ML20127J621

Discusses Visit by Listed Individuals to Chicago Bridge & Iron Shop Facility in Birmingham,Al to Tour Plant & Discuss Fabrication & Insp Methods Employed by CB&I Prior to Shipment of Vessel in Segments to Plant for Final Erection

ML20127J621
Person / Time
Site:	Monticello
Issue date:	11/04/1966
From:	Boyd R US ATOMIC ENERGY COMMISSION (AEC)
To:	US ATOMIC ENERGY COMMISSION (AEC)
References
NUDOCS 9211190382
Download: ML20127J621 (2)

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UNITED STATES GO\'ERNMENT demorandum To g' : Files DATE: Novemler L, 1966 V (Thru) Roger S. Boyd, Chief E< search & Fover Eeacter Safety Eranch, DEL <'

GOM ' J. J. Ehee, Reseerch & Fever Beector Safet> Franch/w~ /'y ,

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Division of Beactor Licensing ,

SUBJECT:

UEF(NOREIE?ll ETATES PCWEE) MOUTICE O ITUCLEAR FIET NO 1 FIELD ERECTED REACTOR VESSEL. (First Eeactor Vessel Welded tegether in the field)

The individuals listed belov visited the Chicago Eridge and Iron Shop Tecility in Edrmingham, Alabama to tour the plett and discues with cognicent personnel the febrication end inspecticn methods to be employed by CE&I prior to shipment cf the vessel in segments to the Menticello site for final erection:

E. Grimes, DRL M. Eclotsky, ES W. Reinmuth, CC J. Shea, DEL E. Lofy, (Parameterc Inc.)

M. Labarkin, (ACES Staff)

Frior to the Birminghar visit the same group of people had visited the E&W 1arge vessel fabrication shop a: Evansville, Indiana (10-27-66) and the C&E vecsel febricetion shops at Chattanooga, Tennessee (11-2 66). One prominent velding and heat treattent feature vac noted. B&W electro-slag velds the longitudinal seatr of each ring before heat and quench treatment of an entire ring. Although great time savings are derived by this method, the advantage hen been offset tv the necessity to cut the rings apart and reveld because or excessive rin,e growth (as much as 5 inches circumferential1y).

FM believes that this growth can be anticipated in the future after sufficient experience with large diameter vessels and the improved heating and controlled quenching of their new facility are fully evaluated.

Eoth B&W and C&E use hot rolling followed by cold pressin6 for final shape in contrest to CE&I which uses only a single cold pressing operation to l

achieve the final desired snape (except for bottom thick EWE heads which ere partially shaped, stress relieved and final shaped).

The CE&I heat and quench treatment is applied to the segments before any shaping or velding. C&E heet treats after shaping but before velding.

These statements are mede merely to note the differences in important fabrication feetures employed by the various manufacturers which are dicteted to a large degree by individual preferences based on experience and shcp facilities.

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I Files Ucvember 4, 1966 Interestingly, no problems in regard to field erection in place of shop fabrication of reactor vessels have been identified up to this stage of our review. Any distortion or fit up problem encountered in the field could also be encountered in the shop. Offset velds will te tapered to ratisfy code requirements in the same manner that shop offsets are corrected.

Our diccussions with the applicant, USP vessel _ fabricator (CE&I) and vessel designer (CL&I assisted by GE in transien, performance analysis) have dwelt to a large extent on non-destructive testing of plate and particularly velds.

There is no design basis for crack, defect, flav, slag, etc., in the plate er velds. Instead, rejections or rework is based on a somewhat indefinite evaluation of ultrasonic tests, electromagnetic particle tests, radiography, etc. , with an unclear overlap. Although non-destructive methods vill be essentially the same or equivalent for field erected vessels (except that a Cobalt source vill be the only radiographic inspecticn method for NSP vhere shop fabricators use a Betatron or have the option of using a Eetatron or Linear Accelerator if desired: also hot ultrasonic tests vill be performed on NSP velds in field 300 k00 F where shop ultrasenic tests are performed at ambient temperatures), JDhis could be an opportune time to require that maximum permissible defects, cracks, etc. , considering orientation, be identified in relation to design requirements in terms of vessel stress concentre*, ions allowing for growth, fatigue, crack propagation and lack of complete inspection or infrequency of hydrostatic tests (if this is significant at all in relation to vessel integrity).

OE informed CB&I recently that fit-up type no :les permitting a reduction in flared no le diameter from 72" in the original specification to approximately 62" could be used as requested by CB&I because. GE was able to relax the design requirement and move the no::le center an Edditional 9 inctes upward from the bottom edge of the first shell rir.g. This permits CE&I to install all nor:les in the shop (except for a bottom 2" drain con-nection) prior to shipment to the field. Concern for field installation and non-destructive testing of large no::les had been expressed at earlier j meetings, i

Summary The staff review of the NSP reactor vessel fabricaticn to date has not isoleted a safety related field erection problem. However, there have been indications that the non-destructive inspection techniques presently

, teing used by the three vessel fabricators are not uniform. It is also evident that the size and type of defect which can be tolerated in any or selected locations has not been identified by the designers. In other vords there is no assurance that a potentially damsging crack would not slip through the non-destructive tests undetected.

i Listribution:

DhL heading

EifESE Eeading

! Crig: J. J. Shea E. G. Cese W. Eeinmuth M. Bolotsky E. Grimes W. Jensen

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