ML16208A082
| ML16208A082 | |
| Person / Time | |
|---|---|
| Issue date: | 07/26/2016 |
| From: | Js Hyslop NRC/NRR/DRA/APLA |
| To: | Anderson V Nuclear Energy Institute |
| Frumkin D | |
| Shared Package | |
| ML16208A081 | List: |
| References | |
| Download: ML16208A082 (5) | |
Text
FAQ Number 16-0076 FAQ Revision 0 FAQ Title NFPA 805 Fire PRA Update Process Page 1 of 4 faq template.doc Plant: NEI NFPA 805 Task Force Date: 2-25-2016
Contact:
Victoria Anderson Phone: 202-739-8101 Email: vka@nei.org Distribution: (NEI Internal Use) 805 TF FPWG RATF RIRWG BWROG PWROG Purpose of FAQ:
To articulate the process for update of Fire PRAs supporting NFPA 805 plants, to reflect new methods and data, as appropriate.
Is this Interpretation of guidance?
Yes /No Proposed new guidance not in NEI 04-02? Yes/No Details:
The NRC and industry have had discussions regarding the schedule for integration of new data or methods, such as heat release rates and ignition frequencies, into licensee Fire PRAs. The industry has proposed that this be done via the normal maintenance and update process as the PRA Configuration Control program describes. This Program will ensure that such new information is integrated as appropriate.
Circumstances requiring guidance interpretation or new guidance:
As additional methods and data for Fire PRA become available for integration into licensee models, it is important that the NRC and licensees have a mutual understanding of when this information will be considered for inclusion in a licensees PRA to support regulatory stability and predictability.
Detail contentious points if licensee and NRC have not reached consensus on the facts and circumstances:
N/A Potentially relevant existing FAQ numbers:
None Response Section:
Commented [HJ1]: Note that industrys recommendation is for language to RG 1.205. Is this answer consistent with that?
FAQ Number 16-0076 FAQ Revision 0 FAQ Title NFPA 805 Fire PRA Update Process Page 2 of 4 faq template.doc Proposed resolution of FAQ and the basis for the proposal:
All licensees transitioning to NFPA 805 support their applications with a Fire PRA that is peer reviewed using NRC-endorsed standards and guidance. This peer review involves, in addition to a thorough technical review, a review of the PRA maintenance procedures against the requirements in the NRC-endorsed ASME/ANS PRA Standard. The results of the peer review, including facts and observations related to the PRA maintenance procedures, are available for NRC review, and are closely evaluated during the NRC NFPA 805 audit. Any new information relevant to the licensees Fire PRA, including new methods or data, is introduced into the PRA using the licensees process. Several key aspects of this process are listed below:
- While undergoing a PRA update, a utilitys "cutoff" time for considering new data varies from 6 months prior to 6 months after the start of the PRA update.
- Generally speaking, new data updates could take up to 8 months depending on the scope.
- In undergoing a PRA upgrade, the "cutoff" time required for considering new methods is anywhere from the beginning of the upgrade period to 6 months after the start of the PRA upgrade.
- The time required for a PRA upgrade can be anywhere from a few months to a few years depending on the complexity of the upgrade.
- The scope of sensitivity studies largely depend on the scope of the upgrades.
Because of this, changes can take anywhere from a few days to many months.
- The time for completion with changes to several new methods or data incorporated into an update/upgrade/sensitivity study involves a small delay (up to 6 months). If a smaller delay occurs, it is usually the result of a large increase in devotion of person-hours towards it.
- For interim and periodic model updates, maintenance and update procedures use criteria of a greater than 10% change (increase or decrease) in the CDF or greater than anywhere from a 1% to 20% change (increase or decrease) in the LERF. The licensees periodic update process to evaluate the impact of a change and potentially incorporate it in the PRA typically takes place every 3-5 years.
- These update processes ensure that new information is evaluated for inclusion in PRAs when there is a measurable impact on the results and applications.
There are threewo relevant mechanisms by which a licensees process would call for an update that would involve consideration of the new information such as new methods or data after completion of the NFPA 805 LAR.
- The first is the NFPA 805 license condition calling for a licensee to, prior to transition to self-approval, update their PRA model to reflect the as-built, as-operated plant following NFPA 805 modifications. Licensees should evaluate the impact of the new information, e.g. method and data updates, prior to completing the requantification of Formatted: Bulleted + Level: 1 + Aligned at: 0" + Indent at: 0.25"
FAQ Number 16-0076 FAQ Revision 0 FAQ Title NFPA 805 Fire PRA Update Process Page 3 of 4 faq template.doc the NFPA 805 transition change-in-risk. The change in risk requantification is as required by the Transition License Condition and associated Implementation Items.
