Number range CHAPTER **APPENDIX A**

**Determining the Significance of Reactor Inspection**

**Findings for At-Power Situations**

I APPLICABILITY

The Significance Determination Process (SDP) described in this Appendix
is designed to provide NRC inspectors and management with a simplified
probabilistic framework for use in identifying potentially
risk-significant issues within the Initiating Events, Mitigation
Systems, and Barrier cornerstones.

II ENTRY CONDITIONS

Findings that have been screened in the Phase 1 - Initial Screening and
Characterization of Findings process described in Inspection Manual
Chapter (IMC) 0609, Attachment 4, and that have an adverse effect on the
Initiating Events, Mitigation Systems, and Barrier Integrity
cornerstones during at-power conditions are assessed using this
Appendix.

III SDP PHASE 2 AND PHASE 3 OVERVIEW

**Phase 2 - Risk Significance Estimation and Justification Using the
Site Specific Pre-Solved Table or the Risk-Informed Inspection
Notebook:**

> Phase 2 is used to develop a plant specific estimate of the risk
> significance of an inspection finding and to develop the basis for
> that determination.
>
> Use of the Phase 2 pre-solved table is intended to be accomplished by
> the inspection staff, with the assistance of an SRA, if needed. SRAs
> may review all completed Phase 2 assessments to ensure the results are
> consistent with the Phase 2 guidance. Use of the Phase 2 risk-informed
> notebook, if required, is intended to be accomplished by the SRA.
>
> The Phase 2 pre-solved tables/worksheets are plant-specific in order
> to account for variations in available mitigation equipment and other
> plant-specific attributes. When conducting a Phase 2 analysis, the
> actual data contained in the pre-solved table should be used if the
> finding affects one of the targets listed in the table or if a listed
> target can directly serve as a surrogate for the finding. If the
> pre-solved table does not contain a target suitable for evaluating the
> finding of interest, then use of the risk-informed notebook will be
> necessary. The examples of Phase 2 Worksheets used in this Appendix
> are identified as Table 3.XX. When conducting a Phase 2 analysis, the
> actual data contained in the various parts of Table 3.XX in the site
> specific risk-informed inspection notebook must be used. The
> pre-solved tables and risk-informed inspection notebooks can be found
> on the NRC internal web-page by accessing "Risk Informed Regulatory
> Activities" on the NRR Home Page, then accessing the "SDP Insp
> Notebooks" at the top of the DRA Licensing and Operational/Maintenance
> Support page. The notebooks and pre-solved tables are sensitive,
> unclassified information and are not publicly available.
>
> The result of the Phase 2 analysis that is White, Yellow, or Red may
> be used as both the preliminary and/or final significance
> determination. Using the Phase 2 result as a preliminary significance
> determination is desirable especially when it is apparent that an
> extensive analysis would be necessary to reduce high levels of
> uncertainty (e.g., increases in initiating event frequencies). The
> intent of the SDP may be better served by acceptance of the Phase 2
> result applying applicable SDP Phase 2 usage rules.
>
> The SRA may make changes to the Phase 2 result when there are known
> refinements such as exposure time, recovery credit, component failure
> probabilities, etc., that provide a more realistic risk estimate.
> Although modifying the established Phase 2 result is considered a
> Phase 3 SDP, the Phase 3 assessment need not involve any greater
> detail than the modified Phase 2 inputs, especially when it is
> recognized that the modified inputs are most influential in the
> outcome of the finding's significance. In these instances, the
> simplified Phase 3 assessment should be the preliminary color of the
> finding and be presented to the SDP and Enforcement Review Panel
> (SERP).
>
> When evaluating the Phase 2 outcome, there may be situations where the
> result predicts a lower risk estimate (by SDP color) than the
> licensee's PRA. In some instances the licensee's PRA results may be
> overly conservative and the SDP notebook may reflect a more realistic
> risk estimate. In these cases, the SRA should try to determine whether
> the Phase 2 result or the licensee's PRA result provides the more
> realistic risk estimate.

**Phase 3 - Risk Significance Estimation Using Any Risk Basis That
Departs from the Phase 1 or 2 Process:**

> Phase 3 is used to address those situations that depart from the
> guidance provided for Phase 1 or Phase 2. A Phase 3 analysis need be
> no more detailed than an adjustment to the Phase 2.
>
> If the Phase 2 SDP pre-solved tables/worksheets do not clearly address
> the inspection finding of concern (e.g., internal flooding, external
> event initiators, etc.), then a Phase 3 analysis should be performed
> to characterize the significance of the finding. In these instances,
> the Phase 3 should focus on the influential affects of the performance
> deficiency. Since there are a limited number of licensees who have
> external event PRA models, the Phase 3 analysis should not attempt to
> place more quantitative emphasis on the SDP result than is reasonable.
> Rather, the SRA or risk analyst should use qualitative insights using
> the licensee's IPEEE for the preliminary significance determination.
> In these cases, the overall SDP is best served by having the licensee
> provide clarifying information for NRC consideration.
>
> Phase 3 is intended to be performed using appropriate PRA techniques
> and rely on the expertise of an SRA or risk analyst using the best
> available information that is accessible or can be determined within
> the SDP timeliness goal established for a particular finding. For the
> purposes of the SDP, it is not necessary to develop new risk analysis
> tools or perform extensive analyses or reviews when SDP timeliness
> would be jeopardized. When it is apparent that the best available
> information may not be sufficient to provide a meaningful result, the
> SRA should transition more of the assessment responsibility to the
> licensee. In these cases, the role of the SRA or other risk analyst
> would be to review the licensee's assessment versus becoming
> unnecessarily overburdened in the assessment process.

When a Phase 2 SDP or simplified Phase 3 SDP is used as the basis for a
preliminary/final decision, the SRA should confirm the results by
engaging with the licensee as early in the process as possible to
determine if the licensee's results are similar. When the results are
similar (i.e., same significance color), the Phase 2 SDP or simplified
Phase 3 result should be used as a basis for the applicable decision and
therefore it would be unnecessary to perform a more detailed Phase 3
analysis.

In the event the initial Phase 2 or Phase 3 SDP result is significantly
different than the licensee's result (i.e., more than one order of
magnitude), the SRA should attempt to determine the reason(s) for the
difference within SDP timeliness constraints. Reasonable effort to
determine the difference may include further evaluation and comparison
with the licensee's PRA model and the use of the Standardized Plant
Analysis Risk (SPAR) model for the plant. The SRA should not however
make extensive SPAR modeling changes to accommodate the Phase 3 analysis
when those changes would cause the SDP timeliness goal to be challenged.
SPAR modeling issues, however, should be forwarded to the Division of
Risk Assessment, NRR for their review in consultation with the Office of
Research.

IV TREATMENT OF CONCURRENT MULTIPLE EQUIPMENT OR FUNCTIONAL DEGRADATIONS

Concurrent multiple equipment or functional degradations are evaluated
based on their cause. If the concurrent multiple equipment or functional
degradations resulted from a common cause (e.g., a single inadequate
maintenance procedure that directly resulted in deficient maintenance
being performed on multiple components), then a single inspection
finding is written. The significance characterization is determined
using a reactor safety Phase 3 SDP, is based on the time periods during
which the degradations existed, and reflects the total increase in core
damage frequency (CDF).

If multiple cornerstones were affected, the single finding will be
assigned to the cornerstone which best reflects the dominant risk
influences. The justification for the existence of a common cause must
be a stronger causal relationship than poor management or cross-cutting
programs (e.g., an inadequate problem identification and resolution
program is an inadequate basis to justify a common cause finding).

If independent causes are determined to have resulted in multiple
equipment or functional degradations, then separate inspection findings
are written. The findings are individually characterized for
significance, assuming none of the other independent findings existed.
This is necessary to account for the probabilistic independence of the
findings.

In all cases, the risk of concurrent multiple equipment or functional
degradations and the staff's basis for treating these effects as either
having a common cause or being independent should be documented in an
inspection report or other appropriate public correspondence.

V RELATIONSHIP OF THE SDP TO THE RISK-INFORMED PERFORMANCE INDICATORS

The NRC Reactor Oversight Process (as defined in IMC 2515) evaluates
licensee performance using a combination of Performance Indicators (PIs)
and inspections. Thresholds have been established for the PIs, which, if
exceeded, may prompt additional NRC actions to focus both licensee and
Agency's attention on areas where there is a potential decline in
licensee performance.

The white-yellow and yellow-red thresholds for the initiating events and
mitigating systems performance indicators were risk-informed using the
same "scale" as the SDP described in Appendix A. The green-white
thresholds were set low enough to identify performance outliers. As a
result, licensee performance is assessed by comparing and "adding" the
contributions of both performance indicators and inspection findings in
the Action Matrix.

END

Attachment 1 - User Guidance for Significance Determination of Reactor
Inspection Findings for At-Power Situations

Attachment 2 - Site Specific Risk-Informed Inspection Notebook Usage
Rules

Attachment 3 - User Guidance for Screening of External Events Risk
Contributions

**APPENDIX A**

**ATTACHMENT 1**

**User Guidance**

**for Phase 2 and Phase 3** **Reactor Inspection Findings**

**for At-Power Situations**

**Phase 1 - Initial Screening and Characterization of Findings**

> **Step 1: Characterize the inspection finding and describe the assumed
> impact using IMC0609.04, Exhibit 1.**

1.  If the finding screens other than Green, perform a Phase 2 analysis.

**Phase 2.1:** **Risk Significance Estimation and Justification Using
the Site Specific Risk-Informed Inspection Notebook and Pre-Solved
Table**

**Step 2.1.1: Check for the most current version of SDP Notebook and
Pre-solved Worksheet**

> The most current version of the SDP notebook and associated pre-solved
> table can be found on the NRC internal web site. The user should
> review the posted "Read Me First" document that provides a brief
> discussion on SDP notebooks and pre-solved tables.

**Step 2.1.2: Determine the appropriate exposure time**

> Determine the exposure time associated with the finding (i.e., \> 30
> days, between 3 and 30 days, or \< 3 days). If the inception of the
> condition is unknown, go to Usage Rule 1.1 of Attachment 2, "Site
> Specific Risk-Informed Inspection Notebook Usage Rules," of this
> Appendix to determine the appropriate exposure time. The maximum
> exposure time used in SDP is limited to one year.

**Step 2.1.3: Find the appropriate target for the inspection finding in
the pre-solved table**

> The targets (front line, support and electrical systems) provided
> across the top row of the pre-solved table, contain a listing of
> various components and operator actions that have been solved for
> their risk significance. The pre-solved table is used if the target
> matches the equipment or operator action associated with the finding
> or if a listed target can directly serve as a substitute for the
> finding. If the pre-solved table does not contain a target (structures
> systems and components, SSCs) suitable for evaluating the finding of
> interest, then bring to the SRAs attention that the use of the
> risk-informed notebook will be necessary. If the Phase 2 risk-informed
> notebook is required, that review is intended to be accomplished by
> the SRA (see Phase 2.2 below).

**Step 2.1.4: Determine the risk significance of the inspection finding
and the potential risk contribution due to Large Early Release Frequency
(LERF)**

(1) Determine if the finding is CDF or LERF dominant for an exposure
    time of one year.

    a.  With the appropriate target identified, follow the column down
        to the bottom of the pre-solved table to the row entitled "FINAL
        RESULT (Largest of SDP CDF and LERF)." This value represents the
        risk significance for the target with a one-year exposure
        period. The row below entitled "Driver of Final Result (CDF or
        LERF or both)" identifies the dominant risk contributor. If the
        dominate risk contributor is CDF, no additional review is
        required for LERF consideration. If LERF is identified as the
        dominate risk contributor, the "FINAL RESULT (Largest of SDP CDF
        and LERF)" row has already incorporated the LERF risk
        contribution.

    b.  If exposure period is less than one year continue to step (2),
        otherwise, continue to step 2.1.5.

(2) Determine the finding's risk-significance based on exposure period
    of less than one year.

    a.  If CDF is the dominant contributor, move up the column to the
        applicable row marked "\<3 Days" or "3 - 30 Days." Starting from
        the bottom of that series of six rows, look for the first row
        that contains a value greater than zero. The color of that row
        is the CDF risk significance for that finding. If all the rows
        for the target in the specified exposure period contain zeros,
        the CDF for that finding is Green.

    b.  If LERF is the dominate risk contributor for the affected
        target, the final LERF result or color will be one order less
        than that described in the "FINAL RESULT (Largest of SDP CDF and
        LERF)" row for the 3 to 30 day exposure period and two orders
        less than that described in the "FINAL RESULT (Largest of SDP
        CDF and LERF)" row for the \< 3 day exposure period.

**Step 2.1.5: Screen for the potential risk contribution due to external
events if results from Step 2.1.4 are Green and is greater than or equal
to 1E-7.**

> licensee if the If the color determined in step 2.1.4 is other than
> "Green," then the SRA will conduct additional review for external
> event contribution using Phase 3 guidance or information from the
> licensee has an available external event PRA model.

