ML18218A195

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Korea Hydro & Nuclear Power Co, Ltd., Revised Response to RAI 434-8352 for Question 19-92 (Rev.5)
ML18218A195
Person / Time
Site: 05200046
Issue date: 08/06/2018
From:
Korea Hydro & Nuclear Power Co, Ltd
To:
Office of New Reactors
Shared Package
ML18218A194 List:
References
MKD/NW-18-0105L
Download: ML18218A195 (59)


Text

Non-Proprietary 19-92_Rev.5 - 1 /18 KEPCO/KHNP REVISED RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION APR1400 Design Certification Korea Electric Power Corporation / Korea Hydro & Nuclear Power Co., LTD Docket No.52-046 RAI No.: 434-8352 SRP Section: SRP 19 Application Section: 19.1 Date of RAI Issue: 03/08/2016 Question No. 19-92 10 CFR 52.47(a)(27) states that a design certification (DC) application must contain an FSAR that includes a description of the design-specific PRA and its results. In addition, SRP Chapter 19.0, draft Revision 3,Section II Acceptance Criteria, Item 4 on Page 19.0-13 states The staff will determine that the applicant has identified risk-informed safety insights based on systematic evaluations of the risk associated with the design such that the applicant can identify and describe the following: A. The designs robustness, levels of defense-in-depth, and tolerance of severe accidents initiated by either internal or external events and B. The risk significance of potential human errors associated with the design. In addition, Item 13 on Page 19.0-16 states The staff will determine that the assumptions made in the applicants PRA during design development and certification, in which a specific site may not have been identified or all aspects of the design (e.g.,

balance of plant) may not have been fully developed, are identified in the DC application and either remain valid or are adequately addressed within the COL application. Furthermore, Item 14 on Page 19.0-16 states that The staff will determine that FSAR Chapter 19 includes PRA qualitative results, including the identification of key PRA assumptions, the identification of PRA-based insights, and discussion of the results and insights from importance, sensitivity, and uncertainty analyses.

Thus, in this context, the staff reviewed APR1400 DCD Table 19.1-4 Risk Insights and Key Assumptions and found this table is not comprehensive in identifying the APR1400 PRA-related key assumptions and insights. Therefore, in order for the staff to reach a reasonable assurance finding, please enhance Table 19.1-4 of the DCD to identify all PRA key assumptions and PRA-based insights, and also the insights from the importance, sensitivity, and uncertainty analyses.

Response - (Rev.5)

The purpose of this revised response (Rev. 5) is to reflect changes due to the following:

1. address conflicts between previous responses to RAI 19-28 Rev.4 and RAI 19-92 Rev.1,
2. reflect vendor proprietary information related to RCP seal LOCA probability provided in RAI 19-16 Rev.2, and

Non-Proprietary 19-92_Rev.5 - 2 /18 KEPCO/KHNP

3. reconcile conflicts between previous responses to RAI 19-92 Rev.1 and AI 19-51 Rev.1.
4. renumbering COL items and to address consistency issues between subsection 19.1.9 and Table 1.8-2,
5. reflect changes due to updates of APR 1400 PRA-based SMA, and
6. make editorial Changes The DCD Table 19.1-4 Risk Insights and Key Assumptions provides risk insights that are based on key design features, severe accident design features, and PRA that includes key assumptions, importance, and sensitivity analyses. There were total of fifty-eight (58) specific items listed in Table 19.1-4, and ten (10) additional items, mostly related to LPSD conditions, were added during the DCD review.

Table 19.1-4 was reviewed during the PRA update, and incorporated the changes to several key PRA assumptions, to ensure that risk insights listed in the table are consistent with the risk insights and the key assumptions, and also the insights from the importance, sensitivity, and uncertainty analyses. The detailed sensitivity and uncertainty analysis will be documented in APR1400-K-P-NR-01308-P, APR1400 PRA Sensitivity and Uncertainty Analysis, which will be made available in the Electronic Reading Room.

a) A comprehensive assessment of the impact of uncertainties in key assumptions will be performed with considerations of risk insights and risk quantifications of CDF and LRF using the PRA update, and the assessment will be documented in APR1400-K-P-NR-01308-P, APR1400 PRA Sensitivity and Uncertainty Analysis.

Some example assumptions (not limited to these examples) that were evaluated for uncertainty are as follows:

  • fire ignition frequencies (e.g., consideration of more recent fire ignition frequency estimates)
  • RCP seal failure probability and model (e.g., based on new technical bases),

Assumption No. 1 in DCD Table 19.1-4.

  • Room heat-up calculations (e.g., based on new calculations) , Assumption No. 5 in DCD Table 19.1-4 b) The uncertainty assessment will consider all PRA models included in the APR1400 DC PRA (i.e., all operating modes, hazards, and PRA levels) using the PRA update.

c) The uncertainty and key assumptions related to the PRA update were identified in DCD Table 19.1-4, see Assumptions 1, 5, 7, 11,.14, 15, 21, and 66.

The DCD markups from the PRA update results and insights are provided in Attachments 1 and 2 of RAI 434-8352 Question 19-92 Rev.1. The Table 1 to this RAI response shows the update status of the DCD Section 19.1 tables from 2017 PRA update.

The Table 2 to this RAI response shows the update status of the DCD Section 19.1 table to add basic event probability in CDF and LRF cutsets in table in Attachment of RAI 434-8352 Question 19-92 Rev.2.

Non-Proprietary 19-92_Rev.5 - 3 /18 KEPCO/KHNP COL item numbers for DCD Section 19.1 have been rearranged given the deletion of COL 19.1(22), and COL 19.1(25) has been inserted to assure consistency between subsection 19.1.9 and Table 1.8-2. These changes are provided in Attachments 2, 4 and 10.

Infor mation provided to address NRC obser vations identified as Punch List Items No. 23, (a) - (f) and No. 32 (c):

Observation 23 (a)

In the top 100 internal events cutsets, cutsets 55 and 73 include only one basic event indicating a potential fundamental issue relevant to the single failure requirement described in GDC 21.

The staff reviewed the DCD markups and finds no discussion, justification, nor technical basis behind these cutsets. The staff is unable to draw any conclusions on these scenarios. Such results restrict staffs ability to make an adequate safety determination.

Response 23 (a)

Components can be impacted or unavailable depending on LLOCA location. For example, if a LLOCA occurs on hot leg connected with SI pump from train D, only one hot leg injection flow path connected with a SI pump from train C can be possible. To consider the different effects by LOCA location, the LLOCA initiator was divided into three areas: (1) cold leg, (2) hot leg and (3) direct vessel injection line (DVI).

However, the recent thermal-hydraulic (T/H) analysis in DCD Chapter.15 shows that boron precipitation is not expected under the condition that there is no hot leg injection during a hot leg LLOCA, and thus no core damage should occur in the accident sequence that hot leg injection fails in a hot leg LLOCA (see APR1400-F-A-NR-14003-P, Rev.1 Post-LOCA Long Term Cooling Evaluation Model, see ML17143A428).

Cutsets #55, #73 appear in table 19.1-19 since hot leg injection in a hot leg LLOCA is assumed and modeled in APR 1400 PRA. The history of this modeling is as follows:

a. To perform realistic analysis for system availability (mitigation capacity) for a LLOCA, KHNP divided three types LLOCAs, i.e. cold leg break, DVI break and hot leg break.
b. When APR1400 PRA model was docketed, T/H analysis results in DCD Chapter 15 were not finalized, and it had not yet been determined whether hot leg injection was required during a LLOCA in the hot leg or not.
c. Consequently, hot leg injection during a LLOCA in hot leg was considered in the PRA model based on the APR 1400 Emergency Operating Guidelines (EOG).

The cutsets (#55 and #73) describes that failure of hot leg injection due to a single failure of the SI pump leads to core damage when a hot leg LLOCA occurs. It does not correspond with the single failure requirement described in GDC 21, however, those cutsets appeared due to the modeling of hot leg injection in a hot leg LLOCA compared to the Chapter 15 analysis. A single failure of the SI pump would not lead to core damage when the COL applicant reviews modeling of hot leg injection in the APR 1400 PRA to decide if the modeling of hot leg injection should be considered in a hot leg LLOCA.

A sensitivity analysis for not modeling hot leg injection during a LLOCA in hot leg shows that the core damage frequency (CDF) is estimated to be 1.1E-06/yr. This is the same as the base model CDF, and therefore, there is no impact even if hot leg injection is modeled.

Non-Proprietary 19-92_Rev.5 - 4 /18 KEPCO/KHNP Other chapters within the DCD would not be affected since the CDF changes are negligible.

Therefore, KHNP believes that hot leg injection in a hot leg LLOCA, for the purposes of risk analysis in Chapter 19, is modeled in APR 1400 PRA. KHNP proposes adding the issue of hot leg injection modeling as a COL item and providing additional information in the DCD as follows:

1) Add assumption I in the DCD section 19.1.4.1.2.5.

i) It is assumed for the purpose of analysis that hot leg injection during a hot leg LLOCA is required and modeled in the APR 1400 PRA. This assumption is less restrained compared to T/H analysis results in DCD Chapter 15.

The mark-up is provided in Attachment 1.

2) Add COL item 19.1(26) in the DCD section 19.1.9 and Table 1.8-2.

COL 19.1(26) The COL applicant will ensure the APR1400 thermal-hydraulic (T/H) analysis supporting the application is reflected in the updated PRA model including those design and operational features for mitigation of a hot leg LLOCA.

The mark-up is provided in Attachment 2.

3) Add Modeling history for hot leg injection in a hot leg LLOCA and explanation for cutsets (#55, #73) in the DCD section 19.1.4.1.2.3.

To perform realistic analysis for system availability (mitigation capacity) for a LLOCA, the PRA analysis evaluated three types of LLOCAs, i.e. cold leg break, DVI break and hot leg break. Consequently, hot leg injection during a LLOCA in hot leg was modeled in the PRA since the guidance in the APR 1400 Emergency Operating Guidelines (EOG) requires the initiation of hot leg injection during a potential LLOCA scenario. For the purposes of the APR 1400 PRA analysis, a failure of hot leg injection due to a single failure of the SI pump resulted in two cutsets within the top 100 which reflected that the modeling could lead core damage when a hot leg LLOCA occurs. However, the recent thermal-hydraulic (T/H) analysis in DCD Chapter.15 shows that boron precipitation is not expected under the condition that there is no hot leg injection during a hot leg LLOCA, and thus no core damage should occur in the accident sequence that hot leg injection fails in a hot leg LLOCA (see APR1400-F-A-NR-14003-P, Rev.1 Post-LOCA Long Term Cooling Evaluation Model, Therefore, based on the T/H analysis performed to support Chapter 15 of the APR1400 design, no single failure will result in core damage or the loss of safety or protection function. To assess this relative to design criteria and T/H analysis performed for deterministic purposes, e.g. Chapter 15, a sensitivity analysis for not modeling hot leg injection during a LLOCA in hot leg shows that the core damage frequency (CDF) is estimated to be 1.1E-06/yr. This is the same as the full power internal base model CDF, and therefore, there is no impact even if hot leg injection is modeled (COL 19.1(26).

The mark-up is provided in Attachment 3.

Non-Proprietary 19-92_Rev.5 - 5 /18 KEPCO/KHNP Observations 23 (b) and (e)

(b) CCF higher in the data notebook than Random Failures. CCF appears to have not been included in the dominant cutsets, e.g. EDG, T-D Pump, etc., explain.

(e) Cutsets #10, #11, and #12 include the combination of individual failures of similar components such as the AFW TDPs or the 2 of the 4 EDGs. However, the CCF of the similar components does not show up in the cutsets, e.g. a CCF of the C and D EDGs would result in a higher cutset probability. This has implications for the CCF combinations omitted and the total plant CDF.

Response 23 (b) and (e)

As shown in the table below, running failure probability for one AF TDP is 3.52E-02, and therefore, running failure probability for two AF TDPs can be calculated to be 1.24E-03 (3.52E-02 x 3.52E-02 = 1.24E-03). This means that the running failure probability for two AF TDPs (1.24E-03) is higher than that of 2/2 running CCF (6.89E-04), and thus, running failure events for AF TDPs can appear in a higher cutset than 2/2 running CCF event. The 2/2 running CCF event for AF TDPs, AFTPKD2-TDP01A/B, appears in a cutset #26.

