Issue Date: 1/17/02

NRC Inspection Manual IIPB

# Inspection Procedure 71153

Table Of Contents

- 71153-01 Inspection Objective
- 71153-02 Inspection Requirements
- 71153-03 Inspection Guidance
- 71153-04 Resource Estimate
- 71153-05 References

## Event Followup

PROGRAM APPLICABILITY: | 2515

CORNERSTONES: | ALL

### 71153-01 Inspection Objective

01.01 | Evaluate licensee events and degraded conditions for plant status and mitigating actions in order to provide input in determining the need for an Incident Investigation Team (IIT), Augmented Inspection Team (AIT), or Special Inspection (SI).
01.02 | Review written event reports.

### 71153-02 Inspection Requirements

02.01 | Event Follow Up
| a. Observe plant parameters and status, including mitigating systems/trains and fission product barriers. Determine alarms/conditions preceding or indicating the event.
| b. Evaluate performance of mitigating systems and licensee actions.
| c. Confirm that the licensee properly classified the event in accordance with emergency action level procedures and made timely notifications to NRC and state/county governments, as required (10 CFR Parts 20, 50.9, 50.72).
| d. Communicate details regarding the event to management, risk analysts and others in the Region and Headquarters as input to their determining the need for an IIT, AIT, or SI.
02.02 | Event Report Review
| Review Licensee Event Reports (LERs) and related documents regarding the accuracy of the LER (e.g., based on independent NRC observations in an SI), appropriateness of corrective actions, violations of requirements, and generic issues.

### 71153-03 Inspection Guidance

General

Management Directive (MD) 8.3, "NRC Incident Investigation Program", defines a significant operational event as a radiological, safeguards, or other safety-related operational event at an NRC-licensed facility that poses an actual or potential hazard to public health and safety, property, or the environment. At power reactors, these events include significant unplanned degraded conditions identified by the licensee or NRC.

Upon receipt of licensee notifications in accordance with 10 CFR 50.72, on-site inspectors provide details regarding plant status and performance of equipment/ operators to regional and headquarters risk analysts, event review staff, and management. The details are used to determine the level of investigatory response if any, i.e., IIT, AIT, or SI.

Appendix A illustrates the relationship between event response and the reactor oversight process.

Appendix B provides guidance for limiting NRC's impact on licensees during an event.

03.01 | Event Follow Up
| a. No specific guidance.
| b. Evaluate whether the licensee has appropriately resolved event issues prior to restart, where applicable, such as by attending meetings of the Plant Oversight Review Committee.
| c. No specific guidance.
| d. MD 8.3 provides deterministic criteria which are applicable to power reactors. Inspectors provide details which help determine whether the event meets the deterministic criteria. An IIT or AIT is considered for events meeting deterministic criteria which are not risk informed, e.g., exceed a safety limit of the licensee's technical specifications, and site area emergency. Some deterministic criteria are risk informed, e.g., loss of a safety function or multiple failures in systems used to mitigate an event. For events meeting these criteria, risk analysts estimate Conditional Core Damage Probability (CCDP) based on best available information, and an evaluation of the most uncertain or influential assumptions. If a quantitative CCDP cannot be obtained, the risk analyst provides qualitative risk insights. Containment performance issues are also considered. The above process is described in MD 8.3, Part I, Pages 4 through 8. Page 6 contains a table which lists appropriate event response options (IIT, AIT, or SI) as a function of CCDP. To assist risk analysts, inspectors provide input (in addition to a and b above), such as equipment malfunctions/unavailabilities and operator errors. Inspectors verify the availability of mitigation equipment not required to operate during the event, but which could contribute to increased risk if unavailable. If the event corresponds to a SDP Phase 2 worksheet (e.g., transient, LOOP), the worksheets can identify the most likely core damage sequences that include known failure of equipment and/or operator error and the remaining mitigation capability for reactor safety. The inspector can verify the availability of this mitigation capability.
03.02 | Event Report Review
| Review written LERs, but not telephone notifications to the NRC Operations Center for invalid actuations, as allowed in 10 CFR 50.73. LERs that involve operator errors are reviewed under IP 71111.14, "Personnel Performance Related to Nonroutine Plant Evolutions and Events". Licensee resolution of issues may be addressed under the Identification and Resolution of Problems sections of individual baseline inspection procedures. MC 0612 (formerly 0610*), "Power Reactor Inspection Reports", covers documentation of LER reviews.

### 71153-04 Resource Estimate

Inspector effort may be minimal for events which do not meet the MD 8.3 deterministic criteria, up to 24 hours for significant operational events, and 1-8 hours for an LER.

### 71153-05 References

Management Directive 8.3, "NRC Incident Investigation Program"

Inspection Procedure 93800, "Augmented Inspection Team"

Inspection Procedure 93812, "Special Inspection"

Inspection Manual Chapter 0609, "Significance Determination Process"

Inspection Manual Chapter 0612, "Power Reactor Inspection Reports"

END