(1) There are seven SDP notebooks and associated pre-solved tables which
    incorporate information allowing the user to screen contribution
    form external events. (Diablo Canyon, Limerick, Salem, Summer,
    Crystal River, Nine Mile Point 2, and Indian Point 3). For
    evaluating external event SDP cases for these seven facilities
    perform the following:

    a.  In the pre-solved table, check the row labeled "External Event
        CDF." If the color is greater than that of the internal events
        "PHASE 2 RESULTS" for CDF or LERF, then the color of the finding
        is dominated by external events and that color should be the
        final color. Otherwise, the internal events CDF or LERF will be
        the final color as determined in step 2.1.4. Note: Due to the
        slight conservatism in the Phase 2 tools, the external event
        contribution should not be added to the internal event
        contribution to determine the final color.

    b.  If the exposure period is less than one year decrease the risk
        significnace by one order of magnitude for exposure periods of 3
        to 30 days, and two orders of magnitude for exposure periods \<3
        days.

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(3) For plants where the SDP Phase 2 pre-solved tables/worksheets do not
    include screening capability for external events or other initiating
    events that are considered by the licensee's IPEEE analysis, and the
    external event contribution for internal events from step 2.1.4 is
    "Green" with a risk-significance greater than or equal to 1E-7, the
    inspector should complete Attachment 3 of this appendix. This is to
    evaluate additional information on external event contribution.
    Inspectors are expected to work with the SRA and provide the
    necessary plant-specific information to complete this step.

**Phase 2.2**: **Risk Significance Estimation and Justification Using
the Site Specific Risk-Informed Inspection Notebook**

Use of the Phase 2 risk-informed notebook, if required, is intended to
be accomplished by the SRA. This process uses the following tables found
in the Site Specific Risk-informed Inspection Notebooks. The plant
specific notebooks can be found on the NRC internal web-page by
accessing "Risk Informed Regulatory Activities" on the NRR Home Page.
The tables presented in this Appendix are generic for the purpose of
illustration.

> Table 1 "Categories of Initiating Events for XXX Plant"
>
> Table 2 "Initiators and System Dependency for XXX Plant"
>
> Table 3 "SDP Worksheets for XXX Plant"
>
> Table 4 "Remaining Mitigation Capability Credit"
>
> Table 5 "Counting Rule Worksheet"

**Step 2.2.1: Select the initiating event scenarios**

> On Table 2, "Initiators and System Dependency for XXX Plant," in the
> plant specific notebook, locate the equipment or safety function that
> was assumed to be affected by the inspection finding. Identify the
> initiating event scenarios that must be evaluated using the plant
> specific worksheets. (See Table 2 in this attachment for an example.)

**Step 2.2.2: Estimate the Initiating Event Likelihood**

(1) On Table 1, "Categories of Initiating Events for XXX Plant," locate
    the exposure time associated with the finding (i.e., \> 30 days,
    between 3 and 30 days, or \< 3 days). If the inception of the
    condition is unknown, go to Usage Rule 1.1 of Attachment 2, "Site
    Specific Risk-Informed Inspection Notebook Usage Rules," of this
    Appendix to determine the appropriate exposure time.

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(4) Determine the Initiating Event Likelihood (i.e., 1 through 8) for
    each of the initiating events identified in Step 2.2.1.

(5) Go to Attachment 2 and review the information contained in Phase 1
    Worksheet to determine if the finding increases the likelihood of
    each initiating event identified in Step 2.2.1.

(6) If the finding increases the likelihood of an initiating event,
    increase the Initiating Event Likelihood (IEL) value in accordance
    with the SDP usage rules in Attachment 2.

(7) Enter the IEL value in the IEL column on the applicable notebook
    worksheet. (See Table 3.XX "SDP Worksheet for Generic BWR,"
    contained in this Appendix.)

**Step 2.2.3: Estimate the Remaining Mitigation Capability in accordance
with the SDP usage rules in Attachment 2**

(1) For each of the inspection scenarios identified in Step 2.2.1,
    determine which safety functions are affected by the finding.

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(8) Circle the affected safety functions on each worksheet identified in
    Step 2.2.1.

(9) If the inspection finding increases the likelihood of an initiating
    event, circle the initiating event for each of the sequences on the
    worksheet for that particular initiating event.

(10) Evaluate the unaffected equipment for each safety function affected
     by the finding. Using Table 4, "Remaining Mitigation Capability
     Credit," determine the remaining mitigation capability credit for
     each of these functions. The remaining mitigation capability credit
     assigned may or may not be reduced as a result of the inspection
     finding. Unaffected safety functions will retain their assigned
     full mitigation capability credit.

(11) Determine if an operator could recover the unavailable equipment or
     function in time to mitigate the assumed initiating event. Credit
     for recovery should be given only if the following criteria are
     satisfied:

     a.  sufficient time is available;

     b.  environmental conditions allow access, where needed;

     c.  procedures describing the appropriate operator actions exist;

     d.  training is conducted on the existing procedures under similar
         conditions;

     e.  any equipment needed to perform these actions is available and
         ready for use.

> If recovery credit is appropriate, enter a value of 1 in the Recovery
> of Failed Train column of the applicable inspection notebook
> worksheets.

**Step 2.2.4: Estimate the risk significance of the inspection finding**

(1) Determine the Sequence Risk Significance for each of the sequences
    circled in Step 2.2.3 (2) as applicable, using the following
    formula:

> Sequence Risk Significance = (Initiating Event Likelihood + Remaining
> Mitigation Capability Credit + Recovery Credit)

(12) Complete Table 5, "Counting Rule Worksheet." The result is the Risk
     Significance (i.e., Green, White, Yellow, or Red) of the inspection
     finding based on the internal initiating events that lead to core
     damage.

**Step 2.2.5: Screen for the potential risk contribution due to external
initiating events**

> The plant-specific SDP Phase 2 Worksheets do not currently include
> initiating events related to fire, flooding, severe weather, seismic,
> or other initiating events that are considered by the licensee's IPEEE
> analysis. Therefore, the increase in risk of the inspection finding
> due to these external initiators is not accounted for in the reactor
> safety Phase 2 SDP result. Because the increase in risk due to
> external initiators may increase the risk significance
> characterization of the inspection finding, the impact of external
> initiators should be evaluated by a SRA or other NRC risk analyst.
> Experience with using the Site Specific Risk-Informed Inspection
> Notebooks has indicated that accounting for external initiators could
> result in increasing the risk significance attributed to an inspection
> finding by as much as one order of magnitude. Therefore, if the Phase
> 2 SDP result for an inspection finding represents an increase in risk
> of greater than or equal to 1E-7 per year (Risk Significance
> Estimation of 7 or less), then an SRA or other NRC risk analyst should
> perform a Phase 3 analysis to estimate the increase in risk due to
> external initiators. This evaluation may be qualitative or
> quantitative in nature. Qualitative evaluations of external events
> should, as a minimum, provide the logic and basis for the conclusion
> and should reference all of the documents reviewed.

**Step 2.2.6: Screen for the potential risk contribution due to Large
Early Release Frequency (LERF)**

> If the total △CDF from the Phase 2 Worksheets (i.e., sum of all
> sequences) is less than 1E-7 per year, then the finding is not
> significant from a LERF perspective and no further evaluation is
> necessary. However, if the total △CDF is greater than or equal to 1E-7
> then the finding must be screened for its potential risk contribution
> to LERF using IMC 0609, Appendix H.

**Phase 3: Risk Significance Estimation Using Any Risk Basis That
Departs from the Phase 1 or 2 Process:**

If necessary, Phase 3 will refine or modify, with sufficient
justification, the earlier screening results from Phases 1 and 2. In
addition, Phase 3 will address findings that cannot be evaluated using
the Phase 2 process. Phase 3 analysis will utilize appropriate PRA
techniques and rely on the expertise of NRC SRAs and risk analysts using
the best available information that is accessible or can be determined
within the established SDP timeliness goal. Phase 3 risk assessments
should be conducted using the Risk Assessment Standardization Project
(RASP) handbooks. The RASP handbooks provide technical guidance for
modeling of internal or external event initiators.

While, for the purposes of the SDP, the level of analysis should be
commensurate with the anticipated significance of the findings, it
should not be necessary to develop new risk analysis tools or perform
extensive analyses, and the evaluation effort should take into account
the importance of SDP timeliness.

**Documentation**

Each finding evaluated through the SDP must be given a color
characterizing its significance. In addition, each inspection finding
must be justified with sufficient detail to allow a knowledgeable reader
to reconstruct the decision logic used to arrive at the final color.
Further guidance on inspection report documentation is provided in IMC
0612.

+-----+--------------+------------------------+-------+-------+-------+
| *   |              |                        |       |       |       |
| *Ta |              |                        |       |       |       |
| ble |              |                        |       |       |       |
| 1 - |              |                        |       |       |       |
| G   |              |                        |       |       |       |
| ene |              |                        |       |       |       |
| ric |              |                        |       |       |       |
| Exa |              |                        |       |       |       |
| mpl |              |                        |       |       |       |
| e - |              |                        |       |       |       |
| C   |              |                        |       |       |       |
| ate |              |                        |       |       |       |
| gor |              |                        |       |       |       |
| ies |              |                        |       |       |       |
| for |              |                        |       |       |       |
| I   |              |                        |       |       |       |
| nit |              |                        |       |       |       |
| iat |              |                        |       |       |       |
| ing |              |                        |       |       |       |
| Ev  |              |                        |       |       |       |
| ent |              |                        |       |       |       |
| s** |              |                        |       |       |       |
+-----+--------------+------------------------+-------+-------+-------+
| Row | Initiating   | Initiating Event Type  | Initi |       |       |
|     | Event (IE)   |                        | ating |       |       |
|     | Frequency    |                        | Event |       |       |
|     |              |                        | Likel |       |       |
|     |              |                        | ihood |       |       |
|     |              |                        |       |       |       |
|     |              |                        | **X** |       |       |
|     |              |                        | = -   |       |       |
|     |              |                        | log~1 |       |       |
|     |              |                        | 0~(IE |       |       |
|     |              |                        | Frequ |       |       |
|     |              |                        | ency) |       |       |
+-----+--------------+------------------------+-------+-------+-------+
| **  | \>1 per 1-10 | -   Reactor Trip       | **1** | **2** | **3** |
| I** | yr           |     (TRANS)            |       |       |       |
|     |              |                        |       |       |       |
|     |              | -   Loss of Power      |       |       |       |
|     |              |     Conversion System  |       |       |       |
|     |              |     (TPCS)             |       |       |       |
+-----+--------------+------------------------+-------+-------+-------+
| **I | 1 per        | -   Loss of Offsite    | **2** | **3** | **4** |
| I** | 10-10^2^ yr  |     Power (LOOP)       |       |       |       |
|     |              |                        |       |       |       |
|     |              | -   Inadvertent or     |       |       |       |
|     |              |     Stuck Open SRV     |       |       |       |
|     |              |     (IORV) - (BWR)     |       |       |       |
+-----+--------------+------------------------+-------+-------+-------+
| *   | 1 per        | -   Steam Generator    | **3** | **4** | **5** |
| *II | 10^2^-10^3^  |     Tube Rupture       |       |       |       |
| I** | yr           |     (SGTR)             |       |       |       |
|     |              |                        |       |       |       |
|     |              | -   Loss of Component  |       |       |       |
|     |              |     Cooling Water      |       |       |       |
|     |              |     (LCCW)             |       |       |       |
|     |              |                        |       |       |       |
|     |              | -   Stuck open         |       |       |       |
|     |              |     PORV/SRV (SORV) -  |       |       |       |
|     |              |     (PWR)              |       |       |       |
|     |              |                        |       |       |       |
|     |              | -   Small LOCA         |       |       |       |
|     |              |     including RCP seal |       |       |       |
|     |              |     failures - (PWR)   |       |       |       |
|     |              |                        |       |       |       |
|     |              | -   MSLB/MFLB          |       |       |       |
+-----+--------------+------------------------+-------+-------+-------+
| **I | 1 per        | -   Small LOCA (RCS    | **4** | **5** | **6** |
| V** | 10^3^-10^4^  |     rupture) - (BWR)   |       |       |       |
|     | yr           |                        |       |       |       |
|     |              | -   Med LOCA           |       |       |       |
|     |              |                        |       |       |       |
|     |              | -   loss of offsite    |       |       |       |
|     |              |     power with loss of |       |       |       |
|     |              |     one AC bus (LEAC)  |       |       |       |
+-----+--------------+------------------------+-------+-------+-------+
| **  | 1 per        | -   Large LOCA         | **5** | **6** | **7** |
| V** | 10^4^-10^5^  |                        |       |       |       |
|     | yr           | -   ATWS - (BWR)       |       |       |       |
+-----+--------------+------------------------+-------+-------+-------+
| **V | \<1 per      | -   ATWS - (PWR)       | **6** | **7** | **8** |
| I** | 10^5^ yr     |                        |       |       |       |
|     |              | -   ISLOCA             |       |       |       |
+-----+--------------+------------------------+-------+-------+-------+
|     |              |                        | \>30  | 30-3  | \<3   |
|     |              |                        |       |       |       |
|     |              |                        | days  | days  | days  |
+-----+--------------+------------------------+-------+-------+-------+
|     |              |                        | Exp   |       |       |
|     |              |                        | osure |       |       |
|     |              |                        | Time  |       |       |
|     |              |                        | for   |       |       |
|     |              |                        | Deg   |       |       |
|     |              |                        | raded |       |       |
|     |              |                        | Cond  |       |       |
|     |              |                        | ition |       |       |
+-----+--------------+------------------------+-------+-------+-------+

