 186.909 0.00E+00 320 WELD 2-BB-04-S011-J 5.190 107.394 192.606 0.00E+00 321 WELD 2-BB-04-S011-H 5.190 105.697 194.303 0.00E+00 322 WELD 2-BB-04-S011-D 5.190 106.611 193.389 0.00E+00 323 WELD 2-BB-04-S011-C 3.440 91.766 208.234 0.00E+00 324 WELD 2-BB-04-FW5 3.440 90.930 209.070 0.00E+00 325 WELD 2-BB-04-S011-A 3.440 90.912 209.088 0.00E+00 326 WELD 2-BB-04-F014 3.440 91.728 208.272 0.00E+00 327 WELD 2-BB-01-S402-4 10.500 277.498 22.502 0.00E+00 328 WELD 2-BB-01-S402-3 11.190 285.791 14.209 0.00E+00 329 WELD 2-RV-301-121-D 29.000 283.377 16.623 0.00E+00 330 WELD 2-BB-01-F403 29.000 198.138 101.862 0.00E+00 331 WELD 2-BB-01-S402-2 29.000 1158.603 -858.603 7.55E-09 332 WELD 2-BB-01-3065D-WDC-001-FW1 29.000 1161.553 -861.553 9.26E-09 333 WELD EBB01D-RSG-INLET-SC010 29.000 1160.681 -860.681 9.14E-09 334 WELD 2-BB-01-S401-7 8.750 249.939 50.061 0.00E+00 335 WELD 2-BB-01-S401-3 1.690 89.216 210.784 0.00E+00 336 WELD 2-BB-01-S401-4 2.120 96.343 203.657 0.00E+00 337 WELD 2-RV-302-121-D 27.500 168.035 131.965 0.00E+00 338 WELD 2-BB-01-F402 27.500 171.998 128.002 0.00E+00

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 43 of 60 DEGB Fiber Inside Fiber Contribution Transported

1. Weld Location Name Diameter Margin to Mean at DEGB Size (lbm) CDF Size (lbm)

(inches) 339 WELD 2-BB-01-S401-2 27.500 199.459 100.541 0.00E+00 340 WELD 2-BB-01-F401 27.500 937.544 -637.544 1.42E-08 341 WELD 2-BB-15-F006 2.630 108.796 191.204 0.00E+00 342 WELD 2-BB-15-F001 2.630 110.866 189.134 0.00E+00 343 WELD 2-BB-01-S405-5 2.630 111.426 188.574 0.00E+00 344 WELD 2-BB-01-S405-6 1.690 88.263 211.737 0.00E+00 345 WELD EBB01D-RSG-OUTLET-SC010 31.000 1145.047 -845.047 1.42E-08 346 WELD 2-BB-01-3065D-WDC-002-FW2 31.000 1143.595 -843.595 1.45E-08 347 WELD 2-BB-01-F406 31.000 1133.995 -833.995 1.63E-08 348 WELD 2-BB-01-S404-3 31.000 1133.738 -833.738 1.66E-08 349 WELD 2-BB-01-F408 31.000 1083.705 -783.705 1.69E-08 350 WELD 2-BB-01-S405-4 31.000 1056.821 -756.821 1.78E-08 351 WELD 2-BB-01-F407 31.000 1004.162 -704.162 1.68E-08 352 WELD 2-EP-01-F019 8.750 200.430 99.570 0.00E+00 353 WELD 2-EP-01-S010-C 8.750 203.372 96.628 0.00E+00 354 WELD 2-EP-01-S010-D 8.750 221.023 78.977 0.00E+00 355 WELD 2-EP-01-S010-E 8.750 238.472 61.528 0.00E+00 356 WELD 2-EP-01-F020 8.750 246.097 53.903 0.00E+00 357 WELD 2-EJ-04-S016-F 5.190 134.282 165.718 0.00E+00 358 WELD 2-EJ-04-F029 5.190 139.493 160.507 0.00E+00 359 WELD 2-EM-05-S005-C 5.190 148.699 151.301 0.00E+00 360 WELD 2-EM-05-S005-B 5.190 149.990 150.010 0.00E+00 361 WELD 2-EM-05-F004 5.190 149.633 150.367 0.00E+00 362 WELD 2-EJ-04-F026 10.500 298.965 1.035 0.00E+00 363 WELD 2-EJ-04-S016-B 10.500 311.199 -11.199 0.00E+00 364 WELD 2-EJ-04-S016-C 10.500 319.269 -19.269 0.00E+00 365 WELD 2-EJ-04-S016-D 10.500 317.662 -17.662 0.00E+00 366 WELD 2-EJ-04-S016-E 10.500 341.292 -41.292 3.78E-10 367 WELD 2-EJ-04-S016-G 10.500 381.197 -81.197 2.26E-09 368 WELD 2-EJ-04-S016-H 10.500 403.966 -103.966 0.00E+00 369 WELD 2-EJ-04-F025 10.500 432.834 -132.834 8.11E-10 370 WELD 2-BB-07-FW004 1.340 79.316 220.684 0.00E+00 371 WELD 2-BB-07-FW003 1.340 79.501 220.499 0.00E+00 372 WELD 2-BB-07-FW002 1.340 79.602 220.398 0.00E+00 373 WELD 2-BB-07-FW001 1.340 80.046 219.954 0.00E+00 374 WELD 2-BB-07-FW005 1.690 80.000 220.000 0.00E+00 375 WELD 2-BB-07-FW006 1.690 79.683 220.317 0.00E+00 376 WELD 2-BB-07-FW007 1.690 79.252 220.748 0.00E+00 377 WELD 2-BB-07-FW008 1.690 78.800 221.200 0.00E+00 378 WELD 2-BB-07-FW011 1.690 78.800 221.200 0.00E+00 379 WELD 2-BB-07-FW012 1.690 78.800 221.200 0.00E+00 380 WELD 2-BB-07-FW013 1.690 78.800 221.200 0.00E+00 381 WELD 2-BB-07-FW014 1.690 78.800 221.200 0.00E+00 382 WELD 2-BB-07-FW019 1.690 78.800 221.200 0.00E+00 383 WELD 2-BB-07-FW020 1.690 78.800 221.200 0.00E+00 384 WELD 2-BB-07-FW021 1.690 78.800 221.200 0.00E+00 385 WELD 2-BB-07-FW022 1.690 78.844 221.156 0.00E+00 386 WELD 2-BB-07-FW023 1.690 78.800 221.200 0.00E+00 387 WELD 2-BB-07-FW024 1.690 78.800 221.200 0.00E+00

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 44 of 60 DEGB Fiber Inside Fiber Contribution Transported

1. Weld Location Name Diameter Margin to Mean at DEGB Size (lbm) CDF Size (lbm)

(inches) 388 WELD 2-BB-07-FW029 1.690 78.800 221.200 0.00E+00 389 WELD 2-BB-07-V211-2 1.690 78.800 221.200 0.00E+00 390 WELD 2-BG-21-F026 2.630 101.482 198.518 0.00E+00 391 WELD 2-BG-21-F027 2.630 105.771 194.229 0.00E+00 392 WELD 2-BB-01-S401-5 2.630 108.802 191.198 0.00E+00 393 WELD 2-BG-23-FW144 1.690 82.410 217.590 0.00E+00 394 WELD 2-BG-23-FW-3 1.690 82.535 217.465 0.00E+00 395 WELD 2-BG-23-FW-4 1.690 82.823 217.177 0.00E+00 396 WELD 2-BG-23-FW-5 1.690 82.754 217.246 0.00E+00 397 WELD 2-BG-23-FW145 1.690 81.805 218.195 0.00E+00 398 WELD 2-BG-23-FW149 1.690 82.831 217.169 0.00E+00 399 WELD 2-BG-23-FW148 1.690 82.583 217.417 0.00E+00 400 WELD 2-BG-23-FW143 1.690 82.114 217.886 0.00E+00 401 WELD 2-BG-23-A175752A-FW02 1.690 83.055 216.945 0.00E+00 402 WELD 2-BG-23-A175752A-FW01 1.690 83.653 216.347 0.00E+00 403 WELD 2-BG-23-FW138 1.690 87.995 212.005 0.00E+00 404 WELD 2-BG-22-F025 2.630 85.541 214.459 0.00E+00 405 WELD 2-BG-22-S020-A 2.630 82.407 217.593 0.00E+00 406 WELD 2-BG-22-S020-B 2.630 82.480 217.520 0.00E+00 407 WELD 2-BG-22-F026 2.630 82.558 217.442 0.00E+00 408 WELD 2-BG-23-FW150 1.690 82.563 217.437 0.00E+00 409 WELD 2-BG-23-FW151 1.690 81.904 218.096 0.00E+00 410 WELD 2-BG-23-FW152 1.690 81.580 218.420 0.00E+00 411 WELD 2-BG-23-FW153 1.690 81.534 218.466 0.00E+00 5.40E-07 10.3 Full Weld List for Particulate Margin This section contains the full weld list for particulate margin. Table 10-3 lists the weld location name, the corresponding pipe diameter (DEGB size), the amount of qualified coatings transported for a DEGB, the total particulate transported by a DEGB at each weld, and the particulate margin (the difference between the coatings debris loading threshold derived from strainer testing and the total coatings transported). Total coatings transported equals the qualified coatings transported in addition to the 4370 lbm of unqualified coatings debris transported and the 163 lbm of latent particulate debris transported for every break.

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 45 of 60 Table 10-3: Full weld list for particulate margin DEGB Qualified Total Inside Coatings Particulate Particulate

1. Weld Location Name Diameter Transported Transported Margin Size at DEGB at DEGB (lbm)

(inches) Size (lbm) Size (lbm) 1 WELD 2-BB-04-F005 3.44 1.337 4534.521 1265.479 2 WELD 2-BB-04-S003-D 3.44 1.139 4534.323 1265.677 3 WELD 2-BB-04-S003-C 3.44 1.306 4534.490 1265.510 4 WELD 2-BB-04-F006 3.44 1.613 4534.797 1265.203 5 WELD 2-BB-04-S004-C 3.44 1.511 4534.695 1265.305 6 WELD 2-BB-04-F007 3.44 3.837 4537.021 1262.979 7 WELD 2-BB-04-S005-D 3.44 3.407 4536.591 1263.409 8 WELD 2-BB-04-S005-C 3.44 3.031 4536.215 1263.785 9 WELD 2-BB-04-S005-B 3.44 1.574 4534.758 1265.242 10 WELD 2-BB-04-F008 3.44 1.498 4534.682 1265.318 11 WELD 2-BB-04-S006-C 3.44 2.191 4535.375 1264.625 12 WELD 2-BB-04-S006-B 3.44 1.960 4535.144 1264.856 13 WELD 2-BB-04-F009 3.44 1.169 4534.353 1265.647 14 WELD 2-BB-04-S007-F 3.44 1.146 4534.330 1265.670 15 WELD 2-BB-04-S007-E 3.44 1.507 4534.691 1265.309 16 WELD 2-BB-04-S007-D 3.44 1.291 4534.475 1265.525 17 WELD 2-BB-04-S007-B 3.44 1.204 4534.388 1265.612 18 WELD 2-BB-04-F010 3.44 1.248 4534.432 1265.568 19 WELD 2-BB-04-S008-D 3.44 1.317 4534.501 1265.499 20 WELD 2-BB-04-S008-C 3.44 1.173 4534.357 1265.643 21 WELD 2-BB-04-S008-B 3.44 1.215 4534.399 1265.601 22 WELD 2-BB-04-F011 3.44 0.872 4534.056 1265.944 23 WELD 2-BB-04-S009-D 3.44 3.356 4536.540 1263.460 24 WELD 2-BB-04-S009-C 3.44 3.007 4536.191 1263.809 25 WELD 2-BB-04-S009-B 3.44 2.991 4536.175 1263.825 26 WELD 2-BB-04-F012 3.44 3.707 4536.891 1263.109 27 WELD 2-BB-01-S101-5 3.44 5.463 4538.647 1261.353 28 WELD 2-BB-04-F015 3.44 1.291 4534.475 1265.525 29 WELD 2-BB-04-S012-F 3.44 1.082 4534.266 1265.734 30 WELD 2-BB-04-S012-E 3.44 1.036 4534.220 1265.780 31 WELD 2-BB-04-S012-D 3.44 1.699 4534.883 1265.117 32 WELD 2-BB-04-S012-C 3.44 2.021 4535.205 1264.795 33 WELD 2-BB-04-F016 3.44 1.669 4534.853 1265.147 34 WELD 2-BB-04-S013-F 3.44 1.627 4534.811 1265.189 35 WELD 2-BB-04-S013-H 3.44 2.056 4535.240 1264.760 36 WELD 2-BB-04-S013-D 3.44 2.528 4535.712 1264.288 37 WELD 2-BB-04-S013-C 3.44 2.143 4535.327 1264.673 38 WELD 2-BB-04-S013-B 3.44 1.992 4535.176 1264.824 39 WELD 2-BB-04-F017 3.44 1.978 4535.162 1264.838 40 WELD 2-BB-04-S014-E 3.44 1.597 4534.781 1265.219 41 WELD 2-BB-04-S014-D 3.44 1.599 4534.783 1265.217 42 WELD 2-BB-04-S014-C 3.44 1.548 4534.732 1265.268 43 WELD 2-BB-04-S014-B 3.44 1.568 4534.752 1265.248 44 WELD 2-BB-04-F018 3.44 1.974 4535.158 1264.842 45 WELD 2-BB-04-S015-F 3.44 2.190 4535.374 1264.626 46 WELD 2-BB-04-S015-E 3.44 1.545 4534.729 1265.271 47 WELD 2-BB-04-S015-D 3.44 1.338 4534.522 1265.478

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 46 of 60 DEGB Qualified Total Inside Coatings Particulate Particulate