- The second is the licensees PRA maintenance and update process, as discussed above. Maintenance and update procedures use criteria of a greater than 10%
change in the CDF or greater than anywhere from a 1% to 20% change in the LERF to identify significant changes. Should the criteria be met, the PRA will be updated with the new information. Should the criteria not be met, then the PRA will not be updated, and the new information will be set aside until the next periodic/interim update or application of the PRA, at which point it will be considered.
- The third is a post transition fire risk evaluation of proposed plant modifications as part of the self-approval process or in support of a post transition risk informed LAR (i.e. self-approval risk acceptance guidelines are exceeded). The licensee will implement their PRA maintenance and update process to evaluate new information for the change analysis.
Licensees who have not yet completed the steps necessary for self-approval should evaluate new methods or data as part of the update process called for in the license condition. Licensees who have already fully transitioned to NFPA 805 can conduct this evaluation as part of their next periodic update. Should self-approval be applied, the licensee will implement their PRA configuration control process according to RG 1.200 and Section 1-5 of the ASME/ANS PRA Standard. In the interim, a licensees use of data and methods previously used to support NRC acceptance of the NFPA 805 LAR for review remains acceptable, and new information should be considered at the appropriate time as described. above Given the above, licensees transitioning to NFPA 805 should address new information consistent with Section 1-5 of the ASME/ANS PRA Standard RA-Sa-2009 and RG 1.200 Rev. 2 as follows:
- Prior to the submittal of the NFPA 805 LAR, the PRA Configuration Control program applies. The cumulative impact of new information which arises before the submittal will be evaluated by the licensee prior to submittal of the LAR, even if the timeliness of this new information requires that the assessment must be performed in less time than discussed at the beginning of this FAQ solution under Proposed resolution of FAQ and the basis for the proposal section. Licensees will indicate in the LAR whether new methods or data are used in order to facilitate NRCs review.
- During the NFPA 805 LAR review, the NRC staff may request that the licensee identify new information, and should a safety issue arise at any time prior to the issuance of the SE, the NRC will raise this issue and ask that its impact be evaluated on the PRA results and acceptance guidelines.
- After the SE is issued, but before completing full transition, the NFPA 805 license condition calls for a licensee, prior to transition to self-approval, to update their PRA model to reflect the as-built, as-operated plant following NFPA 805 modifications.
Licensees should evaluate the impact of the new information, e.g. method and data updates, prior to completing the requantification of the NFPA 805 transition change-Formatted: Highlight Formatted: Font: 12 pt, Not Bold
FAQ Number 16-0076 FAQ Revision 0 FAQ Title NFPA 805 Fire PRA Update Process Page 4 of 4 faq template.doc in-risk. The change in risk requantification is as required by the Transition License Condition and associated Implementation Items.
- After full transition to NFPA 805 has been completed, the cumulative impact of new information should be evaluated per the Configuration Control program when conducting a fire risk evaluation of proposed plant modifications as part of the self-approval process or in support of a post transition risk informed LAR (i.e. self-approval risk acceptance guidelines are exceeded). exercising self-approval for a plant change. New information must be evaluated even if this information becomes available such that the assessment must be performed in less time than discussed at the beginning of this FAQ solution under Proposed resolution of FAQ and the basis for the proposal section. Also, mMaintenance and update procedures use criteria of a greater than 10% change in the CDF or greater than anywhere from a 1% to 20% change in the LERF to identify significant changes for the periodic or interim update. Should the criteria be met, for a periodic or interim update, then the PRA should be updated with the new information. Should the criteria not be met, then the PRA may not be updated, and the new information may be set aside until the next periodic or interim update or application of the PRA, at which point it should be considered.
If appropriate, provide proposed rewording of guidance for inclusion in the next Revision:
Regulatory Guide 1.205, Section 4.3, Fire Probabilistic Risk Assessment (5th Paragraph)
The staff will rely on the guidance in Regulatory Guide 1.200 to review all facility changes associated with implementing NFPA 805 that are submitted for prior staff review and approval. The staff will rely on this guidance to provide confidence that self-approved changes meet the acceptance guidelines.
The licensees self-approval process should include an evaluation of all unresolved peer review issues to assess the potential impact of the unresolved issue on the application-specific evaluation.
Any unresolved issue that could have a substantive impact on the results must be resolved. The licensees self-approval process should also include the methods for modeling the cause and effect relationship described in Regulatory Position 3.2.4. Additionally, the licensee should assess the impact of new methods and data and consider incorporation of these new methods andor data in their model, as appropriate, in accordance with their normal model maintenance and update process consistent with Section 1-5 of the ASME/ANS PRA Standard RA-Sa-2009 and R.G. 1.200 Rev. 2. Licensees will indicate in the LAR whether new methods or data are used.
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