**Number range CHAPTERTable 2 - Generic BWR Example - Initiators and
System Dependency**

+-------+------------+------------+-------------------+---------------+
| N     |            | **Major    | **Support         | **Initiating  |
| umber |            | Co         | Systems**         | Event         |
| range |            | mponents** |                   | Scenarios**   |
| CH    |            |            |                   |               |
| APTER |            |            |                   |               |
| **Aff |            |            |                   |               |
| ected |            |            |                   |               |
| Sys   |            |            |                   |               |
| tem** |            |            |                   |               |
+=======+============+============+===================+===============+
| **C   | **Name**   |            |                   |               |
| ode** |            |            |                   |               |
+-------+------------+------------+-------------------+---------------+
| ADS   | Reactor    | 5 relief   | IA/nitrogen, 125  | All except    |
|       | Vessel     | Valves     | V-DC              | LLOCA         |
|       | Pressure   | (ADS) & 8  |                   |               |
|       | Control    | safety     |                   |               |
|       | and        | valves     |                   |               |
|       | Automatic  |            |                   |               |
|       | Depres     |            |                   |               |
|       | surization |            |                   |               |
|       | System     |            |                   |               |
+-------+------------+------------+-------------------+---------------+
| PCS   | Power      | 3 reactor  | 4160 V-AC, 125    | TRAN, IORV,   |
|       | Conversion | feed       | V-DC, TBCCW, IA   | SLOCA, ATWS   |
|       | System     | pumps, 4   |                   |               |
|       |            | condensate |                   |               |
|       |            | pumps,4    |                   |               |
|       |            | condensate |                   |               |
|       |            | booster    |                   |               |
|       |            | pumps      |                   |               |
+-------+------------+------------+-------------------+---------------+
| RHR   | Residual   | 2 Loops,   | 4160 V-AC, 125    | All           |
|       | Heat       | each with  | V-DC, 480V AC,    |               |
|       | Removal    | 2 RHR      | RHRSW, Pump Room  |               |
|       |            | pumps & 1  | HVAC              |               |
|       |            | RHR HX,    |                   |               |
|       |            | MOVs       |                   |               |
+-------+------------+------------+-------------------+---------------+
| AC    | AC Power   | 4160V AC,  | 125V DC           | All           |
|       | (non-EDG)  | 480V AC    |                   |               |
+-------+------------+------------+-------------------+---------------+
| DC    | DC Power   | 125V DC (2 | 480V AC           | All           |
|       |            | batteries  |                   |               |
|       |            | & 4        |                   |               |
|       |            | battery    |                   |               |
|       |            | charger),  |                   |               |
|       |            | 250V DC (2 |                   |               |
|       |            | batteries  |                   |               |
|       |            | & 3        |                   |               |
|       |            | battery    |                   |               |
|       |            | charger)   |                   |               |
|       |            |            |                   |               |
|       |            | (shared    |                   |               |
|       |            | between    |                   |               |
|       |            | two units) |                   |               |
+-------+------------+------------+-------------------+---------------+

  ------------------------------------------------------------------------------
  **Affected                 **Major**     **Support Systems**  **Initiating
  System**                                                      Event**
  ------------ ------------- ------------- -------------------- ----------------
  EDG          Emergency     1 dedicated   125 V-DC, DGCW, EDG  LOOP
               Diesel        EDG, 1 shared HVAC                 
               Generators    EDG, & 1 SBO                       
                             DG                                 

  RHRSW        RHR Service   2 Loops, 2    HVAC, 4160 V-AC, 480 All
               Water         pump-motor    V-AC, 125 V-DC       
                             set per loop                       

  SW           Service water 5 pumps in    4160 V-AC, 125 V-DC, LOSW
                             Unit 1/ 2     IA                   
                             Crib house;                        
                             shared system                      
                             supplying a                        
                             common header                      

  TBCCW        Turbine       2 pumps, 2    SW, IA, 4160 V-AC    TRAN, TPCS,
               Building      HXs, an                            SLOCA, IORV,
               Closed        expansion                          LOOP, ATWS
               Cooling Water tank                               
               System                                           

  HPCI         High Pressure 1 TDP, MOV    125 V-DC, 250 V-DC,  All except
               Coolant                     Room HVAC            LLOCA, LOSW
               Injection                                        

  LPCS         Low Pressure  2 Trains or   4160 V-AC, 480 V-AC, All except LOSW
               Core Spray    Loops; 1 LPCS 125 V-DC, SW, Pump   
                             pump per      Room HVAC            
                             train                              

  RCIC         Reactor Core  1 TDP, MOV    125 V-DC, Room HVAC  All except
               Isolation                                        LLOCA, MLOCA
               Cooling                                          

  FPS          Fire          2 diesel fire 120V AC, SW, 24V     LOSW, LOIA
               Protection    pumps, MOV    Nickel-cadmium       
               System                      batteries            

  CRD          Control Rod   2 MDP, MOV    Non-emergency ESF AC TRAN, TPCS,
               Drive                       Buses, TBCCW         SLOCA, IORV,
               Hydraulic                                        LOOP, ATWS
               System                                           

  IA           Instrument    2 compressors SW, 480V AC          LOIA
               Air           for each unit                      
                             plus a shared                      
                             compressor                         
                             supplying                          
                             both units                         

  SLC          Standby       2 MDP, 2      480 V-AC, 125 V-DC   ATWS
               Liquid        explosive                          
               Control       valves                             

  APCV         Augmented     Valves,       Essential Service    All
               Primary       Dampers       Bus, IA backed up by 
               Containment                 accumulators for     
               Vent                        each valve operator  
  ------------------------------------------------------------------------------