1. Weld Location Name Diameter Transported Transported Margin Size at DEGB at DEGB (lbm)

(inches) Size (lbm) Size (lbm) 48 WELD 2-BB-04-S015-B 3.44 1.204 4534.388 1265.612 49 WELD 2-BB-04-F019 3.44 1.236 4534.420 1265.580 50 WELD 2-BB-04-FW2 3.44 1.278 4534.462 1265.538 51 WELD 2-BB-04-S016-C 3.44 1.240 4534.424 1265.576 52 WELD 2-BB-04-S016-B 3.44 0.827 4534.011 1265.989 53 WELD 2-BB-04-F020 3.44 0.826 4534.010 1265.990 54 WELD 2-BB-04-S017-B 3.44 0.879 4534.063 1265.937 55 WELD 2-BB-04-F021 3.44 0.879 4534.063 1265.937 56 WELD 2-BB-04-S018-D 3.44 3.803 4536.987 1263.013 57 WELD 2-BB-04-S018-C 3.44 3.241 4536.425 1263.575 58 WELD 2-BB-04-S018-B 3.44 3.217 4536.401 1263.599 59 WELD 2-BB-04-F022 3.44 3.866 4537.050 1262.950 60 WELD 2-EM-03-BBV059-2 1.34 0.197 4533.381 1266.619 61 WELD 2-EM-03-FW225 1.34 0.177 4533.361 1266.639 62 WELD 2-EM-03-FW226 1.34 0.159 4533.343 1266.657 63 WELD 2-EM-03-FW227 1.34 0.223 4533.407 1266.593 64 WELD 2-BB-01-S401-6 2.63 2.333 4535.517 1264.483 65 WELD 2-BB-01-S401-10 2.63 2.056 4535.240 1264.760 66 WELD 2-EM-03-FW259 1.34 0.272 4533.456 1266.544 67 WELD 2-EM-03-FW258 1.34 0.175 4533.359 1266.641 68 WELD 2-EM-03-BBV040-2 1.34 0.200 4533.384 1266.616 69 WELD 2-BB-01-S301-5 2.63 2.432 4535.616 1264.384 70 WELD 2-BB-01-S301-9 2.63 2.213 4535.397 1264.603 71 WELD 2-HB-24-FW67 1.69 1.858 4535.042 1264.958 72 WELD 2-HB-24-FW66 1.69 2.355 4535.539 1264.461 73 WELD 2-HB-24-FW065 1.69 2.630 4535.814 1264.186 74 WELD 2-HB-24-FW064 1.69 0.454 4533.638 1266.362 75 WELD 2-BB-01-F004 11.19 146.870 4680.054 1119.946 76 WELD 2-TBB03-1-W 11.19 146.870 4680.054 1119.946 77 WELD 2-BB-01-S003-3 11.19 160.891 4694.075 1105.925 78 WELD 2-BB-01-S003-2 11.19 173.558 4706.742 1093.258 79 WELD 2-BB-01-S003-8 11.19 104.680 4637.864 1162.136 80 WELD 2-BB-01-F003 11.19 65.119 4598.303 1201.697 81 WELD 2-BB-01-F002 11.19 103.981 4637.165 1162.835 82 WELD 2-BB-01-S001-6 11.19 185.852 4719.036 1080.964 83 WELD 2-BB-01-F001 11.19 136.427 4669.611 1130.389 84 WELD 2-BB-01-S101-8 2.63 3.790 4536.974 1263.026 85 WELD 2-BG-21-F014 2.63 2.450 4535.634 1264.366 86 WELD 2-BG-21-FW-1 2.63 0.992 4534.176 1265.824 87 WELD 2-BG-21-S010-D 2.63 0.663 4533.847 1266.153 88 WELD 2-BG-21-S010-C 2.63 0.641 4533.825 1266.175 89 WELD 2-BG-21-S010-B 2.63 0.641 4533.825 1266.175 90 WELD 2-BG-21-S010-A 2.63 0.671 4533.855 1266.145 91 WELD 2-BG-21-F013 2.63 0.665 4533.849 1266.151 92 WELD 2-EP-02-F008 8.75 80.024 4613.208 1186.792 93 WELD 2-EP-02-S004-E 8.75 82.445 4615.629 1184.371 94 WELD 2-EP-02-FW2 8.75 84.054 4617.238 1182.762 95 WELD 2-EP-02-S004-C 8.75 88.810 4621.994 1178.006 96 WELD 2-EP-02-F007 8.75 91.318 4624.502 1175.498

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 47 of 60 DEGB Qualified Total Inside Coatings Particulate Particulate

1. Weld Location Name Diameter Transported Transported Margin Size at DEGB at DEGB (lbm)

(inches) Size (lbm) Size (lbm) 97 WELD 2-EM-03-F012 5.19 13.658 4546.842 1253.158 98 WELD 2-EM-03-S012-D 5.19 12.190 4545.374 1254.626 99 WELD 2-EM-03-S012-B 5.19 10.478 4543.662 1256.338 100 WELD 2-EM-03-W237498-FW03 5.19 10.288 4543.472 1256.528 101 WELD 2-BB-11-C600739-FW01 1.34 0.456 4533.640 1266.360 102 WELD 2-BB-11-A600739B-FW01 1.34 0.609 4533.793 1266.207 103 WELD 2-BB-11-FW008 1.69 1.066 4534.250 1265.750 104 WELD 2-BB-11-FW011 1.69 0.916 4534.100 1265.900 105 WELD 2-BB-11-FW012 1.69 0.370 4533.554 1266.446 106 WELD 2-BB-11-FW013 1.69 0.331 4533.515 1266.485 107 WELD 2-BB-11-FW014 1.69 0.223 4533.407 1266.593 108 WELD 2-BB-11-FW015 1.69 0.229 4533.413 1266.587 109 WELD 2-BB-11-FW016 1.69 0.267 4533.451 1266.549 110 WELD 2-BB-11-V151-2 1.69 0.225 4533.409 1266.591 111 WELD 2-EM-03-FW269 1.34 0.233 4533.417 1266.583 112 WELD 2-EM-03-FW268 1.34 0.198 4533.382 1266.618 113 WELD 2-EM-03-BBV022-2 1.34 0.229 4533.413 1266.587 114 WELD 2-BB-01-S201-8 2.63 2.377 4535.561 1264.439 115 WELD 2-BB-01-S201-15 2.63 2.091 4535.275 1264.725 116 WELD 2-BB-06-F006 2.63 1.617 4534.801 1265.199 117 WELD 2-BB-06-F001 2.63 1.925 4535.109 1264.891 118 WELD 2-BB-01-S205-5 2.63 2.182 4535.366 1264.634 119 WELD 2-BB-01-S205-6 1.69 1.367 4534.551 1265.449 120 WELD EBB01B-RSG-OUTLET-SC010 31.00 863.064 5396.248 403.752 121 WELD 2-BB-01-3065B-WDC-002-FW2 31.00 862.174 5395.358 404.642 122 WELD 2-BB-01-F206 31.00 857.335 5390.519 409.481 123 WELD 2-BB-01-S204-3 31.00 873.352 5406.536 393.464 124 WELD 2-BB-01-F208 31.00 771.879 5305.063 494.937 125 WELD 2-BB-01-S205-4 31.00 745.361 5278.545 521.455 126 WELD 2-BB-01-F207 31.00 723.804 5256.988 543.012 127 WELD 2-BB-01-S201-7 8.75 67.006 4600.190 1199.810 128 WELD 2-BB-01-S201-3 1.69 1.004 4534.188 1265.812 129 WELD 2-BB-01-S201-4 2.12 1.676 4534.860 1265.140 130 WELD 2-BB-01-S201-5 3.44 6.064 4539.248 1260.752 131 WELD 2-RV-302-121-B 27.50 114.031 4647.215 1152.785 132 WELD 2-BB-01-F202 27.50 121.993 4655.177 1144.823 133 WELD 2-BB-01-S201-2 27.50 161.492 4694.676 1105.324 134 WELD 2-BB-01-F201 27.50 628.465 5161.649 638.351 135 WELD 2-BB-01-S202-3 5.19 13.999 4547.183 1252.817 136 WELD 2-RV-301-121-B 29.00 131.720 4664.904 1135.096 137 WELD 2-BB-01-F203 29.00 123.855 4657.039 1142.961 138 WELD 2-BB-01-S202-2 29.00 877.715 5410.899 389.101 139 WELD 2-BB-01-3065B-WDC-001-FW1 29.00 838.508 5371.692 428.308 140 WELD EBB01B-RSG-INLET-SC010 29.00 836.287 5369.471 430.529 141 WELD 2-EM-03-FW235 1.34 0.262 4533.446 1266.554 142 WELD 2-EM-03-FW234 1.34 0.145 4533.329 1266.671 143 WELD 2-EM-03-BBV001-2 1.34 0.167 4533.351 1266.649 144 WELD 2-BB-01-S101-9 2.63 2.438 4535.622 1264.378 145 WELD 2-BB-01-S101-13 2.63 2.100 4535.284 1264.716

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 48 of 60 DEGB Qualified Total Inside Coatings Particulate Particulate

1. Weld Location Name Diameter Transported Transported Margin Size at DEGB at DEGB (lbm)

(inches) Size (lbm) Size (lbm) 146 WELD 2-EJ-04-F030 10.50 77.399 4610.583 1189.417 147 WELD 2-EJ-04-FW9 10.50 59.661 4592.845 1207.155 148 WELD 2-EJ-04-S018-C 10.50 57.228 4590.412 1209.588 149 WELD 2-EJ-04-FW8 10.50 57.434 4590.618 1209.382 150 WELD 2-EJ-04-S018-E 10.50 56.417 4589.601 1210.399 151 WELD 2-EJ-04-F031 10.50 72.458 4605.642 1194.358 152 WELD 2-BB-08-FW041-A-R-1 1.69 1.485 4534.669 1265.331 153 WELD 2-BB-08-FW099 1.69 1.557 4534.741 1265.259 154 WELD 2-BB-08-FW044 1.69 1.654 4534.838 1265.162 155 WELD 2-BB-08-FW045 1.69 1.546 4534.730 1265.270 156 WELD 2-BB-08-FW046-A 1.69 1.659 4534.843 1265.157 157 WELD 2-BB-08-FW047 1.69 2.103 4535.287 1264.713 158 WELD 2-BB-08-FW052-B 1.69 2.136 4535.320 1264.680 159 WELD 2-BB-08-FW053 1.69 2.360 4535.544 1264.456 160 WELD 2-BB-08-V121-2 1.69 1.463 4534.647 1265.353 161 WELD 2-BB-08-FW039 1.34 0.095 4533.279 1266.721 162 WELD 2-BB-08-FW040 1.34 0.963 4534.147 1265.853 163 WELD 2-BB-05-F006 2.63 1.823 4535.007 1264.993 164 WELD 2-BB-05-F001 2.63 1.961 4535.145 1264.855 165 WELD 2-BB-01-S105-5 2.63 2.141 4535.325 1264.675 166 WELD 2-BB-01-S105-6 1.69 1.384 4534.568 1265.432 167 WELD EBB01A-RSG-OUTLET-SC010 31.00 972.513 5505.697 294.303 168 WELD 2-BB-01-3065A-WDC-002-FW2 31.00 970.928 5504.112 295.888 169 WELD 2-BB-01-F106 31.00 964.310 5497.494 302.506 170 WELD 2-BB-01-S104-3 31.00 979.205 5512.389 287.611 171 WELD 2-BB-01-F108 31.00 841.940 5375.124 424.876 172 WELD 2-BB-01-S105-4 31.00 780.156 5313.340 486.660 173 WELD 2-BB-01-F107 31.00 745.974 5279.158 520.842 174 WELD 2-BB-01-S102-3 10.50 84.016 4617.200 1182.800 175 WELD 2-RV-301-121-A 29.00 131.684 4664.868 1135.132 176 WELD 2-BB-01-F103 29.00 123.256 4656.440 1143.560 177 WELD 2-BB-01-S102-2 29.00 1039.934 5573.118 226.882 178 WELD 2-BB-01-3065A-WDC-001-FW1 29.00 995.956 5529.140 270.860 179 WELD EBB01A-RSG-INLET-SC010 29.00 992.453 5525.637 274.363 180 WELD 2-BB-01-S101-7 8.75 66.120 4599.304 1200.696 181 WELD 2-BB-01-S101-3 1.69 1.053 4534.237 1265.763 182 WELD 2-RV-302-121-A 27.50 117.349 4650.533 1149.467 183 WELD 2-BB-01-F102 27.50 125.438 4658.622 1141.378 184 WELD 2-BB-01-S101-2 27.50 168.924 4702.108 1097.892 185 WELD 2-BB-01-F101 27.50 656.028 5189.212 610.788 186 WELD 2-HB-24-FW001 1.69 1.847 4535.031 1264.969 187 WELD 2-HB-24-FW002 1.69 2.344 4535.528 1264.472 188 WELD 2-HB-24-FW078 1.69 2.505 4535.689 1264.311 189 WELD 2-HB-24-FW079-A 1.69 0.262 4533.446 1266.554 190 WELD 2-EP-01-F008 8.75 73.834 4607.018 1192.982 191 WELD 2-EP-01-S004-E 8.75 74.946 4608.130 1191.870 192 WELD 2-EP-01-S004-D 8.75 76.740 4609.924 1190.076 193 WELD 2-EP-01-S004-C 8.75 82.667 4615.851 1184.149 194 WELD 2-EP-01-F007 8.75 85.849 4619.033 1180.967

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 49 of 60 DEGB Qualified Total Inside Coatings Particulate Particulate

1. Weld Location Name Diameter Transported Transported Margin Size at DEGB at DEGB (lbm)

(inches) Size (lbm) Size (lbm) 195 WELD 2-EJ-04-S018-F 5.19 13.557 4546.741 1253.259 196 WELD 2-EM-05-F007 5.19 13.105 4546.289 1253.711 197 WELD 2-EM-05-S007-D 5.19 12.432 4545.616 1254.384 198 WELD 2-EM-05-S007-C 5.19 9.979 4543.163 1256.837 199 WELD 2-EM-05-W566538-F006 5.19 7.946 4541.130 1258.870 200 WELD 2-BB-01-S102-6 2.12 1.553 4534.737 1265.263 201 WELD 2-BB-14-F006 2.63 1.638 4534.822 1265.178 202 WELD 2-BB-14-F001 2.63 1.948 4535.132 1264.868 203 WELD 2-BB-01-S305-5 2.63 2.147 4535.331 1264.669 204 WELD 2-BB-01-S305-6 2.63 5.550 4538.734 1261.266 205 WELD EBB01C-RSG-OUTLET-SC010 31.00 772.101 5305.285 494.715 206 WELD 2-BB-01-3065C-WDC-002-FW2 31.00 770.606 5303.790 496.210 207 WELD 2-BB-01-F306 31.00 768.948 5302.132 497.868 208 WELD 2-BB-01-S304-3 31.00 800.728 5333.912 466.088 209 WELD 2-BB-01-F308 31.00 701.494 5234.678 565.322 210 WELD 2-BB-01-S305-4 31.00 676.103 5209.287 590.713 211 WELD 2-BB-01-F307 31.00 638.551 5171.735 628.265 212 WELD 2-EP-02-F019 8.75 71.414 4604.598 1195.402 213 WELD 2-EP-02-S009-E 8.75 72.982 4606.166 1193.834 214 WELD 2-EP-02-S009-D 8.75 72.835 4606.019 1193.981 215 WELD 2-EP-02-S009-C 8.75 75.826 4609.010 1190.990 216 WELD 2-EP-02-F018 8.75 53.180 4586.364 1213.636 217 WELD 2-BG-22-F001 2.63 5.739 4538.923 1261.077 218 WELD 2-BG-22-S001-A 2.63 6.104 4539.288 1260.712 219 WELD 2-BG-22-S001-B 2.63 1.393 4534.577 1265.423 220 WELD 2-BG-22-S001-C 2.63 1.031 4534.215 1265.785 221 WELD 2-BG-22-S001-D 2.63 0.874 4534.058 1265.942 222 WELD 2-BG-22-S001-G 2.63 0.863 4534.047 1265.953 223 WELD 2-BG-22-F002 2.63 0.612 4533.796 1266.204 224 WELD 2-EM-03-F016 5.19 11.421 4544.605 1255.395 225 WELD 2-EM-03-S015-C 5.19 7.317 4540.501 1259.499 226 WELD 2-EM-03-S015-B 5.19 8.829 4542.013 1257.987 227 WELD 2-EM-03-F015 5.19 9.881 4543.065 1256.935 228 WELD 2-HB-24-FW051 1.69 0.374 4533.558 1266.442 229 WELD 2-HB-24-FW052 1.69 0.482 4533.666 1266.334 230 WELD 2-BG-22-S001-F 1.69 0.444 4533.628 1266.372 231 WELD 2-BB-01-S301-6 8.75 62.496 4595.680 1204.320 232 WELD 2-BB-01-S301-3 1.69 1.011 4534.195 1265.805 233 WELD 2-BB-01-S301-4 2.12 1.620 4534.804 1265.196 234 WELD 2-RV-302-121-C 27.50 62.992 4596.176 1203.824 235 WELD 2-BB-01-F302 27.50 69.604 4602.788 1197.212 236 WELD 2-BB-01-S301-2 27.50 85.250 4618.434 1181.566 237 WELD 2-BB-01-F301 27.50 581.819 5115.003 684.997 238 WELD 2-BB-01-S302-3 5.19 10.822 4544.006 1255.994 239 WELD 2-RV-301-121-C 29.00 125.830 4659.014 1140.986 240 WELD 2-BB-01-F303 29.00 116.506 4649.690 1150.310 241 WELD 2-BB-01-S302-2 29.00 819.713 5352.897 447.103 242 WELD 2-BB-01-3065C-WDC-001-FW1 29.00 785.996 5319.180 480.820 243 WELD EBB01C-RSG-INLET-SC010 29.00 783.949 5317.133 482.867

