ML22024A033

Breakout Questions - Trp 45 - Masonry Walls

ML22024A033
Person / Time
Site:	Oconee
Issue date:	01/20/2022
From:	Angela Wu NRC/NRR/DNRL/NLRP
To:
Wu A, 301-415-2995
Shared Package
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References
Download: ML22024A033 (2)

Text

ONS SLRA: Breakout Questions SLRA Section B2.1.32, Masonry Walls TRP: 045 Question SLRA SLRA Background / Issue Discussion Question / Request Number Section Page (As applicable/needed) 1 Table 3- Table Item 3.5.1-071 claims that ONS has 1. Please clarify if there are 3.5.1 1343 no masonry walls in an outdoor any masonry walls exposed to environment in the scope of SLR. outdoor environment, and/or However, it was noted in the on-site audit confirm if the claim in item that there are many perimeter masonry 3.5.1-071 is in current license.

walls covered by metal siding. The metal 2. Please discuss whether an siding can protect the masonry walls from air-outdoor environment should rain, but these external masonry walls are be applicable to these masonry exposed to the wind even though they are walls covered by metal siding, not visible from the external inspection. and potential aging effects The outdoor environment consists of caused by air-outdoor moist, possibly salt-laden air and spray, environments should be cooling tower plumes (which might contain managed.

chemical additives), industrial pollutants 3. Please discuss how an (e.g., fly ash, soot), ambient temperatures evaluation of the acceptability and humidity, and exposure to weather of the inaccessible areas for events, including precipitation and wind. masonry walls covered by metal siding should be conducted whenever conditions are detected in accessible areas that could indicate the presence of, or result in, degradation to such inaccessible areas.

2 B2.1.32 B-218 SLRA provides an enhancement for Based on the proposed Element 3 to modify the parameters enhancement to Element 3, monitored to identify potential shrinkage please discuss whether and/or separation of masonry walls and Element 6 "Acceptance include loss of material in addition to the Criteria" needs to be enhanced currently managed cracking at joints. accordingly to be consistent

with the GALL-SRL report Acceptance Criteria of GALL-SLR XI.S5 recommendations.

recommends that observed degradation (e.g., shrinkage and/or separation, cracking of masonry walls, cracking or loss of material at the mortar joints and gaps between the supports and masonry walls) are assessed against the evaluation basis to confirm that the degradation has not invalidated the original evaluation assumptions or impacted the capability to perform the intended functions.

3 B2.1.32 N/A It is noted that the installation of fiber- 1. Discuss whether 6-year reinforced polymer (FRP) to reinforce inspection frequency is masonry walls was approved by NRC considered a deviation or through a license amendment in 2011. exception to GALL-SLR XI.S5 The graded inspection intervals were Masonry Walls AMP during the authorized by NRC. Based on continued SPEO.

no observed FRP degradation, the 2. Discuss how the integrated inspection interval may be increased to a function of masonry walls nominal 6 years (every third unit refueling reinforced with FRP will be outage) thereafter through the end of the maintained and aging effects operating license in July 2034. for both masonry wall and FRP will be properly managed during the SPEO.