**Table 3.XX - SDP Worksheet for Generic BWR --- Transients (Reactor
Trip) (TRAN)**

+---------------------+---+-----+--------------------+------+----+-----+
| **[Safety Functions |   | *   |                    |      |    |     |
| Nee                 |   | *[F |                    |      |    |     |
| ded]{.underline}:** |   | ull |                    |      |    |     |
|                     |   | C   |                    |      |    |     |
|                     |   | red |                    |      |    |     |
|                     |   | ita |                    |      |    |     |
|                     |   | ble |                    |      |    |     |
|                     |   | M   |                    |      |    |     |
|                     |   | iti |                    |      |    |     |
|                     |   | gat |                    |      |    |     |
|                     |   | ion |                    |      |    |     |
|                     |   | C   |                    |      |    |     |
|                     |   | apa |                    |      |    |     |
|                     |   | bil |                    |      |    |     |
|                     |   | ity |                    |      |    |     |
|                     |   | for |                    |      |    |     |
|                     |   | E   |                    |      |    |     |
|                     |   | ach |                    |      |    |     |
|                     |   | Saf |                    |      |    |     |
|                     |   | ety |                    |      |    |     |
|                     |   | Fun |                    |      |    |     |
|                     |   | cti |                    |      |    |     |
|                     |   | on] |                    |      |    |     |
|                     |   | {.u |                    |      |    |     |
|                     |   | nde |                    |      |    |     |
|                     |   | rli |                    |      |    |     |
|                     |   | ne} |                    |      |    |     |
|                     |   | :** |                    |      |    |     |
|                     |   |     |                    |      |    |     |
|                     |   | **  |                    |      |    |     |
|                     |   | 1/3 |                    |      |    |     |
|                     |   | Fee |                    |      |    |     |
|                     |   | dpu |                    |      |    |     |
|                     |   | mps |                    |      |    |     |
|                     |   | and |                    |      |    |     |
|                     |   | 1/4 |                    |      |    |     |
|                     |   | con |                    |      |    |     |
|                     |   | den |                    |      |    |     |
|                     |   | sat |                    |      |    |     |
|                     |   | e/c |                    |      |    |     |
|                     |   | ond |                    |      |    |     |
|                     |   | ens |                    |      |    |     |
|                     |   | ate |                    |      |    |     |
|                     |   | b   |                    |      |    |     |
|                     |   | oos |                    |      |    |     |
|                     |   | ter |                    |      |    |     |
|                     |   | pu  |                    |      |    |     |
|                     |   | mps |                    |      |    |     |
|                     |   | (op |                    |      |    |     |
|                     |   | era |                    |      |    |     |
|                     |   | tor |                    |      |    |     |
|                     |   | act |                    |      |    |     |
|                     |   | ion |                    |      |    |     |
|                     |   | =   |                    |      |    |     |
|                     |   | 3   |                    |      |    |     |
|                     |   | )** |                    |      |    |     |
|                     |   |     |                    |      |    |     |
|                     |   | **H |                    |      |    |     |
|                     |   | PCI |                    |      |    |     |
|                     |   | (1  |                    |      |    |     |
|                     |   | ASD |                    |      |    |     |
|                     |   | tra |                    |      |    |     |
|                     |   | in) |                    |      |    |     |
|                     |   | or  |                    |      |    |     |
|                     |   | R   |                    |      |    |     |
|                     |   | CIC |                    |      |    |     |
|                     |   | (1  |                    |      |    |     |
|                     |   | ASD |                    |      |    |     |
|                     |   | tr  |                    |      |    |     |
|                     |   | ain |                    |      |    |     |
|                     |   | )** |                    |      |    |     |
|                     |   |     |                    |      |    |     |
|                     |   | **  |                    |      |    |     |
|                     |   | 1/5 |                    |      |    |     |
|                     |   | ADS |                    |      |    |     |
|                     |   | val |                    |      |    |     |
|                     |   | ves |                    |      |    |     |
|                     |   | (R  |                    |      |    |     |
|                     |   | Vs) |                    |      |    |     |
|                     |   | ma  |                    |      |    |     |
|                     |   | nua |                    |      |    |     |
|                     |   | lly |                    |      |    |     |
|                     |   | ope |                    |      |    |     |
|                     |   | ned |                    |      |    |     |
|                     |   | (op |                    |      |    |     |
|                     |   | era |                    |      |    |     |
|                     |   | tor |                    |      |    |     |
|                     |   | act |                    |      |    |     |
|                     |   | ion |                    |      |    |     |
|                     |   | =   |                    |      |    |     |
|                     |   | 2   |                    |      |    |     |
|                     |   | )** |                    |      |    |     |
|                     |   |     |                    |      |    |     |
|                     |   | **  |                    |      |    |     |
|                     |   | 1/4 |                    |      |    |     |
|                     |   | RHR |                    |      |    |     |
|                     |   | pu  |                    |      |    |     |
|                     |   | mps |                    |      |    |     |
|                     |   | in  |                    |      |    |     |
|                     |   | ½   |                    |      |    |     |
|                     |   | tra |                    |      |    |     |
|                     |   | ins |                    |      |    |     |
|                     |   | in  |                    |      |    |     |
|                     |   | L   |                    |      |    |     |
|                     |   | PCI |                    |      |    |     |
|                     |   | M   |                    |      |    |     |
|                     |   | ode |                    |      |    |     |
|                     |   | (1  |                    |      |    |     |
|                     |   | mu  |                    |      |    |     |
|                     |   | lti |                    |      |    |     |
|                     |   | -tr |                    |      |    |     |
|                     |   | ain |                    |      |    |     |
|                     |   | s   |                    |      |    |     |
|                     |   | yst |                    |      |    |     |
|                     |   | em) |                    |      |    |     |
|                     |   | or  |                    |      |    |     |
|                     |   | ½   |                    |      |    |     |
|                     |   | L   |                    |      |    |     |
|                     |   | PCS |                    |      |    |     |
|                     |   | tra |                    |      |    |     |
|                     |   | ins |                    |      |    |     |
|                     |   | (1  |                    |      |    |     |
|                     |   | mu  |                    |      |    |     |
|                     |   | lti |                    |      |    |     |
|                     |   | -tr |                    |      |    |     |
|                     |   | ain |                    |      |    |     |
|                     |   | sys |                    |      |    |     |
|                     |   | tem |                    |      |    |     |
|                     |   | )** |                    |      |    |     |
|                     |   |     |                    |      |    |     |
|                     |   | **  |                    |      |    |     |
|                     |   | 1/4 |                    |      |    |     |
|                     |   | RHR |                    |      |    |     |
|                     |   | pu  |                    |      |    |     |
|                     |   | mps |                    |      |    |     |
|                     |   | in  |                    |      |    |     |
|                     |   | ½   |                    |      |    |     |
|                     |   | tra |                    |      |    |     |
|                     |   | ins |                    |      |    |     |
|                     |   | w   |                    |      |    |     |
|                     |   | ith |                    |      |    |     |
|                     |   | h   |                    |      |    |     |
|                     |   | eat |                    |      |    |     |
|                     |   | e   |                    |      |    |     |
|                     |   | xch |                    |      |    |     |
|                     |   | ang |                    |      |    |     |
|                     |   | ers |                    |      |    |     |
|                     |   | and |                    |      |    |     |
|                     |   | 1/4 |                    |      |    |     |
|                     |   | RH  |                    |      |    |     |
|                     |   | RSW |                    |      |    |     |
|                     |   | pu  |                    |      |    |     |
|                     |   | mps |                    |      |    |     |
|                     |   | in  |                    |      |    |     |
|                     |   | SPC |                    |      |    |     |
|                     |   | (1  |                    |      |    |     |
|                     |   | mu  |                    |      |    |     |
|                     |   | lti |                    |      |    |     |
|                     |   | -tr |                    |      |    |     |
|                     |   | ain |                    |      |    |     |
|                     |   | sys |                    |      |    |     |
|                     |   | tem |                    |      |    |     |
|                     |   | )** |                    |      |    |     |
|                     |   |     |                    |      |    |     |
|                     |   | **V |                    |      |    |     |
|                     |   | ent |                    |      |    |     |
|                     |   | ing |                    |      |    |     |
|                     |   | t   |                    |      |    |     |
|                     |   | hro |                    |      |    |     |
|                     |   | ugh |                    |      |    |     |
|                     |   | 8\" |                    |      |    |     |
|                     |   | d   |                    |      |    |     |
|                     |   | ryw |                    |      |    |     |
|                     |   | ell |                    |      |    |     |
|                     |   | or  |                    |      |    |     |
|                     |   | w   |                    |      |    |     |
|                     |   | etw |                    |      |    |     |
|                     |   | ell |                    |      |    |     |
|                     |   | A   |                    |      |    |     |
|                     |   | PCV |                    |      |    |     |
|                     |   | (op |                    |      |    |     |
|                     |   | era |                    |      |    |     |
|                     |   | tor |                    |      |    |     |
|                     |   | act |                    |      |    |     |
|                     |   | ion |                    |      |    |     |
|                     |   | =   |                    |      |    |     |
|                     |   | 2   |                    |      |    |     |
|                     |   | )** |                    |      |    |     |
|                     |   |     |                    |      |    |     |
|                     |   | **  |                    |      |    |     |
|                     |   | 2/2 |                    |      |    |     |
|                     |   | CRD |                    |      |    |     |
|                     |   | pu  |                    |      |    |     |
|                     |   | mps |                    |      |    |     |
|                     |   | (op |                    |      |    |     |
|                     |   | era |                    |      |    |     |
|                     |   | tor |                    |      |    |     |
|                     |   | act |                    |      |    |     |
|                     |   | ion |                    |      |    |     |
|                     |   | =   |                    |      |    |     |
|                     |   | 2   |                    |      |    |     |
|                     |   | )** |                    |      |    |     |
+---------------------+---+-----+--------------------+------+----+-----+
| **Power Conversion  |   |     |                    |      |    |     |
| System (PCS)**      |   |     |                    |      |    |     |
+---------------------+---+-----+--------------------+------+----+-----+
| **High Pressure     |   |     |                    |      |    |     |
| Injection (HPI)**   |   |     |                    |      |    |     |
+---------------------+---+-----+--------------------+------+----+-----+
| **Depressurization  |   |     |                    |      |    |     |
| (DEP)**             |   |     |                    |      |    |     |
+---------------------+---+-----+--------------------+------+----+-----+
| **Low Pressure      |   |     |                    |      |    |     |
| Injection (LPI)**   |   |     |                    |      |    |     |
+---------------------+---+-----+--------------------+------+----+-----+
| **Containment Heat  |   |     |                    |      |    |     |
| Removal (CHR)**     |   |     |                    |      |    |     |
+---------------------+---+-----+--------------------+------+----+-----+
| **Containment       |   |     |                    |      |    |     |
| Venting (CV)**      |   |     |                    |      |    |     |
+---------------------+---+-----+--------------------+------+----+-----+
| **Late Inventory    |   |     |                    |      |    |     |
| Makeup (LI)**       |   |     |                    |      |    |     |
+---------------------+---+-----+--------------------+------+----+-----+
| **[Circle Affected  |   | **[ | **[Remaining       | **[  | *  | *   |
| Funct               |   | IEL | Mitigation         | Reco | *[ | *[L |
| ions]{.underline}** |   | ]{. | Capability Rating  | very | Re | ERF |
|                     |   | und | for Each Affected  | o    | su | Fac |
|                     |   | erl | Seque              | f]{. | lt | tor |
|                     |   | ine | nce]{.underline}** | unde | s] | ]{. |
|                     |   | }** |                    | rlin | {. | und |
|                     |   |     |                    | e}** | un | erl |
|                     |   |     |                    |      | de | ine |
|                     |   |     |                    | *    | rl | }** |
|                     |   |     |                    | *[Fa | in |     |
|                     |   |     |                    | iled | e} |     |
|                     |   |     |                    | Trai | ** |     |
|                     |   |     |                    | n]{. |    |     |
|                     |   |     |                    | unde |    |     |
|                     |   |     |                    | rlin |    |     |
|                     |   |     |                    | e}** |    |     |
+---------------------+---+-----+--------------------+------+----+-----+
| 1 TRAN - PCS -      | * |     |                    |      |    | **  |
| CHR - CV (5, 9)     | * |     |                    |      |    | 0** |
|                     | 9 |     |                    |      |    |     |
| **1 + 3 + 3 + 2**   | * |     |                    |      |    |     |
|                     | * |     |                    |      |    |     |
+---------------------+---+-----+--------------------+------+----+-----+
| 2 TRAN - PCS -CHR - | * |     |                    |      |    | **  |
| LI (4, 8)           | * |     |                    |      |    | 0** |
|                     | 9 |     |                    |      |    |     |
| **1 + 3 + 3 + 2**   | * |     |                    |      |    |     |
|                     | * |     |                    |      |    |     |
+---------------------+---+-----+--------------------+------+----+-----+
| 3 TRAN - PCS -      | * |     |                    |      |    | **  |
| HPI - DEP (11)      | * |     |                    |      |    | 0** |
|                     | 8 |     |                    |      |    |     |
| **1 + 3 + 2 + 2**   | * |     |                    |      |    |     |
|                     | * |     |                    |      |    |     |
+---------------------+---+-----+--------------------+------+----+-----+
| 4 TRAN - PCS -      | * |     |                    |      |    | 0   |
| HPI - LPI (10)      | * |     |                    |      |    |     |
|                     | 1 |     |                    |      |    |     |
| **1 + 3 + 2 + 6**   | 2 |     |                    |      |    |     |
|                     | * |     |                    |      |    |     |
|                     | * |     |                    |      |    |     |
+---------------------+---+-----+--------------------+------+----+-----+
| Identify any        |   |     |                    |      |    |     |
| operator recovery   |   |     |                    |      |    |     |
| actions that are    |   |     |                    |      |    |     |
| credited to         |   |     |                    |      |    |     |
| directly restore    |   |     |                    |      |    |     |
| the degraded        |   |     |                    |      |    |     |
| equipment or        |   |     |                    |      |    |     |
| initiating event:   |   |     |                    |      |    |     |
|                     |   |     |                    |      |    |     |
| If operator actions |   |     |                    |      |    |     |
| are required to     |   |     |                    |      |    |     |
| credit placing      |   |     |                    |      |    |     |
| mitigation          |   |     |                    |      |    |     |
| equipment in        |   |     |                    |      |    |     |
| service or for      |   |     |                    |      |    |     |
| recovery actions,   |   |     |                    |      |    |     |
| such credit should  |   |     |                    |      |    |     |
| be given only if    |   |     |                    |      |    |     |
| the following       |   |     |                    |      |    |     |
| criteria are        |   |     |                    |      |    |     |
| met: 1) sufficient  |   |     |                    |      |    |     |
| time is available   |   |     |                    |      |    |     |
| to implement these  |   |     |                    |      |    |     |
| actions, 2)         |   |     |                    |      |    |     |
| environmental       |   |     |                    |      |    |     |
| conditions allow    |   |     |                    |      |    |     |
| access where        |   |     |                    |      |    |     |
| needed, 3)          |   |     |                    |      |    |     |
| procedures exist,   |   |     |                    |      |    |     |
| 4) training is      |   |     |                    |      |    |     |
| conducted on the    |   |     |                    |      |    |     |
| existing procedures |   |     |                    |      |    |     |
| under conditions    |   |     |                    |      |    |     |
| similar to the      |   |     |                    |      |    |     |
| scenario assumed,   |   |     |                    |      |    |     |
| and 5) any          |   |     |                    |      |    |     |
| equipment needed to |   |     |                    |      |    |     |
| complete these      |   |     |                    |      |    |     |
| actions is          |   |     |                    |      |    |     |
| available and       |   |     |                    |      |    |     |
| available and ready |   |     |                    |      |    |     |
| for use.            |   |     |                    |      |    |     |
+---------------------+---+-----+--------------------+------+----+-----+

**Table 4 - Remaining Mitigation Capability Credit**

+--------------------------------------------------------+-------------+
| **Type of Remaining Mitigation Capability**            | **Remaining |
|                                                        | Mitigation  |
|                                                        | Capability  |
|                                                        | Credit**    |
|                                                        |             |
|                                                        | **X = -     |
|                                                        | log~        |
|                                                        | 10~(failure |
|                                                        | prob)**     |
+--------------------------------------------------------+-------------+
| **Recovery of Failed Train**                           | 1           |
|                                                        |             |
| Operator action to recover failed equipment that is    |             |
| capable of being recovered after an initiating event   |             |
| occurs. Action may take place either in the control    |             |
| room or outside the control room and is assumed to     |             |
| have a failure probability of approximately 0.1 when   |             |
| credited as "Remaining Mitigation Capability." Credit  |             |
| should be given only if the following criteria are     |             |
| satisfied: (1) sufficient time is available; (2)       |             |
| environmental conditions allow access, where needed;   |             |
| (3) procedures describing the appropriate operator     |             |
| actions exist; (4) training is conducted on the        |             |
| existing procedures under similar conditions; and (5)  |             |
| any equipment needed to perform these actions is       |             |
| available and ready for use.                           |             |
+--------------------------------------------------------+-------------+
| **1 Automatic Steam-Driven (ASD) Train**               | 1           |
|                                                        |             |
| A collection of associated equipment that includes a   |             |
| single turbine-driven component to provide 100% of a   |             |
| specified safety function. The probability of such a   |             |
| train being unavailable due to failure, test, or       |             |
| maintenance is assumed to be approximately 0.1 when    |             |
| credited as "Remaining Mitigation Capability."         |             |
+--------------------------------------------------------+-------------+
| **1 Train**                                            | 2           |
|                                                        |             |
| A collection of associated equipment (e.g., pumps,     |             |
| valves, breakers, etc.) that together can provide 100% |             |
| of a specified safety function. The probability of     |             |
| this equipment being unavailable due to failure, test, |             |
| or maintenance is approximately 1E-2 when credited as  |             |
| "Remaining Mitigation Capability."                     |             |
+--------------------------------------------------------+-------------+
| **1 Multi-Train System**                               | 3           |
|                                                        |             |
| A system comprised of two or more trains (as defined   |             |
| above) that are considered susceptible to common cause |             |
| failure modes. The probability of this equipment being |             |
| unavailable due to failure, test, or maintenance is    |             |
| approximately 1E-3 when credited as "Remaining         |             |
| Mitigation Capability," regardless of how many trains  |             |
| comprise the system.                                   |             |
+--------------------------------------------------------+-------------+
| **2 Diverse Trains**                                   | 4 (=2+2)    |
|                                                        |             |
| A system comprised of two trains (as defined above)    |             |
| that are not considered to be susceptible to common    |             |
| cause failure modes. The probability of this equipment |             |
| being unavailable due to failure, test, or maintenance |             |
| is approximately 1E-4 when credited as "Remaining      |             |
| Mitigation Capability."                                |             |
+--------------------------------------------------------+-------------+
| **Operator Action Credit**                             | 1, 2, or 3  |
|                                                        |             |
| Major actions performed by operators during accident   |             |
| scenarios (e.g., primary heat removal using bleed and  |             |
| feed, etc.). These actions are credited using three    |             |
| categories of human error probabilities (HEPs). These  |             |
| categories are Operator Action = 1 which represents a  |             |
| failure probability between 5E-2 and 0.5, Operator     |             |
| Action = 2 which represents a failure probability      |             |
| between 5E-3 and 5E-2, and Operator Action = 3 which   |             |
| represents a failure probability between 5E-4 and      |             |
| 5E-3.                                                  |             |
+--------------------------------------------------------+-------------+