Basic Event Description Failure Probability AFTPR1A-TDP01A FAILS TO RUN AFW TDP PP01A 3.52E-02 AFTPR1B-TDP01B FAILS TO RUN AFW TDP PP01B 3.52E-02 2/2 CCF OF FOR AFW TDP PP01/A/B AFTPKD2-TDP01A/B 6.89E-04 FAIL TO RUN The issue for running failure and 2/4 running CCF for EDGs can also be interpreted in the same context.

In other cases, CCF probability could be higher than that of random failure probability. For instance, as shown in the table below, 4/4 running CCF probability for EDGs (5.95E-05) is higher than that of random failure combination for EDGs (2.50E-02 x 2.50E-02 x 2.50E-02 x 2.50E-02 = 3.91E-07). The 4/4 running CCF event for EDGs appears in a cutset #14 while random failure combination for EDGs appears in a cutset #2151.

Basic Event Description Failure Probability FAILS TO RUN OF EMERGENCY DGDGR-A-DGA 2.50E-02 DIESEL GENERATOR DG01A FAILS TO RUN OF EMERGENCY DGDGR-B-DGB 2.50E-02 DIESEL GENERATOR DG01B FAILS TO RUN OF EMERGENCY DGDGR-C-DGC 2.50E-02 DIESEL GENERATOR DG01C FAILS TO RUN OF EMERGENCY DGDGR-D-DGD 2.50E-02 DIESEL GENERATOR DG01D 4/4 CCF OF EDG 01A/01B/01C/01D DGDGKQ4-DG01ABCD 5.95E-05 FAIL TO RUN In conclusion, the random failures (e.g., start failure and running failure) and the CCFs for EDGs and AF TDPs are modeled as basic events in the APR 1400 PRA model. CCF probability could

Non-Proprietary 19-92_Rev.5 - 6 /18 KEPCO/KHNP be higher and lower than that of random failure probability, and therefore, the cutset level would be different based on events failure probability.

Observation 23 (c)

The cutsets 28, 51 and 100 include the unavailability due to test and maintenance of two of the same type of component that would not be allowed by Tech Specs, e.g. Containment Spray Heat exchanger, EDGs, and DC Batteries.

Response 23 (c)

Cutsets 28, 51 and 100 should not be presented as a PRA result. For example, cutset 28 is that combination of test and maintenance (T&M) for CS heat exchangers of all of CS Trains. This test and maintenance configuration is not allowed by APR1400 Technical Specifications.

Therefore, KHNP reviewed mutually exclusive cutsets (MUX) in the scope of at power and LPSD conditions (for both internal Level 1/Level2 and external Level 1/Level 2), to assess the effects on CDF and LRF. Recovery rules were made and reviewed for deleting MUX. The MUX rule file consists of 91 combinations of T&M cutset. The MUX rules are based on Technical Specifications provided in Chapter 16 of DCD (Rev.1), and are included in the Attachment 8.

The MUX rule file is applied for the PRA results and the effects on other chapters are provided in . The total CDF/LRF slightly decreases about 1.75% and 0.66% respectively.

KHNP has reviewed the impact on the DCD other chapters, and it has been identified that the change of results does not have the impact on the DCD other chapters. However, there is small impact on the DCD related document for chapter 18, Human Factor Engineering. It is limited to editorial issue of the human factors engineering program element technical report, APR1400-E-I-NR-14006, "Treatment of Important Human Actions Implementation Plan."

Considering the results of applying the MUX rule file and their limited impact on the DCD other chapters, KHNP proposes to provide additional information in the DCD as follows:

In Chapter 19, section 19.1.4.1.1.4, Systems Analysis, subsection b. Conditions concerning level of detail, add assumption (6):

6) The APR1400 PRA model currently contains some test and maintenance configurations which are not permissible by APR1400 Technical Specifications. While these configurations are outside current Technical Specifications for operations, inclusion of these maintenance configurations in the current PRA is conservative with respect to CDF and LRF. The improper cutsets will be excluded from the cutsets resulting from the plant specific PRA, maintenance programs and Technical Specifications developed by the COL applicant (COL 19.1(27)).

The mark-up is provided in Attachment 4.

In Chapter 19, section 19.1.9, add the following COL item:

COL 19.1(27) The COL applicant will review the Technical Specifications and incorporate logic into the PRA model to ensure cutsets reflect permissible maintenance configurations.

Non-Proprietary 19-92_Rev.5 - 7 /18 KEPCO/KHNP The mark-up is provided in Attachment 2.

In addition, KHNP notices that APR 1400 PRA model does not meet QU-B7 and QU-B8 in the ASME standard due to the improper cutsets that would not be allowed by Tech Specs of APR1400 PRA. Therefore, KHNP proposes to revise the DCD in Chapter 19, Table 19.1-1, Characterization of PRA Relative to Supporting Requirements in ASME PRA Standard, to change Quantification (QU) characteristics to read as follows:

The quantification was performed by solving the overall core damage model using the linked fault-tree approach. The quantification satisfies at least Category I for each of the supporting requirements except for two (2) supporting requirements, QU-B7 and QU-B8.

The logic of mutually exclusive events (MUX) did not cover all MUX, thus, some improper test and maintenance events appeared in the PRA results.

The mark-up is provided in Attachment 5.

Observation 23 (d)

The list of cutsets does not include the asymmetric equivalent of Cutset 55, such that the unavailability of the A SI pump in combination with a LLOCA would be in a similar and equivalent cutset.

Response 23 (d)

In section 19.1.4.1.1.4 Systems Analysis, in subsection b. Conditions concerning level of detail, add assumption 7):

7) The APR1400 PRA model is an asymmetric model. Therefore, location specific initiating events are assigned to a single location, e.g., SGTR is assumed to occur in SG #2, DVI line Large LOCA is assumed to occur in DVI line 1B, etc. System models reflect these locational initiating events, e.g., DVI large LOCA is assumed to result in the direct failure of SI pump PP02D and SIT TK01D since the injection flow from these components would be lost via the break in DVI line 1B. In addition, normally operating systems whose trains are operated on a rotational basis (e.g., CC, SX, etc.) have an assumed configuration with one train assumed to be the operating train, and the other train is assumed to be the standby train. Note that for the purposes of determining the CDF and LRF risk metrics, model asymmetry has no impact. The main impact is that the importance of equipment in those systems can differ on a train basis; however, for risk applications related to risk ranking, this can be compensated for by assigning the highest importance measure of a component within a group to all members within the group (COL 19.1(22)).

The mark-up is provided in Attachment 4.

Non-Proprietary 19-92_Rev.5 - 8 /18 KEPCO/KHNP Observation 23 (f)

Cutset 55 assumes a LLOCA and Hot Leg Injection using an SI Pump. It is not clear what is the specific SI Pump success criteria for injecting into the core and to prevent boron precipitation by hot leg injection.

Response 23 (f)

Since RCS inventory makeup and hot leg injection by safety injection pumps are required in response to a large break LOCA (LLOCA), components can be impacted or unavailable depending on the LLOCA locations. For example, if a LLOCA occurs on hot leg connected with SI pump from train D, only one hot leg injection flow path connected with SI pump from train C can be possible. To consider the different effects by LOCA location, the LLOCA initiator was divided into three areas: (1) cold leg, (2) hot leg and (3) direct vessel injection line (DVI). As a result, SI Pump success criteria for injecting into the core and to prevent boron precipitation by hot leg injection (HLI) were identified as follows:

Cold Leg Break DVI Leg Break Hot Leg Break SI Pump success criteria for safety DVI : 2/4 DVI : 2/3 DVI : 2/4 injection SI Pump success criteria for hot leg HLI : 1/2 HLI : 1/2 HLI : 1/1 injection DVI : 1/2 DVI : 1/2 DVI : 1/2 Observation 32 (c)

DCD, Risk Insights table, Item 25, on the C & D Batteries, it should say no load shedding instead of not dc loading" Response 32 (c)

The mark-up addressing this observation relating to the risk insights, Table 19.1-4, item No. 25 is provided in Attachment 6, and an editorial change to the same table, item Nos. 40, 41, and 43 is provided in Attachment 7.

Changes due to the conflict between RAI 19-28 Rev.4 response and RAI 19-92 Rev.1 The Tier 2 DCD Rev.2 subsection 19.1.6.2.2.7 is revised in accordance with RAI 409-8325 Question 19-28 Rev.4 to resolve the conflict between RAI 409-8325 Question 19-28 Rev.4 and RAI 434-8352 Question 19-92 Rev.1 in the 19.1.6.2.2.7 Risk insight. Associated markups to resolve the conflict are provided in the Attachment 13.

Changes due to the mark-ups about RCP seal LOCA probability in RAI 19-16 Rev.2

Non-Proprietary 19-92_Rev.5 - 9 /18 KEPCO/KHNP The Tier 2 DCD Rev.2 Table 19.1-16 and Table 19.1-50 are revised to reflect the markups for RCP seal LOCA probability as provided in the Attachment 14.

Changes due to the conflict between RAI 19-92_Rev.1 response and AI 19-51 Rev.1 The Tier 2 DCD subsection 19.1.9 is revised in accordance with AI 19-51 19.1_#PRA-51 Rev.1 to resolve the conflict between AI 19-51 19.1 #PRA-51 Rev.1 and RAI 434-8352 Question 19-92 Rev.1 in the 19.1.9 Combined License Information. Associated mark-ups are provided in the Attachment 15.

Changes due to Update of APR 1400 PRA-based SMA The Tier 2 DCD subsections 19.1.5.1 and 19.1.6.5 are revised in accordance with revised responses to RAI 434-8352 Question 19-85 Rev. 3 and RAI 232-7864 Question 19-10 Rev.2, respectively. Associated mark-ups due to the PRA-based SMA update, including COL items and risk insights, Table 19.1-4 item No. 66, are provided in Attachments 2, 4 and 10.

Editorial Changes The Tier 2 DCD 19.1.6.2.4.2.6 has been revised to correct wording from internal fire to internal flooding, and DCD 19.1.4.1.1.4 has been revised to add a bullet item Initiating events which affect to the system. The markups addressing these corrections are provided in Attachment 11 and 12, respectively Impact on DCD DCD Section 19.1 & DCD Table 1.8-2 will be revised as indicated in the Attachment 1 & 2.

In the previous revised response (Rev.2), the Attachment only includes the tables changed from RAI 434-8352 Question 19-92 Rev.1.

In this revised response (Rev.3), the Attachments 1, 2, 3, 4, 5, 6 and 7 includes mark-ups changed from RAI 434-8352 Question 19-92 Rev.1 & Rev.2.

In this revised response (Rev.4), the Attachments 2, 3, 4, 10, 11 and12 includes mark-ups changed from RAI 434-8352 Question 19-92 Rev.3.

In this revised response (Rev.5), DCD Section 19.1.6.2.2.7, Table 19.1-16 and Table 19.1-50, Section 19.1.9 will be revised as shown in the Attachment 13, 14, 15 respectively.

Non-Proprietary 19-92_Rev.5 - 10 /18 KEPCO/KHNP Impact on PRA There is no impact on the PRA.

Impact on Technical Specifications There is no impact on the Technical Specifications.

Impact on Technical/Topical/Environmental Reports There is no impact on any Technical, Topical, or Environmental Report.

