PWR - LLRT vs ILRT for Secondary Side Steam Generator

[ringdoc]

Hi. For PWRs, can anyone explain why containment isolation valves on secondary side of steam generator (MSIV, MFW, SGBD) are not Type C Local Leak Rate Tested (LLRT)? The tests for these seem to be combined during Type A ILRT. I see various plants using this approach but cannot find any reg document explaining why it is allowed i.e. 10CFR50 Appendix A, Appendix J, SRP 6.2.4, SRP 6.2.6, ANS/ANSI 56.8.

The secondary side of steam generator is also considered an extension of the containment boundary. How?

Thanks for helpful responses.

 

[EnergyMix]

Been a long, long time since I did anything with leak rate testing, but I think it has to do with the fact that they are a closed system inside containment.

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