+-----+-------------------------------------------------+--------------+
| *   |                                                 |              |
| *Ta |                                                 |              |
| ble |                                                 |              |
| 5 - |                                                 |              |
| Co  |                                                 |              |
| unt |                                                 |              |
| ing |                                                 |              |
| R   |                                                 |              |
| ule |                                                 |              |
| Wo  |                                                 |              |
| rks |                                                 |              |
| hee |                                                 |              |
| t** |                                                 |              |
+-----+-------------------------------------------------+--------------+
| **  | **Instructions**                                |              |
| Ste |                                                 |              |
| p** |                                                 |              |
+-----+-------------------------------------------------+--------------+
|     |                                                 |              |
+-----+-------------------------------------------------+--------------+
| \(  | Enter the number of sequences with a risk       | \(1\)        |
| 1\) | significance equal to 9.                        |              |
+-----+-------------------------------------------------+--------------+
| \(  | Divide the result of Step (1) by 3 and round    | \(2\)        |
| 2\) | down.                                           |              |
+-----+-------------------------------------------------+--------------+
| \(  | Enter the number of sequences with a risk       | \(3\)        |
| 3\) | significance equal to 8.                        |              |
+-----+-------------------------------------------------+--------------+
| \(  | Add the result of Step (3) to the result of     | \(4\)        |
| 4\) | Step (2).                                       |              |
+-----+-------------------------------------------------+--------------+
| \(  | Divide the result of Step (4) by 3 and round    | \(5\)        |
| 5\) | down.                                           |              |
+-----+-------------------------------------------------+--------------+
| \(  | Enter the number of sequences with a risk       | \(6\)        |
| 6\) | significance equal to 7.                        |              |
+-----+-------------------------------------------------+--------------+
| \(  | Add the result of Step (6) to the result of     | \(7\)        |
| 7\) | Step (5).                                       |              |
+-----+-------------------------------------------------+--------------+
| \(  | Divide the result of Step (7) by 3 and round    | \(8\)        |
| 8\) | down.                                           |              |
+-----+-------------------------------------------------+--------------+
| \(  | Enter the number of sequences with a risk       | \(9\)        |
| 9\) | significance equal to 6.                        |              |
+-----+-------------------------------------------------+--------------+
| \(1 | Add the result of Step (9) to the result of     | \(10\)       |
| 0\) | Step (8).                                       |              |
+-----+-------------------------------------------------+--------------+
| \(1 | Divide the result of Step (10) by 3 and round   | \(11\)       |
| 1\) | down.                                           |              |
+-----+-------------------------------------------------+--------------+
| \(1 | Enter the number of sequences with a risk       | \(12\)       |
| 2\) | significance equal to 5.                        |              |
+-----+-------------------------------------------------+--------------+
| \(1 | Add the result of Step (12) to the result of    | \(13\)       |
| 3\) | Step (11).                                      |              |
+-----+-------------------------------------------------+--------------+
| \(1 | Divide the result of Step (13) by 3 and round   | \(14\)       |
| 4\) | down.                                           |              |
+-----+-------------------------------------------------+--------------+
| \(1 | Enter the number of sequences with a risk       | \(15\)       |
| 5\) | significance equal to 4.                        |              |
+-----+-------------------------------------------------+--------------+
| \(1 | Add the result of Step (15) to the result of    | \(16\)       |
| 6\) | Step (14).                                      |              |
+-----+-------------------------------------------------+--------------+
|     |                                                 |              |
+-----+-------------------------------------------------+--------------+
| -   |                                                 |              |
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|     |                                                 |              |
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| D). |                                                 |              |
|     |                                                 |              |
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|     |                                                 |              |
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|     |                                                 |              |
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|  13 |                                                 |              |
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|     |                                                 |              |
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| W). |                                                 |              |
|     |                                                 |              |
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| rea |                                                 |              |
| ter |                                                 |              |
|     |                                                 |              |
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|     |                                                 |              |
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|     |                                                 |              |
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|     |                                                 |              |
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| 10, |                                                 |              |
|     |                                                 |              |
|     |                                                 |              |
| 13, |                                                 |              |
|     |                                                 |              |
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| and |                                                 |              |
|     |                                                 |              |
|  16 |                                                 |              |
|     |                                                 |              |
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| ery |                                                 |              |
|     |                                                 |              |
|     |                                                 |              |
| low |                                                 |              |
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|     |                                                 |              |
| saf |                                                 |              |
| ety |                                                 |              |
|     |                                                 |              |
|     |                                                 |              |
| sig |                                                 |              |
| nif |                                                 |              |
| ica |                                                 |              |
| nce |                                                 |              |
|     |                                                 |              |
|  (G |                                                 |              |
| REE |                                                 |              |
| N). |                                                 |              |
|     |                                                 |              |
| *   |                                                 |              |
| *Ph |                                                 |              |
| ase |                                                 |              |
| 2   |                                                 |              |
| Res |                                                 |              |
| ult |                                                 |              |
| :** |                                                 |              |
| **G |                                                 |              |
| REE |                                                 |              |
| N** |                                                 |              |
| **W |                                                 |              |
| HIT |                                                 |              |
| E** |                                                 |              |
| *   |                                                 |              |
| *YE |                                                 |              |
| LLO |                                                 |              |
| W** |                                                 |              |
| *   |                                                 |              |
| *RE |                                                 |              |
| D** |                                                 |              |
+-----+-------------------------------------------------+--------------+
|     |                                                 |              |
+-----+-------------------------------------------------+--------------+

**APPENDIX A**

**ATTACHMENT 2**

**Site Specific Risk-Informed Inspection Notebook Usage Rules**

**Table of Contents**

[1.0 DETERMINING THE INITIATING EVENT LIKELIHOOD Att
2-2](#determining-the-initiating-event-likelihood)

[1.1 Exposure Time Att 2-2](#exposure-time)

[1.2 Inspection Finding (Not Involving a Support System) that Increases
the Likelihood of an Initiating Event Att
2-2](#inspection-finding-not-involving-a-support-system-that-increases-the-likelihood-of-an-initiating-event)

[1.3 Inspection Finding of a Support System that Increases the
Likelihood of an Initiating Event and/or Reduces the Support Redundancy
for Mitigation Capabilities Att
2-3](#inspection-finding-of-a-support-system-that-increases-the-likelihood-of-an-initiating-event-andor-reduces-the-support-redundancy-for-mitigation-capabilities)

[1.4 Inspection Findings Involving Emergency Diesel Generators Att
2-5](#inspection-findings-involving-emergency-diesel-generators)

[1.5 Inspection Findings Involving Loss of an Emergency AC Bus Att
2-6](#inspection-findings-involving-loss-of-an-emergency-ac-bus)

[1.6 Inspection Findings Involving Loss of an Emergency DC Bus Att
2-7](#inspection-findings-involving-loss-of-an-emergency-dc-bus)

[1.7 Inspection Findings Involving Safety-Related Battery Chargers Att
2-8](#inspection-findings-involving-safety-related-battery-chargers)

[1.8 Inspection Findings Involving Safety-Related Battery Att
2-10](#inspection-findings-involving-safety-related-battery)

[2.0 DETERMINING REMAINING MITIGATION CAPABILITY Att
2-11](#determining-remaining-mitigation-capability)

[2.1 Inspection Finding Involving a Loss of Redundancy of the Mitigation
Capabilities Att
2-11](#inspection-finding-involving-a-loss-of-redundancy-of-the-mitigation-capabilities)

[2.2 Inspection Finding Involving Reduced Redundancy of a Support System
for the Mitigation Capabilities Supported Att
2-12](#inspection-finding-involving-reduced-redundancy-of-a-support-system-for-the-mitigation-capabilities-supported)

[2.3 Inspection Findings Involving Equipment that Impact Operator Action
Credit Att
2-13](#inspection-findings-involving-equipment-that-impact-operator-action-credit)

[3.0 CHARACTERIZING THE RISK SIGNIFICANCE OF INSPECTION FINDINGS Att
2-13](#characterizing-the-risk-significance-of-inspection-findings)

[3.1 Treatment of Shared Systems Between Units Att
2-13](#treatment-of-shared-systems-between-units)

[3.2 Counting Rule Att 2-14](#counting-rule)

# 

# 1.0 DETERMINING THE INITIATING EVENT LIKELIHOOD

# 1.1 Exposure Time

[Rule]{.underline}: The exposure time used in determining the Initiating
Event Likelihood (IEL) should correspond to the time period that the
condition being assessed is reasonably known to have existed. If the
inception of the condition is unknown, then an exposure time of one-half
of the time period since the last successful demonstration of the
component or function (*t/2*) should be used. The maximum exposure time
used in SDP is limited to one year.

[Basis]{.underline}: A *t/2* exposure time is used when the inception of
the condition being assessed is unknown because it represents the mean
exposure time for a statistically valid large sample.

[Example]{.underline}: Consider an inspection finding that corresponds
to the loss of a safety function which was identified as a result of a
failed monthly surveillance. Also consider that the loss of safety
function was not the result of a misalignment or human error that took
place in the last maintenance or routine testing. Therefore, the
inception of the condition is unknown. If the monthly surveillance was
last successfully performed 32 days prior to the surveillance failure,
an exposure time of 16 days (greater than 3 but less than 30 days) would
be used for determining the IEL in Table 1 of the SDP notebook in
assessing the inspection finding.

# 1.2 Inspection Finding (Not Involving a Support System) that Increases the Likelihood of an Initiating Event

[Rule]{.underline}: An inspection finding in a system can increase the
likelihood of an initiating event in SDP process when the failure of the
system can cause an initiator. If the increase in the frequency of the
initiating event due to the inspection finding is not known, increase
the Initiating Event Likelihood (IEL) for the applicable initiating
event by one order of magnitude. If specific information exists that
indicates the IEL should be increased by more than one order of
magnitude, consult with the regional Senior Reactor Analyst (SRA) to
determine the appropriate IEL.

[Basis]{.underline}: This simplified rule was needed to facilitate Phase
2 screening. Scaling up the frequency of an initiating event strongly
depends on the type and the severity of the inspection finding.
Judgement and experience with the use of the Phase 2 notebooks were
utilized in the establishment of this rule. If an increase by more than
one order of magnitude is believed to be appropriate, the SRA should be
consulted.

[Example]{.underline}: Consider an inspection finding that involves
improper adjustment of MSIV pressure setpoints. As a result of this
condition, the MSIVs could go shut prematurely and cause a plant trip.
Furthermore, the plant is equipped with turbine-driven feedwater pumps
which would result in a loss of PCS whenever the MSIVs go shut. The
exposure time associated with the inspection finding is 27 days. The
inspection finding is assessed to increase the likelihood of a transient
with the associated loss of the power conversion system (TPCS) about one
order of magnitude during the exposure time; however, the inspection
finding would not affect the safety function of MSIVs during SGTR or
MSLB scenarios. Using Table 1,"Categories of Initiating Events," an IEL
of 2 would normally be used; but because the inspection finding
increases the likelihood of TPCS, an IEL of 1 would be applicable and
should be used. Each of the sequences on the TPCS worksheet would then
have to be solved because the TPCS initiating event frequency is a
component in each of the sequences.

Consider an inspection finding that involves an error in a relay
calibration procedure that results in the undervoltage setpoint on the
supply breakers from each of the offsite power lines being set
incorrectly high. As a result, normal voltage perturbations on the
offsite power distribution system could result in a loss of offsite
power (LOOP) event. The exposure time associated with this inspection
finding is 10 days. Using Table 1, "Categories of Initiating Events," an
IEL of 3 would normally be used; but, because the inspection finding
increases the likelihood of a LOOP event, an IEL of 2 would be
applicable and should be used. Each of the sequences on the LOOP
worksheet would then have to be solved because the LOOP initiating event
frequency is a component in each of these sequences. For those plants
that have a special initiator for LOOP with loss of one AC bus (LEAC),
this worksheet would be solved in a similar manner.

# 1.3 Inspection Finding of a Support System that Increases the Likelihood of an Initiating Event and/or Reduces the Support Redundancy for Mitigation Capabilities

[Rule]{.underline}: For inspection findings that involve the
unavailability of a component in a support system that increases the
likelihood of an initiating event, increase the Initiating Event
Likelihood (IEL) by one order of magnitude for the associated special
initiator and evaluate the impact on mitigation capabilities provided in
usage rule 2.2, "Inspection Finding Involving Reduced Redundancy of a
Support System for the Mitigation Capabilities Supported." There is an
exception to the rule for non-electrical support system cases where the
remaining number of redundant components of the support system is just
sufficient to meet the success criteria. In these cases, the likelihood
of the initiating event should be raised by two orders of magnitude. For
inspection findings on electrical support, e.g., electrical buses (DC or
AC), always increase the initiating event likelihood by one order of
magnitude.

[Basis:]{.underline} Simple reliability models and generic data have
been used to determine that an order of magnitude increase is
appropriate for different configurations of cross-tied support systems.
For example, based on generic data the initiating event frequency for a
cross-tied support system with one running train and two standby trains
is on the order of 1E-4 per year. The initiating event frequency for a
cross-tied support system with one running train and one standby train
is on the order of 1E-3 per year. Therefore, if an inspection finding
causes the former system configuration to be changed to the latter, the
risk significance should be evaluated by increasing the initiating
frequency by one order of magnitude.

Simple reliability models and generic data have also been used to
evaluate the impact of losing a running or standby train in a two-train
system. A generic failure frequency for one normally running train is
approximately 1E-1 per year \[(1E-5 per hour) x (8760hours/year)
**≈**1E-1/year\]. The failure probability of a standby train is about 1
E-2. The failure frequency of a support system with one running train
and one standby train is about 1E-3. Upon experiencing a failure, the
support system will be configured in one running train with a failure
frequency of 1E-1 per year. Therefore, it is appropriate to increase the
IEL by two orders of magnitude for cases when the remaining support
capabilities is one train credit.