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 50 of 60 DEGB Qualified Total Inside Coatings Particulate Particulate

1. Weld Location Name Diameter Transported Transported Margin Size at DEGB at DEGB (lbm)

(inches) Size (lbm) Size (lbm) 244 WELD 2-BB-09-FW152 1.69 0.178 4533.362 1266.638 245 WELD 2-BB-09-FW151 1.69 0.214 4533.398 1266.602 246 WELD 2-BB-09-FW148 1.69 0.232 4533.416 1266.584 247 WELD 2-BB-09-FW147 1.69 0.232 4533.416 1266.584 248 WELD 2-BB-09-FW142 1.69 0.218 4533.402 1266.598 249 WELD 2-BB-09-FW141 1.69 0.286 4533.470 1266.530 250 WELD 2-BB-09-V181-2 1.69 0.211 4533.395 1266.605 251 WELD 2-BB-09-FW153-A 1.34 0.139 4533.323 1266.677 252 WELD 2-BB-09-FW154-A 1.34 0.100 4533.284 1266.716 253 WELD 2-BB-04-S002-L 1.69 1.078 4534.262 1265.738 254 WELD 2-BG-24-FW068 1.69 1.417 4534.601 1265.399 255 WELD 2-BG-24-FW067 1.69 0.271 4533.455 1266.545 256 WELD 2-BG-24-BB-V084-2 1.69 0.231 4533.415 1266.585 257 WELD 2-BG-24-FW062 1.69 0.231 4533.415 1266.585 258 WELD 2-BB-02-F006 5.19 6.802 4539.986 1260.014 259 WELD 2-TBB03-3-C-W 5.19 6.802 4539.986 1260.014 260 WELD 2-BB-02-S007-B 5.19 6.547 4539.731 1260.269 261 WELD 2-BB-02-S007-D 5.19 6.126 4539.310 1260.690 262 WELD 2-BB-02-S007-E 5.19 5.783 4538.967 1261.033 263 WELD 2-BB-02-S007-F 5.19 7.589 4540.773 1259.227 264 WELD 2-BB-02-S007-G 5.19 16.931 4550.115 1249.885 265 WELD 2-BB-02-S007-J 5.19 16.092 4549.276 1250.724 266 WELD 2-BB-02-S001-J 5.19 14.319 4547.503 1252.497 267 WELD 2-BB-02-S001-G 5.19 11.546 4544.730 1255.270 268 WELD 2-BB-02-S001-F 5.19 4.797 4537.981 1262.019 269 WELD 2-BB-02-S001-E 5.19 2.560 4535.744 1264.256 270 WELD 2-BB-02-S001-D 5.19 2.086 4535.270 1264.730 271 WELD 2-BB-02-S001-B 5.19 2.118 4535.302 1264.698 272 WELD 2-TBB03-3-A-W 5.19 2.628 4535.812 1264.188 273 WELD 2-BB-02-F001 5.19 2.628 4535.812 1264.188 274 WELD 2-TBB03-3-B-W 5.19 3.036 4536.220 1263.780 275 WELD 2-BB-02-F005 5.19 3.036 4536.220 1263.780 276 WELD 2-BB-02-S006-B 5.19 2.533 4535.717 1264.283 277 WELD 2-BB-02-S006-D 5.19 2.140 4535.324 1264.676 278 WELD 2-BB-02-S006-E 5.19 3.464 4536.648 1263.352 279 WELD 2-BB-02-S006-F 5.19 5.876 4539.060 1260.940 280 WELD 2-BB-02-S006-G 5.19 15.778 4548.962 1251.038 281 WELD 2-BB-02-S006-J 5.19 16.048 4549.232 1250.768 282 WELD 2-BB-04-F001 3.44 0.572 4533.756 1266.244 283 WELD 2-TBB03-2-W 3.44 0.572 4533.756 1266.244 284 WELD 2-BB-04-S001-D 3.44 0.687 4533.871 1266.129 285 WELD 2-BB-04-S001-C 3.44 0.825 4534.009 1265.991 286 WELD 2-BB-04-F023 3.44 0.950 4534.134 1265.866 287 WELD 2-BB-04-F002 3.44 0.977 4534.161 1265.839 288 WELD 2-BB-04-S002-R 3.44 0.989 4534.173 1265.827 289 WELD 2-BB-04-S002-N 3.44 1.292 4534.476 1265.524 290 WELD 2-BB-02-F008 5.19 5.281 4538.465 1261.535 291 WELD 2-TBB03-4-W 5.19 5.281 4538.465 1261.535 292 WELD 2-BB-02-S009-B 5.19 5.000 4538.184 1261.816

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 51 of 60 DEGB Qualified Total Inside Coatings Particulate Particulate

1. Weld Location Name Diameter Transported Transported Margin Size at DEGB at DEGB (lbm)

(inches) Size (lbm) Size (lbm) 293 WELD 2-BB-02-S009-C 5.19 4.832 4538.016 1261.984 294 WELD 2-BB-02-FW1 5.19 4.228 4537.412 1262.588 295 WELD 2-BB-02-S009-E 5.19 2.946 4536.130 1263.870 296 WELD 2-BB-02-F009 5.19 4.190 4537.374 1262.626 297 WELD 2-BB-02-S010-B 5.19 3.468 4536.652 1263.348 298 WELD 2-BB-02-FW2 5.19 3.359 4536.543 1263.457 299 WELD 2-BB-02-F016 2.63 1.130 4534.314 1265.686 300 WELD 2-BB-02-S014-B 2.63 0.489 4533.673 1266.327 301 WELD 2-BB-02-S014-C 2.63 0.479 4533.663 1266.337 302 WELD 2-BB-02-F017-A 2.63 0.597 4533.781 1266.219 303 WELD 2-BB-02-F010 2.63 0.551 4533.735 1266.265 304 WELD 2-BB-02-S010-H 2.63 0.474 4533.658 1266.342 305 WELD 2-BB-02-S010-G 2.63 0.482 4533.666 1266.334 306 WELD 2-BB-02-S010-F 2.63 0.852 4534.036 1265.964 307 WELD 2-BB-02-FW25 2.63 0.594 4533.778 1266.222 308 WELD 2-BB-02-FW3 2.63 0.990 4534.174 1265.826 309 WELD 2-BB-04-S002-D 3.44 1.542 4534.726 1265.274 310 WELD 2-BB-04-FW6 3.44 1.391 4534.575 1265.425 311 WELD 2-BB-04-S002-B 3.44 1.370 4534.554 1265.446 312 WELD 2-BB-04-F004 3.44 1.626 4534.810 1265.190 313 WELD 2-BB-04-S002-M 5.19 4.454 4537.638 1262.362 314 WELD 2-BB-04-S002-K 5.19 47.749 4580.933 1219.067 315 WELD 2-BB-04-S002-J 5.19 45.291 4578.475 1221.525 316 WELD 2-BB-04-S002-E 5.19 15.577 4548.761 1251.239 317 WELD 2-BB-04-F003 5.19 46.819 4580.003 1219.997 318 WELD 2-BB-04-S011-M 5.19 45.736 4578.920 1221.080 319 WELD 2-BB-04-S011-L 5.19 38.807 4571.991 1228.009 320 WELD 2-BB-04-S011-J 5.19 4.467 4537.651 1262.349 321 WELD 2-BB-04-S011-H 5.19 3.119 4536.303 1263.697 322 WELD 2-BB-04-S011-D 5.19 3.040 4536.224 1263.776 323 WELD 2-BB-04-S011-C 3.44 1.240 4534.424 1265.576 324 WELD 2-BB-04-FW5 3.44 1.123 4534.307 1265.693 325 WELD 2-BB-04-S011-A 3.44 1.136 4534.320 1265.680 326 WELD 2-BB-04-F014 3.44 1.169 4534.353 1265.647 327 WELD 2-BB-01-S402-4 10.50 86.547 4619.731 1180.269 328 WELD 2-BB-01-S402-3 11.19 125.406 4658.590 1141.410 329 WELD 2-RV-301-121-D 29.00 125.324 4658.508 1141.492 330 WELD 2-BB-01-F403 29.00 116.127 4649.311 1150.689 331 WELD 2-BB-01-S402-2 29.00 1032.108 5565.292 234.708 332 WELD 2-BB-01-3065D-WDC-001-FW1 29.00 1004.506 5537.690 262.310 333 WELD EBB01D-RSG-INLET-SC010 29.00 1002.198 5535.382 264.618 334 WELD 2-BB-01-S401-7 8.75 62.584 4595.768 1204.232 335 WELD 2-BB-01-S401-3 1.69 1.027 4534.211 1265.789 336 WELD 2-BB-01-S401-4 2.12 1.658 4534.842 1265.158 337 WELD 2-RV-302-121-D 27.50 62.282 4595.466 1204.534 338 WELD 2-BB-01-F402 27.50 67.804 4600.988 1199.012 339 WELD 2-BB-01-S401-2 27.50 84.482 4617.666 1182.334 340 WELD 2-BB-01-F401 27.50 769.705 5302.889 497.111 341 WELD 2-BB-15-F006 2.63 2.250 4535.434 1264.566

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 52 of 60 DEGB Qualified Total Inside Coatings Particulate Particulate

1. Weld Location Name Diameter Transported Transported Margin Size at DEGB at DEGB (lbm)

(inches) Size (lbm) Size (lbm) 342 WELD 2-BB-15-F001 2.63 2.274 4535.458 1264.542 343 WELD 2-BB-01-S405-5 2.63 2.351 4535.535 1264.465 344 WELD 2-BB-01-S405-6 1.69 1.368 4534.552 1265.448 345 WELD EBB01D-RSG-OUTLET-SC010 31.00 1016.714 5549.898 250.102 346 WELD 2-BB-01-3065D-WDC-002-FW2 31.00 1016.794 5549.978 250.022 347 WELD 2-BB-01-F406 31.00 1015.553 5548.737 251.263 348 WELD 2-BB-01-S404-3 31.00 1020.436 5553.620 246.380 349 WELD 2-BB-01-F408 31.00 956.658 5489.842 310.158 350 WELD 2-BB-01-S405-4 31.00 888.856 5422.040 377.960 351 WELD 2-BB-01-F407 31.00 873.405 5406.589 393.411 352 WELD 2-EP-01-F019 8.75 57.528 4590.712 1209.288 353 WELD 2-EP-01-S010-C 8.75 101.538 4634.722 1165.278 354 WELD 2-EP-01-S010-D 8.75 87.944 4621.128 1178.872 355 WELD 2-EP-01-S010-E 8.75 82.721 4615.905 1184.095 356 WELD 2-EP-01-F020 8.75 76.369 4609.553 1190.447 357 WELD 2-EJ-04-S016-F 5.19 23.383 4556.567 1243.433 358 WELD 2-EJ-04-F029 5.19 25.022 4558.206 1241.794 359 WELD 2-EM-05-S005-C 5.19 22.924 4556.108 1243.892 360 WELD 2-EM-05-S005-B 5.19 19.624 4552.808 1247.192 361 WELD 2-EM-05-F004 5.19 17.310 4550.494 1249.506 362 WELD 2-EJ-04-F026 10.50 80.907 4614.091 1185.909 363 WELD 2-EJ-04-S016-B 10.50 78.882 4612.066 1187.934 364 WELD 2-EJ-04-S016-C 10.50 76.562 4609.746 1190.254 365 WELD 2-EJ-04-S016-D 10.50 76.914 4610.098 1189.902 366 WELD 2-EJ-04-S016-E 10.50 69.639 4602.823 1197.177 367 WELD 2-EJ-04-S016-G 10.50 72.057 4605.241 1194.759 368 WELD 2-EJ-04-S016-H 10.50 80.408 4613.592 1186.408 369 WELD 2-EJ-04-F025 10.50 95.112 4628.296 1171.704 370 WELD 2-BB-07-FW004 1.34 0.732 4533.916 1266.084 371 WELD 2-BB-07-FW003 1.34 0.642 4533.826 1266.174 372 WELD 2-BB-07-FW002 1.34 0.561 4533.745 1266.255 373 WELD 2-BB-07-FW001 1.34 0.288 4533.472 1266.528 374 WELD 2-BB-07-FW005 1.69 1.359 4534.543 1265.457 375 WELD 2-BB-07-FW006 1.69 1.327 4534.511 1265.489 376 WELD 2-BB-07-FW007 1.69 1.403 4534.587 1265.413 377 WELD 2-BB-07-FW008 1.69 1.175 4534.359 1265.641 378 WELD 2-BB-07-FW011 1.69 1.028 4534.212 1265.788 379 WELD 2-BB-07-FW012 1.69 0.722 4533.906 1266.094 380 WELD 2-BB-07-FW013 1.69 0.484 4533.668 1266.332 381 WELD 2-BB-07-FW014 1.69 0.198 4533.382 1266.618 382 WELD 2-BB-07-FW019 1.69 0.198 4533.382 1266.618 383 WELD 2-BB-07-FW020 1.69 0.223 4533.407 1266.593 384 WELD 2-BB-07-FW021 1.69 0.220 4533.404 1266.596 385 WELD 2-BB-07-FW022 1.69 3.491 4536.675 1263.325 386 WELD 2-BB-07-FW023 1.69 3.643 4536.827 1263.173 387 WELD 2-BB-07-FW024 1.69 2.783 4535.967 1264.033 388 WELD 2-BB-07-FW029 1.69 1.772 4534.956 1265.044 389 WELD 2-BB-07-V211-2 1.69 1.312 4534.496 1265.504 390 WELD 2-BG-21-F026 2.63 1.584 4534.768 1265.232

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 53 of 60 DEGB Qualified Total Inside Coatings Particulate Particulate

1. Weld Location Name Diameter Transported Transported Margin Size at DEGB at DEGB (lbm)

(inches) Size (lbm) Size (lbm) 391 WELD 2-BG-21-F027 2.63 2.030 4535.214 1264.786 392 WELD 2-BB-01-S401-5 2.63 2.692 4535.876 1264.124 393 WELD 2-BG-23-FW144 1.69 0.299 4533.483 1266.517 394 WELD 2-BG-23-FW-3 1.69 0.329 4533.513 1266.487 395 WELD 2-BG-23-FW-4 1.69 0.419 4533.603 1266.397 396 WELD 2-BG-23-FW-5 1.69 0.389 4533.573 1266.427 397 WELD 2-BG-23-FW145 1.69 0.238 4533.422 1266.578 398 WELD 2-BG-23-FW149 1.69 0.411 4533.595 1266.405 399 WELD 2-BG-23-FW148 1.69 0.410 4533.594 1266.406 400 WELD 2-BG-23-FW143 1.69 0.399 4533.583 1266.417 401 WELD 2-BG-23-A175752A-FW02 1.69 0.472 4533.656 1266.344 402 WELD 2-BG-23-A175752A-FW01 1.69 0.663 4533.847 1266.153 403 WELD 2-BG-23-FW138 1.69 1.858 4535.042 1264.958 404 WELD 2-BG-22-F025 2.63 0.480 4533.664 1266.336 405 WELD 2-BG-22-S020-A 2.63 0.483 4533.667 1266.333 406 WELD 2-BG-22-S020-B 2.63 0.482 4533.666 1266.334 407 WELD 2-BG-22-F026 2.63 0.570 4533.754 1266.246 408 WELD 2-BG-23-FW150 1.69 0.338 4533.522 1266.478 409 WELD 2-BG-23-FW151 1.69 0.277 4533.461 1266.539 410 WELD 2-BG-23-FW152 1.69 0.262 4533.446 1266.554 411 WELD 2-BG-23-FW153 1.69 0.294 4533.478 1266.522 10.4 Full Isolable Weld List This section contains the full weld list for isolable welds. Table 10-4 lists the weld location name, the corresponding pipe diameter (DEGB size), the amount of fiber transported by a DEGB, the fiber margin (the difference between the RoverD failure threshold and the amount of fiber transported), and the 25-year CDF contributions for each isolable weld before and after applying the isolation valve failure probability. All per weld contributions to CDF are based on geometric aggregation and the 25-year NUREG-1829 frequencies at the smallest critical break size. Welds that do not exceed the RoverD limit for a DEGB are not deemed critical welds, have a negative difference from threshold (i.e., positive fiber margin), and do not contribute to mean CDF. Note that the per weld contributions to CDF in the last two columns sum to the mean CDF values reported for isolable welds reported in Table 8-1.

