ML20213F396
| ML20213F396 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 05/07/1987 |
| From: | Standerfer F GENERAL PUBLIC UTILITIES CORP. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| 4410-87-L-0067, 4410-87-L-67, NUDOCS 8705150317 | |
| Download: ML20213F396 (5) | |
Text
e GPU Nuclear Corporation Nuclear
- ,ome:r8o s
Middletown, Pennsylvania 17057-0191 717 944 7621 TELEX 84-2386 Writer's Direct Dial Number:
(717) 948-8461 4410-87-L-0067 Document ID Ol74P May 7, 1987 US Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
Dear Sirs:
Three Mile Island Nuclear Station, Unit 2 (TMI-2)
Operating 1.icense No. DPR-73 Docket No. 50-320 Plasma Arc Cutting Attached is the GPU Nuclear response to the NRC request for additional information regarding the formation of nickel carbonyl during plasma arc cutting fowarded by NRC Letter dated March 20, 1957 Additionally, GPU Nuclear letter 4410-86-L-0143 dated August 27, 19E6, stated,
...the gases to be used with the plasma arc torch, either separately or in combination, are nitrogen, carbon dioxide, and argon..."
GPU Nuclear is currently planning to use nitrogen for both the primary and secondary torch gas (i.e., carbon dioxide will not be used and use of argon is unlikely). The off-gas releases from the use of nitrogen are currently being evaluated. Any safety concerns that may arise as a result of this evaluation will be discussed under separate cover.
Sincerely,
/
8705150317 870007 9
dy PDR ADOCK 05000320 P
PUR F. R. Ste d..ief Director, fMI-2 FRS/CJD/eml Attachment cc: Regional Administrator, Region 1 - W. T. Russell Director, TMI-2 Cleanup Project Directorate - Dr. W. D. Travers GPU Nuc! car Corporation is a subsidiary of the General Public Utilities Corporation t\\
ATTACHMENT 4410-87-L-0067
' On January 20, 1987, GPU Nuclear responded to NRC concerns regarding the use of a plasma arc torch to cut fuel assembly upper end fittings (Reference 1).
In that response, GPU Nuclear attempted to demonstrate that nickel carbonyl would not present a worker safety concern during cutting operations. However, NRC Letter dated March 20,1987 (Reference 2), requested additional information regarding the generation of nickel carbonyl since the January 20, 1987, GPU Nuclear submittal apparently did not adequately address your concerns.
Specifically, your letter states that "...there are literature references which indicate a potential for the formation of nickel carbonyl..." It was requested that GPU Nuclear "... provide the staff with adequate analytical data and literature references describing the chemical processes that affect the formation of nickel carbonyl to further support your position that this compound presents no safety hazard." The following discussion responds to your concerns and supports GPU Nuclear's position that j
nickel carbonyl will not pose a worker safety problem during plasma arc torch cutting operations.
The response to your concern is organized as follows:
I.
Summary of pertinent chemical / physical prcperties of nickel carbonyl, and II.
Discussion of technical data and existing analyses reported for high temperature cutting and welding operations.
~
1.
CHEMICAL / PHYSICAL PROPERTIES FOR NICKEL CARBONYL The chemical and physical properties of a compound provide a general basis for anticipating the behavior of that compound in a given environment.
Conse-quently, behavior inconsistent with a compound's chemical / physical properties should be regarded as unlikely. The following chemical / physical properties of nickel carbonyl provide a basis for the conclusion that nickel carbonyl is of minimal concern relative to worker safety during plasma arc torch cutting operations.
Particularly noteworthy, given the multicomponent solution chemistry of the TMI-2 reactor vessel coolant, is the fact that the formation of nickel carbonyl is not theImodynamically favored. Nickel compounds such as borates, halides, etc., are more thermodynamically favored than carbonyl formations in a multicomponent system (References 3 and 4).
However, if it is assumed that nickel carbonyl is formed during underwater plasma arc cutting, the chemical and physical properties listed celow argue against the presence of nickel carbonyl as a concern to worker safety, 1.
Boiling point = 430C (1090F); Melting point = -19.30C (-2.70F),
i (Refererce 5) i 2.
Specific Gravity of Liquid = 1.318 at 170C (630F) (Reference 5) 3.
Specific Gravity of Vapor = 5.9 (Reference 6) 4.
Solubility in Water = 180 ppm at 25oC (77oF) (Reference 5) i
ATTACHENT 4410-87-L-0067 5.
Chemical Stability:
a.
Compound oxidizes in air and is increasingly unstable thermody-namically with increasing temperatute in air with very rapid decomposition at 100oC (212oF) (Reference 5).
The decomposition rate (i.e., life-time) in air at 23oC (73oF) is 60 +5 seconds (Reference 7).
b.
Autoignition temperature reported to be approximately 60oC (140oF) with reports that vapor fanns explosive mixtures with air or oxygen (Reference 5),
i Assuming that nickel carbonyl is formed under water (reactor coolant tempera-ture approximately 700F): the boiling point (#1) and specific gravity (#2) would dictate that it remain a liquid and sink. Assuming further that vapor l
was transported to the coolant surface: the vapor specific gravity (#3) and ccmpound reactivity (#5a and 5b) would dictate that it remain near the coolant surface and chemically react (i.e., oxidize) or reret with the oxides of i
nitrogen present as as result of primary / secondary torch gas reations.
Therefore, on the basis of the chemical / physical properties of nickel carbonyl, it can be reasonably concluded that the potential for creating a safety hazard for workers during plasma cutting is small.
