ML20207A690
| ML20207A690 | |
| Person / Time | |
|---|---|
| Site: | 07201008 |
| Issue date: | 05/24/1999 |
| From: | Gutherman B, Singh K HOLTEC INTERNATIONAL |
| To: | Hoyle J NRC OFFICE OF THE SECRETARY (SECY) |
| References | |
| FRN-64FR1542, RULE-PR-72 64FR1542-00011, 64FR1542-11, TAC-L22019, NUDOCS 9905270145 | |
| Download: ML20207A690 (5) | |
Text
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.n Holtec Center,555 L b In Drive West, Marlton, NJ 08053 HOLTEC w m a edNM@%
iNTERNATlONAL BY FAX AND OVERNIGIIT MAIIg v
May 24,1999 Ah.;
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Mr. John C. Hoyle Secretary of the Commission DOCKET NUMBER PROPOSED RULE PRm U.S. Nuclear Regulatory Commission 11555 Rockville Pike (I,t/fR/ p/;2)
Rockville, MD 20852 Attention: Rulemakings and Adjudications Staff l
Subject:
Proposed Rulemaking to 10 CFR 72.214, List of Approved Spent Fuel Storage Casks (Federal Register Vol. 64, No. 6 - January 11, 1999), Holtec Public
)
Comment Letter No. 5014-1.
References:
1.
Docket 72-1008, TAC L22019 f
2.
Holtec lxtter, B. Gilligan to NRC, J. Hoyle, dated March 12,1999 3.
Holtec Users' Group Ixtter, D. Bland to NRC, J. Iloyle, Dated March 24, 1999 in an effort to assist the NRC in resolving the public comments received on the above-referenced rulemaking, Holtec International provides the following information:
)
1.
Comment 0.5 in the Reference 2 letter is superseded by Comment 15 in the Reference 3 letter. Therefore, Comment 0.5 in the Reference 2 letter is withdrawn.
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2.
Comment 0.3 in the Reference 2 letter is clarified as follows:
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Issue Statement:
i The containment (pressure) boundary of the HI-STAR 100 overpack consists of a low alloy cryogenic steel designed with full penetration butt weld joints which are 100%
radiographed during fabrication to comply with the ASME Code,Section III, Subsection NB. In accordance with the provisions of NB-5120, the radiography of the containment boundary butt welds follows any post-weld heat treatment (PWHT) applied to them.
Holtec International requests that, in the interest of enhancing hardware quality, the company be permitted to perform 100% radiography on the "NB" containment boundary 9905270145 990524 PDR PR 72 64FR1542 PDR 0
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Holtec Center,555 Lincoln Drive West, Marlton, NJ 08053 HOLTEC Telephone (609) 797-0900 Fax (609) 797-0909 INTERNATIONAL Mr. John C. Hoyle U.S. Nuclear Regulatory Commission May 24,1999 Page 2 of 5 followed by PWIIT of the entire containment boundary / gamma shell assemblage. In other words, the following manufacturing /NDE sequence is proposed:
a.
Fabricate the lil-STAR 100 overpack containment boundary; i.e., the inner shell, baseplate, and top forging assemblage, b.
Perform all required liquid penetrant (PT) and radiographic (RT) examinations on the containment boundary in accordance with the ASME Code, Subsection NB.
i c.
Assemble and weld the gamma shells.
d.
Perform all required NDE on the gamma shell attachment welds as required by the overpack design drawings j
1 c.
Perform PWIIT on the completed weldment.
Justification:
One hundred percent radiography of the pressure boundary upon completion of its fabrication can be performed most effectively when other attachments to the pressure boundary are not yet installed. Upon completion of full radiography, the manufacturing of the overpack can continue with installation of the multi-layer gamma shield. The composite shell structure, along with the baseplate forging and the top forging can be post-weld heat treated in a furnace resulting in stress relief ofil.1 pressure boundary and l
gamma shell welds. This sequence of manufacturing and inspection ensures that the overpack structure will be stripped of residual stresses in the welds and heat affected zones throughout the compos:te shell overpack structure. Following the sequence in the Code verbatim, on the other hand, would fail to eliminate residual stresses in the overpack gamma shells. Stated differently, our proposal to stress relieve the entire containment boundary / gamma st 'l assemblage would produce a much more ductile (stress relieved) overpack with greatly enhanced fracture resistance properties.
