NASA Scientific and Technical Aerospace Reports

This report summarizes the findings of a reconnaissance effort to determine the extent to which lead-based paint liquid
encapsulants are currently being used for residential lead hazard control and to obtain an informal assessment of users
experiences with encapsulants. The effort included a literature search to identify and review the relevant literature on
encapsulant use and performance, interviews with officials from states that were considered to be likely to regulate encapsulant
use, surveys of major encapsulant users and other lead hazard control professionals, and site visits to selected users. The most
important outcome of the literature search is that there is no detailed discussion on the long-term performance of encapsulants
in the published literature. In addition, technical reviews and theoretical discussions concerning the chemical composition of
encapsulants and comparisons between various chemical alternatives are lacking in the published literature. In the past, there
has been a difference of opinion among various encapsulant manufacturers and other professionals concerning the optimal
properties of encapsulants; however, results of any research into these issues apparently have not been published. The only
document that reported on the long-term effectiveness of encapsulation looked at cases where products had been installed for
only two years. Encapsulant manufacturers were identified from various state registries and other lists compiled between 1993
and 1997. New encapsulant manufacturers were sought out using Internet searches, personal contacts, exhibitor lists from lead
conferences, and advertisements in various coatings journals and lead-oriented newsletters. Fifteen current manufacturers,
which make 19 different encapsulant products, were identified as a result of this effort.
NTIS
Pain; Lead (Metal); Hazards; Chemical Composition
20040120933 Savannah River Ecology Lab., Aiken, SC, USA
Investigation of Plutonium and Uranium Precipitation Behavior with Gadolinium as a Neutron Poison
Visser, A. E.; Rudisill, T. S.; Bronikowski, M. G.; May 2003; In English
Report No.(s): DE2004-812302; WSRC-TR-2003-00193; No Copyright; Avail: National Technical Information Service
(NTIS)
The neutralization of solutions containing significant quantities of fissile material at the Department of Energy’s Savannah
River Site and the subsequent transfer of the slurry to the High Level Waste (HLW) system is accomplished with the addition
of a neutron poison to ensure nuclear safety. Gd, depleted U, Fe, and Mn have been used as poisons in the caustic precipitation
of process solutions prior to discarding to HLW. However, the use of Gd is preferred since only small amounts of Gd are
necessary for effective criticality control, smaller volumes of metal hydroxides are produced, and the volume of HLW glass
resulting from this process is minimized.
NTIS
Depletion; Fissionable Materials; Gadolinium; Plutonium; Uranium
20040120937 Savannah River Ecology Lab., Aiken, SC, USA
Repair of a Melter Pour Spout using an Expanding Ring
Peacock, H. B.; Imrich, K. J.; Lam, P. S.; Leader, D. R.; Iverson, D. C.; 2003; 7 pp.; In English
Report No.(s): DE2004-812068; WSRC-MS-2003-00369-REV-0; No Copyright; Avail: Department of Energy Information
Bridge
An expanding ring was developed that provided remote repair of the pour spout for a radioactive waste vitrification melter.
This passive device used gas pressure to expand a metal ring against the irregularly shaped pour spout wall. Laboratory
modeling and testing were performed for proof of concept and optimization before final design and field deployment. The ring
expanded radially more than 4.8 mm and successfully repaired the melter pour spout allowing continued glass pouring
operation.
NTIS
Radioactive Wastes; Vitrification; Maintenance
20040120957 NASA Langley Research Center, Hampton, VA, USA
Measurement of the Specific Refractivities of CF4 and C2F6
Burner, A. W.; Goad, W. K.; [1977]; 2 pp.; In English; No Copyright; Avail: CASI; A01, Hardcopy
In order to relate the measured fringe shift of an interferometer to density, the relation between density rho and refractive
index n must be known. For gases where the refractive index is close to unity, this relation between density and refractive
index is very closely approximated by (n - 1) = K rho where K is the specific refractivity, or the Gladstone-Dale constant. The
specific refractivity, which is weakly dependent on wavelength and temperature, is readily available for a number of common
test gases such as N2 and air. For more unique test gases such as CF4 and C2F6 for which refractive index data at optical
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