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 54 of 60 Table 10-4: Full isolable weld list DEGB Fiber Inside Fiber Contribution Contribution Transported

1. Weld Location Name Diameter Margin to GM CDF to GM CDF at DEGB Size (lbm) (Unweighted) (Weighted)

Size (lbm)

(inches) 1 AFIVWELD 2-HB-24-FW063 1.690 80.627 219.373 0.00E+00 0.00E+00 2 AFIVWELD 2-HB-24-FW062 1.690 80.163 219.837 0.00E+00 0.00E+00 3 AFIVWELD 2-BG-21-F012 2.630 83.157 216.843 0.00E+00 0.00E+00 4 AFIVWELD 2-BG-21-S009-B 2.630 82.887 217.113 0.00E+00 0.00E+00 5 AFIVWELD 2-BG-21-S009-A 2.630 82.773 217.227 0.00E+00 0.00E+00 6 AFIVWELD 2-BG-21-F011 2.630 82.939 217.061 0.00E+00 0.00E+00 7 AFIVWELD 2-BB-11-V151-1 1.690 79.806 220.194 0.00E+00 0.00E+00 8 AFIVWELD 2-BB-11-FW017 1.690 79.811 220.189 0.00E+00 0.00E+00 9 AFIVWELD 2-BB-11-V150-2 1.690 79.979 220.021 0.00E+00 0.00E+00 10 AFIVWELD 2-BB-08-V121-1 1.690 78.800 221.200 0.00E+00 0.00E+00 11 AFIVWELD 2-BB-08-FW054 1.690 78.800 221.200 0.00E+00 0.00E+00 12 AFIVWELD 2-BB-08-V120-2 1.690 78.800 221.200 0.00E+00 0.00E+00 13 AFIVWELD 2-EM-05-FW099 1.690 85.923 214.077 0.00E+00 0.00E+00 14 AFIVWELD 2-EM-05-FW098 1.690 85.497 214.503 0.00E+00 0.00E+00 15 AFIVWELD 2-EM-05-FW109 1.690 85.595 214.405 0.00E+00 0.00E+00 16 AFIVWELD 2-EM-05-FW9 1.690 82.485 217.515 0.00E+00 0.00E+00 17 AFIVWELD 2-EM-05-BB8949E-2 1.690 81.029 218.971 0.00E+00 0.00E+00 18 AFIVWELD 2-HB-24-FW080 1.690 80.706 219.294 0.00E+00 0.00E+00 19 AFIVWELD 2-HB-24-FW081 1.690 80.550 219.450 0.00E+00 0.00E+00 20 AFIVWELD 2-HB-24-FW083-C 1.690 80.428 219.572 0.00E+00 0.00E+00 21 AFIVWELD 2-HB-24-FW084 1.690 80.217 219.783 0.00E+00 0.00E+00 22 AFIVWELD 2-EM-05-W566538-F005 5.190 132.252 167.748 0.00E+00 0.00E+00 23 AFIVWELD 2-EM-05-S006-B 5.190 141.226 158.774 0.00E+00 0.00E+00 24 AFIVWELD 2-HB-24-FW049 1.690 80.380 219.620 0.00E+00 0.00E+00 25 AFIVWELD 2-HB-24-FW050 1.690 81.838 218.162 0.00E+00 0.00E+00 26 AFIVWELD 2-BB-09-V181-1 1.690 81.302 218.698 0.00E+00 0.00E+00 27 AFIVWELD 2-BB-09-FW140 1.690 82.534 217.466 0.00E+00 0.00E+00 28 AFIVWELD 2-BB-09-V180-2 1.690 84.171 215.829 0.00E+00 0.00E+00 29 AFIVWELD 2-BB-02-F018-A 2.630 78.800 221.200 0.00E+00 0.00E+00 30 AFIVWELD 2-BB-02-F019 2.630 78.800 221.200 0.00E+00 0.00E+00 31 AFIVWELD 2-BB-02-F012 2.630 78.800 221.200 0.00E+00 0.00E+00 32 AFIVWELD 2-BB-02-F011 2.630 78.800 221.200 0.00E+00 0.00E+00 33 AFIVWELD 2-BB-07-V211-1 1.690 78.800 221.200 0.00E+00 0.00E+00 34 AFIVWELD 2-BB-07-FW030 1.690 78.800 221.200 0.00E+00 0.00E+00 35 AFIVWELD 2-BB-07-V210-2 1.690 78.800 221.200 0.00E+00 0.00E+00 36 AFIVWELD 2-BG-21-F024 2.630 87.894 212.106 0.00E+00 0.00E+00 37 AFIVWELD 2-BG-21-S019-A 2.630 91.176 208.824 0.00E+00 0.00E+00 38 AFIVWELD 2-BG-21-S019-B 2.630 91.133 208.867 0.00E+00 0.00E+00 39 AFIVWELD 2-BG-21-S019-C 2.630 87.151 212.849 0.00E+00 0.00E+00 40 AFIVWELD 2-BG-21-S019-D 2.630 88.893 211.107 0.00E+00 0.00E+00 41 AFIVWELD 2-BG-21-F025 2.630 93.327 206.673 0.00E+00 0.00E+00 42 AFIVWELD 2-BG-23-FW146 1.690 80.983 219.017 0.00E+00 0.00E+00 43 AFIVWELD 2-BG-23-FW147 1.690 80.205 219.795 0.00E+00 0.00E+00 44 AFIVWELD 2-BG-22-F027 2.630 82.499 217.501 0.00E+00 0.00E+00 45 AFIVWELD 2-BG-22-F028 2.630 82.860 217.140 0.00E+00 0.00E+00 46 AFIVWELD 2-BG-24-FW061 1.690 81.139 218.861 0.00E+00 0.00E+00 47 AFIVWELD 2-BG-24-BB-V084-1 1.690 81.139 218.861 0.00E+00 0.00E+00

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 55 of 60 DEGB Fiber Inside Fiber Contribution Contribution Transported

1. Weld Location Name Diameter Margin to GM CDF to GM CDF at DEGB Size (lbm) (Unweighted) (Weighted)

Size (lbm)

(inches) 48 AFIVWELD 2-EP-02-8818B-1 5.190 93.514 206.486 0.00E+00 0.00E+00 49 AFIVWELD 2-EP-01-8818A-1 5.190 98.998 201.002 0.00E+00 0.00E+00 50 AFIVWELD 2-EJ-04-F032 10.500 436.815 -136.815 2.17E-09 2.41E-12 51 AFIVWELD 2-EJ-04-S019-D 10.500 409.533 -109.533 4.78E-10 5.30E-13 52 AFIVWELD 2-EJ-04-FW7 10.500 408.380 -108.380 3.21E-09 3.56E-12 53 AFIVWELD 2-EJ-04-S019-F 10.500 416.886 -116.886 3.86E-09 4.28E-12 54 AFIVWELD 2-EJ-04-F033 10.500 410.195 -110.195 0.00E+00 0.00E+00 55 AFIVWELD 2-EJ-04-F034 10.500 224.764 75.236 0.00E+00 0.00E+00 56 AFIVWELD 2-EJ-04-S037-A 10.500 212.222 87.778 0.00E+00 0.00E+00 57 AFIVWELD 2-EJ-04-S037-B 10.500 167.932 132.068 0.00E+00 0.00E+00 58 AFIVWELD 2-EJ-04-S037-C 10.500 163.056 136.944 0.00E+00 0.00E+00 59 AFIVWELD 2-EJ-04-F048 10.500 163.933 136.067 0.00E+00 0.00E+00 60 AFIVWELD 2-EP-02-8818C-1 5.190 100.117 199.883 0.00E+00 0.00E+00 61 AFIVWELD 2-EJ-04-S015-E 10.500 372.189 -72.189 0.00E+00 0.00E+00 62 AFIVWELD 2-EJ-04-S015-C 10.500 181.500 118.500 0.00E+00 0.00E+00 63 AFIVWELD 2-EJ-04-F023 10.500 180.166 119.834 0.00E+00 0.00E+00 64 AFIVWELD 2-EJ-04-S014-C 10.500 178.584 121.416 0.00E+00 0.00E+00 65 AFIVWELD 2-EJ-04-S014-D 10.500 168.162 131.838 0.00E+00 0.00E+00 66 AFIVWELD 2-EJ-04-F022 10.500 168.542 131.458 0.00E+00 0.00E+00 67 AFIVWELD 2-EJ-04-S013-B 10.500 169.887 130.113 0.00E+00 0.00E+00 68 AFIVWELD 2-EJ-04-F021 10.500 173.843 126.157 0.00E+00 0.00E+00 69 AFIVWELD 2-EJ-04-F024 10.500 452.401 -152.401 1.57E-09 1.74E-12 70 AFIVWELD 2-EP-01-8818D-1 5.190 105.762 194.238 0.00E+00 0.00E+00 71 AFIVWELD 2-EM-03-S003-F 1.340 81.439 218.561 0.00E+00 0.00E+00 72 AFIVWELD 2-EM-03-FW270 1.340 81.369 218.631 0.00E+00 0.00E+00 73 AFIVWELD 2-EM-03-FW271 1.340 80.203 219.797 0.00E+00 0.00E+00 74 AFIVWELD 2-EM-03-FW207 1.340 80.180 219.820 0.00E+00 0.00E+00 75 AFIVWELD 2-EM-03-FW208 1.340 80.215 219.785 0.00E+00 0.00E+00 76 AFIVWELD 2-EM-03-FW209 1.340 80.216 219.784 0.00E+00 0.00E+00 77 AFIVWELD 2-EM-03-FW210 1.340 80.593 219.407 0.00E+00 0.00E+00 78 AFIVWELD 2-EM-03-FW215 1.340 80.184 219.816 0.00E+00 0.00E+00 79 AFIVWELD 2-EM-03-FW078 1.340 80.873 219.127 0.00E+00 0.00E+00 80 AFIVWELD 2-EM-03-FW079 1.340 80.521 219.479 0.00E+00 0.00E+00 81 AFIVWELD 2-EM-03-FW216 1.340 80.843 219.157 0.00E+00 0.00E+00 82 AFIVWELD 2-EM-03-FW221 1.340 80.774 219.226 0.00E+00 0.00E+00 83 AFIVWELD 2-EM-03-FW222 1.340 80.202 219.798 0.00E+00 0.00E+00 84 AFIVWELD 2-EM-03-FW082 1.340 80.059 219.941 0.00E+00 0.00E+00 85 AFIVWELD 2-EM-03-FW223 1.340 80.389 219.611 0.00E+00 0.00E+00 86 AFIVWELD 2-EM-03-FW224 1.340 81.712 218.288 0.00E+00 0.00E+00 87 AFIVWELD 2-EM-03-BBV059-1 1.340 81.497 218.503 0.00E+00 0.00E+00 88 AFIVWELD 2-EM-03-BBV040-1 1.340 80.312 219.688 0.00E+00 0.00E+00 89 AFIVWELD 2-EM-03-FW257 1.340 80.376 219.624 0.00E+00 0.00E+00 90 AFIVWELD 2-EM-03-FW256 1.340 80.464 219.536 0.00E+00 0.00E+00 91 AFIVWELD 2-EM-03-FW251 1.340 80.384 219.616 0.00E+00 0.00E+00 92 AFIVWELD 2-EM-03-FW250 1.340 81.119 218.881 0.00E+00 0.00E+00 93 AFIVWELD 2-EM-03-FW115 1.340 80.146 219.854 0.00E+00 0.00E+00 94 AFIVWELD 2-EM-03-FW114 1.340 80.146 219.854 0.00E+00 0.00E+00 95 AFIVWELD 2-EM-03-FW113 1.340 81.507 218.493 0.00E+00 0.00E+00 96 AFIVWELD 2-EM-03-FW249 1.340 80.031 219.969 0.00E+00 0.00E+00

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 56 of 60 DEGB Fiber Inside Fiber Contribution Contribution Transported

1. Weld Location Name Diameter Margin to GM CDF to GM CDF at DEGB Size (lbm) (Unweighted) (Weighted)

Size (lbm)

