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SUMMARY
OF MEETING WITH JERSEY CENTRAL POWER & LIGHT CO. ON 8-7-68 Jersey Central Power 6 Light Co. and GE presented a summary of the proble.as encountered with sensitized stainless stcel as applied in the reactor vessel. Highlights of the experience with similar applications such as the Nine Mile Point and Tarapur were also discussed.
The presentation included information which was previously submitted in amendments and extended these to the present state of progress.
A new Amendment (#40) is being prepared and is expected to be available after w/o 8-12-68.
GE has concluded that EDTA and TSP are not the decisive corrodants.
Chlorides alone are not the sole contributor but an as yet unidentified accelerator is suspected. However, it is felt that chlorides are now the most likely contaminant, and that seme synergistic effect. other than the c1 caning solutions is responsibic for the failure. The staff suggested that the synergist may be simply high residual febrichting stress. GE will start more tests-to explore the effect of a marine environment on problems of this nature.
It was disclosed that cladding overlay will be applied to the oyster Creek and Tarapur vessels but not to the Nine Mile Point vessel. When asked about the potential influence of the recctor coolant on the unclad stub tubes for NMP, GE replied that their surveillance in presently operating plants have not shown any difference for samples ir":ated in water or steam arcab.
These samples are loaded beam specimen. The staff inquired about a potential influence of chloride accumulation in crud, which can attract and hold the contaminant by a f actor of 10 or more above the coolant concentration. GE stated that the crud at-tracted chlorides do not act to accelerate attack on the stainless steel at this area.
GE mentioned that further review of the shroud support ring for Oyster Creek had disclosed that the ring dimensions had been " built up" by weld deposition, and that most of the DP indications were in the welded area which of course does not resemble the material properties of the sensitized ring forgin p The DP indication in the welded area would there-l fore be slag inclusions.
Of special interest was the repair planning for the shroud support ring for the three plants: For Oyster Creek a l
redundant structure will be supplied, for Tarapur the ring forgings 9210120303 920520 PDR ORG NRCHIST l
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l will be clad similar to the stub tubes, and for UMP no cladding wD.1 be provided for stub tubes and no cladding or rodeadLat support 1
structure is pahnned for the ring forging, 3
i For tt.a Tarapur plant' proMens have been encount er&d with the steam generators.
At this time it has beet. establiaksd that the st.aialoes steel tuhas have cracked La the vicinity of tbs tubs ebeets.
When-the tubes have been renewed the full extent of the demage will be ascertaiand.
It is planned te completely retu'ae the etsaa generators.
Prelialaary investigations have disclosed a wry coarse grain slaa of 2-3 for the tube asterial, a condittu that weisee the material more s
l pecas to attack by corrodants.
i GE elaborated on the redundant shroud ring swppert structure. N initial i
turnbuckle design has been discarded la fever of a pia-kaschle devies of which there will be 34 N banekle is wk up of 1-tach plates solddd i
together, stataloss steel, and 1 inned to as laeonel bracket with a 2.4 inch stais. lass steel pin. Each assembly w ighs approximately 60 lbs.
N structure has been analysed for moraal_ operating conditione, earth-quaka plus ac mal operating, and a " worst upset condities" sith'a temper-1 i
ature difforence of ap knuckle linkage at 30 ximately 240*F ever the shroud and with tha j
N kighnet stress was found at the shroud j
to lug weld during an energ'saoy eeoling e.oadities, but was within the i
3 Se (Code) limit.
91gnL2icantly to peak stresses.N heat-up and coo 14ews transtants do not contribe l
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A discussion evolved about the significance of fabrication t' residual stress, its potential importance if any.
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GE's stress amation f
is based on the operational mode and not en fabriesting technigm.
was shows that the residual stress af ter f abricaties will be changed and It GE stated that they are act commermed with stress dur i
l and that the fabrication sad /or operattenal stress is not important whom the " deceased" stub tube material has _been clad.
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RT-845 Containment' & Component-Technology
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