C - Hanford Site

WHC-SD-EN-TI-136, Rev. 0
Mr. Mike C. Osweiler -2- SII-141~
The advance notification for removal of these USTs (Letter 90-ERB-117,
Mr. R. D. Izatt, DOE-RL, to Mr. Timothy L. Nord, Ecology, 'Advance
Notification for Closure of Underground Storage Tanks at the Hanford Site,w
dated September 20, 1990) stated that approximately 1,200 linear feet of
2-inch and 4-inch diameter piping associated with the USTs to be removed at
the N Reactor site would be pressure tested, capped, and left in place until
final remediation of the N Reactor site. Since pressure testing is not a
requirement of 40 CFR 280.71, nor of WAC 173-360-385, the lines were capped,
but not pressure tested. There was no history of any leakage associated with
these tanks/piping, and therefore, no reason to suspect any leakage. However,
a recent site inspection resulted in notification to Ecology of a site
leak/spill associated with the piping system.
The advance notification also stated that a non-regulated, abandoned UST
(tank 325) located in the 3000 Area would be removed along with tanks
3000-1/-2/-3/'-4. Because of funding considerations, this tank was not removed
at that time. Its removal will be rescheduled as funding becomes available
and advance notification will be provided as required by the regulations.
The sites of LISTs 100-N-SS-27 and 3000-1/-2/-3/-4 (one site) were discovered
to be release sites after the tanks were removed. These sites were
contaminated with gasoline and diesel fuel which, apparently, were the result
of spills/tank overfills and, in the 3000 Area, the result of leaking
pressurized piping associated with the LISTs. Notifications were made to
Ecology as required by the regulations, and the sites have been inspected by
Ecology personnel. A remediation plan is being prepared for the 3000 Area
site and will be made available to Ecology for review and comments prior to
being finalized. (The initial draft is expected to be completed by June 25.)
The sister tank to the 100-N-SS-27 tank (UIST 100-N-22-28) is planned to be
removed in mid-July to facilitate the characterization/remediation of this
site. 30-day advance notification has been provided to Ecology for the
removal effort.
All the LISTs that have been removed as indicated above (with the exception of
the 105-LFT tank) are currently stored at the 100-C Area on the Hanford Site
and are scheduled to be disposed of at off site as scrap. A subcontract for
this action is currently being prepared and is expected to be completed by
August 1991. After its removal, the 105-LFT tank was discovered to be
radioactively contaminated on its exterior surface and is undergoing
decontamination at N Area prior to its being cut up and disposed of at the low
level waste burial ground on the Hanford Site.
The site of LISTs 3000-5/46 (which were removed in September 1989) was also
discovered to have been a release site (see the 45-day report dated
November 1, 1989) and was resampled and then backfilled in January 1991.
Based on the initial sampling results, no additional remedlatlon was required.
Confirmation soil samples were taken and the results of the analysis, along
with the applicable forms as required by WAC 173-360, will be submitted to
Ecology for concurrence on closing the site.
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