(inches) 97 AFIVWELD 2-EM-03-FW248 1.340 80.408 219.592 0.00E+00 0.00E+00 98 AFIVWELD 2-EM-03-FW243 1.340 80.910 219.090 0.00E+00 0.00E+00 99 AFIVWELD 2-EM-03-FW242 1.340 80.298 219.702 0.00E+00 0.00E+00 100 AFIVWELD 2-EM-03-FW241 1.340 80.310 219.690 0.00E+00 0.00E+00 101 AFIVWELD 2-EM-03-FW240 1.340 80.257 219.743 0.00E+00 0.00E+00 102 AFIVWELD 2-EM-03-FW275 1.340 80.249 219.751 0.00E+00 0.00E+00 103 AFIVWELD 2-EM-03-FW274 1.340 81.796 218.204 0.00E+00 0.00E+00 104 AFIVWELD 2-EM-03-S003-N 1.340 81.752 218.248 0.00E+00 0.00E+00 105 AFIVWELD 2-EM-03-S003-P 2.630 85.017 214.983 0.00E+00 0.00E+00 106 AFIVWELD 2-EM-03-S003-M 2.630 84.807 215.193 0.00E+00 0.00E+00 107 AFIVWELD 2-EM-03-S003-L 2.630 84.325 215.675 0.00E+00 0.00E+00 108 AFIVWELD 2-EM-03-S003-K 2.630 83.630 216.370 0.00E+00 0.00E+00 109 AFIVWELD 2-EM-03-S003-J 2.630 83.303 216.697 0.00E+00 0.00E+00 110 AFIVWELD 2-EM-03-FW2 2.630 83.580 216.420 0.00E+00 0.00E+00 111 AFIVWELD 2-EM-03-S003-D 2.630 83.566 216.434 0.00E+00 0.00E+00 112 AFIVWELD 2-EM-03-S003-B 2.630 84.012 215.988 0.00E+00 0.00E+00 113 AFIVWELD 2-EM-03-F003 2.630 83.623 216.377 0.00E+00 0.00E+00 114 AFIVWELD 2-EM-03-FW3 2.630 82.484 217.516 0.00E+00 0.00E+00 115 AFIVWELD 2-EM-03-F002 2.630 82.217 217.783 0.00E+00 0.00E+00 116 AFIVWELD 2-EM-03-W237498-FW02 5.190 116.051 183.949 0.00E+00 0.00E+00 117 AFIVWELD 2-EM-03-W237498-FW01 5.190 111.016 188.984 0.00E+00 0.00E+00 118 AFIVWELD 2-EM-03-S011-G 5.190 108.669 191.331 0.00E+00 0.00E+00 119 AFIVWELD 2-EM-03-S011-F 5.190 108.464 191.536 0.00E+00 0.00E+00 120 AFIVWELD 2-EM-03-S011-D 5.190 109.302 190.698 0.00E+00 0.00E+00 121 AFIVWELD 2-EM-03-S011-C 5.190 109.925 190.075 0.00E+00 0.00E+00 122 AFIVWELD 2-EM-03-FW-1 5.190 118.067 181.933 0.00E+00 0.00E+00 123 AFIVWELD 2-EM-03-S011-B 5.190 113.535 186.465 0.00E+00 0.00E+00 124 AFIVWELD 2-EM-03-F009 5.190 110.808 189.192 0.00E+00 0.00E+00 125 AFIVWELD 2-EJ-04-F014 5.190 93.713 206.287 0.00E+00 0.00E+00 126 AFIVWELD 2-EM-03-S013-B 1.690 84.422 215.578 0.00E+00 0.00E+00 127 AFIVWELD 2-EM-03-FW170 1.690 84.671 215.329 0.00E+00 0.00E+00 128 AFIVWELD 2-EM-03-FW169 1.690 80.745 219.255 0.00E+00 0.00E+00 129 AFIVWELD 2-EM-03-FW353 1.690 81.668 218.332 0.00E+00 0.00E+00 130 AFIVWELD 2-EM-03-FW352 1.690 81.820 218.180 0.00E+00 0.00E+00 131 AFIVWELD 2-EM-03-FW351 1.690 82.051 217.949 0.00E+00 0.00E+00 132 AFIVWELD 2-EM-03-FW345 1.690 81.976 218.024 0.00E+00 0.00E+00 133 AFIVWELD 2-EM-03-FW344 1.690 80.768 219.232 0.00E+00 0.00E+00 134 AFIVWELD 2-EM-03-V002-2 1.690 80.495 219.505 0.00E+00 0.00E+00 135 AFIVWELD 2-EM-03-S010-B 1.690 84.392 215.608 0.00E+00 0.00E+00 136 AFIVWELD 2-EM-03-FW153 1.690 84.572 215.428 0.00E+00 0.00E+00 137 AFIVWELD 2-EM-03-FW321 1.690 81.514 218.486 0.00E+00 0.00E+00 138 AFIVWELD 2-EM-03-FW320 1.690 81.599 218.401 0.00E+00 0.00E+00 139 AFIVWELD 2-EM-03-FW319 1.690 81.432 218.568 0.00E+00 0.00E+00 140 AFIVWELD 2-EM-03-FW313 1.690 81.238 218.762 0.00E+00 0.00E+00 141 AFIVWELD 2-EM-03-FW312 1.690 80.477 219.523 0.00E+00 0.00E+00 142 AFIVWELD 2-EM-03-V001-2 1.690 80.281 219.719 0.00E+00 0.00E+00 143 AFIVWELD 2-EM-03-BBV022-1 1.340 81.121 218.879 0.00E+00 0.00E+00 144 AFIVWELD 2-EM-03-FW267 1.340 81.161 218.839 0.00E+00 0.00E+00 145 AFIVWELD 2-EM-03-FW266 1.340 81.375 218.625 0.00E+00 0.00E+00

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 57 of 60 DEGB Fiber Inside Fiber Contribution Contribution Transported

1. Weld Location Name Diameter Margin to GM CDF to GM CDF at DEGB Size (lbm) (Unweighted) (Weighted)

Size (lbm)

(inches) 146 AFIVWELD 2-EM-03-FW265 1.340 81.614 218.386 0.00E+00 0.00E+00 147 AFIVWELD 2-EM-03-FW264 1.340 80.310 219.690 0.00E+00 0.00E+00 148 AFIVWELD 2-EM-03-FW263 1.340 80.309 219.691 0.00E+00 0.00E+00 149 AFIVWELD 2-EM-03-FW262 1.340 80.257 219.743 0.00E+00 0.00E+00 150 AFIVWELD 2-EM-03-FW261 1.340 80.197 219.803 0.00E+00 0.00E+00 151 AFIVWELD 2-EM-03-FW260 1.340 81.526 218.474 0.00E+00 0.00E+00 152 AFIVWELD 2-EM-03-BBV001-1 1.340 80.794 219.206 0.00E+00 0.00E+00 153 AFIVWELD 2-EM-03-FW233 1.340 80.873 219.127 0.00E+00 0.00E+00 154 AFIVWELD 2-EM-03-FW232 1.340 80.794 219.206 0.00E+00 0.00E+00 155 AFIVWELD 2-EM-03-FW094 1.340 80.674 219.326 0.00E+00 0.00E+00 156 AFIVWELD 2-EM-03-FW231 1.340 80.233 219.767 0.00E+00 0.00E+00 157 AFIVWELD 2-EM-03-FW230 1.340 80.224 219.776 0.00E+00 0.00E+00 158 AFIVWELD 2-EM-03-FW229 1.340 80.223 219.777 0.00E+00 0.00E+00 159 AFIVWELD 2-EM-03-FW228 1.340 80.180 219.820 0.00E+00 0.00E+00 160 AFIVWELD 2-EM-03-FW273 1.340 80.434 219.566 0.00E+00 0.00E+00 161 AFIVWELD 2-EM-03-FW272 1.340 81.430 218.570 0.00E+00 0.00E+00 162 AFIVWELD 2-EM-03-S003-G 1.340 81.439 218.561 0.00E+00 0.00E+00 163 AFIVWELD 2-EM-05-BB8949E-1 1.690 80.833 219.167 0.00E+00 0.00E+00 164 AFIVWELD 2-EM-05-FW086 1.690 80.728 219.272 0.00E+00 0.00E+00 165 AFIVWELD 2-EM-05-FW084 1.690 81.505 218.495 0.00E+00 0.00E+00 166 AFIVWELD 2-EM-05-FW083 1.690 81.639 218.361 0.00E+00 0.00E+00 167 AFIVWELD 2-EM-05-FW082 1.690 81.187 218.813 0.00E+00 0.00E+00 168 AFIVWELD 2-EM-05-FW076 1.690 81.067 218.933 0.00E+00 0.00E+00 169 AFIVWELD 2-EM-05-FW075 1.690 80.695 219.305 0.00E+00 0.00E+00 170 AFIVWELD 2-EM-05-V003-2 1.690 80.574 219.426 0.00E+00 0.00E+00 171 AFIVWELD 2-EM-03-F014 5.190 113.299 186.701 0.00E+00 0.00E+00 172 AFIVWELD 2-EM-03-FW5 5.190 108.657 191.343 0.00E+00 0.00E+00 173 AFIVWELD 2-EM-03-S014-C 5.190 111.498 188.502 0.00E+00 0.00E+00 174 AFIVWELD 2-EM-03-FW4 5.190 121.945 178.055 0.00E+00 0.00E+00 175 AFIVWELD 2-EM-03-F013 5.190 117.736 182.264 0.00E+00 0.00E+00 176 AFIVWELD 2-EJ-04-F017 5.190 92.631 207.369 0.00E+00 0.00E+00 177 AFIVWELD 2-EM-05-FW005 1.690 81.684 218.316 0.00E+00 0.00E+00 178 AFIVWELD 2-EM-05-FW006 1.690 80.848 219.152 0.00E+00 0.00E+00 179 AFIVWELD 2-EM-05-FW007 1.690 80.730 219.270 0.00E+00 0.00E+00 180 AFIVWELD 2-EM-05-FW008 1.690 81.077 218.923 0.00E+00 0.00E+00 181 AFIVWELD 2-EM-05-FW013 1.690 81.187 218.813 0.00E+00 0.00E+00 182 AFIVWELD 2-EM-05-FW016 1.690 82.547 217.453 0.00E+00 0.00E+00 183 AFIVWELD 2-EM-05-FW017 1.690 82.482 217.518 0.00E+00 0.00E+00 184 AFIVWELD 2-EM-05-FW018 1.690 82.596 217.404 0.00E+00 0.00E+00 185 AFIVWELD 2-EM-05-FW024 1.690 82.614 217.386 0.00E+00 0.00E+00 186 AFIVWELD 2-EM-05-FW025 1.690 82.297 217.703 0.00E+00 0.00E+00 187 AFIVWELD 2-EM-05-V004-2 1.690 82.124 217.876 0.00E+00 0.00E+00 188 AFIVWELD 2-EM-05-F003 5.190 151.639 148.361 0.00E+00 0.00E+00 189 AFIVWELD 2-EM-05-S004-B 5.190 154.985 145.015 0.00E+00 0.00E+00 190 AFIVWELD 2-EP-02-F006 8.750 216.123 83.877 0.00E+00 0.00E+00 191 AFIVWELD 2-EP-02-S003-M 8.750 210.728 89.272 0.00E+00 0.00E+00 192 AFIVWELD 2-EP-02-S003-L 8.750 214.921 85.079 0.00E+00 0.00E+00 193 AFIVWELD 2-EP-02-S003-J 8.750 265.551 34.449 0.00E+00 0.00E+00 194 AFIVWELD 2-EP-02-S003-H 8.750 265.445 34.555 0.00E+00 0.00E+00

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 58 of 60 DEGB Fiber Inside Fiber Contribution Contribution Transported

1. Weld Location Name Diameter Margin to GM CDF to GM CDF at DEGB Size (lbm) (Unweighted) (Weighted)

Size (lbm)

(inches) 195 AFIVWELD 2-EP-02-S003-G 8.750 248.277 51.723 0.00E+00 0.00E+00 196 AFIVWELD 2-EP-02-S003-F 8.750 236.195 63.805 0.00E+00 0.00E+00 197 AFIVWELD 2-EP-02-S003-E 8.750 208.442 91.558 0.00E+00 0.00E+00 198 AFIVWELD 2-EP-02-S003-D 8.750 201.957 98.043 0.00E+00 0.00E+00 199 AFIVWELD 2-EP-02-F005 8.750 189.919 110.081 0.00E+00 0.00E+00 200 AFIVWELD 2-EP-02-8818B-2 5.190 94.490 205.510 0.00E+00 0.00E+00 201 AFIVWELD 2-EP-02-3066B-WDC-001-FW1 5.190 94.759 205.241 0.00E+00 0.00E+00 202 AFIVWELD 2-EP-02-S005-G 5.190 98.671 201.329 0.00E+00 0.00E+00 203 AFIVWELD 2-EP-02-FW4 5.190 114.274 185.726 0.00E+00 0.00E+00 204 AFIVWELD 2-EP-02-FW3 5.190 115.926 184.074 0.00E+00 0.00E+00 205 AFIVWELD 2-EP-02-S005-D 5.190 125.110 174.890 0.00E+00 0.00E+00 206 AFIVWELD 2-EP-02-F009 5.190 139.905 160.095 0.00E+00 0.00E+00 207 AFIVWELD 2-EP-02-V020-2 1.690 81.896 218.104 0.00E+00 0.00E+00 208 AFIVWELD 2-EP-02-FW010 1.690 81.983 218.017 0.00E+00 0.00E+00 209 AFIVWELD 2-EP-02-FW009 1.690 82.089 217.911 0.00E+00 0.00E+00 210 AFIVWELD 2-EP-02-FW008 1.690 82.024 217.976 0.00E+00 0.00E+00 211 AFIVWELD 2-EP-02-FW007 1.690 81.907 218.093 0.00E+00 0.00E+00 212 AFIVWELD 2-EP-02-FW006 1.690 81.770 218.230 0.00E+00 0.00E+00 213 AFIVWELD 2-EP-02-FW005 1.690 84.146 215.854 0.00E+00 0.00E+00 214 AFIVWELD 2-EP-02-S005-B 1.690 83.910 216.090 0.00E+00 0.00E+00 215 AFIVWELD 2-EP-01-F012 5.190 142.220 157.780 0.00E+00 0.00E+00 216 AFIVWELD 2-EP-01-S006-B 5.190 128.887 171.113 0.00E+00 0.00E+00 217 AFIVWELD 2-EP-01-F011 5.190 119.445 180.555 0.00E+00 0.00E+00 218 AFIVWELD 2-EP-01-FW5 5.190 100.343 199.657 0.00E+00 0.00E+00 219 AFIVWELD 2-EP-01-S005-E 5.190 99.674 200.326 0.00E+00 0.00E+00 220 AFIVWELD 2-EP-01-S005-D 5.190 99.791 200.209 0.00E+00 0.00E+00 221 AFIVWELD 2-EP-01-S005-C 5.190 95.510 204.490 0.00E+00 0.00E+00 222 AFIVWELD 2-EP-01-S005-B 5.190 95.640 204.360 0.00E+00 0.00E+00 223 AFIVWELD 2-EP-01-3066A-WDC-002-FW2 5.190 97.279 202.721 0.00E+00 0.00E+00 224 AFIVWELD 2-EP-01-3066A-WDC-003-FW3 5.190 98.251 201.749 0.00E+00 0.00E+00 225 AFIVWELD 2-EP-01-8818A-2 5.190 98.388 201.612 0.00E+00 0.00E+00 226 AFIVWELD 2-EP-01-F006 8.750 218.262 81.738 0.00E+00 0.00E+00 227 AFIVWELD 2-EP-01-S003-L 8.750 212.093 87.907 0.00E+00 0.00E+00 228 AFIVWELD 2-EP-01-FW3 8.750 214.413 85.587 0.00E+00 0.00E+00 229 AFIVWELD 2-EP-01-S003-H 8.750 262.348 37.652 0.00E+00 0.00E+00 230 AFIVWELD 2-EP-01-S003-G 8.750 260.829 39.171 0.00E+00 0.00E+00 231 AFIVWELD 2-EP-01-S003-F 8.750 266.997 33.003 0.00E+00 0.00E+00 232 AFIVWELD 2-EP-01-S003-E 8.750 256.198 43.802 0.00E+00 0.00E+00 233 AFIVWELD 2-EP-01-S003-D 8.750 225.784 74.216 0.00E+00 0.00E+00 234 AFIVWELD 2-EP-01-S003-C 8.750 220.440 79.560 0.00E+00 0.00E+00 235 AFIVWELD 2-EP-01-F005 8.750 221.448 78.552 0.00E+00 0.00E+00 236 AFIVWELD 2-EP-01-S005-F 1.690 85.121 214.879 0.00E+00 0.00E+00 237 AFIVWELD 2-EP-01-FW049 1.690 84.776 215.224 0.00E+00 0.00E+00 238 AFIVWELD 2-EP-01-FW050 1.690 82.431 217.569 0.00E+00 0.00E+00 239 AFIVWELD 2-EP-01-FW051 1.690 82.083 217.917 0.00E+00 0.00E+00 240 AFIVWELD 2-EP-01-FW052 1.690 81.865 218.135 0.00E+00 0.00E+00 241 AFIVWELD 2-EP-01-FW053 1.690 81.572 218.428 0.00E+00 0.00E+00 242 AFIVWELD 2-EP-01-FW054 1.690 81.422 218.578 0.00E+00 0.00E+00 243 AFIVWELD 2-EP-01-FW055 1.690 81.407 218.593 0.00E+00 0.00E+00

