Kindly advice from your experiance ,
How much the WRC297 Flexibility is closer to reality.

Dear Jacob
we have similar discussion in past. we are re-posting same herewith. Hope this would add some value in better understanding.
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pl. note following point.
1. WRC 107 is prepared based of bijlaard's work.
2. WRC 297 is extension of WRC 107, covering more number of geometric parameter.
3. ASME SEC VIII Div-1 doesn't say anything regarding applicability of either WRC 107 or 297.
4. However, Div-2 says to use WRC 107 for Nozzle to shell/D'end junction & WRC 297 for Nozzle to Shell junction only
5. However, many EPC prefer to use WRC 297 for Nozzle to Shell junction & WRC 107 for Nozzle to D'end junction

6. WRC 107 & WRC 297 is compared with FEA Results , it has been found that WRC 107 under-predict the membrane stress, hence higher piping local is achieved. However, WRC- 297 over-predict the membrane stress, hence lower piping load is achieved.
therefore, it can be said that actual stress value lays in-between the stress evaluated by WRC 107 & WRC-297.