Non-Proprietary 19-92_Rev.5 - 11 /18 KEPCO/KHNP Table 1 - Section 19.1 Table Update Status from 2017 PRA Update Table Number Table Title Update Status Characterization of PRA Relative to Supporting Table 19.1-1 Unchanged Requirements in ASME PRA Standard Table 19.1-2 Key Design Features in APR1400 Unchanged Table 19.1-3 Design Features Addressing Potential Risk Challenges Unchanged Table 19.1-4 Risk Insights and Key Assumptions Partial Update Relation of the Plant Safety Functions and the Initiating Table 19.1-5 Unchanged Events Types Table 19.1-6 Internal Events PRA Initiating Event Frequencies Table Replaced Table 19.1-7 Level 1 Internal Events PRA Event Tree List Unchanged Table 19.1-8 Event Tree Top Events and Success Criteria Unchanged Table 19.1-9 PRA Modeled Systems Unchanged Dependency between Initiating Events and Front Line Table 19.1-10a Unchanged Systems Dependency between Initiating Events and Support Table 19.1-10b Unchanged Systems Table 19.1-11a Front Line System Dependencies on Support Systems Unchanged Table 19.1-11b Support System Dependencies on Other Support Systems Unchanged Table 19.1-12 RELAP Thermal-Hydraulic Run Summaries Unchanged Table 19.1-13 MAAP Thermal-Hydraulic Run Summaries Unchanged Table 19.1-14 Component Failure Rate Data Table Replaced Table 19.1-14a Component Unavailability Data New Table Table 19.1-15 Component Boundaries Unchanged Table 19.1-16 Special Basic Events Table Replaced Level 1 Internal Events CDF Contribution by Initiating Table 19.1-17 Table Replaced Events Table 19.1-18 Level 1 Internal Events Top Accident Sequences Table Replaced Table 19.1-19 Level 1 Internal Events Top 100 CDF Cutsets Table Replaced Table 19.1-20 Level 1 Internal Events Key Basic Events RAW (CDF) Table Replaced Table 19.1-21 Level 1 Internal Events Key Basic Events by FV (CDF) Table Replaced Table 19.1-22 Level 1 Internal Events Key CCF Events by RAW (CDF) Table Replaced Table 19.1-23 Level 1 Internal Events Key CCF Events by FV (CDF) Table Replaced Level 1 Internal Events Key Operator Actions by RAW Table 19.1-24 Table Replaced (CDF)

Level 1 Internal Events Key Operator Actions by FV Table 19.1-25 Table Replaced (CDF)

Table 19.1-26 PDS Grouping Parameters Unchanged Table 19.1-27 Frequency of Dominant PDSs Table Replaced Table 19.1-28 Containment Failure Modes and Results Unchanged

Non-Proprietary 19-92_Rev.5 - 12 /18 KEPCO/KHNP Table 1 - Section 19.1 Table Update Status from 2017 PRA Update Table Number Table Title Update Status Comparison of Containment Pressure Between 19.1, 19.2 Table 19.1-28a Unchanged and 19.3 Table 19.1-29 Summary of Source Term Evaluation Unchanged Source Term Category Frequencies and Contributions to Table 19.1-30 Table Replaced LRF for Internal Events Source Term Category Frequencies and Contributions to Table 19.1-30a Table Replaced LRF for Internal Fire Events Source Term Category Frequencies and Contributions to Table 19.1-30b Table Replaced LRF for Internal Flooding Events Table 19.1-31 Level 2 Internal Events Top 100 LRF Cutsets Table Replaced Level 2 Internal Events LRF Contributions by Initiating Table 19.1-32 Table Replaced Events Table 19.1-33 Significant PDS Contributors to LRF Table Deleted Table 19.1-34 Level 2 Internal Events Key Basic Events by RAW (LRF) Table Replaced Table 19.1-35 Level 2 Internal Events Key Basic Events by FV (LRF) Table Replaced Table 19.1-36 Level 2 Internal Events Key CCF Events by RAW (LRF) Table Replaced Table 19.1-37 Level 2 Internal Events Key CCF Events by FV (LRF) Table Replaced Level 2 Internal Events Key Operator Actions by RAW Table 19.1-38 Table Replaced (LRF)

Level 2 Internal Events Key Operator Actions by FV Table 19.1-39 Table Replaced (LRF)

Table 19.1-40 Results of LRF Sensitivity Analyses Table Replaced See RAI 19-10 Table 19.1-41 Systems Considered for Seismic Equipment List

Response

See RAI 19-10 Table 19.1-42 Seismic Equipment List

Response

See RAI 19-10 Table 19.1-43 Seismic Fragility Analysis Results Summary

Response

Table 19.1-44 Dominant Contributors to the Plant HCLPF Table Replaced Table 19.1-45 Fire Compartment Initiator Development and Screening Unchanged Table 19.1-46a Internal Fire PRA Fire - Induced Initiators IEF Table Replaced Internal Fire PRA CDF Contribution by Top Fire Induced Table 19.1-46b Table Replaced Initiators Internal Fire PRA LRF Contribution by Top Fire Induced Table 19.1-46c Table Replaced Initiators Table 19.1-47 Internal Fire PRA CDF Contribution by Top Fire Scenario Table Replaced Table 19.1-48 Internal Fire PRA LRF Contribution by Top Fire Scenario Table Replaced Table 19.1-49 Internal Fire PRA Top 100 CDF Cutsets Table Replaced Table 19.1-50 Internal Fire PRA Top 100 LRF Cutsets Table Replaced

Non-Proprietary 19-92_Rev.5 - 13 /18 KEPCO/KHNP Table 1 - Section 19.1 Table Update Status from 2017 PRA Update Table Number Table Title Update Status Table 19.1-51 Internal Fire PRA Key Basic Events by RAW (CDF) Table Replaced Table 19.1-52 Internal Fire PRA Key Basic Events by FV (CDF) Table Replaced Table 19.1-53 Internal Fire PRA Key CCF Events by RAW (CDF) Table Replaced Table 19.1-54 Internal Fire PRA Key CCF Events by FV (CDF) Table Replaced Table 19.1-55 Internal Fire PRA Key Operator Actions by RAW (CDF Table Replaced Table 19.1-56 Internal Fire PRA Key Operator Actions by FV (CDF) Table Replaced Table 19.1-57 Internal Fire PRA Key Basic Events by RAW (LRF) Table Replaced Table 19.1-58 Internal Fire PRA Key Basic Events by FV (LRF) Table Replaced Table 19.1-59 Internal Fire PRA Key CCF Events by RAW (LRF) Table Replaced Table 19.1-60 Internal Fire PRA Key CCF Events by FV (LRF) Table Replaced Table 19.1-61 Internal Fire PRA Key Operator Actions by RAW (LRF) Table Replaced Table 19.1-62 Internal Fire PRA Key Operator Actions by FV (LRF) Table Replaced Table 19.1-62a Flood Sources by Flood Area Unchanged Table 19.1-63 Internal Flooding Initiating Event Summary Table Replaced Internal Flooding PRA CDF Contribution by Top Table 19.1-64 Table Replaced Flooding Induced Initiators Internal Flooding PRA LRF Contribution by Top Table 19.1-65 Table Replaced Flooding Induced Initiators Table 19.1-66 Internal Flooding PRA Top 100 CDF Cutsets Table Replaced Table 19.1-67 Internal Flooding PRA Top 100 LRF Cutsets Table Replaced Table 19.1-68 Internal Flooding PRA Key Basic Events by RAW (CDF) Table Replaced Table 19.1-69 Internal Flooding PRA Key Basic Events by FV (CDF) Table Replaced Table 19.1-70 Internal Flooding PRA Key CCF Events by RAW (CDF) Table Replaced Table 19.1-71 Internal Flooding PRA Key CCF Events by FV (CDF) Table Replaced Internal Flooding PRA Key Operator Actions by RAW Table 19.1-72 Table Replaced (CDF)

Internal Flooding PRA Key Operator Actions by FV Table 19.1-73 Table Replaced (CDF)

Table 19.1-74 Internal Flooding PRA Key Basic Events by RAW (LRF) Table Replaced Table 19.1-75 Internal Flooding PRA Key Basic Events by FV (LRF) Table Replaced Table 19.1-76 Internal Flooding PRA Key CCF Events by RAW (LRF) Table Replaced Table 19.1-77 Internal Flooding PRA Key CCF Events by FV (LRF) Table Replaced Internal Flooding PRA Key Operator Actions by RAW Table 19.1-78 Table Replaced (LRF)

Internal Flooding PRA Key Operator Actions by FV Table 19.1-79 Table Replaced (LRF)

See RAI 19-14 Table 19.1-80 Summary of External Hazard Dispositions

Response

Non-Proprietary 19-92_Rev.5 - 14 /18 KEPCO/KHNP Table 1 - Section 19.1 Table Update Status from 2017 PRA Update Table Number Table Title Update Status Table 19.1-81 LPSD Plant Operating States Unchanged Table 19.1-82 LPSD PRA Loss of SCS Initiators Unchanged Table 19.1-83 LPSD PRA General LOCA Initiators Table Replaced Table 19.1-84 LPSD PRA Shutdown-Specific LOCA Initiators Unchanged Table 19.1-85 LPSD PRA (LOOP)(SBO) Initiators Table Replaced Table 19.1-86 LPSD PRA Loss of Supporting System Initiators Table Replaced Table 19.1-87 LPSD PRA Transient Events Initiators Table Replaced Table 19.1-88 LPSD PRA Accident Sequences Summary Unchanged LPSD PRA Success Criteria Summary for Events Table 19.1-89 Unchanged Involving Loss of Operating SCS Train LPSD PRA Success Criteria Summary for Events Table 19.1-90 Unchanged Involving RCS Inventory Table 19.1-91 LPSD PRA Success Criteria Summary for SBO Events Unchanged LPSD PRA Success Criteria Summary for Table 19.1-92 Unchanged TLOCCW/TLOESW Events Table 19.1-92a The Results of Thermal-Hydraulic Analyses for POS 12B Unchanged Table 19.1-92b Summary of Analysis Results for Plant Operating States Unchanged LPSD PRA Internal Events CDF Contributions for Table 19.1-93 Table Replaced Initiating Event - All POS LPSD PRA Internal Events CDF Contributions for Table 19.1-94 Table Replaced Initiating Event - Reduced Inventory LPSD Internal Events PRA CDF Contributions by Plant Table 19.1-95 Table Replaced Operating State LPSD Internal Events PRA Top 100 CDF Cutsets - All Table 19.1-96 Table Replaced POS LPSD Internal Events PRA Top 100 CDF Cutsets -

Table 19.1-97 Table Replaced Reduced Inventory LPSD Internal Events PRA Key Basic Events by RAW Table 19.1-98 Table Replaced (CDF) - All POS LPSD Internal Events PRA Key Basic Events by RAW Table 19.1-99 Table Replaced (CDF) - Reduced Inventory LPSD Internal Events PRA Key Basic Events by FV Table 19.1-100 Table Replaced (CDF) - All POS LPSD Internal Events PRA Key Basic Events by FV Table 19.1-101 Table Replaced (CDF) - Reduced Inventory LPSD Internal Events PRA Key CCF Events by RAW Table 19.1-102 Table Replaced (CDF)

LPSD Internal Events PRA Key CCF Events by FV Table 19.1-103 Table Replaced (CDF)

Table 19.1-104 LPSD Internal Events PRA Key Operator Actions by Table Replaced

Non-Proprietary 19-92_Rev.5 - 15 /18 KEPCO/KHNP Table 1 - Section 19.1 Table Update Status from 2017 PRA Update Table Number Table Title Update Status RAW (CDF)

LPSD Internal Events PRA Key Operator Actions by FV Table 19.1-105 Table Replaced (CDF)

LPSD Internal Events PRA Key Initiating Events by FV Table 19.1-105a Table Replaced (CDF)

LPSD Internal Events PRA Key Initiating Events by Table 19.1-105b Table Replaced RAW (CDF)

LPSD Internal Events PRA Key Initiating Events by Table 19.1-105c Table Replaced RRW (CDF)

LPSD Internal Flooding PRA CDF Contributions for Table 19.1-106 Table Replaced Initiating Events - All POS LPSD Internal Flooding PRA CDF Contributions for Table 19.1-107 Table Replaced Initiating Events - Reduced Inventory LPSD Internal Events PRA Key Initiating Events by See Table Table 19.1-107a RAW (CDF) 19.1-105b LPSD Internal Flooding PRA CDF Contributions by Plant Table 19.1-108 Table Replaced Operating State LPSD Internal Events PRA Key Initiating Events by See Table Table 19.1-108a RRW (CDF) 19.1-105c LPSD Internal Flooding PRA CDF Top 100 Cutsets - All Table 19.1-109 Table Replaced POS LPSD Internal Flooding PRA CDF Top 100 Cutsets -

Table 19.1-110 Table Replaced Reduced Inventory LPSD Internal Flooding PRA Key Basic Events by RAW Table 19.1-111 Table Replaced (CDF) - All POS LPSD Internal Flooding PRA Key Basic Events by RAW Table 19.1-112 Table Replaced (CDF) - Reduce Inventory LPSD Internal Flooding PRA Key Basic Events by FV Table 19.1-113 Table Replaced (CDF) - All POS LPSD Internal Flooding PRA Key Basic Events by FV Table 19.1-114 Table Replaced (CDF) - Reduced Inventory Table 19.1-115 LPSD Internal Flooding PRA Key CCF by RAW (CDF) Table Replaced Table 19.1-116 LPSD Internal Flooding PRA Key CCF by FV (CDF) Table Replaced LPSD Internal Flooding PRA Key Operator Actions by Table 19.1-117 Table Replaced RAW (CDF)

