ML20010E991
| ML20010E991 | |
| Person / Time | |
|---|---|
| Site: | 07106375 |
| Issue date: | 08/20/1981 |
| From: | Marsh C CHEM-NUCLEAR SYSTEMS, INC. |
| To: | Odegaarden R NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| 19553, NUDOCS 8109090237 | |
| Download: ML20010E991 (3) | |
Text
{{#Wiki_filter:_ _ _ _ _ _ _ _ _ _ '7/437S yon cm CHEM-NUCLEAR SYSTEMS INC. /gau To P.O. Box 1866 e Bellevud, Washington 98009 e (206) 827-0711 g , - i.b August 20, 1981 N t Richard H. Odegaarten %raco Tran:portation Certification Branch Mac k-{ Division of Fuel Cycle and Material Safety p g 2 779Of ~[p' U. S. Nuclear Regulatory Conmission 2 t Washington, D.C. 20555 ug.vg q, % %y //' Re: Docket #71-6375 4% CNSI Letter dated 6/12/81 (attached) q, A", - Temus Report dated 8/11/21 (attached)
Dear Mr. Odegaarten:
Our letter dated June 12, 1981 advised that the 4-45 shipping cask had been removed from service for repairs. Following is the sequence of events regarding this matter: - Cracks discovered in fire shield upon arrival at Vermont Yankee - CNSI engineer flown to Vermont Yankee to verify and N' Q ' O, V g>V determine best course of action -jl' O g ' sf j c 4 n S ff C - Temporary repairs performed and cask returned to Barnwell 'f/ e
- y 6
e w - CNSI Quality Assurance directed the cask be removed from service until further notice n ,o: jid - NRC notified of this action - Test results from Southwest Research and Law Engineering confirmed CNSI's engineering evaluation regarding the cause of the cracks /Q C ",/ - Repairs completed at Barnwell t ,s -;u! gif in) - Cask was liquid penetrant tested by Quality Assurance / and repairs determined complete Chuck Temus, Project Manager, reported that every ef# ort has been made to determine the cause of the cracks, that the cracks did not represent a significant less of the conductive properties of the fire shield and that the carben steel inner shell showed no signs of damage. 1L".i53 8109090237 810820 PDR ADOCK 07106375 C PDR
Page two Docket No. 71-6375 8/20/81 We are convinced that there was no reduction in the effectiveness of the package during its use. The 4-45 cask h:.s been returned to service as of this date. As a precautionary measure, the cask will be subjected to an intensified inspection program in the future. If you have any questions conce 'ing this matter, please do not hesitate to contact us. Sincerely, CHEM-NUCLEAR SYSTEMS, INC. fyf $. Chryl A. Marsh Licensing Coordinator CAM: des Enclosures (2) cc: Lou Reynolds
A CHEM NUCLEAR SYSTEMS INC, g a August 11, 1981 .Ua.U. Date: To: Lou Reyne1ds Location: Corporate / Regulatory Affairs ChuckTemusd Location: Corporate / Technology Center From: subject: 4-45 FIRE SHIELD DAMAGE The 4-45 fire shield was cracked in three locations on the bottom side of the cask as it is placed on the trailer. These cracks were fine hairline type cracks. The cracks or indications (all except one or two did not penetrate the 1/4-inch fire shield) did not represent a safety problem. The fire shield is not considered to be a structural part of the cask. The weight of the cask is carried by the 1-1/2" carbon steel shell behind the fire shield. The small cracks did not re-present ar; significant loss of conductive properties of fire shield. Therefore, the: fire shield was not down graded in its design capabilities. The metal in the areas of damage had been sensitized. Sensitized metal is more susceptible to corrosion. Careful examination of the entire cask shows no other sensitized areas. These sensitized areas could have been caused by heating during manufacture or some repair activity. The indications appear to be typical of chloride stress corrosion. This has been confirmed by two outside firms, Southwest Research and Law Engineering. Chemical analysis has indicated no free chlorides. The chlorides would have been removed by decontamination procedures. Chlorides do exist in the road environment the cask sees. It is known that sensitized 304 SS is more susceptable to chloride stress corrosion then non-sentized metal. This would explain why the chloride stress corrosion occured at temperatures well below the normal threshold temp-eratures. Although fatigue is a possible contributing factor, metallurgical examination showed no indication that these were fatigue cracks. l The entire bottom half of the center section shell has been replaced. The entire cask has been liquid penetrate examined and no indication has been found. It is recomended that the cask be put on a program of inspection. The cask should be liquid penetrate examined over its entire surface every 3 to 6 months, plus visual examinations every time it is used. When the bottom half of the shell was removed, the carbon steel inner shell was in good condition and showed no signs of damage. CT:la cc: Bill Bridges -Chryl Marsh Mike Mattingly - Tom McCord John Potter \\
i CHEM-NUCLEAR SYSTEMS INC. P.O. Box 1866 e Bellevue, Washington 98009 e (206) 8274)711 June 12, 1981 Mr. Dick Odegaarten Transportation Certification Branch Division of Fuel Cycle and Material Safety U. S. Nuclear Regulatory Comission Washington, D. C. 20555 RE: Docket No. 71-6375
Dear Mr. Odegaarten:
In accordance with your directive, Chem-Nuclear Systems has removed shipping cask CNS 4-45 USA /6375/B ( ) from service pending further notice. An evaluation will be performed to detennine what caused the development of cracks in the heat shield. Questions concerning this matter should be directed to Louis E. i l Reynolds, CNSI Director of Regulatory Affairs. Sincerely, CHEM-NUCLEAR SYSTEMS, INC. l 0 $f Chryl A. Marsh l Licensing Coordinator l CAM:slj cc: Louis E. Reynolds e% \\ 'M o N 1}}