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 59 of 60 DEGB Fiber Inside Fiber Contribution Contribution Transported

1. Weld Location Name Diameter Margin to GM CDF to GM CDF at DEGB Size (lbm) (Unweighted) (Weighted)

Size (lbm)

(inches) 244 AFIVWELD 2-EP-01-FW056 1.690 81.792 218.208 0.00E+00 0.00E+00 245 AFIVWELD 2-EP-01-FW059 1.690 81.993 218.007 0.00E+00 0.00E+00 246 AFIVWELD 2-EP-01-V010-2 1.690 80.286 219.714 0.00E+00 0.00E+00 247 AFIVWELD 2-EP-01-FW060 1.690 80.286 219.714 0.00E+00 0.00E+00 248 AFIVWELD 2-EP-02-F017 8.750 191.849 108.151 0.00E+00 0.00E+00 249 AFIVWELD 2-EP-02-S008-K 8.750 172.035 127.965 0.00E+00 0.00E+00 250 AFIVWELD 2-EP-02-S008-J 8.750 167.027 132.973 0.00E+00 0.00E+00 251 AFIVWELD 2-EP-02-S008-H 8.750 203.197 96.803 0.00E+00 0.00E+00 252 AFIVWELD 2-EP-02-S008-G 8.750 213.213 86.787 0.00E+00 0.00E+00 253 AFIVWELD 2-EP-02-S008-F 8.750 223.119 76.881 0.00E+00 0.00E+00 254 AFIVWELD 2-EP-02-S008-D 8.750 230.384 69.616 0.00E+00 0.00E+00 255 AFIVWELD 2-EP-02-F016 8.750 224.572 75.428 0.00E+00 0.00E+00 256 AFIVWELD 2-EP-02-V030-2 1.690 81.668 218.332 0.00E+00 0.00E+00 257 AFIVWELD 2-EP-02-FW027 1.690 81.710 218.290 0.00E+00 0.00E+00 258 AFIVWELD 2-EP-02-FW026 1.690 81.707 218.293 0.00E+00 0.00E+00 259 AFIVWELD 2-EP-02-FW025 1.690 81.788 218.212 0.00E+00 0.00E+00 260 AFIVWELD 2-EP-02-FW024 1.690 84.290 215.710 0.00E+00 0.00E+00 261 AFIVWELD 2-EP-02-S010-B 1.690 83.900 216.100 0.00E+00 0.00E+00 262 AFIVWELD 2-EP-02-8818C-2 5.190 98.980 201.020 0.00E+00 0.00E+00 263 AFIVWELD 2-EP-02-3066C-WDC-001-FW1 5.190 98.644 201.356 0.00E+00 0.00E+00 264 AFIVWELD 2-EP-02-FW5 5.190 122.358 177.642 0.00E+00 0.00E+00 265 AFIVWELD 2-EP-02-F020 5.190 125.332 174.668 0.00E+00 0.00E+00 266 AFIVWELD 2-EP-01-F018 8.750 182.311 117.689 0.00E+00 0.00E+00 267 AFIVWELD 2-EP-01-S013-E 8.750 175.616 124.384 0.00E+00 0.00E+00 268 AFIVWELD 2-EP-01-S013-D 8.750 186.079 113.921 0.00E+00 0.00E+00 269 AFIVWELD 2-EP-01-S013-C 8.750 203.790 96.210 0.00E+00 0.00E+00 270 AFIVWELD 2-EP-01-S013-B 8.750 208.781 91.219 0.00E+00 0.00E+00 271 AFIVWELD 2-EP-01-F017 8.750 210.468 89.532 0.00E+00 0.00E+00 272 AFIVWELD 2-EP-01-V040-2 1.690 81.472 218.528 0.00E+00 0.00E+00 273 AFIVWELD 2-EP-01-FW048 1.690 81.654 218.346 0.00E+00 0.00E+00 274 AFIVWELD 2-EP-01-FW047 1.690 85.714 214.286 0.00E+00 0.00E+00 275 AFIVWELD 2-EP-01-FW046 1.690 85.512 214.488 0.00E+00 0.00E+00 276 AFIVWELD 2-EP-01-S011-J 1.690 84.606 215.394 0.00E+00 0.00E+00 277 AFIVWELD 2-EP-01-S013-K 5.190 112.329 187.671 0.00E+00 0.00E+00 278 AFIVWELD 2-EP-01-S013-J 5.190 111.497 188.503 0.00E+00 0.00E+00 279 AFIVWELD 2-EP-01-F024 5.190 112.355 187.645 0.00E+00 0.00E+00 280 AFIVWELD 2-EP-01-FW4 5.190 115.749 184.251 0.00E+00 0.00E+00 281 AFIVWELD 2-EP-01-S012-H 5.190 114.042 185.958 0.00E+00 0.00E+00 282 AFIVWELD 2-EP-01-S012-F 5.190 111.530 188.470 0.00E+00 0.00E+00 283 AFIVWELD 2-EP-01-S012-E 5.190 112.045 187.955 0.00E+00 0.00E+00 284 AFIVWELD 2-EP-01-S012-D 5.190 114.238 185.762 0.00E+00 0.00E+00 285 AFIVWELD 2-EP-01-S012-C 5.190 116.698 183.302 0.00E+00 0.00E+00 286 AFIVWELD 2-EP-01-S012-B 5.190 120.477 179.523 0.00E+00 0.00E+00 287 AFIVWELD 2-EP-01-F023 5.190 121.196 178.804 0.00E+00 0.00E+00 288 AFIVWELD 2-EP-01-S011-F 5.190 121.864 178.136 0.00E+00 0.00E+00 289 AFIVWELD 2-EP-01-S011-D 5.190 113.157 186.843 0.00E+00 0.00E+00 290 AFIVWELD 2-EP-01-S011-C 5.190 112.769 187.231 0.00E+00 0.00E+00 291 AFIVWELD 2-EP-01-3066D-WDC-002-FW2 5.190 110.719 189.281 0.00E+00 0.00E+00 292 AFIVWELD 2-EP-01-3066D-WDC-003-FW3 5.190 108.694 191.306 0.00E+00 0.00E+00

ULNRC-06690 Enclosure 3, Attachment 3-3 Page 60 of 60 DEGB Fiber Inside Fiber Contribution Contribution Transported

1. Weld Location Name Diameter Margin to GM CDF to GM CDF at DEGB Size (lbm) (Unweighted) (Weighted)

Size (lbm)

(inches) 293 AFIVWELD 2-EP-01-8818D-2 5.190 107.601 192.399 0.00E+00 0.00E+00 1.13E-08 1.25E-11 11 References

[1] Regulatory Guide 1.174 "An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis,"

Revision 3, January 2018 (ADAMS Accession No. ML17317A256)"

[2] NEI 04-07 Volume 1, Pressurized Water Reactor Sump Performance Evaluation Methodology, Revision 0: Nuclear Energy Institute, December 2004.

[3] NEI 04-07 Volume 2, Safety Evaluation by the Office of Nuclear Reactor Regulation Related to NRC Letter 2004-02, Revision 0: Nuclear Energy Institute, December 2004.

[4] ALION-REP-ALION-2806-01, Insulation Debris Size Distribution for use in GSI-191 Resolution, Revision 4, May 19, 2009.

[5] NUREG 1829, "Estimating Loss-of-Coolant Accident (LOCA) Frequencies Through the Elicitation Process," Nuclear Regulatory Commission, 2008.

[6] ALION-REP-CEC-9143-014 Revision 0, "GSI-191 Risk Aggregation Methodology Report," Alion Science and Technology, 2018.

[7] MEMO-9143-WMC-2K17-01 Revision 0, "MSLB MFLB Conditional Sump Failure Probabilities," Alion Science and Technology, 2017.

[8] NOC-AE-15003241, STP Piloted Risk-informed Approach to Ciosure for GS1-191, 2015.

ULNRC-06690 Enclosure 3, Attachment 3-4 Page 1 of 19 Attachment 3-4 Defense-In-Depth and Safety Margin

ULNRC-06690 Enclosure 3, Attachment 3-4 Page 2 of 19 1 Introduction The defense-in-depth (DID) and safety margin (SM) evaluation applies for all debris effects addressed in the risk-informed element of the Callaway risk over deterministic (RoverD) methodology described in Attachment 3-3. That scope is generally described as breaks larger than approximately 9-inch breaks in reactor coolant system (RCS) primary loop piping and the pressurizer surge line where debris can be generated and transported to the sump strainers in excess of plant-specific tests. Sixty weld locations transport debris to the sump strainers in excess of plant-specific tests.

DID evaluations show that there is adequate system capability to provide assurance that public health and safety are protected in the event there is a loss-of-coolant accident (LOCA) that threatens strainer performance. It identifies operator actions that can be taken to mitigate the event and the robustness of the containment design.

SM evaluations identify margins and conservatisms in the design, analysis, and construction of the engineered safety features. Evaluations credit very low susceptibility of the welds to degradation mechanisms that could lead to a LOCA, expected smaller actual amount of debris that would be generated and transported to the sump, little or no actual contribution to head loss from chemical effects, and margin in head loss evaluations.

The conclusion of the evaluation is that substantial defense-in-depth and safety margin exists.

2 Defense-in-Depth DID for Callaway Unit 1 is based on the plant design, operating procedures, and administrative controls. In responses to Nuclear Regulatory Commission (NRC) Bulletin 2003-01 and Generic Letter (GL) 2004-02, Callaway described modifications to plant hardware (most notably new advanced design recirculation strainers), and operating procedures and administrative controls that were implemented to address GL 2004-02 concerns. Callaway operating procedures have actions that prevent and mitigate strainer blockage based on indications available to operators such as instrumentation to monitor core water levels, sump water levels, and containment temperatures. Actions include initiation of core flush (combined cold leg and hot leg injection), which provides an alternate flow path that bypasses core inlet blockage, and refilling the refueling water storage tank (RWST), which allows temporary termination of recirculation and a return to injection mode of operation. Callaway surveillance procedures implement Technical Specification (TS) requirements for cleanliness in accessible areas of the reactor containment building to verify no loose debris (rags, trash, clothing, etc.) is present which could be transported to the sump strainers during a LOCA. Also, visual inspections of the recirculation strainer to verify inlets are not restricted by debris and that the strainer components show no evidence of structural distress or abnormal corrosion are conducted.

ULNRC-06690 Enclosure 3, Attachment 3-4 Page 3 of 19 The current licensing basis for the containment emergency sump strainer installed to address GL 2004-02 consists of the current assumptions, initial conditions, and conclusions of GL 2004-02 related evaluations, including the current evaluations of design basis accident debris generation and transport, recirculation strainer performance, impact of chemical effects, and downstream effects of debris. Substantial plant-specific testing that supports assumptions and corresponding conclusions contained in the GL 2004-02 evaluations for Callaway was performed. This information supporting the previous deterministic methodology for demonstrating compliance is documented in supplemental information provided in response to GL 2004-02 and forms the deterministic basis for the Callaway simplified risk-informed (RI) methodology. RI elements of the analyses associated with the proposed exemption and license amendment along with the design, procedure, and administrative controls already incorporated demonstrate that the risk from LOCAs where the containment emergency sump strainer will not perform its required functions is very small and acceptable in accordance with the criteria of Regulatory Guide (RG) 1.174. The Callaway RI approach follows RG 1.174, verifying DID and SM are maintained through design modifications, ongoing design modification controls, and maintenance procedures including the in-service inspection (ISI) program. The approach is comprehensive in nature, analyzing a full spectrum of LOCAs including double-ended guillotine breaks (DEGB) for all piping sizes up to and including the largest pipe in the RCS. By requiring that mitigative capability be maintained in a realistic and RI evaluation of GL 2004-02 for a full spectrum of LOCAs, the approach ensures that DID is maintained.

The proposed change to the licensing basis is consistent with maintaining DID in that the following aspects of the facility design and operation are maintained:

• Functional requirements and design configurations of systems

• Existing plant barriers to the release of fission products

• Design provisions for redundancy, diversity, and independence

• Plant response to transients and other initiating events

• Preventative and mitigative capability of plant design features.

Based on the results of the risk-informed method and the hardware, operating procedures and administrative controls already implemented to address GL 2004-02 concerns, Callaway has high confidence that plant systems and operators would respond as required to mitigate postulated LOCAs. This confidence is bolstered by the DID features for Callaway described below.

2.1 Effectiveness of Defense-in-Depth Actions The effectiveness of DID actions is shown to be acceptable when considering the following:

ULNRC-06690 Enclosure 3, Attachment 3-4 Page 4 of 19

• Callaway Emergency-Operating Procedures (EOPs) are based on the approved industry standard Emergency Response Guidelines (ERGs). These symptom-based EOPs have generic or site-specific analyses that support them.

• Callaway Severe Accident Mitigation Guidelines (SAMGs) are based on approved industry standard guidance.

• Procedures are trained upon and evaluated as part of the training.

• DID actions are trained upon using the simulator to demonstrate effectiveness.

• Procedures that make framework for DID actions are evaluated during the Callaway station review and approval process.

2.2 Evaluations Callaway DID measures that are associated with the concerns of GL 2004-02 are evaluated by applying regulatory guidance and industry guidance.

2.2.1 Guidance in RG 1.174 Callaway proposes a licensing basis change to use a risk-informed approach to address the concerns of GL 2004-02 with respect to maintaining long term cooling post-LOCA on the basis that the change meets the principles and acceptance guidelines of RG 1.174. As discussed below, DID elements given in Section 2.1.1 of RG 1.174 have been evaluated to show that the proposed change is consistent with DID for Callaway.

DID is based on hardware, operating procedures, and administrative controls and design modifications that have been implemented or planned to address the concerns of GL 2004-02. The proposed licensing basis change does not propose any additional DID measures.

A reasonable balance is preserved among prevention of core damage, prevention of containment failure, and consequence mitigation.

Callaway has two trains of emergency core cooling system (ECCS) equipment for the prevention of core damage. Each train includes a high head centrifugal charging pump (CCP), an intermediate head safety injection (SI) pump, and a low head residual heat removal (RHR) pump that is routed through the RHR heat exchanger for cooling by component cooling water (CCW). Each primary cooling loop has an accumulator. Also, there are two independent trains of equipment for containment heat removal to prevent containment failure. The heat removal equipment for each train includes a Containment Spray (CS) pump and two containment air cooler (CAC) units per train that are cooled by safety-related essential service water (ESW) during an event. Consequence mitigation is achieved using active equipment of these Engineered Safety Features and by maintaining the containment building as an effective barrier to radioactive release.

ULNRC-06690 Enclosure 3, Attachment 3-4 Page 5 of 19 The proposed license change does not involve any change to the design or design requirements of the current plant equipment associated with GL 2004-02.

As discussed further below, the proposed change does not affect the containment integrity or the capability of the independent and safety-related CACs to remove post-LOCA decay heat from containment. There is no change to the strategies for the prevention of core damage, for prevention of containment failure, or for consequence mitigation. Thus, the existing balance among these is preserved.

Over-reliance on programmatic activities as compensatory measures associated with the change in the licensing basis is avoided.