LPSD Internal Flooding PRA Key Operator Actions by Table 19.1-118 Table Replaced FV (CDF)

LPSD Fire PRA CDF Contributions by Plant Operating Table 19.1-119 Table Replaced State LPSD PRA CDF Contributions for Internal Fire Initiating Table 19.1-120 Table Replaced Events - All POS

Non-Proprietary 19-92_Rev.5 - 16 /18 KEPCO/KHNP Table 1 - Section 19.1 Table Update Status from 2017 PRA Update Table Number Table Title Update Status LPSD PRA CDF Contributions for Internal Fire Initiating Table 19.1-121 Table Replaced Events - Reduced Inventory Table 19.1-122 LPSD PRA CDF Internal Fire Top 100 Cutsets - All POS Table Replaced LPSD PRA CDF Internal Fire Top 100 Cutsets - Reduced Table 19.1-123 Table Replaced Inventory LPSD Internal Fire PRA Key Basic Events by RAW Table 19.1-124 Table Replaced (CDF) - All POS LPSD Internal Fire PRA Key Basic Events by RAW Table 19.1-125 Table Replaced (CDF) - Reduced Inventory LPSD Internal Fire PRA Key Basic Events by FV (CDF)

Table 19.1-126 Table Replaced

- All POS LPSD Internal Fire PRA Key Basic Events by FV (CDF)

Table 19.1-127 Table Replaced

- Reduced Inventory Table 19.1-128 LPSD Internal Fire PRA Key CCF by RAW (CDF) Table Replaced Table 19.1-129 LPSD Internal Fire PRA Key CCF by FV (CDF) Unchanged LPSD Internal Fire PRA Key PRA Operator Actions by Table 19.1-130 Table Replaced RAW (CDF)

LPSD Internal Fire PRA Key PRA Operator Actions by Table 19.1-131 Table Replaced FV (CDF)

Table 19.1-132 APR1400 Shutdown LRF Screening Methodology Table Replaced Table 19.1-133 APR1400 LPSD Internal Events Release Fractions Table Replaced Table 19.1-134 Internal Events LPSD LRF by POS Table Replaced LPSD Internal Events PRA Top 100 Cutsets (LRF) - All Table 19.1-135 Table Replaced POS LPSD Internal Events PRA Top 100 Cutsets (LRF) -

Table 19.1-136 Table Replaced Reduced Inventory LPSD Internal Events PRA LRF Contribution by Table 19.1-137 Table Replaced Initiating Events - POS 4B to 12A LPSD Internal Events PRA LRF Contribution by Table 19.1-138 Table Replaced Initiating Events - Reduced Inventory POS LPSD Internal Events PRA Key Basic Events by RAW Table 19.1-139 Table Replaced (LRF) - POS 4B to 12A LPSD Internal Events PRA Key Basic Events by RAW Table 19.1-140 Table Replaced (LRF) - Reduced Inventory LPSD Internal Events PRA Key Basic Events by FV Table 19.1-141 Table Replaced (LRF) - POS 4B to 12A LPSD Internal Events PRA Key Basic Events by RAW Table 19.1-142 Table Replaced (LRF) - Reduced Inventory LPSD Internal Events PRA Key CCF Events by RAW Table 19.1-143 Table Replaced (LRF)

Table 19.1-144 LPSD Internal Events PRA Key CCF Events by FV Table Replaced

Non-Proprietary 19-92_Rev.5 - 17 /18 KEPCO/KHNP Table 1 - Section 19.1 Table Update Status from 2017 PRA Update Table Number Table Title Update Status (LRF)

LPSD Internal Events PRA Key Operator Actions by Table 19.1-145 Table Replaced RAW (LRF)

LPSD Internal Events PRA Key Operator Actions by FV Table 19.1-146 Table Replaced (LRF)

LPSD Internal Events Source Term Category Frequencies Table 19.1-147 Table Replaced and Contributions to LRF (POS 4B-12A)

Table 19.1-148 LPSD Fire LRF by POS Table Replaced LPSD Internal Fire PRA Top 100 Cutsets (LRF) - All Table 19.1-149 Table Replaced POS LPSD Internal Fire PRA Top 100 Cutsets (LRF) -

Table 19.1-150 Table Replaced Reduced Inventory LPSD Internal Fire PRA LRF Contribution by Initiating Table 19.1-151 Table Replaced Events - All POS LPSD Internal Fire PRA LRF Contribution by Initiating Table 19.1-152 Table Replaced Events - Reduced Inventory POS LPSD Internal Fire PRA Key Basic Events by RAW Table 19.1-153 Table Replaced (LRF) -All POS LPSD Internal Fire PRA Key Basic Events by RAW Table 19.1-154 Table Replaced (LRF) -Reduced Inventory LPSD Internal Fire PRA Key Basic Events by FV (LRF)

Table 19.1-155 Table Replaced

- All POS LPSD Internal Fire PRA Key Basic Events by FV (LRF)

Table 19.1-156 Table Replaced

- Reduced Inventory LPSD Internal Fire PRA Key CCF Events by RAW Table 19.1-157 Table Replaced (LRF)

Table 19.1-158 LPSD Internal Fire PRA Key CCF Events by FV (LRF) Table Replaced LPSD Internal Fire PRA Key Operator Actions by RAW Table 19.1-159 Table Replaced (LRF)

LPSD Internal Events PRA Key Operator Actions by FV Table 19.1-160 Table Replaced (LRF)

LPSD FPRA Source Term Category Frequencies and Table 19.1-161 Table Replaced Contributions to LRF (POS 4B-12A)

Table 19.1-162 AFWS Unreliability Results See RAI 19-45

Non-Proprietary 19-92_Rev.5 - 18 /18 KEPCO/KHNP Table 2 - Section 19.1 Revised Table Update Status Table Number Table Title Update Status Table 19.1-31 Level 2 Internal Events Top 100 LRF Cutsets Table Modified Table 19.1-66 Internal Flooding PRA Top 100 CDF Cutsets Table Modified Table 19.1-67 Internal Flooding PRA Top 100 LRF Cutsets Table Modified LPSD Internal Events PRA Top 100 CDF Cutsets - All Table 19.1-96 Table Modified POS LPSD Internal Events PRA Top 100 CDF Cutsets -

Table 19.1-97 Table Modified Reduced Inventory LPSD Internal Flooding PRA CDF Top 100 Cutsets - All Table 19.1-109 Table Modified POS LPSD Internal Flooding PRA CDF Top 100 Cutsets -

Table 19.1-110 Table Modified Reduced Inventory LPSD Internal Events PRA Top 100 Cutsets (LRF) - All Table 19.1-135 Table Modified POS LPSD Internal Events PRA Top 100 Cutsets (LRF) -

Table 19.1-136 Table Modified Reduced Inventory

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APR1400 DCD TIER 2 RAI 434-8352 Question 19-92_Rev.3 RAI 434-8352 Question 19-92_Rev.4 COL 19.1(20) The COL applicant is to perform the seismic-fire interactions walkdown to confirm a qualitative seismic-fire interaction assessment.

COL 19.1(21) The COL applicant is to develop outage procedures to ensure that in fire compartments containing post-seismic or post-fire safe shutdown equipment that: 1) the seismic ruggedness of temporary ignition sources is adequate, or that the duration that these temporary ignition sources are in these areas is minimized, 2) the seismic ruggedness of temporary equipment such as scaffolding in fire compartments containing potential seismic-fire ignition sources, or near fire protection equipment is adequate, and 3) either the duration of activities which could impact manual firefighting is minimized, or alternative firefighting equipment (e.g., pre-stage portable smoke removal equipment, prestage additional firefighting equipment, etc.) is supplied.

COL 19.1(22) The COL applicant is to demonstrate that failure of buildings that are not seismic Category I (e.g., turbine building and compound building) does not impact SSCs designed to be seismic Category I.

COL 19.1(23) The COL applicant is to ensure that asymmetric conditions due to modeling simplicity will be addressed or properly accounted for when the 22 PRA is used for decision making.

COL 19.1(24) The COL applicant will demonstrate that maintenance-induced floods are negligible contributors to flood risk when the plant specific data are 23 available.

Add A 19.1.10 References

1. ASME/ANS RA-S-2008, Standard for Level 1/Large Early Release Frequency Probabilistic Risk Assessment for Nuclear Power Plant Applications (Revision 1 RA-S-2002), American Society of Mechanical Engineers, April 2008.
2. ASME/ANS RA-Sa-2009, Addenda to ASME/ANS RA-S-2008, American Society of Mechanical Engineers, February 2009.

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APR1400 DCD TIER 2 RAI 434-8352 Question 19-92_Rev.3 RAI 434-8352 Question 19-92_Rev.4 Table 1.8-2 (36 of 38)

Item No. Description COL 19.1(21) The COL applicant is to develop outage procedures to ensure that in fire compartments containing post-seismic or post-fire safe shutdown equipment that: 1) the seismic ruggedness of temporary ignition sources is adequate, or that the duration that these temporary ignition sources are in these areas is minimized, 2) the seismic ruggedness of temporary equipment such as scaffolding in fire compartments containing potential seismic-fire ignition sources, or near fire protection equipment is adequate, and 3) either the duration of activities which could impact manual firefighting is minimized, or alternative firefighting equipment (e.g.,

pre-stage portable smoke removal equipment, prestage additional firefighting equipment, etc.) is supplied.

COL 19.1(22) The COL applicant is to demonstrate that failure of buildings that are not seismic Category I (e.g., turbine building and compound building) does not impact SSCs designed to be seismic 22 Category I.

COL 19.1(23) The COL applicant is to ensure that asymmetric conditions due to modeling simplicity will 23 be addressed or properly accounted for when the PRA is used for decision making.

COL 19.1(24) The COL applicant will demonstrate that maintenance-induced floods are negligible Add B contributors to flood risk when the plant specific data are available.

COL 19.2(1) The COL applicant is to perform and submit site-specific equipment survivability assessment in accordance with 10 CFR 50.34(f) and 10 CFR 50.44 which reflects the equipment identified and the containment atmospheric assessments of temperature, pressure and radiation described in Subsection 19.2.3.3.7.

COL 19.2(2) The COL applicant will demonstrate that the covers for large penetrations such as equipment hatch and personnel airlocks meet the Service Level C requirements in Subsection NE-3220 of the ASME code and explain how the consideration of containment leakage is accounted for when modeling local regions of containment.

COL 19.2(3) The COL applicant is to develop and submit an accident management plan.

COL 19.3(1) The COL applicant is to perform site-specific seismic hazard evaluation and seismic risk evaluation as applicable in accordance with NTTF Recommendation 2.1 as outlined in the NRC RFI.

COL 19.3(2) The COL applicant is to address the flood requirements for wet sites COL 19.3(3) The COL applicant is to develop the details for offsite resources.

COL 19.3(4) The COL applicant is to address the details of selecting suitable storage locations for FLEX equipment that provide reasonable protection during specific external events as provided in NEI 12-06 guidance Sections 5 through 9, and the details of the guidance for storage of FLEX equipment provided in the Technical Report (Reference 5) Section 6.2.9.G COL 19.3(5) The COL applicant is to confirm, satisfy, or fulfill the specific design functional requirements of raw water tank including the associated instrument, capacity, location, flow path to on-site, the valve pit connected to FLEX equipment, and any other design features as described in Section 19.3 in support of BDBEE mitigation strategies.

COL 19.3(6) The COL applicant is to confirm and ensure that the raw water tank and flow path to the FLEX equipment (structures, piping, components, and connections) are designed to be robust with respect to applicable hazards (e.g., seismic events, floods, high winds, and associated missiles).

