ML19220A773
| ML19220A773 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 11/14/1968 |
| From: | Arndt E US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Deyoung R US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 7904240608 | |
| Download: ML19220A773 (3) | |
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{ -Q C R. C. De'f ounit. Deputy Assistant Director for Peactor Technolozy, DT'L C3SER7ATION OF PRESTRESSINC AS*D CROL'!ING TEST 703 OTSTEX CREEK #2 On November 8 & 9,1968, at the Wilkes-Barre Pa. plant of the Stremstee10erporation the followinr, test program was conducted uncer the auspices of the Jersev Central Power & 1.ir,ht Co., and Burns & Poe,
Inc.
A list of these initially present is enciesed.
P re s t ru s in e A 7reyssinet 36-0.6" tendon and an SEEE 49-0.S" tendon draped under and erst an asstcaed opening at 20'-O" radii were tensioned to 80% of ultinate load in a 900 section of wall. The SEEE tendon, in being pulled through during installation, damared the spiral duct
.c its apex. The " window" which resulted was unlised to place a
stress riser bicck under one of the upper strands in 9 'er to check the potential aff act of hydrogen embrittle:nent on the strand.
The calculated friction f actor was checked by installing load es11s en both ends of the tendons, and also measuring e lon g ations at ths jacking and and at the " window".
"'ha results were reported to be cocrpatible on earlier s tressing ruas.
The two candona vere simultaneously jacked to 80% of ultimate load, except that the SEE2 tendon beund up and did not shev enough almgation. It was taken to 90% of ultimate, several
" ticks" and a heavy thu:rp were bea-d, and it was reported that some wires or a strand had parted, the ba.se plate had developed a vertical crack, and the load had drepped to 50% of ultimate.
The crack in the bass plate was sealzd with epoxy, as well as the perimater of the base plate in cmtset with the wall. It was estisated that the wire / strand break had occurred at the damaged spex of the duct, and souw wire slack was noticeable at the jacking and.
The tanden was rej acked to 80% of ultimate lead and locked off.
Be arin g Plate N TE)
- nvesti;;atien of the b aring plate revealed a crack runnin;:
-+* -211, f m l e f t-o f-cen te r at the top to center at the bottom.
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"he citek w as " vee" shaped, open at the wall and closed (not visib le to the eye) at the outside face.
~he a:nbient terperature at the time var about 42 7 It was learned that a manila hemo seal had been placed all around the perimeter under the plate in order to seal in the grout. The plate consists of 1040 steel, and Stressteel expressed a wish to use A441 (nor:alized) for this ccepenent in the
- future. Eepairs were made as above, and B urns & Roe p ronis e d to subnit a comple ta inve s ti;;ative repo rt.
Some of the possible influencing factorr to be checked are:
1.
Plate quality (flaws, ductility - this was the 4th loading, of this place) 2.
!!UT te=perature 3.
Shock due to rapid change is tendon seals 4
ver.en t induced by perimter seals 5.
Bearine surface centact and unifornity 6.
Ccx2 crete voids under base piste.
Croutinc on !!averi:er 9,1968 both the SIZE and ?reyssinet ducts were pressure testad to 50 pst and flushed with line water, then bicwn cican with air pre ssure. The SIZE tendon was selected for the first grouting ope ra tion. The grout contained Penn-Dixie Type II cement, ambient water (about 42 ?) and an expansive atent Intrzplast RD-4 (its 0
retarding ef fect neutralized)
The desired ficw rate of 16 seconds through the flow cone was achieved. The grout was then pu= ped in toward a design pressure of 60 psi from the non.iacked end of the duct. Vents vers located at both and caps and at the apex near the center of the wall '.ength.
Crout was observed to flou f rom the j acked end vent and the ape 2 vent. However, only water flowed from the non-J acked end vent. A blocka:;e then resulted which could not be cleared by pu:: ping ua to 200 psi. Tha grout pump was relocated to the jacked end of the duct and operated untM grout flowed from the apex vent.
It was preaumed that the epory trouting of the base place had sealed the nain grout passages into the end cap, allowing only water to pass through the wire-to-wire spaces in the strands.
Therefors, the grout would have rapidly been dahydrated under pressure, and a blockage would have bedted up to the grout pipe which was within a few feet of the end cap.
A conclusion as to the ef fectiveness of the grout penetratien for this tenden will depend on the results obtained vSen the observation crrer >
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windows are opened and sa=ples removed.
The Freyssinet tenden vill be grouted at a later date.
E. C. Arndt RT-1064 Contain=ent & Cocponent Technology Branch DRL:CSCT3 ECA Division of Reactor Licensing
Enclosure:
Attendanca List ec:
S. Levine, DRL, w/ encl.
R. Tedes co, DRL, w/ encl.
R. Powell, D"L, w/ encl.
A. L. Cluck ann, DRL, w/ enc 1.
N. Davison, DRL, w/ encl.
Di s t rib uti en :
LS.3991 *"O DRL Raading CSC3 Readin; ADR'" Readin:;
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