ML22024A055

Breakout Questions - Trps 62 and 145 - Tendon Prestress

ML22024A055
Person / Time
Site:	Oconee
Issue date:	01/20/2022
From:	Angela Wu NRC/NRR/DNRL/NLRP
To:
Wu A, 301-415-2995
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Download: ML22024A055 (1)

Text

ONS SLRA: Breakout Questions SLRA Section B3.4 - Concrete Containment Unbonded Tendon Prestress AMP & TLAA TRP: 062 and 145 Question Number SLRA Section SLRA Page Background / Issue (As applicable/needed)

Discussion Question / Request 1

4.5, B3.4 and B2.1.29 B-204 Section 4.5 of SLR-ONS-AMPR-X.S1 (Containment Tendon AMP Basis Doc) states, the calculations for tendon prestressing losses and predicted tendon forces are consistent with NRC RG 1.35.1.

However, SLRA Section B2.1.29 (ASME Section XI, Subsection IWL) contains an exception to element 6 which states, the predicted lower limit values consider the same factors, but are not in complete accordance with RG 1.35.1 for determining predicted lower limit values.

Please explain this apparent discrepancy and elaborate on the justification for the exception in SLRA Section B2.1.29.

2 4.5, Figure 4.5-8, and B3.4 4 - 90 and B

- 299 SLRA Section B3.4 states that acceptance criteria consist of predicted values on the forces in individual tendons SLRA Figure 4.5-8 has two points below the predicted lower limit (PLL) with one of those points close to the MRV.

What, if any, corrective actions were taken to address the lower than predicted values?

3 4.5 and B3.4 B -

301 SLRA Section B3.4 includes exceptions to elements 3 and 5 based on initial lift-off data not being available for trending.

Please explain why it is acceptable to develop the pre-stressing force trend lines without the data from the initial tendon surveillance program.