Industry experience as well as discussions in germane literature support our position that the PWIIT process in low alloy nickel steels does not lead to the creation of new volumetric discontinuities in weld deposits which have been confirmed to be void-free by radiography, in fact, nickel is widely recognized as the alloying element used to improve
Holtec Center,555 Lincoln Drive West, Marlton, NJ 08053 HOLTEC Telephone (609) 797-0900 Fax (609) 797-0909 INTERNATIONAL Mr. John C. licyle U.S. Nuclear Regulatory Commission May 24,1999 Page 3 of 5 weldability and fracture resistance in steels. For example, F. J. Winsor, writing in an American Society of Metals volume (" Welding of Low Alloy Steels", pp. 662-676) states on page 667, " Steels with from 1% to 9% Ni provide greater resistance to notch j
cmbrittlement than do carbon steels or many other low alloy steels and are widely used in low temperature service."
M. D. Jackson, in his book entitled " Welding Methods and Metallurgy", comments on page 23 on the beneficial attributes of nickel as an alloying element in steel, observing,
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" Nickel lowers the transformation temperature and also forms a solid solution with alpha-i iron. For this reason, it raises the tensile strength with little loss of ductility. Nickel also inhibits grain growth when the steel is heated into the austenitic region."
In the book "The Science and Practice of Welding" by W. J. Patton, (pages 117-118) states, "The place of nickel in our technical civilization may be summed up by the statement that this metal takes care of a very wide range of problems in corrosion resistance, instrument work, metal joining, cryogenics (very low temperature work), and high-temperature applications. It is a most unusual metal in that it is equally useful both at extremely low and extremely high temperatures, being found in pressure vessels containing lox (liquid oxygen) on the one hand and in gas turbine engines at 1800 F red heat on the other. Nickel is a face-centered cubic metal, quite ductile and workable, corrosion-and heat-resistant. Tensile strength, modulus of clasticity, melting point, specific heat, and magnetic properties of nickel are roughly the same as the corresponding properties of steel."
In fact, PWIIT of nickel steels is considered to add little value by some experts. In his text," Metallurgy of Welding", page 172, J. F. Lancaster writes,"The value of PWIIT for nickel alloy steels is uncertain, but when it is carried out, the soaking temperature for 3%
% Ni should be below 620 degrees C, the lower transformation temperature being reduced by the nickel content."
In closure, this request for Code exemption does not seek to eliminate any inspection or manufacturing steps. It merely seeks to re-arrange the sequence of operations (i.e.,
PWIIT after the entire steel weldment is fabricated) to better accomplish the design objectives of the overpack.
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Holtec Center,555 Lincoln Drive West, Marlton, NJ 08053 1
HOLTEC Telephone (609) 797-0900 Fax (609) 797-0909 iNTERNATlONAL Mr. John C. Iloyle U.S. Nuclear Regulatory Commission May 24,1999 Page 4 of 5 i
Please contact us if you have any questions or require additional information Sincerely, f
Bernard Gilligan Project Manager, Ill-STAR /III-STORM Licensing Document I.D. 5014314 Cc:
Mr. Mark Delligatti, USNRC Approvals lU L O n
_ Brian Guthernian K. i'. Singh, Ph.D., P.E.
Licensing Manager President and CEO Client Distribution Mr. David Bland Southern Nuclear Operating Company Mr. Ken Phy New York Power Authority Mr. J. Nathan Leech Commonwealth Edison Dr. Max Del 2mg Private Fuel Storage Mr. Stan Miller Yankee Atomic Mr. Bruce Patton Pacific Gas & Electric Mr. Rodney Pickard American Electric Power Mr. David Larkin Washington Public Power Supply System Mr. Eric Meils Wisconsin Electric Power Company Mr. Paul Plante Maine Yankee Atomic Power Company Mr. Stan Miller Vermont Yankee Corporation Mr. Jim Clark Southern California Edison Mr. Ray Kellar Entergy Operations-Arkansas Nuclear One
i Holtec Center,555 Lincoln Drive West, Marlton, NJ 08053 H O L T E, Telephone (609) 797-0900 Fax (609) 797-0909 INTERNATION<
Mr. John C licyle U.S. Nuclear Regulatory Commission May 24,1999 Page 5 of 5 Client Distribution (cont'd):
Mr. Joe Andrescavage GPUN - Oyster Creek Nuclear Power Station Mr. Ron Bowker IES Utilities Mr. William Swantz Nebraska Public Power District l
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