ML20058K511
| ML20058K511 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 12/06/1972 |
| From: | Wachter L NORTHERN STATES POWER CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| NUDOCS 9102110343 | |
| Download: ML20058K511 (2) | |
Text
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V NORTHERN STATES POWER COMPANY M I N N C A Po t l S. M I N N E 5s OTA 55401 D2cember 6,1972 Mr B H Grier Regional Director United States Atomic ?nergy Commission Directorate of Regulatory Operations Region III, 799 Roosevelt Road Glen Ellyn, Illinois 60137 D;ar Mr Crier:
MONTICELLO NUCLEAR GENEPEfING PIANT Ibeket No 50-263 License no DPR-22 Support Hangers for Emergency Core Cooling System Suction Header The following letter is submitted to report the final status of corrections of the hanger assembly system for the 20" torus suction ring header at our Monticello Huclear Generating Plant.
As reported in our July 5,1972 letter to you, the hanger assembly for the torus suction ring header was found to have been installed with full threaded 3/4" HEX HD bolts, without washers or locking nuts, and with several elongaicd and repositioned torched cut bolt holes. At that time a temporary fix was made by replacing all the bolts with SAE grade 8 or 9, 3/4" HEX HD shanked bolts and locked with double nuts. General Electric and Chicago Bridge &
Iron Company were in the process of providing us a program to restore the hanger system to the original design requirements.'
Tne program now has been completed and the hanger asseably system restored to the original design intent.
The only change from the original installation design was the use of ASME A325 HEX HD 3/4" shanked bolts instead of ASME A3C7 3/4" HEX HD bolts.
The following list compares the as found vertical hanger loads with C.B.&I. 's target load and the hanger loads after final adjustment.
DEC 11 G72 9102110343 721206 ~
I NOR
'RN STATES POWER CO ANY Mrp H crier Dece:Ar 6, 2 ?72 lb n;:. <
Ac Foand Ta rr e t Fina'l I;a.
Icad (LSc)
Icad (Lbc) 1m d (Lbs) 1 0
5800 6100 2
7850 5000 h000 3
2740 5500 5850 4
Hazzle Rozzle Hozzle 5
1070 6hoo 5650 6
03h0 5200 5175 7
1960 6900 5800 8
Uozzle Nozzle Dozzle 9
0 5500 5250 lo 7850 4800 4850 11
'/950 5100 5500 12 Nozzle Nozzle Rozzle 13 6080 7300 6400 14 2550 h800 5850 15 h310 5000 h2OO 16 Nozzle Nozzle Hozzle i
Youra very truly, 1
f L J Wachter, Vice President Pover Production & Syctem operation i
IxTd/c:
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