ML012570017
| ML012570017 | |
| Person / Time | |
|---|---|
| Issue date: | 08/03/2001 |
| From: | Beckner W Technical Specifications Branch |
| To: | Bradley B Nuclear Energy Institute |
| Robert T. Tjader, NRR-RTSB, 301-415-1187 | |
| References | |
| Download: ML012570017 (10) | |
Text
Proposed Process for Initiative 4b
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Introduction:==
Under the current regulations, when plant equipment is taken out of service both Technical Specification (TS) and Maintenance Rule (MR) requirements must be evaluated and complied with. These two separate requirements can result in inconsistent results and required actions.
Objective:. NEI proposes to modify Technical Specifications in order to make these two requirements more consistent.
Proposed AOT Extension Process:
The current TS AOT requirements will be retained, but the TS will be modified to allow each licensee to perform a plant specific risk evaluation in accordance with MR (a)(4) requirements which could extend the original AOT, if warranted. This evaluation would consider equipment within the scope of (a)(4).
If the current AOT is expected to be exceeded, then the licensee will have the option of determining a configuration-specific AOT. The configuration specific AOT would be determined by performing a risk assessment in accordance with MR (a)(4) requirements and comparing the results to established acceptance criteria. In order to address concerns involving PSA quality, uncertainties, assumptions, and modeling techniques, a TS not-to-exceed value for each AOT would be provided. This value would be referred to as the Abackstop AOT@, which could never be exceeded regardless of the risk evaluation results. The backstop AOT value would be based on the following requirements:
- 1. Provide consistency with risk insights
- 2. Allow a reasonable time to effect repairs.
- 3. Require return to original design basis within a reasonable time period.
- 4. Prevent AOT conditions from existing indefinitely.
The following criteria and actions are recommended in order to be consistent with MR (a)(4) requirements:
- 1. ICDP<1E-6 (ILERP<1E-7): No compensatory measures required. AOT can be extended based on the risk assessment for up to the backstop AOT.
- 2. ICDP<1E-5 (ILERP<1E-6): Compensatory measures required. With these measures in place AOT can be extended for up to the back-stop AOT.
- 3. ICDP>1E-5 (ILERP>1E-6): Compensatory measures required which will reduce ICDP<1E-5 (ILERP<1E-6). Risk evaluation can be qualitative or quantitative. The configuration can only be entered with management approval. With these measures in place AOT can be extended for up to the back-stop AOT.
- 4. If the above risk guidelines are not met, then the required actions and completion times of the existing AOT(s) must be entered.
- 5. If emergent work arises, or the risk profile changes with other systems becoming unavailable, risk must be promptly re-evaluated. If above values change, the resultant new risk guideline must be complied with.
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Conclusion:==
This proposed change to TS provides a risk informed approach by retaining the current TS AOTs, while allowing a risk evaluation to extend the AOTs. The risk evaluation can never allow an extension past an established backstop AOT and the risk evaluation must be promptly re-evaluated if plant configuration changes. This proposed change allows additional licensee flexibility without compromising plant safety and makes TS and MR (a) 4 requirements more consistent.