Hi all,
I'm with a pipe line (16'', CS) that serves steam to three vessels. I have done the stress analysis and everything is OK. But if I do a WRC107 analysis at the nozzles of the vessels, problems arise:
I have four hypothesis,
1. The three vessels operating, and so all hot.
2, 3 and 4. Two operating and one off.
In the first case, I have no problems in the nozzles, but in the other ones the test fails (only in one vessel). In the Vessel Stress Summation at Reinforcing Pad Edge, not in the Vessel Stress Summation at Nozzle Junction. And only in the Pm+Pl+Q sumation, not in the other ones. I have taken into consideration sustained, expansion and occasional loads.
The question is if I should reconsider the whole design of the line, making again the stress analysis and again studying the nozzle or if I can handle with this "failed" on the WRC107 test, taken into account that it only appears in these conditions.
In the case that I can't pass over the test, which methods do you know to relax the stress at nozzles in vessels?
Advanced thanks
I'm with a pipe line (16'', CS) that serves steam to three vessels. I have done the stress analysis and everything is OK. But if I do a WRC107 analysis at the nozzles of the vessels, problems arise:
I have four hypothesis,
1. The three vessels operating, and so all hot.
2, 3 and 4. Two operating and one off.
In the first case, I have no problems in the nozzles, but in the other ones the test fails (only in one vessel). In the Vessel Stress Summation at Reinforcing Pad Edge, not in the Vessel Stress Summation at Nozzle Junction. And only in the Pm+Pl+Q sumation, not in the other ones. I have taken into consideration sustained, expansion and occasional loads.
The question is if I should reconsider the whole design of the line, making again the stress analysis and again studying the nozzle or if I can handle with this "failed" on the WRC107 test, taken into account that it only appears in these conditions.
In the case that I can't pass over the test, which methods do you know to relax the stress at nozzles in vessels?
Advanced thanks
