Method for installing extension tube in a nuclear reactor
Arrangements and devices for reducing and/or preventing wear of a thermal sleeve in a nuclear reactor are disclosed. Arrangements include a first structure provided on or in one the thermal sleeve and a second structure provided on or in the head penetration adapter. At least a portion of the first structure and at least another portion of the second structure interact to resist, reduce, and/or prevent rotation of the thermal sleeve about its central axis relative to the head penetration adapter. Devices include a base for coupling to a guide tube of the reactor and a plurality of protruding members extending upward from the base. Each member having a portion for engaging a corresponding portion of a guide funnel of the thermal sleeve.
1. A method for installing an extension tube in a nuclear reactor comprising a control rod drive mechanism (CRDM) housing with a threaded head penetration nozzle and a thermal sleeve disposed therein, the method comprising:
removing the thermal sleeve from the threaded head penetration nozzle;
installing the extension tube in lieu of a replacement thermal sleeve, wherein the installing comprises:
aligning the extension tube with a threaded end of the threaded head penetration nozzle, the extension tube comprising a threaded end and non-threaded end, the threaded end sized and configured to threadably couple to the threaded head penetration nozzle;
threading the threaded end of the extension tube to the threaded end of the threaded head penetration nozzle;
torqueing the extension tube to the threaded end of the threaded head penetration nozzle;
gauging the alignment of the extension tube relative to the threaded head penetration nozzle; and
installing retention fillet welds between the extension tube and the threaded end of the threaded head penetration nozzle; and
installing a guide funnel to the non-threaded end of the extension tube.
2. The method of claim 1 , comprising installing a compressible guide sleeve to the CRDM housing.
3. The method of claim 2 , wherein installing the compressible guide sleeve to the CRDM housing comprises:
compressing the compressible guide sleeve;
inserting the compressed guide sleeve into the guide funnel, through the extension tube, the threaded head penetration nozzle, and the CRDM housing; and
releasing the compression of the compressible guide sleeve to retainably couple the compressible guide sleeve to the CRDM housing.
4. The method of claim 3 , wherein the compressible guide sleeve comprises multiple leaf compressible flex sections, wherein each of the multiple leaf compressible flex sections comprises a flange, the method comprising:
compressing the multiple leaf compressible flex sections to contract the flanges prior to inserting the compressed guide sleeve into the guide funnel; and
releasing the compression of the compressible guide sleeve after insertion into the CRDM housing to release the flanges to engage a counterbore ledge defined by the CRDM housing.
5. The method of claim 4 , comprising performing a gauging of an alignment of the extension tube.
6. The method of claim 3 , wherein the compressible guide sleeve is inserted into the guide funnel from a position below a reactor vessel head of the nuclear reactor.
7. The method of claim 1 , wherein the extension tube is installed from a position below a reactor vessel head of the nuclear reactor.
8. The method of claim 1 , wherein the extension tube comprises a threaded adapter comprising the threaded end of the extension tube.
9. A method for installing an extension tube in a nuclear reactor comprising a control rod drive mechanism (CRDM) housing with a threaded head penetration nozzle and a thermal sleeve disposed therein, the method comprising:
removing the thermal sleeve from the threaded head penetration nozzle; and
replacing the removed thermal sleeve with an extension tube, wherein the replacing comprises coupling the extension tube to the threaded head penetration nozzle.
10. The method of claim 9 , wherein coupling the extension tube to the threaded head penetration nozzle comprises:
aligning a threaded end of the extension tube to the threaded head penetration nozzle; and
torqueing the extension tube to the threaded end of the threaded head penetration nozzle.
11. The method of claim 10 , further comprising coupling a guide funnel to the extension tube.
12. The method of claim 11 , wherein coupling the guide funnel to the extension tube comprises coupling the guide funnel to a non-threaded end of the extension tube.
13. The method of claim 11 , further comprising installing a compressible guide sleeve to the CRDM housing.
14. The method of claim 13 , wherein installing the compressible guide sleeve to the CRDM housing comprises:
compressing the compressible guide sleeve;
inserting the compressed guide sleeve into the guide funnel, through the extension tube, the threaded head penetration nozzle, and the CRDM housing; and
releasing the compression of the compressible guide sleeve to retainably couple the compressible guide sleeve to the CRDM housing.
15. The method of claim 14 , wherein the compressible guide sleeve comprises multiple leaf compressible flex sections, wherein each of the multiple leaf compressible flex sections comprises a flange, wherein the method further comprises:
compressing the multiple leaf compressible flex sections to contract the flanges prior to inserting the compressed guide sleeve into the guide funnel; and
releasing the compression of the compressible guide sleeve after insertion into the CRDM housing to release the flanges to engage a counterbore ledge defined by the CRDM housing.
16. The method of claim 9 , further comprising installing retention fillet welds between the extension tube and a threaded end of the threaded head penetration nozzle.
17. The method of claim 9 , wherein the extension tube is installed from a position below a reactor vessel head of the nuclear reactor.
18. The method of claim 9 , wherein the extension tube comprises a threaded adapter, and wherein coupling the extension tube to the threaded head penetration nozzle comprises coupling the threaded adapter to the threaded head penetration nozzle.
19. A method for installing an extension tube in a nuclear reactor comprising a control rod drive mechanism (CRDM) housing with a threaded head penetration nozzle and a thermal sleeve disposed therein, the method comprising:
removing the thermal sleeve from the threaded head penetration nozzle; and
replacing the removed thermal sleeve with an extension tube and a threaded adapter, wherein the replacing comprises:
coupling a first threaded end of the threaded adapter to the extension tube; and
coupling a second threaded end of the threaded adapter to the threaded head penetration nozzle.
20. The method of claim 19 , further comprising coupling a guide funnel to the extension tube.