ASME/BPVC - CASE N-769
N-769 Roll Expansion of Class 1 In-Core Housing Bottom Head Penetrations in BWRs Section XI, Division 1 Supp 8
| Organization: | ASME/BPVC |
| Publication Date: | 1 July 2007 |
| Status: | inactive |
| Page Count: | 7 |
scope:
This Case applies to use of mechanical roll expansion for the purpose of sealing leakage from cracks detected in the following locations:
(a) In-core housing-to-vessel attachment weld (BWR/2-6)
(b) ICH stub tube base metal (ABWR) (c) ICH stub-tube-to-housing
(d) ICH stub-tube-to-vessel attachment weld (ABWR)
This Case shall not be used when leakage is due to through-wall cracking in the housing.
The following conditions shall apply to this Case:
(a) Housing material: any P-No. 8 or P-No. 43.
(b) Vessel material: any P-No. 3.
(c) Measured percent wall thinning: 2% − 5%. (d) Roll-band length shall not exceed 6 in. (150 mm).
(e) Roller top and bottom end radius shall be at least 1⁄4 in. (6 mm).
(f) Ratio of housing specified minimum yield strength to vessel head specified minimum yield strength shall be less than 1.0.
(g) If more than one roll is required to achieve the required roll-band length, the minimum overlap for each roll shall be at least 0.5 in. (13 mm).
(h) Rollers shall be lubricated.
The provisions of IWA-4140, IWA-4150, IWA-4170, and IWA-4310 shall be met.
Document History
