Patent Number: 059011920
Section: description

DETAILED DESCRIPTION FIG. 1 is a perspective view with parts cut away of a reactor pressure vessel (RPV) 10. RPV 10 includes a shroud 11, core spray lateral pipes 12A and 12B, core spray line risers 14A and 14B, a T-box junction 16, a T-box 18, and core spray spargers (not shown in FIG. 1). Core spray line risers 14A and 14B each include a lower elbow 20A and 20B. Elbows 20A and 20B each include an opening (not shown). Core spray line riser 14A is configured to couple core spray pipe 12A and T-box 18. Referring to FIG. 2, T-box 18 includes a substantially cylindrical pipe 30 having a bore 34 extending therethrough, two core spray sparger openings 38 (only one shown), and an end plate (which has been machined off in the FIG. 2 illustration). Core spray line lower elbow 20A is secured to T-box 18, typically with a lower weld (not shown). Core spray line riser 14A may, for example, be secured to T-box 18 in various manners, including, inserting pipe 30 into elbow 20A and welding, or inserting elbow 20A into pipe 30 and welding, as well as abutting elbow 20A to pipe 30 and welding. Core spray spargers 44A and 44B are coupled to T-box openings 38, for example by welding. Referring to FIGS. 2 and 3, repair apparatus 48 includes a substantially cylindrical sleeve 50, a draw bolt 54, and a block 58. Cylindrical sleeve 50 includes a flange 62 at one end 64, and a main cylinder body 68 having an axial bore 72 extending therethrough. Opposing water flow openings 76A and 76B are located in sleeve main body 68. Main body 68 is sized to be inserted within T-box pipe 30 so that sleeve flange 62 engages T-box 18. Flange 62 outer diameter is greater than the outer diameter of T-box pipe 30 and includes an opening (not shown) sized to receive draw bolt 54. Flange 62, may for example, be integral or welded to main body 68. Water flow openings 76A and 76B are configured to provide a fluid passage from core spray spargers 44A and 44B to T-box 18. Draw bolt 54 is of sufficient length to extend through flange opening, main body bore 72, elbow opening (not shown), and block 58. Draw bolt 54 is threaded and configured to engage block 58. Block 58 includes a threaded opening (not shown) and is configured to threadedly engage bolt 54 to draw block 58 into tight engagement with riser lower elbow 20A or 20B. Sleeve 50 may, for example, be fabricated from type 304L or 316L stainless steel. Bolt 54 and block 58 may be fabricated from type XM-19 stainless steel. After replacing core spray riser 14A, repair apparatus 48 is coupled between T-box 18 and core spray line riser 14A. Specifically, in one embodiment, core spray line riser elbow 20A is coupled to T-box 18, for example with a weld. T-box end plate (not shown) is removed, for example by machining. Main cylindrical body 68 is inserted into T-box pipe 30 until flange 62 fully engages T-box 18. Draw bolt 54 is inserted through flange opening, main body bore 72, and core spray line riser elbow opening. Block 58 is engaged to draw bolt 54 and engaged with lower elbow 20A. Sleeve 50 is rotated to ensure that sleeve water flow openings 76A and 76B are substantially aligned with core spray spargers 44A and 44B attached to T-box 18. An opening (not shown) in lower elbow 20A corresponds to a centerline of sleeve 50. The lower elbow opening is formed, for example, by machining or drilling. Draw bolt 54 is inserted through flange opening, bore 72, and elbow opening. Bolt 54 is then engaged to block 58. Draw bolt 54 is torqued until block 58 fully engages lower elbow 20A and locked into place. The resulting connection provides a fluid passage from T-box junction 16 to core spray spargers 44A and 44B. Repair apparatus 48 provides axial restraint for core spray line riser 14A and T-box 18 connection. Additionally, because draw bolt 54 is positioned within T-box bore 34, draw bolt 54 is exposed to the injection waters temperature only and would, therefore, be expected to contract at the same rate or slightly less than core spray riser 14A and 14B and T-box 22, which facilitates minimizing leakage. From the preceding description of various embodiments of the present invention, it is evident that the objects of the invention are attained. Although the invention has been described and illustrated in detail, it is to be clearly understood that the same is intended by way of illustration and example only and is not to be taken by way of limitation. Accordingly, the spirit and scope of the invention are to be limited only by the terms of the appended claims.