Programmatic activities associated with the proposed change include the ISI program, plant personnel training, RCS leak detection program, and containment cleanliness inspection activities. The ISI program requires non-destructive examinations of the RCS components and piping. The in-service testing (IST) program requires testing of active components such as pumps and valves in the RCS, ECCS, and containment spray systems (CSS). The proposed change does not rely heavily on programmatic activities as compensatory measures nor propose any new programmatic activities that could be heavily relied upon. The risk-informed approach does consider pipe break frequencies. Callaway has previously implemented a risk-informed ISI program that was approved by the NRC. The ISI program is an effective element of DID that performs an important role in the prevention of pipe breaks. It is important to note that the risk-informed GL 2004-02 program and the risk-informed ISI program are complementary in that the risk insights from the stations plant-specific probabilistic risk assessment (PRA) are used in conjunction with deterministic information to improve the safety and effectiveness of the ISI program.

The leak detection program at Callaway is capable of early identification of RCS leakage in accordance with RG 1.45 to provide time for appropriate operator action before a flaw causing a leak would propagate to a break. This program is an important contributor to DID.

Containment cleanliness inspection activities are performed prior to reactor startup following outages, as required by the TS. The deterministic element of the GL 2004-02 program uses an input for the assumed amount of latent debris inside containment after the cleanup activity is complete that is in accordance with the Nuclear Energy Institute (NEI) 04-07 guidance for a deterministic approach. Thus, there is no over-reliance on programmatic activities to quantify or manage latent debris as compensatory measures for the risk-informed approach.

System redundancy, independence, and diversity are preserved commensurate with the expected frequency, consequences of challenges to the system, and uncertainties (for example, no risk outliers).

ULNRC-06690 Enclosure 3, Attachment 3-4 Page 6 of 19 Callaway has two trains of ECCS equipment for the prevention of core damage.

Each train includes a high head CCP, an intermediate head SI pump, and a low head RHR pump that is routed through the RHR heat exchanger for cooling by CCW. There are two independent trains of equipment for containment heat removal to prevent containment failure. The heat removal equipment for each train includes a CS pump and two CAC units per train that are cooled by safety-related ESW during and event. Each ECCS train draws recirculation suction through the emergency recirculation sump strainers to provide suction flow during the recirculation mode to the respective trains pumps. Also, each primary cooling loop has an accumulator.

The proposed license change does not require any design change to these systems. Thus, system redundancy, independence, and diversity are preserved.

The proposed licensing basis change also does not call for any changes to the system operating procedures. These systems have been fully analyzed relative to their contribution to nuclear safety through the Callaway plant-specific PRA.

The PRA includes the risk contributions for the full spectrum of LOCA events and meets industry PRA standards for risk-informed applications. The treatment of uncertainties in the risk-informed model ensures results are obtained for realistic assessments. The uncertainties using the risk-informed approach methodology have been examined in the PRA and there are no risk outliers.

Defenses against potential common-cause failures are preserved, and the potential for the introduction of new common-cause failure mechanisms is assessed.

The proposed license change does not change any defenses against common-cause failures. A potential common cause failure would be the recirculation strainer becoming clogged so that there would not be adequate flow to any of the ECCS and CS pumps. The defenses that apply to potential strainer clogging (for example refilling the RWST, use of alternate injection sources, and stopping/starting of pumps) are not changed by the use of the risk-informed methodology since there are no design changes to the equipment or changes to the EOPs.

The potential for new common-cause failure mechanisms has been assessed for the GL 2004-02 issues through decades of plant-specific and industry research.

The primary failure mechanisms of concern are recirculation strainer clogging or in-vessel effects. However, the defenses against impediments to cooling delivery or impediments to heat rejection in the core are effective, reasonable, and acceptable operational measures to mitigate or ameliorate adverse strainer performance. Additionally, these defenses do not change due to the proposed licensing basis change to use the RG 1.174 risk-informed approach. Since the risk-informed approach does not involve any design changes to the equipment or changes to the operating procedures beyond those already taken in response to the concerns raised in GL 2004-02, it does not introduce any new common-

ULNRC-06690 Enclosure 3, Attachment 3-4 Page 7 of 19 cause failures or reduce the current plant defenses against common-cause failures.

Independence of barriers is not degraded.

The three barriers to a radioactive release are fuel cladding, RCS piping and components, and the containment building. For the evaluation of a LOCA, the RCS barrier is postulated to be breached. The proposed licensing basis change does not involve any change to the design and analysis requirements for the fuel.

Thus, the fuel barrier independence is not degraded. Consequently, the risk-informed GL 2004-02 analysis approach focuses primarily on addressing the integrity of the fuel cladding by assuring the ECCS and CS cooling function is maintained. The Callaway risk-informed evaluation includes both the ECCS and CS cooling function and the containment function.

In the recirculation mode of accident mitigation, the post-LOCA fluid that collects in the containment sump pits is pumped by the CCP and CS pumps that are located in the Auxiliary Building. Thus, the recirculated fluid goes from the containment to the Auxiliary Building and back to the containment. The barrier to release from the Auxiliary Building is the ECCS and CS piping and components in the recirculation flow path. The Auxiliary Building heating, ventilation, and air conditioning (HVAC) system has filters to handle gaseous leakage that would come from any recirculating sump water leakage in the Auxiliary Building. The proposed licensing basis change does not involve any change to the design and operating requirements for this equipment. Thus, there is no change to the containment cooling water recirculation flow path.

The containment is fully analyzed for not only design basis considerations but also from a Level 2 PRA perspective. Detailed analyses for severe accident phenomena, including LOCAs, have been evaluated for impact to containment building integrity; and these events do not challenge the overall capability of containment to remain intact. Also, it should be noted that additional DID capability is available through the use of the CACs. The CACs have enough cooling capability to remove decay heat from the containment through containment atmosphere cooling during the ECCS and CS recirculation phase thereby further reducing containment integrity challenges.

The proposed license change does not involve any design change to these barriers (fuel, piping, building, HVAC filters). Thus, the independence of the barriers is maintained and not degraded.

Defenses against human errors are preserved.

The proposed license change does not involve any design change to the current equipment or operating procedures. Operator actions during the initial accident mitigation stage are focused on monitoring of the automatic mitigation actions

ULNRC-06690 Enclosure 3, Attachment 3-4 Page 8 of 19 and performing manual actions to switchover several pumps from injection mode to recirculation mode. Prior to depletion of the RWST, there is an automatic switchover of the low head RHR pumps, while operator action is required to switchover the intermediate head SI pumps, high head CCPs, and CS pumps.

As part of the switchover sequence, operators close the individual pump suction valves associated with the RWST. Also in accordance with EOPs, the switchover from cold leg injection to core flush (combined cold leg and hot leg injection) is a manual action performed by the operator. The use of the methodology for the risk-informed approach does not change any of the EOPs that would be used or impose any additional operator actions or complexity.

Thus, the defenses that are already in place with respect to human errors are not impacted by the proposed licensing basis change.

The intent of the plants design criteria is maintained.

The proposed license change does not involve any change to the design or design requirements of the current plant equipment associated with GL 2004-02.

Based on results of the proposed license change showing that the risk-informed approach meets RG 1.174 acceptance criteria, the proposed license change revises the licensing basis for acceptable emergency recirculation sump strainer design and performance in support of ECCS and CS operation in recirculation mode following postulated LOCAs. Therefore, the intent of the plants design criteria is maintained.

Design and licensing basis descriptions of accidents requiring ECCS and CS operation including analysis methods, assumptions, and results provided in Final Safety Analysis Report (FSAR) Chapters 6 and 15 remain unchanged. The proposed change to the licensing basis continues to meet the intent of the general design criteria (GDC) that apply to functions addressed by GL 2004-02.

This conclusion is based on the results of the risk-informed approach that demonstrate that the calculated risk associated with GL 2004-02 concerns for Callaway is very small and in accordance with the Region III acceptance guidelines defined by RG 1.174.

Performance evaluations for accidents requiring ECCS and CS operation described in FSAR Chapters 6 and 15 are based on the Callaway 10 CFR 50, Appendix K large-break LOCA analysis. These evaluations demonstrate that for breaks up to and including the DEGB of a reactor coolant pipe, the ECCS will limit the clad temperature to below the limit specified in 10 CFR 50.46, thus assuring that the core will remain in place and substantially intact with its essential heat transfer geometry preserved. The proposed license change does not involve a change to the ECCS acceptance criteria specified in 10 CFR 50.46.

Therefore, the intent of the plants design criteria is maintained.

ULNRC-06690 Enclosure 3, Attachment 3-4 Page 9 of 19 2.3 NEI Guidance for Defense-in-Depth Measures in Support of Response to GL 2004-02 For the purposes of GL 2004-02 resolution, the primary regulatory objective is specified in 10 CFR 50.46(b)(5) as long-term cooling. A method for ensuring adequate DID is to maintain the capability for operators to detect and mitigate inadequate flow through recirculation strainers and inadequate flow through the reactor core due to the potential impacts of debris blockage. The following evaluation of the DID measures that support the application for a risk-informed approach to closing GL 2004-02 is based on NEI guidance that includes additional justification for the measures discussed.

2.3.1 Prevention of Inadequate Recirculation Strainer Flow Callaway has within their EOP framework, specific steps for monitoring for indications of sump strainer blockage and actions to be taken if this condition occurs. These actions are described in the Callaway response to NRC Bulletin 2003-01 and the subsequent responses to the NRC requests for additional information. The actions taken in response to NRC Bulletin 2003-01 are still in effect at Callaway.

In summary, these actions include (1) reducing flow through the strainer by stopping pumps, (2) monitoring for proper pump operation, core exit thermocouples, and reactor water level indication, (3) refilling the RWST for injection flow, (4) using injection flow from alternate sources, and (5) transferring to combined hot leg/cold leg injection flow paths.

Callaway EOPs that implement these actions include:

• E-0, Reactor Trip or Safety Injection EOP

• E-1, Loss of Reactor or Secondary Coolant

• ECA-1.1, Loss of Emergency Coolant

• ECA-1.2, LOCA Outside Containment

• ES-0.1, Reactor Trip Response

• ES-0.2, Natural Circulation Cooldown

• ES-1.1, SI Termination

• ES-1.2, Post-LOCA Cooldown and Depressurization

• ES-1.3, Transfer to Cold Leg Recirculation

• ES-1.4, Transfer to Hot Leg Recirculation

• FR-C.1, Response to Inadequate Core Cooling

• FR-C.2, Response to Degraded Core Cooling

• FR-Z.1, Response to High Containment Pressure

• FR-Z.3, Response to High Containment Radiation Level

• FR-1.2, Response to Low Pressurizer Level

• SAG-3, Severe Accident Control Room Guideline After the TSC is Functional

ULNRC-06690 Enclosure 3, Attachment 3-4 Page 10 of 19 2.3.2 Detection of Inadequate Strainer Flow Callaway has operational procedures to monitor the ECCS and CS pump flow, discharge pressure, and amperage. By monitoring these operating parameters, control room personnel could properly diagnose the occurrence of cavitation, which would be an indication of sump clogging or significant deaeration. Control room personnel have been trained to evaluate this type of indication and take appropriate action such as reducing strainer flow rate by securing containment spray pumps.

2.3.3 Mitigation of Inadequate Recirculation Strainer Flow RWST Refill and Realignment for Injection Flow - The Callaway Emergency Response Plan Implementing Procedures (ERPIPs) provide guidance for refilling the RWST and realigning the ECCS system for injection flow. Refilling the RWST and realigning the ECCS system for injection flow will increase containment water level which will reduce the potential for deaeration and cavitation. Also, terminating recirculation flow temporarily may allow buoyancy forces to eject the non-condensable gases inside the strainer effectively back-flushing and disrupting the debris bed. The disrupted debris bed may potentially fall to the bottom of the sump pit as agglomerated large clumps of debris which would not be expected to re-suspend in the flow and transport back to the strainer pockets.

In response to the NRC Order EA-12-049, Mitigation Strategies for Beyond-Design-Basis External Event (BDBEE), Callaway developed diverse and flexible coping strategies (FLEX) to maintain RCS inventory control, RCS cooling, and containment integrity. Various modifications have been implemented such that non-emergency equipment can be credited during an event.

2.3.4 Prevention of Inadequate Reactor Core Flow Callaway successfully performed in-vessel analysis per WCAP-17788 methodology for hot and cold leg breaks, which did not result in addition contributions to core damage.

DID measures for inadequate reactor core flow are described in the following paragraphs.

2.3.5 Detection of Inadequate Reactor Core Flow Inadequate core cooling due to debris blocking the core or boric acid precipitation would be primarily indicated by an increase in core exit thermocouple temperature. Reactor vessel water level and containment radiation levels are also monitored to identify inadequate reactor core flow.

2.3.6 Mitigation of Inadequate Reactor Core Flow FR-C.1 and FR-C.2 provide operator guidance for commencing core flush to restore and maintain RCS subcooling. Also, as discussed in Section 2.3.3, the FLEX RCS

ULNRC-06690 Enclosure 3, Attachment 3-4 Page 11 of 19 Makeup Pump can be used to inject coolant into the RCS should the emergency recirculation strainer fail.

2.3.7 Implementation of SAMGs and the Plant Engineering Staff Evaluation Manual SAMGs provide additional guidance and actions for addressing inadequate core flow conditions. Typically, SAMGs will be entered when directed by the EOPs and are used without Technical Support Center (TSC) Engineer involvement. The SAMGs provide guidance for flooding containment above the reactor vessel hot and cold leg nozzles thus covering the break location to provide convective circulation cooling of the reactor vessel. EOPs may direct operators to Engineering for guidance, where TSC engineers consult the Plant Engineering Staff Evaluation Manual to provide Operations with additional guidance during the mitigation of an accident.

2.4 Training Related to the Proposed Change The proposed change does not result in changes to the symptom-based response procedures and guidelines beyond those already implemented in response to Bulletin 2003-01 and GL 2004-02. Initial training on sump blockage issues was completed, and licensed operator classroom and simulator training on indications of, and responses to, degraded pump flow indications which may be caused by containment emergency sump clogging is provided during initial and requalification training. Training has been conducted for Emergency Response Organization decision makers and evaluators in the TSC on indications of sump blockage and compensatory actions.

2.5 Barriers for Release of Radioactivity The following evaluation demonstrates that the proposed change maintains sufficient safety margin for the current barriers for release of radioactivity, which are the fuel cladding, the RCS boundary, the containment, and the Emergency Plan (EP) actions.

The evaluation concludes that the proposed licensing basis change:

• Does not affect or remove any of these levels of protection.

• Does not result in a significant increase in the existing challenges to the integrity of the barriers.

• Does not significantly change the failure probability of any individual barrier.

• Does not introduce new or additional failure dependencies among barriers that significantly increase the likelihood of failure when compared to the existing conditions.

• Does not change the overall redundancy and diversity features among the barriers that are sufficient to ensure compatibility with the risk acceptance guidelines.

ULNRC-06690 Enclosure 3, Attachment 3-4 Page 12 of 19 2.5.1 Fuel Cladding The fuel cladding barrier is maintained by the ECCS following a LOCA. After the initial phase of the accident mitigation, long term cooling is maintained post-LOCA by the ECCS and shutdown cooling system. The proposed licensing basis change for the change in methodology to use a RG 1.174 risk-informed approach for the effects of debris does not make any change to the previous analyses and testing programs that demonstrate the acceptability of the ECCS for the initial phase of providing core cooling.