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VDHVM-A-HV13A VDHVM-D-HV13D VDHVM-B-HV12B VDHVM-C-HV12C VDHVM-B-HV12B VDHVM-C-HV13C VDHVM-B-HV13B VDHVM-C-HV12C VDHVM-B-HV13B VDHVM-C-HV13C VDHVM-C-HV12C VDHVM-D-HV12D VDHVM-C-HV12C VDHVM-D-HV13D VDHVM-C-HV13C VDHVM-D-HV12D VDHVM-C-HV13C VDHVM-D-HV13D DGDGM-A-DGA DOMPM-B-PP01B DOMPM-B-PP02B DGDGM-A-DGA DOMPM-D-PP01D DOMPM-D-PP02D DGDGM-B-DGB DOMPM-A-PP01A DOMPM-A-PP02A DGDGM-B-DGB DOMPM-C-PP01C DOMPM-C-PP02C DGDGM-C-DGC DOMPM-B-PP01B DOMPM-B-PP02B DGDGM-C-DGC DOMPM-D-PP01D DOMPM-D-PP02D DGDGM-D-DGD DOMPM-A-PP01A DOMPM-A-PP02A DGDGM-D-DGD DOMPM-C-PP01C DOMPM-C-PP02C DOMPM-A-PP01A DOMPM-A-PP02A VDHVM-B-HV12B DOMPM-A-PP01A DOMPM-A-PP02A VDHVM-B-HV13B DOMPM-A-PP01A DOMPM-A-PP02A VDHVM-D-HV12D DOMPM-A-PP01A DOMPM-A-PP02A VDHVM-D-HV13D DOMPM-B-PP01B DOMPM-B-PP02B VDHVM-A-HV12A DOMPM-B-PP01B DOMPM-B-PP02B VDHVM-A-HV13A DOMPM-B-PP01B DOMPM-B-PP02B VDHVM-C-HV12C DOMPM-B-PP01B DOMPM-B-PP02B VDHVM-C-HV13C DOMPM-C-PP01C DOMPM-C-PP02C VDHVM-B-HV12B DOMPM-C-PP01C DOMPM-C-PP02C VDHVM-B-HV13B DOMPM-C-PP01C DOMPM-C-PP02C VDHVM-D-HV12D DOMPM-C-PP01C DOMPM-C-PP02C VDHVM-D-HV13D DOMPM-D-PP01D DOMPM-D-PP02D VDHVM-A-HV12A DOMPM-D-PP01D DOMPM-D-PP02D VDHVM-A-HV13A DOMPM-D-PP01D DOMPM-D-PP02D VDHVM-C-HV12C DOMPM-D-PP01D DOMPM-D-PP02D VDHVM-C-HV13C DOMPM-A-PP01A DOMPM-A-PP02A DOMPM-B-PP01B DOMPM-B-PP02B DOMPM-A-PP01A DOMPM-A-PP02A DOMPM-D-PP01D DOMPM-D-PP02D DOMPM-B-PP01B DOMPM-B-PP02B DOMPM-C-PP01C DOMPM-C-PP02c DOMPM-C-PP01C DOMPM-C-PP02C DOMPM-D-PP01D DOMPM-D-PP02D

LCO 3.8.4 DCBTM-A-BT01A DCBTM-B-BT01B DCBTM-A-BT01A DCBTM-C-BT01C DCBTM-A-BT01A DCBTM-D-BT01D DCBTM-B-BT01B DCBTM-C-BT01C DCBTM-B-BT01B DCBTM-D-BT01D DCBTM-C-BT01C DCBTM-D-BT01D
LCO 3.8.7 IPINM-A-IN01A IPINM-B-IN01B IPINM-A-IN01A IPINM-C-IN01C IPINM-A-IN01A IPINM-D-IN01D IPINM-B-IN01B IPINM-C-IN01C IPINM-B-IN01B IPINM-D-IN01D IPINM-C-IN01C IPINM-D-IN01D

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Attachment 6. The sensitivity Analysis Results for Appling MUX Rule File

1. The MUX rule file is applied for all parts of PRA and the results are introduced below.
a. At-Power
1) At-Power Level 1 Internal Event CDF Decrease CDF MCS Rev.1 model 1.10E-06 - 655,609 Delete MUX 1.01E-06 9.00E-08 (8.18%) 591,841
2) At-Power Level 1 Internal Fire CDF Decrease CDF MCS Rev.1 model 2.22E-06 - 620,856 Delete MUX 2.20E-06 2.00E-08 (0.90%) 594,235
3) At-Power Level 1 Internal Flooding CDF Decrease CDF MCS Rev.1 model 4.00E-07 - 190,960 Delete MUX 4.00E-07 0.00E-00 (0.00%) 189,374
4) At-Power Level 2 Internal Event LRF Decrease LRF MCS Rev.1 model 1.00E-07 - 52,966 Delete MUX 9.65E-08 3.50E-09 (3.50%) 44,764
5) At-Power Level 2 Internal Fire LRF Decrease LRF MCS Rev.1 model 1.85E-07 - 93,971 Delete MUX 1.85E-07 0.00E-00 (0.00%) 92,751
6) At-Power Level 2 Internal Flooding LRF Decrease LRF MCS Rev.1 model 2.54E-08 - 226,874 Delete MUX 2.54E-08 0.00E-00 (0.00%) 226,106
b. Low Power and Shutdown
1) LPSD Level 1 Internal Event CDF Decrease CDF MCS Rev.1 model 1.80E-06 - 80,843 Delete MUX 1.80E-06 0.00E-00 (0.00%) 79,914
2) LPSD Level 1 Internal Fire CDF Decrease CDF MCS Rev.1 model 1.25E-06 - 39,639 Delete MUX 1.25E-06 0.00E-00 (0.00%) 39,639

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3) LPSD Level 1 Internal Flooding CDF Decrease CDF MCS Rev.1 model 8.02E-08 - 10,923 Delete MUX 8.02E-08 0.00E-00 (0.00%) 10,923
4) LPSD Level 2 Internal Event LRF Decrease LRF MCS Rev.1 model 7.02E-08 - 129,683 Delete MUX 7.02E-08 0.00E-00 (0.00%) 129,679
5) LPSD Level 2 Internal Fire LRF Decrease LRF MCS Rev.1 model 6.68E-08 - 56474 Delete MUX 6.68E-08 0.00E-00 (0.00%) 56474
6) LPSD Level 2 Internal Flooding CDF Decrease CDF MCS Rev.1 model 8.02E-08 - 10,923 Delete MUX 8.02E-08 0.00E-00 (0.00%) 10,923 Note: The CDF for LPSD level 1 internal flooding is 8.02E-08/y. This value is very low compared with LPSD level 1 internal event and internal fire, both of which are 1.8E-06/year and 1.2E-06/y respectively. Thus, LPSD internal flooding CDF is conservatively assigned to the LRF. In other words, there is no separate cutsets for LRF and it is bounded by level 1 LPSD flooding.
c. Summary of Results The table below summarizes the results above. As shown in the table, there is a CDF decrease 9.00E-08 (8.18%) by deleting MUX for at-power Level 1 internal events PRA. Overall, the total CDF and LRF are decreased by 1.75% and 0.66% respectively. With deletion of MUX, it has no effect on the LPSD PRA.

This is due to the configuration of each system and the maintenance of equipment are analyzed separately during shutdown cooling operation (POS 3A through 13). Therefore, the results of CDF and LRF are not changed.

At-Power LPSD Level 1 Level 1 Total CDF IE Fire Flood IE Fire Flood Rev.1 model 1.10E-06 2.22E-06 4.00E-07 1.80E-06 1.25E-06 8.02E-08 6.85E-06 Delete MUX 1.01E-06 2.19E-06 4.00E-07 1.80E-06 1.25E-06 8.02E-08 6.73E-06 Decrease 9.00E-08 2.00E-08 0.00E+00 0.00E+00 0.00E+00 0.00E+00 1.20E-07 Decrease (%) 8.18% 0.90% 0.00% 0.00% 0.00% 0.00% 1.75%

At-Power LPSD Level 2 Level 2 Total LRF IE Fire Flood IE Fire Flood Rev.1 model 1.00E-07 1.85E-07 2.54E-08 7.02E-08 6.68E-08 8.02E-08 5.28E-07 Delete MUX 9.65E-08 1.85E-07 2.54E-08 7.02E-08 6.68E-08 8.02E-08 5.24E-07 Decrease 3.50E-09 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 3.50E-09 Decrease (%) 3.50% 0.00% 0.00% 0.00% 0.00% 0.00% 0.66%

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2) The impact of DCD Other Chapters by Appling MUX Rule File KHNP has reviewed the impact on DCD other chapters resulted from applying MUX rule file. With respect to Physical Security (Ch. 13.6), ITAAC (Ch. 14.3), Technical Specifications (Ch. 16), Reliability Assurance Program (Ch. 17.4) and Severe Accidents (Ch. 19.2) are not affected by deleting cutsets in the PRA results. With respect to Human Factor Engineering (Ch. 18), two (2) human failure events were identified and added as a RIHA by deleting MUX. However, Most of specific human factors designs in the APR1400 are COL items.

PRA Scope Additional RIHA Remark added by FV in at power Level 1 internal CVOPH-S-BORATION Internal Events at power events Level 1 & Level 2 added by FV in at power Level 2 internal VKOPH-S-ECCS events Internal Fire at Power

- No Change Level 1 & Level 2 Internal Flood at Power

- No Change Level 1 & Level 2 Internal Events for LPSD

- No Change Level 1 & Level 2 Internal Fire for LPSD

- No Change Level 1 & Level 2 Internal Flood for LPSD

- No Change Level 1 & Level 2 Thus, it is expected that the change of RIHAs has no effect on human factors design, but only one document, APR1400-E-I-NR-14006 Treatment of Important Human Actions Implementation Plan, is required for revising RIHAs list.

RAI 434-8352 - Question 19-92_Rev.5 Non-Proprietary Attachment 10 (1/12)

APR1400 DCD TIER 2 RAI 434-8352 Question 19-92_Rev.4 Table 1.8-2 (35 of 39)

Item No. Description COL 17.5(1) The COL applicant is to establish and implement a QA program that is applicable to site-specific design activities related to the plant construction and operation phases.

COL 17.6(1) The COL applicant is to provide in its Final Safety Analysis Report a description of the Maintenance Rule program and a plan for implementing it to meet the requirements of 10 CFR 50.65.

COL 18.12(1) The COL applicant is to provide the human performance monitoring program.

COL 19.0(1) The COL applicant is either to confirm that the PRA in the design certification bounds the site-specific design information and any design changes or departures, or to update the PRA to reflect the site-specific design information and any design changes or departures.

COL 19.1(1) The COL applicant is to describe the uses of PRA in support of licensee programs, and to identify and describe risk-informed applications being implemented during the combined license application phase.

COL 19.1(2) The COL applicant is to describe the uses of PRA in support of licensee programs, and identify and describe risk-informed applications being implemented during the construction phase.

COL 19.1(3) The COL applicant is to describe the uses of PRA in support of licensee programs, and identify and describe risk-informed applications being implemented during the operational phase.

COL 19.1(4) The COL applicant is to review as-designed and as-built information and conduct walkdowns as necessary to confirm that the assumptions used in the PRA (including PRA inputs to RAP and SAMDA) remain valid with respect to internal events, internal flood and fire events (fire barrier and fire barrier penetrations, routings and locations of pipe, cable, and conduit), and HRA analyses (development of operating procedures, emergency operating procedures, and severe accident management guidelines and training), external events including PRA-based seismic margins and HCLPF fragilities, and LPSD procedures.

COL 19.1(5) The COL applicant is to conduct a peer review of the PRA relative to the industry PRA Standard prior to use of the PRA to support risk-informed applications, as applicable.

COL 19.1(6) The COL applicant is to describe the PRA maintenance and upgrade program.

COL 19.1(7) The COL applicant is to develop management procedures for charging pump operation, following recovery from a loss of offsite power (LOOP), to ensure that deboration is not resumed until after at least one Reactor Coolant Pump (RCP) has been restarted.G COL 19.1(8) The COL applicant is to confirm that the PRA-based seismic margin assessment is bounding for the selected site, and to update the assessment to include site-specific SSC and soil effects (including sliding, overturning liquefaction, and slope failure). The COL applicant is to confirm that the as-built plant has adequate seismic margin and do not exceed the CDF and LERF design targets specified in Subsection 1.2.1.1.1 e.

The COL applicant is to demonstrate that HCLPF capacity is equal to or exceed 1.67 times the GMRS for site-specific structures (ESWIS and CCW Hx Building).