[Example]{.underline}: Consider an inspection finding that involves the
unavailability of a standby pump in the component cooling water (CCW)
system. The CCW system is a two train support system cross-tied into a
common header with one pump normally running to provide cooling to the
RCPs and a second pump in a standby mode. There is also a swing pump
available that can be aligned to either of the trains, if necessary, to
support the cooling of essential loads for mitigation capability.
However, the swing pump cannot be credited as part of the initial
mitigation credit to prevent sudden loss of the CCW system as an
initiator. The operation of one CCW pump is sufficient to meet the
cooling needs of the RCPs and all essential loads. The unavailability of
the standby pump will present a condition where the CCW system is
operating with only one running pump to provide cooling to the RCPs. The
exposure time associated with this inspection finding is 21 days. The
loss of CCW is a special initiator is located in Row III of Table 1,
"Categories of Initiating Events," for the affected plant. As a result,
an IEL of 4 would normally be assigned when solving loss of CCW accident
sequences. But because of the inspection finding, the remaining
configuration of the CCW system is a single running pump just sufficient
to meet the demands, the likelihood of the initiating event should be
raised by two orders of magnitude. An IEL of 2 would be applicable and
should be used. Each of the sequences on the loss of CCW worksheet would
then have to be solved because the loss of CCW initiating event
frequency is a component in each of these sequences. The impact on the
mitigating capability would then be assessed through usage rule 2.2,
"Inspection Finding Involving Reduced Redundancy of a Support System for
the Mitigation Capabilities Supported," which in this case implies an
evaluation of the affected sequences with CCW having no more than single
train credit. NOTE: If the system configuration had been such that the
swing pump could be aligned and started in a timely manner to warrant
inclusion in the CCW mitigation success criteria, the CCW system would
have twice the mitigtion capacity required to meet the success criteria.
Under this condition, mitigation capabilities for the affected scenarios
would be evaluated nominally for those scenarios.

Consider an inspection finding that involves the unavailability of a
standby pump in a service water system. The service water system is a
support system to CCW and Chilled water. It has six pumps. Operation of
two pumps would be sufficient to carry worst case post trip loads. The
exposure time associated with this inspection finding is 21 days. The
loss of service water is located in Row III of Table 1, "Categories of
Initiating Events," for the affect plant. As a result, an IEL of 4 would
normally be assigned when solving loss of service water accident
sequences. But because of the inspection finding, the likelihood of the
initiating event increases by one order of magnitude and an IEL of 3
would be applicable and should be used. The impact on mitigating
capability would then be assessed through usage rule 2.2, "Inspection
Finding Involving Reduced Redundancy of a Support System for the
Mitigation Capabilities Supported," which in this case requires no
further assessment since the success of the system requires operation of
two pumps out of five pumps remaining in the post trip conditions.

Consider an inspection finding that involves the unavailability of a
standby compressor in an instrument air system. The instrument air
system consists of four compressors and successful operation of one of
the compressors is needed. Loss of instrument air is modeled as an
initiator. The exposure time associated with the inspection finding is
90 days. The loss of instrument air is located in Row II of Table 1,
"Categories of Initiating Events," for the affect plant. As a result, an
IEL of 2 would normally be assigned when solving loss of instrument air
sequences. Because of the inspection finding, the likelihood of the
initiating event increases by one order of magnitude and an IEL of 1
would be applicable and should be used. The impact on mitigating
capability would then be assessed through usage rule 2.2, "Inspection
Finding Involving Reduced Redundancy of a Support System for the
Mitigation Capabilities Supported," which in this case requires no
further assessment since the success of the system requires operation of
one compressor out of three remaining compressors.

# 1.4 Inspection Findings Involving Emergency Diesel Generators

[Rule]{.underline}: For inspection findings that involve the
unavailability of emergency diesel generators (EDGs), determine the
impact on mitigation capability of the supported systems and evaluate
the loss of offsite power (LOOP) worksheet accounting for the
unavailability of the EDG and the affected supported systems. In
addition, if the LOOP with loss of one AC bus (LEAC) special initiator
is modeled, then increase the Initiating Event Likelihood (IEL) by two
orders of magnitude and evaluate the worksheet with the changed
likelihood for LEAC.

[Basis]{.underline}: The unavailability of an EDG does not increase the
likelihood of a LOOP event; therefore, the LOOP IEL is not adjusted when
performing the LOOP worksheet. The frequency of LEAC is estimated by
multiplying the frequency of a LOOP event with the unavailability of an
EDG (approximately 1E-2). If the inspection finding is related to the
unavailability of an EDG, then the frequency of LEAC should be the same
as the frequency of a LOOP event. In addition, because most plants have
two trains of emergency AC power and many of the mitigating systems have
more than two trains, the loading of the emergency AC buses is
asymmetrical. Therefore, the LEAC worksheet reflects the loss of the
emergency AC bus with the greatest risk impact.

[Example]{.underline}: Consider an inspection finding that involves the
unavailability of one of two EDGs at a PWR. The supported mitigating
systems that are impacted by the unavailability of one train of
emergency AC power includes one train of each of the auxiliary feedwater
(AFW), high pressure safety injection (HPSI), and residual heat removal
(RHR) systems. The exposure time associated with this inspection finding
is 270 days. In accordance with Table 2, "Initiators and System
Dependency," for the affected plant, the LOOP and LEAC worksheets need
to be evaluated. The LOOP initiator is located in Row II of Table 1,
"Categories of Initiating Events," for the affected plant. As a result,
an IEL of 2 is assigned when solving LOOP accident sequences. The LEAC
initiator is located in Row IV of Table 1, "Categories of Initiating
Events." As a result, an IEL of 4 would normally be assigned when
solving LEAC accident sequences; but, because the inspection finding
increases the likelihood of a LEAC event, an IEL of 2 would be
applicable and should be used. When solving the LOOP worksheet, the EDG
and the equipment that it supports needs to be considered unavailable
and the remaining mitigation capability modified accordingly. In this
example, one train of each of the AFW, HPSI, and RHR systems is assumed
unavailable in determining the remaining mitigation capability. In those
sequences where AC power has been recovered (annotated as AC Recovered
on the worksheets), full credit is given for the supported mitigating
equipment because offsite power is available and the equipment does not
need the unavailable EDG to perform its function. The LEAC worksheet
already takes into account the equipment lost by the unavailability of
the EDG; however, each sequence needs to be solved because the LEAC
initiating event frequency is a component in each of these sequences.

# 1.5 Inspection Findings Involving Loss of an Emergency AC Bus 

For inspection findings that involve the unavailability of an emergency
AC Bus that increases the likelihood of an initiating event, increase
the Initiating Event Likelihood (IEL) by one order of magnitude for the
associated special initiator. Evaluate loss of offsite power (LOOP)
worksheet accounting for both the unavailability of the EDG and the
affected mitigation capabilities (even if the normal AC is recovered).
In addition, if the LOOP with loss of one AC bus (LEAC) special
initiator is modeled, then increase the Initiating Event Likelihood
(IEL) by two orders of magnitude and evaluate the worksheet with the
changed likelihood for LEAC. Determine the impact of the loss of the
emergency bus on mitigation capabilities and evaluate all other
worksheets assuming the loss of the affected mitigation capabilities.

[Basis:]{.underline} The unavailability of an emergency bus could result
in a reactor trip and it may be considered as a special initiator. It
therefore behaves like a risk significant event rather than a condition.
A stylized evaluation of the loss of an emergency AC bus is utilized in
the SDP notebook. This stylized evaluation reflects the logic models
that are typically implemented in PRAs to the extent possible. As such,
the impact on all mitigation capabilities are evaluated similar to a
comprehensive PRA approach, and the frequency of the special initiator
of loss of an emergency AC bus is increased by one order of magnitude to
avoid direct event evaluation which is not within the SDP scope. The
frequency of LEAC is estimated by multiplying the frequency of a LOOP
event with the unavailability of an emergency bus. If the inspection
finding is related to the unavailability of an emergency bus, then the
frequency of LEAC should be raised by two orders of magnitudes to become
the same as the frequency of a LOOP event.

[Example:]{.underline} Consider an inspection finding that involves the
unavailability of one of two emergency AC bus at a PWR. The supported
mitigating systems that are impacted by the unavailability of one train
emergency AC power includes one train of each of the auxiliary feedwater
(AFW), high pressure safety injection (HPSI), residual heat removal
(RHR) systems, and the associated support systems to these systems
trains (e.g. for component cooling). The exposure time associated with
this inspection finding is 3 hr. The Loss of an Emergency AC Bus is set
to Row III of Table 1,"Categories of Initiating Events," for the
affected plant. As a result, an IEL of 5 would normally be assigned;
but, because of the inspection finding increases the likelihood of a
loss of that AC bus initiator, an IEL of 4 would be applicable and
should be used when solving the accident sequences associated with the
loss of that AC bus initiator. The LOOP initiator is located in Row II
of Table 1, "Categories of Initiating Events," for the affected plant.
As a result, an IEL of 4 is assigned when solving LOOP accident
sequences. The LEAC initiator is located in Row IV of Table 1,
"Categories of Initiating Events." As a result, an IEL of 6 would
normally be assigned when solving LEAC accident sequences; but, because
the inspection finding increases the likelihood of a LEAC event, an IEL
of 4 would be applicable and should be used. When solving the LOOP
worksheet, the EDG and the equipment that it supports needs to be
considered unavailable and the remaining mitigation capability modified
accordingly. In this example, one train of each of the AFW, HPSI, and
RHR systems is assumed unavailable in determining the remaining
mitigation capability even in those sequences where AC power has been
recovered (annotated as AC Recovered on the worksheets).

# 1.6 Inspection Findings Involving Loss of an Emergency DC Bus 

For inspection findings that involve the unavailability of an emergency
DC Bus that increases the likelihood of an initiating event, increase
the Initiating Event Likelihood (IEL) by one order of magnitude for the
associated special initiator. Evaluate loss of offsite power (LOOP)
worksheet accounting for both the unavailability of the EDG and the
affected mitigation capabilities (even if offsite power is recovered).
In addition, if the LOOP with loss of one AC bus (LEAC) special
initiator is modeled, then increase the Initiating Event Likelihood
(IEL) by two orders of magnitude and evaluate the worksheet with the
changed likelihood for LEAC. Determine the impact of the loss of the
emergency bus on mitigation capabilities and evaluate all other
worksheets assuming the loss of the affected mitigation capabilities.

[Basis:]{.underline} The unavailability of an emergency DC bus could for
some plants result in a reactor trip therefore considered as a special
initiator. For these plants loss of DC bus behaves like a risk
significant event rather than a condition. A stylized evaluation of the
loss of an emergency DC bus is utilized in the SDP notebook. This
stylized evaluation reflects the logic models that are typically
implemented in PRAs to the extent possible. As such, the impact on all
mitigation capabilities are evaluated similar to a comprehensive PRA
approach, and the frequency of the special initiator of loss of an
emergency DC bus is increased by one order of magnitude to avoid direct
event evaluation which is not within the SDP scope. The frequency of
LEAC is estimated by multiplying the frequency of a LOOP event with the
unavailability of an emergency bus (or the associated EDG). If the
inspection finding is related to the unavailability of an emergency DC
bus and there is an EDG that relies on that Bus for field flashing, then
the frequency of LEAC should be raised by two order to become the same
as the frequency of a LOOP event. If the EDG is not supported by the
affected DC bus, then the sequences associated with LEAC worksheet will
be evaluated by reflecting the impact of the DC bus on the mitigation
capabilities.

[Example:]{.underline} Consider an inspection finding that involves the
unavailability of one of two emergency DC bus at a PWR. The supported
mitigating systems that are impacted by the unavailability of one train
emergency DC power includes one train of each of the auxiliary feedwater
(AFW), high pressure safety injection (HPSI), residual heat removal
(RHR) systems, and their associated support systems (e.g. required
component cooling). The exposure time associated with this inspection
finding is 3 hr. The Loss of an emergency DC bus is set to Row III of
Table 1,"Categories of Initiating Events," for the affected plant. As a
result, an IEL of 5 would normally be assigned; but, because of the
inspection finding increases the likelihood of a loss of that DC bus
initiator, an IEL of 4 would be applicable and should be used when
solving the accident sequences associated with the loss of that DC bus
initiator. The LOOP initiator is located in Row II of Table 1,
"Categories of Initiating Events," for the affected plant. As a result,
an IEL of 4 is assigned when solving LOOP accident sequences. The LEAC
initiator is located in Row IV of Table 1, "Categories of Initiating
Events." As a result, an IEL of 6 would normally be assigned when
solving LEAC accident sequences; but, because the inspection finding
increases the likelihood of a LEAC event, an IEL of 4 would be
applicable and should be used. When solving the LOOP worksheet, the EDG
and the equipment that it supports needs to be considered unavailable
and the remaining mitigation capability modified accordingly. In this
example, one train of each of the AFW, HPSI, and RHR systems is assumed
unavailable in determining the remaining mitigation capability, even in
those sequences where AC power has been recovered (annotated as AC
Recovered on the worksheets).

# 1.7 Inspection Findings Involving Safety-Related Battery Chargers

[Rule]{.underline}: Inspection findings that involve the unavailability
of a battery charger for a safety-related DC bus when there is no spare
battery charger available and no recovery action can be taken should be
treated by (1) increasing the initiating event frequency for loss of DC
bus by one order of magnitude if the loss of DC bus is a special
initiator, and (2) solving all other worksheets that contain equipment
powered by the affected DC bus, assuming the loss of the DC bus.