The proposed licensing basis change shows that long term cooling is met for the additional accident mitigation and recovery phase for the LOCAs in the deterministic scope of the GL 2004-02 evaluation. The evaluation of DID and safety margin provides confidence that adequate mitigation will be provided for the risk-informed scope of the GL 2004-02 evaluation. The proposed license change does not involve any change to the design or design requirements of the current plant equipment associated with GL 2004-02. There is no change to the design and analysis requirements for the fuel.

Therefore, the fuel cladding barrier is expected to be maintained by the ECCS following a risk significant LOCA.

2.5.1.1 Emergency Core Cooling Callaway has a system to provide abundant emergency core cooling. The system safety function is to transfer heat from the reactor core following any loss of reactor coolant at a rate such that: (1) fuel and clad damage that could interfere with continued effective core cooling is prevented and; (2) clad metal-water reaction is limited to negligible amounts. Suitable redundancy in components and features, and suitable interconnections, leak detection, isolation, and containment capabilities are provided to assure that for onsite electric power system operation (assuming offsite power is not available) and for offsite electric power system operation (assuming onsite power is not available) the system safety function can be accomplished, assuming a single failure.

2.5.1.2 Long Term Cooling To comply with 10 CFR 50.46(b)(5), Long-term cooling, the Callaway RG 1.174 risk-informed approach for post-LOCA sump performance shows that after the successful initial operation of the ECCS, the core temperature is maintained at an acceptable low value and decay heat is removed for the extended period of time required by the long-lived radioactivity remaining in the core.

2.5.2 Reactor Coolant System Pressure Boundary Integrity of the RCS pressure boundary is postulated to be broken for the GL 2004-02 sump performance evaluation that is concerned with post-LOCA debris effects.

However, the proposed change does not make any change to the previous analyses and testing programs that demonstrate the integrity of the RCS. Since the proposed

ULNRC-06690 Enclosure 3, Attachment 3-4 Page 13 of 19 licensing basis change does not impact any design or programmatic requirements for the reactor coolant pressure boundary, the likelihood of a LOCA is not affected.

2.5.2.1 In-Service Inspection Program The ISI program performs an important role in the prevention of pipe breaks.

The integrity of the welds in ASME Class 1 piping and components are maintained at a high level of reliability through the ASME Section XI inspection program. The Callaway ISI program procedure ensures that the following requirements of 10 CFR 50.55a and ASME/BPVC Section XI, 2007 Edition through 2008 Addenda are satisfied:

• Verification of the structural integrity of ASME Class 1, 2, and 3 components are within the limits specified in the In-Service Inspection Program, and

• Verification of the structural integrity of the main steam and main feedwater piping is within the limits specified in the augmented In-Service Inspection Program.

2.5.2.2 Reactor Coolant System Weld Mitigation All large bore reactor vessel welds susceptible to pressurized water stress corrosion cracking (PWSCC) have been mitigated by water jet peening in 2017.

2.5.2.3 RCS Leakage Detection The leak detection program at Callaway is capable of early identification of RCS leakage in accordance with RG 1.45 to provide time for appropriate operator action to identify and address RCS leakage. The effectiveness of this program is not reduced by the proposed licensing basis change to the risk-informed approach for GL 2004-02.

2.5.3 Containment Integrity The evaluation of sump performance using a risk-informed approach is not a component of the analyses that demonstrates containment integrity. Previous analyses show that the containment structure can withstand the peak pressures calculated without loss of integrity. The containment remains a low leakage barrier against the release of fission products for the duration of postulated LOCAs.

2.5.3.1 Containment Design Basis The principal design basis for the containment is that it be capable of withstanding the internal pressure resulting from a LOCA with no loss of integrity. In this event, the total energy contained in the water of the RCS is assumed to be released into the containment atmosphere through a break in the reactor coolant piping. Subsequent pressure behavior is determined by the building volume, engineered safety features, and the combined influence of energy sources and heat sinks.

ULNRC-06690 Enclosure 3, Attachment 3-4 Page 14 of 19 2.5.3.2 Containment Heat Removal The proposed license change does not involve changes to the design or design requirements of the current plant equipment associated with GL 2004-02.

Thus, there is no change to any of the containment heat removal components needed to maintain containment integrity. Therefore, the proposed change does not significantly impact the structural capability and integrity of the containment as an effective fission product barrier post-LOCA. The Callaway large, dry containment with safety-grade CACs is likely to survive a significant core damage event, even with a loss of the containment emergency recirculation sump.

CACs are designed to operate independently in the post-LOCA environment and are not directly affected by the loss of the recirculation sump or containment spray. This additional and independent capability to reject decay heat from containment ensures that the containment would not fail because of overpressure or overheating. Although core melt could be postulated, containment integrity would be maintained by operation of the CACs and the containment would continue to be maintained as an effective fission product barrier.

Energy released to the containment atmosphere from the postulated accidents is removed by the CS and CACs. Callaway has four cooling units located entirely within the containment. Safety-related ESW is circulated through the air cooling coils during an event. The CACs are designed to remove heat from the containment during both normal operation and accident conditions. (During normal operation non-safety-related service water is circulated through the CACs.)

Upon receipt of a safety injection signal (SIS), any idle cooling unit is automatically started and, simultaneously, any running fan is switched from the normally operating high speed setting to low speed operation. The CACs are supplied cooling water from the safety-related ESW.

The CACs remove thermal energy from inside the containment to reduce the containment atmosphere pressure and temperature following loss-of-offsite power (LOOP) or a design basis accident (DBA). The containment response analysis evaluated many single failure scenarios ranging from single component failure to complete train failure and allowable peak pressure and temperature of the containment was not reached following a DBA.

Other industry studies have indicated the ability of the containment systems to survive challenges of 2.5 to 3 times the design levels. The Zion Probabilistic Safety Study showed that the containment ultimate capacity was 2.55 to 2.86 times the design capacity.

ULNRC-06690 Enclosure 3, Attachment 3-4 Page 15 of 19 2.5.3.3 Containment Testing TS Surveillance Requirement 3.6.1.1 requires a Containment Leakage Rate Testing Program to be established to implement leakage rate testing of the containment as required by 10 CFR 50.54(o) and 10 CFR 50, Appendix J, Option B, as modified by approved exemptions. This program is in accordance with the guidelines contained in RG 1.163.

The proposed change does not impact the requirements for structural integrity and leak-tightness of the containment and does not involve any changes to the containment leakage testing requirements for demonstrating the effectiveness of the containment as a low leakage barrier.

2.5.4 Emergency Plan Actions The proposed change to the licensing basis to use the methodology of a risk-informed approach does not involve any changes to the Emergency Plan. There is no change to the strategies for prevention of core damage, for prevention of containment failure, or for consequence mitigation. The use of the risk-informed approach does not impose any additional operator actions or complexity. Implementation of the proposed change would not result in any changes to the response requirements for emergency response personnel during an accident. The DID approach includes the ability to detect, prevent, and mitigate post-LOCA strainer debris blockage and in-vessel debris blockage.

3 Safety Margin There are numerous conservatisms used throughout the Callaway risk-informed GL 2004-02 evaluation. The safety margin evaluation identifies margins and conservatisms in the design, analysis, construction, and operation of the plant to show that the proposed methodology change by this licensing submittal will maintain sufficient safety margins. Per the guidance stated in RG 1.174, the evaluation of the proposed change shows that sufficient safety margins exist to ensure:

• Codes and standards or their alternatives approved for use by the NRC are met.

• Safety analysis acceptance criteria in the FSAR and supporting analyses are met or proposed revisions provide sufficient margin to account for analysis and data uncertainty.

3.1 Break Selection The RoverD approach implemented CASA Grande to automate the zone of influence (ZOI) debris generation and analyze each weld location for DEGB, spherical ZOI destruction, as well as partial-break, hemispherical ZOI destruction. Fiber debris generation at each location and for each break size is determined. Since all weld locations in ASME Class 1 piping are analyzed for various break sizes, a break selection criterion is not needed.

ULNRC-06690 Enclosure 3, Attachment 3-4 Page 16 of 19 3.2 Debris Generation Debris generation analysis was performed in accordance with approved methods documented in NEI 04-07 that include multiple levels of conservatism:

• Smaller piping ruptures, while still unlikely, provide a better measure of expected behavior.

• The wide recognition that a large RCS pipe is more likely to leak and be detected by the plants leakage monitoring systems long before cracks grow to unstable sizes is referred to as leak before break and is an accepted part of regulatory compliance with GDC 4.

• Full destruction of materials is assumed within a conservatively determined spherical ZOI based upon a conservative extrapolation of limited test data performed under non-prototypic conditions, with limiting configurations. Sparse data on insulation destruction testing has forced the use of bounding results. All insulation is presumed to have a worst case seam orientation relative to the break. The ZOI for insulation materials is expected to be significantly smaller than that predicted by the NRC guidance due to real factors such as greater structural integrity than tested materials, non-limiting seam orientations, etc.

• The debris generation analysis does not take credit for shielding within the ZOI by equipment (e.g. steam generators, reactor coolant pumps) and large piping.

• Instantaneous failure of 100% of the unqualified coatings inside containment as particulates is a very conservative assumption.

• Latent debris evaluations were completed in accordance with the approved guidance documented in NEI 04-07. The results of the latent debris calculation conservatively determined the debris loading to be less than 100 lbm in each containment building.

3.3 Debris Transport Debris transport analysis was performed in accordance with approved methods documented in NEI 04-07, that include multiple levels of conservatism:

• All fine debris is assumed to wash down to the sump pool elevation with no holdup on structures. Although fine debris would be easily carried by draining spray flow, a quantity of fine debris would likely be retained on walls and structures above the containment pool due to incomplete spray coverage and hold up on structures. Even in areas that are directly impacted by sprays, some amount of fine debris would agglomerate together and likely be held up.

• Most fine debris is assumed to transport to the surface of the strainer. Debris present or generated at the beginning of the event will generally be pushed by break and spray flows into quiescent regions and will reside as debris piles. At the start of recirculation, it would take substantially higher flow rate than what would actually occur to cause movement of these piles of debris. Even if these

ULNRC-06690 Enclosure 3, Attachment 3-4 Page 17 of 19 piles of debris were to move, there are numerous obstacles (supports, equipment, curbs, etc.) that would prevent debris from reaching the strainers.

• For each debris type and size, debris transport fractions were determined at four break locations. The largest transport fraction for each debris type and size was implemented for RoverD analysis.

• Debris barriers, which are similar to debris interceptors, are installed in all the openings through the secondary shield wall nearest to the emergency recirculation sumps. These openings provide the most direct path from inside the secondary shield wall to the strainers. However, debris barriers were not credited for debris retention.

3.4 Chemical Effects Predictions Chemical effects analysis was performed in accordance with approved guidance documented in WCAP-16530-NP-A that includes multiple levels of conservatism:

• WCAP-16530 relies largely upon short-term release rates (hours) for the determination of long-term releases (30 days). Long-term release rates of constituent materials are expected to be significantly lower than that predicted by design basis models due to saturation, surface passivation, inhibition effects due to other ions, and formation of surface films.

• One hundred percent of chemical species of interest are assumed to precipitate.

When solubility limits are taken into account, the predicted precipitation is reduced by a significant factor. In addition, precipitates will form during periods when net positive suction head margins are greater.

• The WCAP-16530 models result in chemical precipitate formation that is completely transported to the sump screen. A portion of precipitates generated will not reach the containment sump strainers because precipitates will deposit on other surfaces in containment.

• The pH profile had a steady state pH equal to the highest deterministic pH bound.

• The pilot plant and Callaway have similar conditions (pH, temperature, material inventories, etc.). Therefore, trends from the chemical effects tests conducted by the pilot plant are applicable to Callaway. Results and conclusions of chemical effects testing conducted by the pilot plant are below.

o Integrated corrosion tests with bounding conditions for large breaks show relatively little precipitate formation.

o Vertical loop head loss tests with dissolved aluminum show that precipitate formation would not occur prior to significant pool cooling (days into the event).

3.5 Strainer Head Loss Tests Strainer head loss tests were performed in 2016 at Alden Research Laboratories in accordance with the NRC guidance and included multiple levels of conservatism:

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• During strainer head loss tests, fiber fines were conservatively implemented as the surrogate for small and large pieces of fiber. This is conservative because small and large pieces of fiber typically reduce debris bed head loss. Should large quantities of debris be generated and transported to the strainer, it would be a mixture of fiber fines, small pieces, and large pieces.

• During head loss tests, all fiber and particulate debris was collected on the strainer prior to addition of chemical precipitates. The chemical precipitate coating on the debris bed observed in head loss testing is not prototypical. In reality it would be less uniform than that achieved during testing since some of the precipitates would be expected to form in the debris bed, producing a less uniform deposit. A less uniform deposition of precipitates would yield a lower debris bed head loss.

• The head loss tests did not credit near-field settling, which was credited by the pilot with the implementation of a test flume. Callaway head loss tests were conducted in a test tank that was designed to promote complete and uniform transport by inducing non-prototypical turbulence and neglecting the six-inch curb surrounding the strainers installed in Callaway containment.

• Metallic insulation debris and paint chips were excluded from the tested debris loads in order to conservatively bound head loss. This debris is predicted to transport to the strainer and would disrupt the formation of a uniform fiber/particulate debris bed. This results in lower strainer head loss. Also, particulate was implemented as a surrogate for the paint chips.

• Strainer head loss tests were conducted at an approach velocity approximately 15% larger than the expected approach velocity. Note, the expected approach velocity accounted for miscellaneous debris. This results in larger head losses and is conservative.

3.6 Strainer Performance Strainer performance considerations include net positive suction head (NPSH), air release, potential for flashing, vortex formation, and structural qualification. These analyses included multiple levels of conservatism:

• The maximum strainer head loss is applied at the beginning of the event, which inherently assumes all debris (conventional debris, eroded debris, and chemical precipitates) is on the strainer at the very beginning of recirculation. In reality, debris accumulates on the strainer over time when margins are greater.

• The minimum pool height is calculated based on several conservative inputs with conditions that Callaway has never realized during its operational history. For example, the calculation assumes the refueling water storage tank water level is at the technical specification minimum, while Callaways operational history shows more water is always in the refueling water storage tank. These assumptions reduce the water level in containment, as well as the margin.

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• Strainer head losses determined by tests at a temperature of 120 °F were conservatively applied at increased temperatures without any scaling. This results in the application of larger strainer head losses, which reduces margin.

• Strainer head losses determined by tests at an approach velocity approximately 15% greater than the expectation were conservatively applied without scaling.

This results in the application of larger strainer head losses, which reduces margin.

• For the structural analysis, loads such as change in pressure due to post-LOCA debris and inertial forces due to a safe shutdown earthquake are concurrently analyzed. This increases the forces on the strainer and over estimates stresses.

3.7 RoverD and Risk The RoverD analysis adheres to the pilot plants methodology with multiple levels of conservatism:

• For the pilot plant, the RoverD risk metric is fine LDFG but Callaway implemented a risk metric that included all LDFG (fine, small, large, eroded LDFG, latent LDFG, and fiber safety margin) that is transported to the strainer.

The additional conservatism that Callaway applied causes more breaks to be assumed to failure.

• Callaway performed RoverD analysis assuming a single operable train. This results in a conservative quantification of change in core damage frequency.

• A fiber safety margin of 50 lbm is applied to all postulated breaks. This 50 lbm of fiber is in addition to ZOI-generated and latent fiber sources. This 50 lbm margin provides additional assurance that the quantified change in core damage risk is conservative.