ML21153A130

TSTF-579-T Response to Comments - 05/26/2021

ML21153A130
Person / Time
Issue date:	06/03/2021
From:	Sunil Weerakkody NRC/NRR/DRA
To:
Weerakkody S
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ML21153A118	List: ML21153A130
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Download: ML21153A130 (1)

Text

TSTF and RITSTF Questions and Comments Regarding Staff 4-20-21 Response to Draft TSTF-579-T, "RICT Program Update"

1) There appears to be a significant change in intent in Paragraph e. The TSTF-579-T draft stated:

A RICT must be calculated using the following PRA and non-PRA approaches approved by the NRC, including [list specific PRA and non-PRA approaches used for fire and seismic analysis (e.g., Fire PRA and Seismic Margins Analysis)]. Changes to these PRA and non-PRA approaches require prior NRC approval.

The comment document states:

A RICT must be calculated using [list specific approaches used (e.g., internal events probabilistic risk assessment (PRA), fire PRA, addition of bounding seismic risk to RICT calculations, etc.)] based on the as-built, as-operated, and as-maintained plant.

The TSTF-579-T wording was intended to require NRC prior approval to use an approach other than those used in the TSTF-505 submittal. The revision appears to be saying that the licensee may change those approaches in order to reflect the "as-built, as-operated, and as-maintained plant." The requirement for NRC prior approval is removed.

2) TSTF-579-T Paragraph e continued, "The PRA maintenance and upgrade process will validate that other changes to the PRA models used in the RICT program, including changes involving newly developed methods, following [standard]." The intent was that changes to anything other than the listed approaches could be revised by the licensee following the referenced standard.

The comment document states, "PRA models used to calculate a RICT shall be maintained and upgraded in accordance with processes described in Regulatory Positions C.1, C.2, C.3, and C.4 in Regulatory Guide (RG) 1.200, Revision 3, Acceptability of Probabilistic Risk Assessment Results for Risk- Informed Activities." The reference to "other changes" is eliminated and it appears to be saying that changes to models or approaches may be made in accordance with RG 1.200R3, positions C.1, C.2, C.3, and C.4.

3) Paragraph f addresses newly developed methods. Since RG 1.200R3 contains the same requirements regarding PWROG-19027 and NEI 17-07, could a reference to regulatory positions in RG 1.200R3 be substituted? Also, "oversight and inspection" is redundant and should only state "inspection."

4) Paragraph g. only addresses reporting of newly development methods and should be part of Paragraph f. The phrase " unless it has already been submitted to the NRC" is ambiguous (submitted by the licensee or any licensee?).

5) The first three paragraphs of 5.6.x appear to be redundant to 5.5 Paragraph g. and to each other. Recommend deleting the first two paragraphs.

6) Footnotes are not used in the Administrative Controls section of the TS. The footnote is explanatory, and does not state a requirement. Should be moved to paragraph "c" or removed.

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