Inspection findings that involve the unavailability of a battery charger
for a safety-related DC bus when a spare charger is available and/or
recovery action can be taken should be treated by: (1) increasing the
initiating event frequency for loss of the DC bus by one order of
magnitude if the loss of DC bus is a special initiator, and (2)
nominally solving the base case for all other worksheets that contain
equipment powered by the affected DC bus.

Inspection findings that involve the unavailability of a battery charger
for a safety-related DC bus, when a dedicated spare charger is available
for the safety-related bus and is automatically aligned when the primary
charger fails, should be treated as a "Green" finding, unless the loss
of the associated DC bus is a special initiator. If the loss of DC bus
is a special initiator, the inspection finding should be evaluated by
increasing the initiating event frequency for the loss of DC bus by one
order of magnitude, and solving the worksheet.

[Basis:]{.underline} Loading of a DC bus without an operable charger
would result in eventual battery depletion and therefore the loss of the
associated DC bus. Also, prolonged loss of a battery charger without any
recovery action or alignment of an alternate charger could render the DC
bus inoperable.

[Example]{.underline}: Consider an inspection finding that involves the
unavailability of the battery charger for one of two safety-related DC
buses and the facility does not have an installed spare. The exposure
time associated with this inspection finding is 1 day. The loss of DC
bus special initiator is located in Row IV of Table 1, "Categories of
Initiating Events," for the affected plant. As a result, an Initiating
Event Likelihood (IEL) of 6 would normally be assigned when solving loss
of DC bus accident sequences; but, because the inspection finding
increases the likelihood of a loss of DC bus event, an IEL of 5 would be
applicable and should be used. Each of the sequences on the loss of DC
bus worksheet would then have to be solved because the loss of DC bus
initiating event frequency is a component in each of these sequences. In
addition, each of the worksheets specified by Table 2, "Initiators and
System Dependency," for the equipment powered by the affected DC train
need to be solved considering this equipment unavailable.

Consider an inspection finding that involves the unavailability of the
battery charger for one of two safety-related DC buses and the facility
does have a spare charger available. The exposure time associated with
this inspection finding is 1 day. The loss of DC bus special initiator
is located in Row IV of Table 1, "Categories of Initiating Events," for
the affected plant. As a result, an Initiating Event Likelihood of 6
would normally be assigned when solving loss of DC bus accident
sequences; but, because the inspection finding increases the likelihood
of a loss of DC bus event, an Initiating Event Likelihood of 5 would be
applicable and should be used. Each of the sequences on the loss of DC
bus worksheet would then have to be solved because the loss of DC bus
initiating event frequency is a component in each of these sequences. In
addition, each of the worksheets specified by Table 2, "Initiators and
System Dependency," for the equipment powered by the affected DC train
need to be solved nominally.

Consider an inspection finding that involves the unavailability of the
battery charger for one of two safety-related DC buses and the facility
does have an installed spare which can be shared between the DC buses
and needs to be manually aligned. The exposure time associated with this
inspection finding is 1 day. The loss of DC bus special initiator is
located in Row IV of Table 1, "Categories of Initiating Events," for the
affected plant. As a result, an Initiating Event Likelihood (IEL) of 6
would normally be assigned when solving loss of DC bus accident
sequences; but, because the inspection finding increases the likelihood
of a loss of DC bus event, an IEL of 5 would be applicable and should be
used. Each of the sequences on the loss of DC bus worksheet would then
have to be solved nominally because they are fed by the affected DC bus.

Finally consider an inspection finding that involves the unavailability
of a battery charger for one of the two DC safety buses and the facility
does have an installed, dedicated and automatically aligned spare
charger for each DC bus. The exposure time associated with this
inspection finding is 1 day. The loss of DC bus special initiator is
located in Row IV of Table 1, "Categories of Initiating Events," for the
affected plant. As a result, an Initiating Event Likelihood (IEL) of 6
would normally be assigned when solving loss of DC bus accident
sequences; but, because the inspection finding increases the likelihood
of a loss of DC bus event, an IEL of 5 would be applicable and should be
used. No further evaluation is needed due to sufficient levels of
built-in redundancy are designed for the battery chargers. If loss of
the DC bus is not a special initiator, the inspection finding should be
considered as Green.

# 1.8 Inspection Findings Involving Safety-Related Battery 

[Rule:]{.underline} Inspection findings that involve the unavailability
of an emergency battery bank should be treated differently depending on
the capacity of the associated battery charger in carrying the safety
injection (SI) loads. If the battery chargers cannot carry the SI loads,
the inspection finding that involves the unavailability of an emergency
battery should be treated as the loss of the associated DC bus for all
initiators specified in Table 2. If the battery chargers can carry the
SI loads as footnoted in Table 2, the inspection finding that involves
the unavailability of an emergency battery should be treated as the loss
of the associated DC bus only in LOOP and LEAC worksheets. In addition,
the loss of Battery bank would also necessitate increasing the Loss of
DC frequency (if it is a special initiator) by one order of magnitude.

[Basis:]{.underline} In some plants the battery charger cannot carry the
SI loads. Loss of the associated battery will therefore render the DC
bus unavailable for all initiators when SI is actuated. Alternatively,
when the charger is capable of carrying the SI loads, the DC bus will
only be unavailable under Station Blackout (SBO) scenarios where there
would be no AC power to the chargers.

[Example:]{.underline} Consider an inspection finding that involves the
unavailability of the battery for one of two safety-related DC buses and
the facility does not have battery chargers capable of carrying the SI
loads. The exposure time associated with this inspection finding is 1
day. The loss of DC bus special initiator is located in Row IV of Table
1, "Categories of Initiating Events," for the affected plant. As a
result, an Initiating Event Likelihood (IEL) of 6 would normally be
assigned when solving loss of DC bus accident sequences; but, because
the inspection finding increases the likelihood of a loss of DC bus
event, an IEL of 5 would be applicable and should be used. Each of the
sequences on the loss of DC bus worksheet would then be solved because
the loss of DC bus initiating event frequency is a component in each of
these sequences. In addition, each of the worksheets specified by Table
2, "Initiators and System Dependency," for the

equipment powered by the affected DC train needs to be solved
considering the associated DC bus is unavailable.

Now consider the case where the facility has battery chargers of
sufficient capacity to carry the SI loads. The exposure time associated
with this inspection finding is 1 day. The LOOP and LEAC initiators are
in Rows II and IV respectively. For 1 day exposure time, the LOOP and
LEAC will have an initiating event likelihood of 4 and 6 respectively.
Since one of the emergency diesel generators (EDGs) cannot be started
without the associated battery, the LEAC IEL should be raised by two
orders of magnitude to an IEL of 4. The LOOP worksheet therefore will be
solved assuming an IEL of 4 and failure of one DC bus and the associated
EDG. The LEAC worksheet will be solved nominally with an IEL of 4.
Similarly, the loss of DC bus special initiator is located in Row IV of
Table 1, "Categories of Initiating Events," for the affected plant. As a
result, an Initiating Event Likelihood (IEL) of 6 would normally be
assigned when solving loss of DC bus accident sequences; but, because
the inspection finding increases the likelihood of a loss of DC bus
event, an IEL of 5 would be applicable and should be used.

# 2.0 DETERMINING REMAINING MITIGATION CAPABILITY

# 2.1 Inspection Finding Involving a Loss of Redundancy of the Mitigation Capabilities

[Rule]{.underline}: For an inspection finding that reduces the remaining
mitigation capability such that the total available equipment is less
than two times the equipment that is required to fulfill the safety
function, the remaining mitigation capability credit should not exceed
one train. For an inspection finding that reduces the remaining
mitigation capability such that two or more times the equipment that is
required to fulfill the safety function remains, solve all of the
worksheet sequences that contain the safety function giving full
mitigation credit.

[Basis]{.underline}: The SDP worksheets typically assume that if the
mitigation capability is such that a single failure can be tolerated
without loss of a function, then multi-train credit is assigned.
However, if an inspection finding indicates that a performance issue
contributed to the failure of at least one train of a system, there is a
higher potential for a common cause failure mechanism. In such cases
single train credit is more appropriate when the remaining mitigation
capability does not provide full redundancy (twice the number of trains
required).

[Example]{.underline}: Consider a finding that involves the
unavailability of one train of a low pressure injection system. The
system is normally a four train system that requires two trains to
satisfy the success criteria (e.g., 2/4 trains \[multi-train system\]).
Each of the worksheets specified by Table 2, "Initiators and System
Dependency," for this system needs to be solved considering one train
unavailable. When solving each of the worksheets that credit this
system, only one train of remaining mitigation capability credit would
be given because of the loss of redundancy (e.g., 2/3 trains \[1
train\]) in this system.

# 2.2 Inspection Finding Involving Reduced Redundancy of a Support System for the Mitigation Capabilities Supported

[Rule]{.underline}: For inspection findings that involve the
unavailability of a component in a support system, determine the reduced
redundancy for the support system to the mitigation capabilities, and
evaluate each of the worksheets directed by Table 2, "Initiators and
System Dependency," for the unavailability of the affected supported
systems. The reduced redundancy of an affected support system is defined
as the remaining number of redundant paths including the backup systems
and any diversified equipment that could be aligned to support the
function of the associated mitigation capability. The backup systems and
the manually aligned diversified equipment that can be credited should
be limited to those identified in the SDP worksheet associated with the
support system initiator, if applicable, or those systems that are noted
in Table 2. If the inspection finding reduces the support system
redundancy such that the total remaining support system redundancy is
more than two times the equipment that is required to directly support
the associated mitigation function, no further evaluation of the
affected scenarios are required. If the inspection finding reduces the
support system redundancy such that the total remaining support system
redundancy is equal to two times the equipment that is required to
directly support the associated mitigation function, the affected
scenarios that include the mitigation function are solved nominally. If
the inspection finding reduces the support system redundancy such that
the total remaining support system redundancy is less than two times the
equipment that is required to directly support the associated mitigation
function, the remaining credit should not exceed one train credit for
the affected scenarios that include the mitigation function.

[Basis]{.underline}: Evaluation of this type of inspection finding, if
not caused by a common cause failure mechanism, involves a direct
application of the SDP rules derived from generic reliability models and
generic reliability data for evaluation of simultaneous unavailability
of multiple systems.

[Example]{.underline}: Consider an inspection finding that involves the
unavailability of one of three pump of an emergency service water (ESW)
system. The ESW system is a standby, support system with two headers
which support two motor-driven auxiliary feedwater pump trains , two
high pressure safety injection system trains , two residual heat removal
system trains, and two emergency diesel generators. The third pump
(i.e., swing pump) can be aligned and started from the MCR. As a result
of this condition, ESW will be configured with one pump train dedicated
to each header supporting one train of the mitigation capability (i.e.,
equal to twice the mitigation capability needed). As identified in Table
2, "Initiators and System Dependency," the applicable worksheets would
be evaluated nominally for each of the mitigation systems associated
with the support system finding.

# 2.3 Inspection Findings Involving Equipment that Impact Operator Action Credit

[Rule]{.underline}: When evaluating inspection findings that impact
safety functions involving mitigating equipment and operator action, the
remaining mitigation credit should correspond to the equipment or
operator action credit, whichever is most limiting.

[Basis]{.underline}: The failure of safety functions that are composed
of both equipment and operator action can occur by the failure of either
the equipment or the operator action. Because the associated failure
probabilities are relatively small, the failure probability of the
safety function can be determined by adding the individual failure
probabilities together. Consequently, the failure probability of the
safety function can be approximated by the order of magnitude of the
most limiting component. For example, a safety function is comprised of
a multi-train system which has a failure probability of 1E-3 coupled
with an operator action which has a failure probability of 1E-2.
Therefore, the failure probability of the safety function is 1.1E-2, or
approximately 1E-2.

[Example]{.underline}: Consider an inspection finding involving the
failure of one of the high pressure safety injection (HPSI) pumps. One
of the safety functions impacted by this finding is high pressure
recirculation (HPR). The success criteria for the HPR function is one of
two HPSI pumps, one of two residual heat removal (RHR) pumps and one of
two RHR heat exchangers with operator action for switchover (operator
action credit = 3). With one HPSI pump unavailable, the remaining
mitigation capability becomes equipment limited and a credit of 2 (1
train) should be assigned to the HPR function.

# 3.0 CHARACTERIZING THE RISK SIGNIFICANCE OF INSPECTION FINDINGS

# 3.1 Treatment of Shared Systems Between Units

[Rule]{.underline}: When evaluating inspection findings that involve
systems that impact multiple units, the inspection finding should be
evaluated for each unit separately.

[Basis]{.underline}: The risk significance of an inspection finding is
attributed to the unit on which it is applicable. If the inspection
finding affects more than one unit and it affects the units differently,
then the SDP should be conducted once for each unit as it applies to
that unit.

[Example]{.underline}: Consider an inspection finding that involves the
unavailability of an emergency diesel generator (EDG). The particular
EDG is credited as mitigating equipment on the dedicated unit and a
second unit via an operator action to cross-tie the EDG. Therefore, the
inspection finding needs to be evaluated separately for each unit. For
the dedicated unit, the finding would be evaluated as a finding
involving a normally standby, split train support system that increases
the likelihood of an initiating event and the impact on mitigating
system capability can explicitly be determined. For the other unit, the
inspection finding would be evaluated as a finding that impacts the
remaining mitigation capability, the ability to cross-tie the EDG, which
is credited in certain accident sequences. Specifically, only LOOP and
LEAC accident sequences that contain the emergency AC power function
need to be solved. As a result, the inspection finding will result in
separate risk characterizations for each unit which may or may not be
the same.