II. TECHNICAL DATA DISCUSSION OF HIGH TEWERATURE CUTTING AND WELDING OPEPATIONS Nickel carbonyl, Ni(CO)4, is given a TLV/TWA = 0.35 mg/m3 (as N1) by the American Conference of Governmental Industrial Hygienists, Inc. (ACGIH)
(Reference 8), and the National Institute of Occupational Safety and Health (NIOSH) recommends its reguhtion as a carcinogen (Reference 5).
Conse-quently, the potential for nickel carbonyl to constitute a health hazard to workers during high temperature metal cutting / welding operations of stainless steels has led to conservative speculation and data interpretation in the past (References 9 through 12). However, recently published work, summarizing extensive studies by the International Nickel Company (INCO) on this issue, l
provides a clear and definitive demonstration that nickel carbonyl is not an issue of concern during high temperature cutting / welding operations.
The INCO work summarized several years of testing, analysis, and evaluation of data from high temperature metal operation (Reference 13).
The study was I
primarily undertaken to ascertain if nickel carbonyl was formed during typical high temperature welding and cutting
- operations. Secondarily, it was I
designed to measure CO gas concentrations (C0 is required for carbonyl formation). During the study, a wide range of welding processes, as well as plasma cutting, were examined. The majority of the base metals used during toe study were of high nickel content (e.g., Nickel 200, Inconel 600, Incoloy 800, Monel 400) although 304 and 316 stainless steels also were utilized. The inject.lun vf a CG cover gas was employed to increase the potentici for carbonyl formation. The study involved use of continuous monitors for:
- 1) Ni(CO) by a chemiliminescence analyzer with a detection limit of 0.1 ppb of Ni(CO)4 in air and 2) a CO analyzer with detection scales of 0-100 and 4
CReference 13 presents the test results for MIG and TIG welding only. Test results for plasma arc cutting have not been formally presented. However, they do not differ from those for MIG and TIG welding. -
ATTACHFENT 4410-87-L-0067 0-500 ppm with an accuracy of 15% of scale. The cutting / welding was performed in a welding chamber and the generated fumes / gases were exhausted by fan through a filter with the continuous monitors for N1(CO)4 and CO located just downstream of the filter. The results indicated that nickel carbonyl was nondetectable in the majority of cases.
In those few cases where detection occurred, it was at the detection limit (0.1 to 0.2 ppb). The test results support the conclusion that nickel carbonyl (TLV/TWA = 133 ppb Ni(CO)4))
does not present a concern for worker health and safety.
Thus, considering the basic nickel carbonyl chemistry and the data collected and evaluated on high temperature metal operations by INCO, it may be concluded that nickel carbonyl is not an issue of concern regarding the health and safety of workers during plasma arc cutting operations.
l ATTACHENT 4410-87-L-0067 REFERENCES 1.
GPU Nuclear letter 4410-87-L-0012 dated January 20,1937, " Plasma Arc Cutting," F. R. Standerfer (GPU Nuclear) to W. D. Travers (NRC).
2.
tilC Letter NRC/TMI-87-022 dated March 20, 1987, " Plasma Arc Cutting,"
W. D. Travers (NRC) to F. R. Standerfer (GPU Nuclear).
3.
I. Barin and O. Knacke, Thermochemical Properties of Inorganic Substances, Springer-Verlag (1973).
4 J. A. Dean, Langes Handbook of Chemistry, McGraw-Hill Book Company, 13th Edition, 1985.
5.
N. Irving Sax, Editor, Hazardous Chemicals Information Annual No. 1, van Nostrand Reinhould Information Services (1986).
6.
U.S. Department of Transportation, United States Coast Guard, CHRIS Hazardous Chemical Data, June 1985.
i 7.
D. H. Stedman et. al., " Nickel Carbonyl: Decomposition in Air and Related Kinetic Studies," Science, Vol. 208 (30 May 1980).
8.
American Conference of Governmental Industrial Hygienists, Inc., Document of the Threshold Limit Values, Fourth Edition (1980), with Supplemental Documentation for 1984.
9.
G. J. Newton, M. D. Hoover, E. B. Barr, B. A. Wong, and P. D. Ritter,
" Aerosols from Metal Cutting Techniques Typical of Decommissioning Nuclear Facilities - Experimental System for Collection and Characterization," 1982-International Decommissioning Symposium Proceedings, Seattle, Washington (CONF-821005).
10.
M. D. Hoover, G. J. Newton, E. B. Barr, and B. A. Wong, " Aerosols from Metal Cutting Techniques Typical of Decommissioning Nuclear Facilities - Inhalation Hazard and Worker Protection," 1982 International Decommissioning Symposium Proceedings, Seattle, Washington, (CONF-821005).
11.
K. M. Croft, TMI Lower Sup) ort Disassembly Project Underwater -- Cutting Using the Plasma Arc Cutting Metlod, Preliminary Test Report, DOE Contract No.
DE-AC07 - 761001570 (May 1985).
12.
D. L. Smith, Final Report SPERT - IV Decontamination and Decommissioning, TREE-1373 (August 1979).
13.
L. G. Wiseman and E. T. Chapman, " Test Program to Determine Whether Nickel Carbonyl Forms During the Welding of Nickel Containing Alloys," Proceedinos of the International Conference on Health Hazards and Biological Effects of Welding Fumes and Gases, Copenhagen, February 1986, Elsevir Science Publishers (1986).