ML22024A037

Breakout Questions - Trp 74 - Concrete

ML22024A037
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: ML22024A037 (4)

Text

Oconee SLRA: Breakout Questions SLRA Section 3.5.2.2, Further Evaluation of Aging Management as Recommended by NUREG-2192 TRP: 074, Concrete Question SLRA SLRA Background / Issue Discussion Question / Request Number Section Page (As applicable/needed) 1 3.5.2.2.1.2 3-1306 SRP-SLR Section 3.5.3.2.1.2 guidance 1. Explain how aging effects says that the reviewer ensures that the associated with the cooling aging effects associated with the cooling fans and stacks system are system are being properly managed or being probably managed or temperatures are being monitored to temperatures are being identify a problem with the cooling monitored to identify a system if an active cooling system is problem with the cooling and relied upon to maintain acceptable stacks system.

temperatures. If the temperature limits are exceeded, the reviewer reviews the 2. Clarify the actual technical basis provided by the temperature of concrete applicant to justify the higher around the penetration due to temperature. limitations of air movement.

The FE Section 3.5.2.2.1.2 indicates 3. Provide volumetric that the main steam penetrations rely on nondestructive concrete cooling fans and stacks to main testing technical basis and its acceptable temperature, and a review of results on the portal.

ONS OE reflects that localized concrete temperatures at the main steam penetrations have marginally exceeded 200°F areas around the penetrations due to limitations of air movement.

The FE Section 3.5.2.2.1.2 also states that volumetric nondestructive concrete testing was performed to address the exposure to elevated temperature concern.

2 3.5.2.2.1.7 3-1311 SRP-SLR Sections 3.5.3.2.1.7, 1. Provide air content of 3.5.2.2.2.1.1 3-1313 3.5.3.2.2.1.1, and 3.5.3.2.2.3.1 concrete for Groups 1-3, 5,6 3.5.2.2.2.3.1 3-1315 guidance say a plant-specific program is and 7-9 structures.

not necessary if the concrete was constructed with air content of 3 to 8 2. Clarify the discrepancy percent. However, the associated FE between FE Sections and OE.

Sections do not provide information on the air content of concrete for Groups 1- 3. Discuss plans to update the 3, 5,6 and 7-9 structures. SLRA to address the above.

FE Sections state that review of plant OE has not identified any aging effects related to freeze-thaw in accessible areas. However, OE indicates exposed aggregate with up to 1 profile near water level in the south face of discharge structure. Cracking with leachate possibly indicating impending spall due to freeze-thaw or rebar corrosion. (Ref: CCW Intake and discharge Structures, and Underwater Weir, 5 year civil/structural inspection, July, 2017, Calculation # OSC-7019) 3 Table 3.5.1- 3-1335 AMR item 3.5.1-042 claims to be Clarify the discrepancy 042 consistent with NUREG-2191, and between Table 2 items.

manages Loss of material (spalling, Revise SLRA as necessary.

Table 3.5.2- 3-1438 scaling) and cracking due to freeze-20 thaw.

Table 3.5.2- 3-1441 However, Table 2 items associated with 21 item 3.5.1-042 in Tables 3.5.2-20 and 3.5.2-21 cite note I, stating Aging effect in NUREG-2191 for this component, material, and environment is not applicable. In addition, the staff noted that other Table 2 items associated with

item 3.5.1-042 are applicable, and consistent with NUREG-2191.

4 3.5.2.2.2.1.4 3-1313 SRP-SLR guidance says a plant- 1. Clarify the discrepancy specific program is not required for the between FE Sections and OE.

3.5.2.2.2.3.3 3-1317 reinforced concrete exposed to flowing Revise SLRA as necessary.

water if evaluation determined that the observed leaching of calcium hydroxide 2. Evaluate whether the and carbonation in accessible has no observed leaching of calcium impact on the intended function of the hydroxide and carbonation in concrete structure. accessible areas has any impact on the intended The associated SLRA FE Sections state function of the concrete that review of plant OE has not structure.

identified aging effects related to increase in porosity and permeability due to leaching of calcium hydroxide and carbonation.

However, the staff identified the following:

1. Calcium leaching was identified in the hallway oriented from northeast to southeast at elevation +600 at Keowee Hydro Station(reference: Table 1 in Keowee Hydro Station 5 year civil/structural inspection, Oct. 2007) .

2. OE item 6 in Inspection of Water-Control Structures AMP states that the piers and walls have some pattern cracking and efflorescence; however, the concrete looks to be structurally sound and serviceable.

3. Crack and leaching along ceiling N71 and P71 all long beam and ceiling connection, also crack and leaching noted on the north wall (5yr civil/structural inspection of the auxiliary building, 01830000).

4. Calcium leaching was identified on the basement wall of the Keowee powerhouse during our onsite audit walkdown.

5 3.5.2.2.2.2 3-1315 SRP-SLR Section 3.5.3.2.2.2 guidance 1. Provide, on the portal, says the reviewer reviews the technical analyses (design assumptions basis provided by the applicant to justify and results) performed for the the higher temperature if the seismic and structural integrity temperature limit is exceeded. of the pool liner, SFP and fuel racks at the operating limit of The FE Section 3.5.2.2.2.2 states the 205F.

spent fuel pools have an actual operating limit of 205°F (abnormal 2. Provide, on the portal, the case). analysis demonstrating the maximum temperature of the The FE Section 3.5.2.2.2.2 also primary shield wall.

mentions analyses performed to ensure the seismic and structural integrity of the pool liner, supporting concrete, and fuel racks, and an analysis performed to determine the maximum concrete temperature of the primary shield wall.