# 3.2 Counting Rule

[Rule]{.underline}: Every three affected accident sequences that have
the same order of magnitude of risk, as determined by the addition of
the initiating event likelihood and the remaining mitigation capability,
constitute one equivalent sequence which is more risk significant by one
order of magnitude. This rule is applied in a cascading fashion.

[Basis]{.underline}: The Counting Rule is necessary because the risk
significance of an inspection finding is determined by the increase in
core damage frequency due to the associated performance deficiency. This
risk increase represents the summation of the changes in risk associated
with each of the affected accident sequences. A simplified rule was
needed to relate accident sequences that represent different orders of
magnitude of risk significance. Judgement and experience with the use of
the Phase 2 Notebooks were used in the establishment of this rule.

[Examples]{.underline}: Consider an inspection finding that affects
three accident sequences in the Phase 2 Notebook that each have a risk
significance of 7, which is Green. Using the Counting Rule, these three
accident sequences would constitute an equivalent accident sequence that
is one order of magnitude more risk significant, which is 6 or White.

Now, consider an inspection finding that affects a total of eight
accident sequences in the Phase 2 Notebook. One sequence has a risk
significance of 7, Green, and seven sequences have a risk significance
of 8. Using the Counting Rule, the seven sequences of 8 would constitute
two equivalent sequences one order of magnitude more risk significant,
7. In turn, these two sequences, when added with the sequence that had a
risk significance of 7, would constitute an equivalent accident sequence
that is one order of magnitude more risk significant, 6 or White.

END

**APPENDIX A**

**ATTACHMENT 3**

**User Guidance for Screening of External Events Risk Contributions**

When the Phase 2 SDP analysis results for an inspection finding show an
increase in risk estimate of greater than 1E-7 (Risk Significance
Estimation of 7), the SRA or risk analyst can perform a Phase 3 analysis
of external events risk contributions, **or** proceed to Step 1.0,
"Screening of Fire Risk Contributions." Step 1.0 is the first step in
screening of risk contributions from external events that may add to the
significance of an inspection finding.

All three steps of this process to screen risk contributions from
external events (Steps 1.0-3.0) should be performed to further assess
the significance of an inspection finding that has a preliminary risk
significance estimation of greater than 1E-7 for internal events risk
contributions. If any one area of the external events screening process
requires a Phase 3 evaluation, the other remaining areas should also be
screened or evaluated. Flow charts for Steps 1.0 and 2.0 of the process
are provided to show the decision points for screening of external event
risk contributions.

**1.0 Screening of Fire Risk Contributions**

**Step 1.1** Determine whether the affected SSC is in the protected
train of a post-fire safe shutdown path. If yes, proceed to Step 1.2. If
no, proceed to Step 2.0, "Screening of Seismic Risk Contributions."

**Step 1.2** If the affected SSC is part of a safe shutdown path,
identify the risk significant fire areas for which the affected SSC is
credited as part of the safe shutdown path. Estimate the fire frequency
for the identified fire area(s) using Table 1.4.2 of IMC 0609 Appendix
F, "Fire Protection SDP," or consult with Operational Support and
Maintenance Branch (APOB). Proceed to Step 1.3.

**Step 1.3** For each fire area of concern, multiply its fire frequency
estimate with the duration factor of the inspection finding. Then, add
the product values to generate the screening value of change in CDF due
to fire risk contributions.

**Step 1.4** If the total sum of the products of the duration factor and
fire area fire frequency estimates is less than 1E-6, proceed to Step
2.0. If no, proceed to Step 1.5.

**Step 1.5** The fire risk contributions may be substantial enough to
alter the preliminary Phase 2 significance determination of the
inspection finding. Using guidance in the RASP External Events Handbook,
evaluate the fire risk contributions that may add to the significance of
an inspection finding. After this evaluation is completed, proceed to
Step 2.0 for screening of seismic risk contributions.

**2.0 Screening of Seismic Risk Contributions**

**Step 2.1** Determine whether the affected SSC is on the seismic safe
shutdown list (i.e., addressed in Seismic Margins approach) or credited
in a seismic PRA. If yes, proceed to Step 2.2. If no, the seismic risk
should be considered as insignificant to the finding, proceed to Step
3.0, "Screening of Flood Risk Contributions."

**Step 2.2** Determine whether the affected SSC is used to mitigate the
consequences of a loss of offsite AC power supply. If the affected SSC
is required to perform its intended functions to mitigate the
consequences of loss of offsite AC power during a seismic event, proceed
to Step 2.3. If no, proceed to Step 3.0, "Screening of Flood Risk
Contributions."

**Step 2.3** Determine whether the exposure time of the finding is less
than 3 days. If the exposure time of the finding is less than 3 days,
proceed to Step 3.0, "Screening of Flood Risk Contributions." If no,
proceed to Step 2.4.

**Step 2.4** The seismic risk contributions may be substantial enough to
alter the preliminary Phase 2 significance determination of the
inspection finding. Using guidance in the RASP External Events Handbook,
evaluate the seismic risk contributions that may add to the significance
of an inspection finding. After this evaluation is completed, proceed to
Step 3.0 for screening of flood risk contributions.

**3.0 Screening of Flood Risk Contributions**

**Step 3.1** Determine whether the affected SSC is identified as
critical to avoiding core damage for any flood scenario of significance.
A list of significant flood scenarios identified at specific U.S.
nuclear power plants is shown in Table 3.1 of this Attachment. The flood
initiator frequency estimate for each significant flood scenario is also
provided in Table 3.1. If the affected SSC is identified on the list in
Table 3.1, proceed to Step 3.2. If no, flood risk contributions are
screened out from further external events risk analysis in Step 4.0.

**Step 3.2** If the affected SSC is identified on Table 3.1 for a
specific plant with a reported flood scenario(s) of significance, the
SRA or risk analyst should determine the conditional core damage
probability (CCDP) estimate of the flood scenario(s) as identified in
the plant-specific IPE internal flood analysis.

**Step 3.3** For an identified flood scenario(s), multiply the flood
initiator frequency estimate and the CCDP estimate of the flood
scenario(s) that credits the affected SSC. If the product of the flood
frequency estimate and the CCDP estimate is less than 1E-8, the risk
contribution from the flood scenario(s) are screened out from further
external events risk analysis. If no, proceed to Step 3.4. (Note: LERF
multiplier used for internal event risk estimates is not be applied for
multiplying with external event significance.)

**Step 3.4** Multiply the above product(s) of flood frequency
estimate(s) and the CCDP estimate(s) for the flood scenario(s) and the
duration factor. If this value(s) is less than 1E-8, the risk
contributions from the flood scenario(s) are screened out from further
external events risk analysis. If no, proceed to Step 3.5.

**Step 3.5** The flood risk contributions may be substantial enough to
alter the preliminary Phase 2 significance determination of the
inspection finding. Using guidance in the RASP External Events Handbook,
evaluate the flood risk contributions that may add to the significance
of an inspection finding. After this evaluation is completed, proceed to
step 4.0 for the determination of the estimate of total risk
contributions from external events.

**4.0 Estimation of External Event Risk Contributions**

**Step 4.1** Determine the estimate of total risk contributions from
external events based on the results of evaluations performed in Steps
1.5, 2.4, and 3.5. This estimate must be added to the preliminary risk
significance estimation for internal events risk contributions.
\[Caution: the LERF multiplier for the internal events risk estimate may
not be applicable for multiplication with the external event risk
estimate.\]

**Step 4.2** Document the results.

**Table 3.1 Plant Specific Flood Scenarios and Initiator Frequencies**.

The subject Table may contain proprietary plant specific information.
Therefore, the Table content is located in the RASP Hand Book and on the
ROP Digital City Internal Website under the drop-down menu titled Forms,
Templates, Sample Report & More.

**END**

ATTACHMENT 4

Revision History For

IMC 0609 Appendix A

+------+--------+-----------------+-----------------+--------+---------+
| Com  | Issue  | Description of  | Training Needed | Tr     | Comment |
| mit- | Date   | Change          |                 | aining | Res     |
| ment |        |                 |                 | Comp   | olution |
| Trac |        |                 |                 | letion | Ac      |
| king |        |                 |                 | Date   | cession |
| Nu   |        |                 |                 |        | Number  |
| mber |        |                 |                 |        |         |
+------+--------+-----------------+-----------------+--------+---------+
| >    | 09/1   | Multiple        | N/A             | N/A    | N/A     |
|  N/A | 0/2004 | editorial       |                 |        |         |
|      |        | changes to      |                 |        |         |
|      |        | enhance user    |                 |        |         |
|      |        | friendliness of |                 |        |         |
|      |        | the document.   |                 |        |         |
|      |        | For example,    |                 |        |         |
|      |        | re-format       |                 |        |         |
|      |        | action steps,   |                 |        |         |
|      |        | provided        |                 |        |         |
|      |        | additional      |                 |        |         |
|      |        | examples, added |                 |        |         |
|      |        | the reference   |                 |        |         |
|      |        | to Appendix J   |                 |        |         |
|      |        | for steam       |                 |        |         |
|      |        | generator       |                 |        |         |
|      |        | issues.         |                 |        |         |
+------+--------+-----------------+-----------------+--------+---------+
| N/A  | 12/0   | Corrected two   | N/A             | N/A    | N/A     |
|      | 1/2004 | errors on page  |                 |        |         |
|      |        | 4 of the        |                 |        |         |
|      |        | worksheet,      |                 |        |         |
|      |        | under MS        |                 |        |         |
|      |        | cornerstone for |                 |        |         |
|      |        | screening       |                 |        |         |
|      |        | issues and      |                 |        |         |
|      |        | under BI        |                 |        |         |
|      |        | cornerstone     |                 |        |         |
|      |        | guidance for    |                 |        |         |
|      |        | question 3 for  |                 |        |         |
|      |        | screening to    |                 |        |         |
|      |        | Green.          |                 |        |         |
+------+--------+-----------------+-----------------+--------+---------+
| N/A  | 11     | Enhanced        | N/A             | N/A    | N/A     |
|      | /22/05 | guidance to     |                 |        |         |
|      |        | help meet       |                 |        |         |
|      |        | timeliness      |                 |        |         |
|      |        | requirements    |                 |        |         |
|      |        | for finalizing  |                 |        |         |
|      |        | the SDP for     |                 |        |         |
|      |        | inspection      |                 |        |         |
|      |        | findings.       |                 |        |         |
+------+--------+-----------------+-----------------+--------+---------+
| N/A  | 03     | Incorporate     | 1.Training has  | 1\.    | ML07    |
|      | /23/07 | references to   | been provided   | 1      | 0720624 |
|      |        | the             | to the SRAs at  | 0/2006 |         |
|      | CN     | site-specific   | last two SRA    |        |         |
|      | 07-011 | inspection      | counterpart     | 2\. FY |         |
|      |        | notebooks and   | meetings, and   | 2008   |         |
|      |        | associated      | the SRAs have   |        |         |
|      |        | Pre-Solved      | provided        |        |         |
|      |        | Tables; In      | training to the |        |         |
|      |        | Attachment 2,   | region based    |        |         |
|      |        | update the site | and resident    |        |         |
|      |        | specific        | inspectors.     |        |         |
|      |        | risk-informed   |                 |        |         |
|      |        | inspection      | 2\. Formalized  |        |         |
|      |        | notebooks usage | training will   |        |         |
|      |        | rules;          | be introduced   |        |         |
|      |        | Attachment 3,   | through the     |        |         |
|      |        | provide user    | P-111 course.   |        |         |
|      |        | guidance for    |                 |        |         |
|      |        | screening of    |                 |        |         |
|      |        | external events |                 |        |         |
|      |        | risk            |                 |        |         |
|      |        | contributions.  |                 |        |         |
+------+--------+-----------------+-----------------+--------+---------+
| N/A  | 01     | Removed the     | N/A             | N/A    | ML07    |
|      | /10/08 | Phase 1 Initial |                 |        | 3460588 |
|      |        | Screening and   |                 |        |         |
|      | CN     | C               |                 |        |         |
|      | 08-002 | haracterization |                 |        |         |
|      |        | of Findings     |                 |        |         |
|      |        | process to      |                 |        |         |
|      |        | create the new  |                 |        |         |
|      |        | IMC 0609,       |                 |        |         |
|      |        | Attachment 4.   |                 |        |         |
|      |        | Added           |                 |        |         |
|      |        | clarification   |                 |        |         |
|      |        | statement to    |                 |        |         |
|      |        | Step 2.1.2 and  |                 |        |         |
|      |        | Usage Rule 1.1  |                 |        |         |
|      |        | that the        |                 |        |         |
|      |        | maximum         |                 |        |         |
|      |        | exposure time   |                 |        |         |
|      |        | used in SDP is  |                 |        |         |
|      |        | limited to one  |                 |        |         |
|      |        | year.           |                 |        |         |
+------+--------+-----------------+-----------------+--------+---------+