The COL applicant is to demonstrate that HCLPF capacity is equal to or exceed 1.67 times the CSDRS for BOP components and is to complete the SEL.

The COL applicant is to demonstrate that the seismic capacity for equipment qualified by testing should remain functionally operational within 1.67 times the required response spectra (CSDRS-based RRS) in the procurement specification.

Replace with "A" 1.8-39 Rev. 2

RAI 434-8352 - Question 19-92_Rev.5 Non-Proprietary Attachment 10 (2/12)

RAI 434-8352 Question 19-92_Rev.4 RAI 434-8352 Question 19-92_Rev.5 "A"

The COL applicant will confirm and update from new information from the site, e.g.

site features, design departures, etc, that the PRA-based seismic margin assessment is bounding for the selected site, site-specific SSC and soil effects (including sliding, overturning, liquefaction, and slope failure).

The COL applicant is to confirm that the as-built plant has adequate seismic margin and do not exceed the CDF and LRF design targets specified in Subsection 1.2.1.1.1

e. See Subsection 19.1.5.1.2.

The COL applicant is to demonstrate that site-specific structures (the turbine building, compound building, ESW IS and CCW HX building) have a HCLPF capacity that is equal to or greater than 0.5g and will update the PRA-based seismic margin analysis with the site-specific structure HCLPF value, accordingly.

The COL applicant is to demonstrate that HCLPF capacity is equal to or exceed 1.67 times the CSDRS for BOP components and is to complete the SEL.

The COL applicant is to demonstrate that the seismic capacity for equipment and relay qualified by testing should remain functionally operational within 1.67 times the required response spectra (CSDRS based RRS) in the procurement specification.

The COL applicant is to demonstrate that the inherently rugged components identified in 19.1.5.1.1.2 have seismically rugged capacity.

The COL applicant is to demonstrate that the steam generator tube HCLPF is higher than HCLPF for the steam generator nozzle.

1.67 times GMRS

RAI 434-8352 - Question 19-92_Rev.5 Non-Proprietary Attachment 10 (3/12)

APR1400 DCD TIER 2 RAI 434-8352 Question 19-92_Rev.4 Table 1.8-2 (37 of 39)

Item No. Description COL 19.1(19) The COL applicant is to describe the uses of PRA in support of licensee programs such as the reactor oversight process during the operational phase.

COL 19.1(20) The COL applicant is to perform the seismic-fire interactions walkdown to confirm a qualitative seismic-fire interaction assessment.

COL 19.1(21) The COL applicant is to develop outage procedures to ensure that in fire compartments containing post-seismic or post-fire safe shutdown equipment that: 1) the seismic ruggedness of temporary ignition sources is adequate, or that the duration that these temporary ignition sources are in these areas is minimized, 2) the seismic ruggedness of temporary equipment such as scaffolding in fire compartments containing potential seismic-fire ignition sources, or near fire protection equipment is adequate, and 3) either the duration of activities which could impact manual firefighting is minimized, or alternative firefighting equipment (e.g.,

pre-stage portable smoke removal equipment, prestage additional firefighting equipment, etc.) is supplied.

COL 19.1(22) The COL applicant is to demonstrate that failure of buildings that are not seismic Category I (e.g., turbine building and compound building) does not impact SSCs designed to be seismic 22 Category I.

COL 19.1(23) The COL applicant is to ensure that asymmetric conditions due to modeling simplicity will 23 be addressed or properly accounted for when the PRA is used for decision making.

COL 19.1(24) The COL applicant will demonstrate that maintenance-induced floods are negligible 24 contributors to flood risk when the plant specific data are available.

COL 19.1(25) SAMGs are entered to initiate SI with the core exit thermocouple indicating 1200 °F.

COL 19.2(1) The COL applicant is to perform and submit site-specific equipment survivability assessment including flooding effect in accordance with 10 CFR 50.34(f) and 10 CFR 50.44 which reflects the equipment identified and the containment atmospheric assessments of temperature, pressure and radiation described in Subsection 19.2.3.3.7.

COL 19.2(2) The COL applicant will demonstrate that the covers for large penetrations such as equipment hatch and personnel airlocks meet the Service Level C requirements in Subsection NE-3220 of the ASME code and explain how the consideration of containment leakage is accounted for when modeling local regions of containment.

COL 19.2(3) The COL applicant and/or holder is to develop and submit an accident management plan including the evaluation of the effect of higher water level in the cavity on steam explosion loading when using In-Vessel Retention and External Reactor Vessel Cooling for accident management.

COL 19.3(1) The COL applicant is to perform site-specific seismic hazard evaluation and seismic risk evaluation as applicable in accordance with NTTF Recommendation 2.1 as outlined in the NRC RFI.

COL 19.3(2) The COL applicant is to address the flood requirements for wet sites COL 19.3(3) The COL applicant is to develop the details for offsite resources.

COL 19.3(4) The COL applicant is to address the details of selecting suitable storage locations for FLEX equipment that provide reasonable protection during specific external events as provided in NEI 12-06 guidance Sections 5 through 9, and the details of the guidance for storage of FLEX equipment provided in the Technical Report (Reference 5) Section 6.2.9.

COL 19.3(5) The COL applicant is to confirm, satisfy, or fulfill the specific design functional requirements of raw water tank including the associated instrument, capacity, location, flow path to on-site, the valve pit connected to FLEX equipment, and any other design features as described in Section 19.3 in support of BDBEE mitigation strategies.

COL 19.1(25) The COL applicant and/or holder ensures that the fire protection features required for preventing fire-induced damage of the PRA-credited components will be properly incorporated in the cable design.

1.8-41 Rev. 2

RAI 434-8352 - Question 19-92_Rev.5 Non-Proprietary Attachment 10 (4/12)

APR1400 DCD TIER 2 RAI 434-8352 Question 19-92_Rev.4

l. Failure of auxiliary steam (AS) or steam generator blowdown (SD) system piping in the auxiliary building is assumed to be incapable of resulting in pipe whip or unique jet impingement failures.
m. Lines that are not normally pressurized or charged, such as drain lines or abandoned in-place systems, are not considered as credible flood or spray sources. For example, relief lines downstream of a relief valve are not normally pressurized and are not included.

19.1.5.3.1.5 Initiating Event Analysis The flooding-induced initiating events are divided into three categories of causes:

a. Tank rupture events causing flooding
b. Maintenance-related events causing flooding
c. System pipe rupture events causing flooding No tank ruptures are identified as causing unique effects or contributing to internal flooding events. Maintenance-induced flooding events are expected to be insignificant contributors to overall flooding risk. However, absent the availability of plant-specific maintenance procedures and equipment unavailability data, calculation of maintenance-induced flood frequency cannot be performed. The COL applicant will demonstrate that maintenance-induced floods are negligible contributors to risk when such information is available (COL 19.1(24)).

23 A limited number of flood-vulnerable plant systems are identified for inclusion as potential flood sources, and are listed in below along with their corresponding rupture rate group as defined in EPRI 1021086 (Reference 46). Reasons for selecting these systems include:

a. The system has adequate inventory to present an obvious submergence threat.
b. The system piping is close to equipment that is important to accident mitigation.
c. The system itself is important to accident mitigation and could be made unavailable by a system pipe rupture.

19.1-192 Rev. 2

RAI 434-8352 - Question 19-92_Rev.5 Non-Proprietary Attachment 10 (5/12)

APR1400 DCD TIER 2 RAI 434-8352 Question 19-92_Rev.4 Ruptures of the heat sinks for the SCS (component cooling and service water) are subsumed into general failures of the SCS and are not reanalyzed. Some CC system ruptures are retained because they could potentially fail a power supply and thus posed a broader threat than the loss of an SC train.

Consistent with the assumption one SDC train is operating during the first part of the outage and other SDC train is operating during the second part of the outage, the LPSD internal flooding analysis assumes that flood barriers separating the two divisions of the auxiliary building are maintained consistent with the internal flooding design basis during POS that SDC is required. Therefore, the propagation analysis developed for the at-power internal flooding analysis should be applicable to the LPSD flooding analysis when considering events that could cause failure of the operating SDC train.

Outage work is conducted on a train basis. That is, while work on train A equipment is planned, no maintenance is performed on any train B equipment and vice versa. This assumption regarding maintenance includes flood barriers separating the two divisions.

Additionally, the analysis assumes that auxiliary building flood barriers separating trains within a division are maintained consistent with the internal flooding design basis for the normally operating SDC train. The normally-operating SDC train is from the Division which is not scheduled for maintenance during that portion of the outage. Therefore, the propagation analysis developed for the at-power internal flooding analysis should be applicable to the LPSD flooding analysis when considering events that could cause failure of the operating SDC train. Maintenance-induced flooding events are expected to be insignificant contributors to overall flooding risk. However, absent the availability of plant-specific maintenance procedures and equipment unavailability data, calculation of maintenance-induced flood frequency cannot be performed. The COL applicant will demonstrate that maintenance-induced floods are negligible contributors to risk when such information is available (COL 19.1(24)).

23 19.1.6.4.1.3 Accident Sequence The AS development for LPSD flooding uses the loss of shutdown cooling sequences in the LPSD internal events analysis. While there are many initiating events (i.e., many floods that can fail one or both trains of SC), each unique IE use the same, basic loss of shutdown cooling (LOSC) event tree for the subsequent accident analysis.

19.1-272 Rev. 2

RAI 434-8352 - Question 19-92_Rev.5 Non-Proprietary Attachment 10 (6/12)

APR1400 DCD TIER 2 RAI 434-8352 Question 19-92_Rev.4 respect to internal events, internal flood and fire events (fire barrier and fire barrier penetrations, routings and locations of pipe, cable, and conduit),

and HRA analyses (development of operating procedures, emergency operating procedures, and severe accident management guidelines and training), external events including PRA-based seismic margins and HCLPF fragilities, and LPSD procedures. See Subsection 19.1.2.2.

COL 19.1(5) The COL applicant and/or holder is to conduct a peer review of the PRA relative to the industry PRA Standard prior to use of the PRA to support risk-informed applications, as applicable. See Subsection 19.1.2.3.

COL 19.1(6) The COL applicant is to describe the PRA maintenance and upgrade program. See Subsection 19.1.2.4.

COL 19.1(7) The COL applicant and/or holder is to develop management procedures for charging pump operation, following recovery from a loss of offsite power (LOOP), to ensure that deboration is not resumed until after at least one Reactor Coolant Pump (RCP) has been restarted.

COL 19.1(8) The COL applicant is to confirm that the PRA-based seismic margin assessment is bounding for the selected site, and to update the assessment to include site-specific SSC and soil effects (including sliding, overturning liquefaction, and slope failure). The COL holder is to confirm that the as-built plant has adequate seismic margin and does not exceed the CDF and LRF design targets specified in Subsection 1.2.1.1.1 item e. See Subsection 19.1.5.1.2.

The COL applicant is to demonstrate that HCLPF capacity is equal to or exceed 1.67 times the GMRS for site-specific structures (ESWIS and CCW Hx Building).

The COL applicant is to demonstrate that HCLPF capacity is equal to or exceed 1.67 times the CSDRS for BOP components and is to complete the SEL.

The COL holder is to demonstrate that the seismic capacity for equipment qualified by testing should remain functionally operational within 1.67 19.1-299 Rev. 2

RAI 434-8352 - Question 19-92_Rev.5 Non-Proprietary Attachment 10 (7/12)

APR1400 DCD TIER 2 RAI 434-8352 Question 19-92_Rev.4 times the required response spectra (CSDRS-based RRS) in the Add "B" procurement specification.

COL 19.1(9) When developing post-earthquake safe shutdown procedures, the COL applicant and/or holder should consider the potential for multiple spurious alarms from photoelectric detectors following a seismic event.

COL 19.1(10) The COL applicant and/or holder needs to ensure that screened events do not have a site-specific susceptibility and do not exceed the CDF and LRF design targets specified in Subsection 1.2.1.1.1 item e. The COL applicant and/or holder is to address the following issues with a site-specific risk assessment, as applicable:

Tsunami Aircraft crash event External flooding Extreme winds and tornadoes Industrial or military facility Lightning Pipeline accident Release of chemicals from onsite storage River diversion/River flooding Storm surge Toxic gas Transportation accidents In addition, the COL applicant and/or holder is to ensure the site-specific susceptibility is not an outlier for the following issues, as applicable:

Avalanche 19.1-300 Rev. 2

RAI 434-8352 - Question 19-92_Rev.5 Non-Proprietary Attachment 10 (8/12)

RAI 434-8352 Question 19-92_Rev.4 RAI 434-8352 Question 19-92_Rev.5 "B"

The COL applicant will confirm and update from new information from the site, e.g. site features, design departures, etc, that the PRA-based seismic margin assessment is bounding for the selected site, site-specific SSC and soil effects (including sliding, overturning, liquefaction, and slope failure).

1.67 times GMRS The COL applicant is to confirm that the as-built plant has adequate seismic margin and do not exceed the CDF and LRF design targets specified in Subsection 1.2.1.1.1 e. See Subsection 19.1.5.1.2.

The COL applicant is to demonstrate that site-specific structures (the turbine building, compound building, ESW IS and CCW HX building) have a HCLPF capacity that is equal to or greater than 0.5g and will update the PRA-based seismic margin analysis with the site-specific structure HCLPF value, accordingly.

The COL applicant is to demonstrate that HCLPF capacity is equal to or exceed 1.67 times the CSDRS for BOP components and is to complete the SEL.

The COL applicant is to demonstrate that the seismic capacity for equipment and relay qualified by testing should remain functionally operational within 1.67 times the required response spectra (CSDRS based RRS) in the procurement specification.

The COL applicant is to demonstrate that the inherently rugged components identified in 19.1.5.1.1.2 have seismically rugged capacity.

The COL applicant is to demonstrate that the steam generator tube HCLPF is higher than HCLPF for the steam generator nozzle.

RAI 434-8352 - Question 19-92_Rev.5 Non-Proprietary Attachment 10 (9/12)

APR1400 DCD TIER 2 RAI 434-8352 Question 19-92_Rev.4 COL 19.1(18) The COL applicant is to describe the uses of PRA in support of licensee programs such as Maintenance Rule implementation during the operational phase. See Subsection 19.1.7.2.

COL 19.1(19) The COL applicant is to describe the uses of PRA in support of licensee programs such as the reactor oversight process during the operational phase. See Subsection 19.1.7.3.

COL 19.1(20) The COL holder is to perform the seismic-fire interactions walkdown to confirm a qualitative seismic-fire interaction assessment.

COL 19.1(21) The COL applicant and/or holder is to develop outage procedures to ensure that in fire compartments containing post-seismic or post-fire safe shutdown equipment that: 1) the seismic ruggedness of temporary ignition sources is adequate, or that the duration that these temporary ignition sources are in these areas is minimized, 2) the seismic ruggedness of temporary equipment such as scaffolding in fire compartments containing potential seismic-fire ignition sources, or near fire protection equipment is adequate, and 3) either the duration of activities which could impact manual firefighting is minimized, or alternative firefighting equipment (e.g., pre-stage portable smoke removal equipment, prestage additional firefighting equipment, etc.) is supplied.

COL 19.1(22) The COL applicant and/or holder is to demonstrate that failure of buildings that are not seismic Category I (e.g., turbine building and compound building) does not impact SSCs designed to be seismic Category I.

COL 19.1(23) The COL applicant and/or holder is to ensure that asymmetric conditions 22 due to modeling simplicity will be addressed or properly accounted for when the PRA is used for decision making.

COL 19.1(24) The COL holder will demonstrate that maintenance-induced floods are 23 negligible contributors to flood risk when the plant specific data are available.

COL 19.1(25) SAMGs are entered to initiate SI with the core exit thermocouple 24 indicating 1200oF.

19.1-303 Rev. 2

RAI 434-8352 - Question 19-92_Rev.5 Non-Proprietary Attachment 10 (10/12)

APR1400 DCD TIER 2 RAI 434-8352 Question 19-92_Rev.4 COL 19.1(26) The COL applicant and/or holder ensures that the fire protection features 25 required for preventing fire-induced damage of the PRA-credited components will be properly incorporated in the cable design.

19.1.10 References

1. ASME/ANS RA-S-2008, Standard for Level 1/Large Early Release Frequency Probabilistic Risk Assessment for Nuclear Power Plant Applications (Revision 1 RA-S-2002), American Society of Mechanical Engineers, April 2008.
2. ASME/ANS RA-Sa-2009, Addenda to ASME/ANS RA-S-2008, American Society of Mechanical Engineers, February 2009.
3. Regulatory Guide 1.200, An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities, Rev. 2, U.S.

Nuclear Regulatory Commission, March 2009.

4. NUREG/CR-2300, PRA Procedures Guide, U.S. Nuclear Regulatory Commission, January 1983.
5. NUREG/CR-1150, Severe Accident Risks: An Assessment for Five U.S. Nuclear Power Plants, U.S. Nuclear Regulatory Commission, December 1990.
6. NUREG/CR-6850, EPRI/NRC-RES Fire PRA Methodology for Nuclear Power Facilities, U.S. Nuclear Regulatory Commission, September 2005.
7. APR1400-E-P-NR-14001-P, PRA Summary Report, Rev. 0, KHNP.
8. SECY-93-087, Policy, Technical, and Licensing Issues Pertaining to Evolutionary and Advanced Light-Water Reactor Designs, U.S. Nuclear Regulatory Commission, Letter issued April 2, 1993 and Staff Requirements Memoranda issued July 21, 1993.
9. ANS/ASME-58-22-201x draft, Low Power and Shutdown PRA Methodology,"

American Nuclear Society, American Society of Mechanical Engineers, July 2013.

10. Regulatory Guide 1.206, Combined License Applications for Nuclear Power Plants, U.S. Nuclear Regulatory Commission, June 2007.

19.1-304 Rev. 2

Non-Proprietary RAI 434-8352 - Question 19-92_Rev.5 Attachment 10 (11/12)

APR1400 DCD TIER 2 RAI 434-8352 Question 19-92_Rev.4 Replaced with "C" Table 19.1-4 (26 of 27)

No. Insight Disposition Risk Insights from PRA Models 66 The COL applicant is to demonstrate that HCLPF capacity is equal to or exceed 1.67 times the COL 19.1(8)

GMRS for site-specific structures (ESWIS and CCW Hx Building) and HCLPF capacity is equal to or exceeds 1.67 times the CSDRS for BOP components, and is to complete the SEL.

At the design certification phase, specific design data for the BOP components such as material properties, analysis results, qualification test information, etc. are not available. Appendix E of EPRI-NP-1002988 (Reference 58) presents example calculations showing that the equipment designed for 0.25g SSE can have 0.5g or higher HCLPF considering the conservatism in the design process. The EPRI-NP-6041 (Reference 39) indicates that Seismic Category I concrete structure and BOP equipment can have 0.5g HCLPF as long as the structure and the equipment are designed in accordance with the current code and standard and the anchorage is rugged. The generic fragility data provided by the Electric Power Research Institute (EPRI) Utility Requirements Document (Reference 37) show the BOP components have HCLPF capacities higher than 0.5g.

The COL applicant is to demonstrate that failure of buildings that are not seismic Category I (e.g., COL 19.1(22) turbine building and compound building) does not impact SSCs designed to be seismic Category I.

The containment structure is assumed to have the same median capacity in shutdown configurations as it does for the full power fragility calculation. That is, collapse of the structure is not affected by whether or not the equipment hatch is removed or installed with four bolts. Additionally, failure of the containment to provide an effective fission product boundary during LPSD conditions when the equipment hatch installed using four bolts has the same fragility as for at-power conditions when the equipment hatch is installed with all bolts.

19.1-354 Rev. 2

Non-Proprietary RAI 434-8352 - Question 19-92_Rev.5 Attachment 10 (12/12)

RAI 434-8352 Question 19-92_Rev.4 RAI 434-8352 Question 19-92_Rev.5 "C"

The HCLPF capacity is equal to or exceeds 1.67 times the CSDRS for COL 19.1(8)

BOP components, and is to complete the SEL.

1.67 times GMRS The COL applicant is to demonstrate that site-specific structures (the turbine COL 19.1(8) building, compound building, ESW IS and CCW HX building) have a HCLPF capacity that is equal to or greater than 0.5g and will update the PRA-based seismic margin analysis with the site-specific structure HCLPF value, accordingly.

The HCLPF for test equipment including relay need to be equal to or higher COL 19.1(8) than 1.67 times CSDRS.

The COL applicant is to demonstrate that the inherently rugged components COL 19.1(8) identified in 19.1.5.1.1.2 have seismically rugged capacity.

The important operator action and random failure event for PRA-based SMA Subsection 19.1.5.1.2.4 should be managed by COL holder to improve the human error.

RAI 434-8352 - Question 19-92_Rev. Non-Proprietary Attachment 11 (1/1)

APR1400 DCD TIER 2 RAI 434-8352 Question 19-92_Rev.4 Due to their low probability, common cause events are relatively low contributors to average plant risk; there are only 3 CCF events that have an FV value in excess of 0.5 percent, and all 3 relate to recovery from LOOP events.

19.1.6.4.2.5 Sensitivity Analysis No sensitivity analyses have been performed for LPSD flooding, because its contribution to total LPSD and plant risk is very low.

19.1.6.4.2.6 Uncertainty Analysis flooding The parametric uncertainty results for Level 1 internal fire CDF during LPSD are summarized below:

5 percent value: 3.2 x 10-8/year Mean value: 8.4 x 10-8/year 95 percent value: 1.8 x 10-7/year Parametric uncertainty was represented by selecting an uncertainty distribution for each parameter type. Modeling uncertainty was not represented in the shutdown model.

19.1.6.4.2.7 Risk Insights The general risk insight from the LPSD flooding analysis is that the APR1400 has been effectively designed to establish flood protection at shutdown. Specific insights are described below:

a. The overall LPSD internal flooding CDF is extremely low. This low frequency may be attributed primarily to the following factors: (1) low initiating event frequencies; (2) effective separation of divisions, for the SC pumps and their power supplies, via flood barriers; and (3) the large emergency overflow lines (EOLs), which serve as high capacity drains.
b. The dominant initiating event is a fire protection flood in room 78-A44B. This flood submerges both trains of the SC pumps as well as one power supply. This IE is the dominant risk contributor at 23 percent of the total internal flooding CDF.

19.1-276 Rev. 2

RAI 434-8352 - Question 19-92_Rev. Non-Proprietary Attachment 12 (1/1)

APR1400 DCD TIER 2 RAI 434-8352 Question 19-92_Rev.4 The fault tree models include contributions due to the following:

x Random component failures x Outages for maintenance and testing x Support system failures x CCFs Initiating events which affect the system x Human errors involving failure to restore equipment to its operable state x Human errors involving failure to perform procedural actions Fault trees are developed to the level of detail for which existing data can be applied. For active systems, passive failures that are potentially significant are included.

General assumptions and conditions applied to system analysis are summarized below.

a. General modeling conditions:
1) Models reflect the design as-designed and as-to-be-built to the extent possible.
2) Systems that participate in the necessary response to events or that provide critical support to such systems are modeled.
3) Models reflect the success criteria for the systems to mitigate each identified accident sequence.
4) Models capture the impact of dependencies, including support systems and harsh environmental impacts.
5) Operator errors of commission are not included in the system model.
b. Conditions concerning level of detail
1) The level of detail in the model matches one for one the simplified diagrams and includes key active components and potential misaligned components based upon data availability.

19.1-52 Rev. 2

RAI 434-8352 - Question 19-92_Rev.5 Non-Proprietary Attachment 13 (1/2)

APR1400 DCD TIER 2 RAI 434-8352 Question 19-92_Rev.5 Offsite power recovery for LOOP sequences that did not result in SBO has a significant impact on the LRF. The Level 2 analysis credits offsite power recovery in non-SBO LOOP sequences to estimate a more realistic LRF.

The ability to close the containment equipment hatch in POS 3B and 4A is significant.

Without credit for hatch closure, these POS would yield an LRF of 2.5x10-8/year.

However, with credit for hatch closure, these two POS contribute 7.9x10-9/year to the LRF (6.7 percent).

The LPSD CDF and LRF are highly dependent on the LPSD human error probabilities, as is expected for an LPSD PRA. To ensure that dependence between HEPs is properly evaluated, the LPSD Level 2 performed an HEP dependency analysis using the same methodology as the Level 1 PRA.

Add "A" 19.1.6.3 Internal Fire PRA for Low Power and Shutdown Operations The following subsections describe the development of the internal fires risk evaluation during low power and shutdown conditions, and the analysis results.

19.1.6.3.1 Description of Internal Fire PRA for Low Power and Shutdown Operations The low power and shutdown (LPSD) fire PRA (FPRA) methodology for the APR1400 is based on NUREG/CR-7114 (Reference 52) and NUREG/CR-6850 (Reference 6).

NUREG/CR-7114 provides a framework for quantitative analysis of fire risk during LPSD conditions. NUREG/CR-6850 provides a state-of-the-art methodology for fire PRAs. The steps in the LPSD fire PRA methodology are the same as those used in the at-power internal fire PRA (AP-FPRA) (see Subsection 19.1.5.2.1) with the exception that they are applied to the LPSD internal events model (see Subsection 19.1.6.1). The exceptions to the at-power FPRA methodology used in the development of the LPSD FPRA are described below. It should be noted that units for CDF and LRF are expressed in terms of reactor calendar year (shortened to /year when displayed in the text in this section).

19.1.6.3.1.1 Deviations from the Industry Methodology All of the tasks described in Subsection 19.1.5.2.1 are required to perform a LPSD FPRA.

These tasks involve various types of screening to eliminate assessment of non-risk-significant fire scenarios. Since the plant is in the design stage, some specific plant details 19.1-247 Rev. 2

RAI 434-8352 - Question 19-92_Rev.5 Non-Proprietary Attachment 13 (2/2)

"A" RAI 434-8352 Question 19-92_Rev.5 The LPSD CDF and LRF are highly dependent on the LPSD human error probabilities, as is expected for an LPSD PRA. In the development of the LRF model, consistent with the CDF model, a floor HEP of 10-6 was applied to cutsets with a combined probability of all human errors below 10-6. A sensitivity was performed examining what the impact to LRF would be if a floor HEP of 1E-5 was utilized. The result of the sensitivity was that the total LRF of POSs 4B-12A would increase from 7.0x10-8/year to 9.3x10-8/year (33 percent increase). The total LRF of all POSs would increase from 1.2x10-7/year to 1.4x10-7/year (20 percent increase). Therefore, the sensitivity demonstrates that the impact on the total LPSD LRF is small, and would not alter the conclusions of the DCD.

RAI 434-8352 - Question 19-92_Rev.5 Non-Proprietary Attachment 14 (1/4)

APR1400 DCD TIER 2 RAI 434-8352 Question 19-92_Rev.5 Table 19.1-16 (1 of 2)

Special Basic Events Basic Event Value EF Description Data Source MTC-UET- Adverse MTC UET percentage given 0.027 N/A TTS-1 turbine trip when no POSRVs fail MTC-UET- Adverse MTC UET percentage given 0.3241 N/A TTS-2 turbine trip when 1 POSRV fails MTC-UET- Adverse MTC UET percentage given 0.4859 N/A TTS-3 turbine trip when 2 POSRV fail MTC-UET- Adverse MTC UET percentage given 0.7552 N/A TTS-4 turbine trip when 3 POSRV fail Adverse MTC UET percentage given KEPCO E&C /ND/

MTC-UET-0.2702 N/A turbine trip failure and no POSRVs TR/12-022 TTF-1 fail (Reference 69)

Adverse MTC UET percentage given MTC-UET-0.4320 N/A turbine trip failure when 1 POSRV TTF-2 fails Adverse MTC UET percentage given MTC-UET-0.6475 N/A turbine trip failure when 2 POSRVs TTF-3 fail Adverse MTC UET percentage given MTC-UET-0.8627 N/A turbine trip failure when 3 POSRVs TTF-4 fail Conditional seal failure probability WCAP-18067-P RC-CSFP- 1.05E- given CBO is isolated within 20 min

 (Reference 64, CBO-ISO 07* and RCS Cold Leg Subcooling <

50oF Table 9.1-7)

Conditional seal failure probability WCAP-18067-P RC-CSFP- 1.00E- given CBO is NOT isolated within NO-CBO-ISO 07* 20 min and RCS Cold Leg (Reference 64, Subcooling < 50oF Table 9.1-7)

Probability of non-recovery of offsite Analysis of LOOP RAC16H-PL 1.09E-01 34.25 power within 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> after plant- events, 2014 update centered LOOP (Reference 67)

Probability of non-recovery of offsite Analysis of LOOP RAC16H-SW 1.25E-01 15.30 power within 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> after events, 2014 update switchyard-centered LOOP (Reference 67) 19.1-424 Rev. 2

RAI 434-8352 - Question 19-92_Rev.5 Non-Proprietary Attachment 14 (2/4)

APR1400 DCD TIER 2 RAI 434-8352 Question 19-92_Rev.5 Table 19.1-16 (2 of 2)

Basic Event Value EF Description Data Source Probability of non-recovery of offsite Analysis of LOOP RAC16H-GR 5.34E-02 7.91 power within 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> after grid- events, 2014 update related LOOP (Reference 67)

Probability of non-recovery of offsite Analysis of LOOP RAC16H-WE 3.73E-01 27.53 power within 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> after weather- events, 2014 update related LOOP (Reference 67)

Probability of non-recovery of offsite Analysis of LOOP RAC12H-PL 1.36E-01 34.25 power within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after plant- events, 2014 update centered LOOP (Reference 67)

Probability of non-recovery of offsite Analysis of LOOP RAC12H-SW 1.64E-01 15.30 power within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after events, 2014 update switchyard-centered LOOP (Reference 67)

Probability of non-recovery of offsite Analysis of LOOP RAC12H-GR 8.30E-02 7.91 power within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after grid- events, 2014 update related LOOP (Reference 67)

Probability of non-recovery of offsite Analysis of LOOP RAC12H-WE 4.29E-01 27.53 power within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after weather- events, 2014 update related LOOP (Reference 67)

EPRI Interim PFLOOP-NO- Conditional LOOP after Initiators Technical Report, 2.0E-03 N/A SI which do not Initiate a SI Signal Section 3.1.5.3 (Reference 68)

EPRI Interim Conditional LOOP after Initiators PFLOOP-SI 2.0E-02 N/A Technical Report which Initiate a SI Signal (Reference 68)

  • Variance provided in Reference 18 is used as the uncertainty parameter.

64

    • Values are provided in Reference 64 (Table 9.1-7).

19.1-425 5HY

Non-Proprietary RAI 434-8352 - Question 19-92_Rev.5 Attachment 14 (3/4)

RAI 434-8352 Question 19-92_Rev.5 APR1400 DCD TIER 2 Table 19.1-50 (45 of 46)

Rank Cutset Prob. Cum. % BE Prob Event Event Description 97 8.01E-11 62.7% 2.86E-04 %F120-AGAC FIRE IN F120-AGAC - GENERAL ACCESS AREA-120' C RC-CSFP-NO-CBO- COND. FAILURE PROB. OF RCP SEALS GIVEN FAILURE TO



ISO ISOLATE CBO WITHIN 20 MIN.

BF_F120- BARRIER FAILURE BETWEEN FIRE COMPS F120-AGAC & F120-1.20E-03 AGAC_F120-AGAD AGAD 98 7.90E-11 62.8% 1.75E-03 %F000-AFHL FIRE IN F000-AFHL - FUEL HANDLING LOWER AREA L2-PROB-RCSFAIL-9.00E-02 RCSFAIL DET - prob that SG-LEAK = 2OF2-LEAK 2-2-LK L2-PROB-RCSFAIL-9.00E-01 RCSFAIL DET - prob that SGDEPRESS = NO-DEPRESS NOSG-DEP L2-PROB-RCSFAIL-9.76E-01 RCSFAIL DET - prob that SGSORV = NO-DEPRESS NOSGSORV L2-PROB-RCSFAIL-8.89E-01 RCSFAIL DET - probability that RCSSORV = Intact NOSORV L2-PROB-RCSFAIL-5.00E-01 RCSFAIL DET - prob that CSSORV_LATE = RCS-DEPR RCSDEPR L2-PROB-RCSFAIL-1.07E-01 RCSFAIL DET - prob that PI-SGTR = PI-SGTR (2 SGs depressurized)

SGTR-2D 1.20E-05 PPSO-AP-LC CCF OF PPS LC APPLICATION SOFTWARE 19.1-721 Rev. 2

Non-Proprietary RAI 434-8352 - Question 19-92_Rev.5 Attachment 14 (4/4)

RAI 434-8352 Question 19-92_Rev.5 APR1400 DCD TIER 2 Table 19.1-50 (46 of 46)

Rank Cutset Prob. Cum. % BE Prob Event Event Description 99 7.90E-11 62.8% 1.75E-03 %F000-AFHL FIRE IN F000-AFHL - FUEL HANDLING LOWER AREA L2-PROB-RCSFAIL-9.00E-02 RCSFAIL DET - prob that SG-LEAK = 2OF2-LEAK 2-2-LK L2-PROB-RCSFAIL-9.00E-01 RCSFAIL DET - prob that SGDEPRESS = NO-DEPRESS NOSG-DEP L2-PROB-RCSFAIL-9.76E-01 RCSFAIL DET - prob that SGSORV = NO-DEPRESS NOSGSORV L2-PROB-RCSFAIL-8.89E-01 RCSFAIL DET - probability that RCSSORV = Intact NOSORV L2-PROB-RCSFAIL-5.00E-01 RCSFAIL DET - prob that CSSORV_LATE = RCS-INTACT RCSINT L2-PROB-RCSFAIL-1.07E-01 RCSFAIL DET - prob that PI-SGTR = PI-SGTR (2 SGs depressurized)

SGTR-2D 1.20E-05 PPSO-AP-LC CCF OF PPS LC APPLICATION SOFTWARE 100 7.86E-11 62.8% 2.86E-04 %F120-AGAC FIRE IN F120-AGAC - GENERAL ACCESS AREA-120' C 3.52E-02 AFTPR1A-TDP01A AFW TDP PP01A FAILS TO RUN FOR > 1HR 6.49E-03 AFTPS1B-TDP01B AFW TDP PP01B FAILS TO START BF_F120- BARRIER FAILURE BETWEEN FIRE COMPS F120-AGAC & F120-1.20E-03 AGAC_F120-AGAD AGAD

  • Value is provided in Reference 64 (Table 9.1-7).

19.1-722 5HY

RAI 434-8352 - Question 19-92_Rev.5 Non-Proprietary Attachment 15 (1/2)

APR1400 DCD TIER 2 RAI 434-8352 Question 19-92_Rev.5 times the required response spectra (CSDRS-based RRS) in the procurement specification.

COL 19.1(9) When developing post-earthquake safe shutdown procedures, the COL applicant and/or holder should consider the potential for multiple spurious alarms from photoelectric detectors following a seismic event.

COL 19.1(10) The COL applicant and/or holder needs to ensure that screened events do not have a site-specific susceptibility and do not exceed the CDF and LRF design targets specified in Subsection 1.2.1.1.1 item e. The COL applicant and/or holder is to address the following issues with a site-specific risk assessment, as applicable:

Tsunami Dam failure Aircraft crash event External flooding Extreme winds and tornadoes Industrial or military facility Lightning Pipeline accident Release of chemicals from onsite storage River diversion/River flooding Storm surge Toxic gas Transportation accidents In addition, the COL applicant and/or holder is to ensure the site-specific susceptibility is not an outlier for the following issues, as applicable:

Avalanche 19.1-300 Rev. 2

RAI 434-8352 - Question 19-92_Rev.5 Non-Proprietary Attachment 15 (2/2)

APR1400 DCD TIER 2 RAI 434-8352 Question 19-92_Rev.5 Biological events Coastal erosion Drought Forest fire High summer temperature Hurricane Landslide Low lake/river water level Low winter temperature Sandstorm Tsunami Volcanic activity See Subsection 19.1.5.4.

COL 19.1(11) The COL applicant and/or holder is to develop outage management procedures that limit planned maintenance that can potentially impair one or both SC trains during the shutdown modes.

COL 19.1(12) The COL applicant and/or holder is to develop procedures and a configuration management strategy to address the period of time when one SC train is unexpectedly unavailable (including the termination of any testing or maintenance that can affect the remaining train and restoration of all equipment to its nominal availability). The COL applicant is to ensure operation of the emergency diesel generator sequencer throughout low power and shutdown operations (not including defueled plant operating states).

19.1-301 Rev. 2