European
Nuclear Society
e-news
Issue 8 Spring 2005
http://www.euronuclear.org/e-news/e-news-8/siemens.htm
Mr. Eckhard Raabe |
Mr. Roelof Hadders |
Mr. Manfred Wilke |
This paper has been condensed from its original version to meet publication requirements. The full document is available upon request from the authors.
Off-site decontamination of protective clothing is new in Europe.
In the past, facilities established their own on-site laundries and decontaminated
their own protective clothing. But, operating a laundry within an operating
nuclear facility brings with it a number of complicated problems, including
staffing, variable workloads, wastewater, and as a support priority it is often
not handled as well as it could be.
For the past five years, the former Siemens fuel rod fabrication facility in
Hanau, Germany, has been using the services of an off-site laundry service provider
(LSP) for cleaning radioactively contaminated protective clothing. This paper
discusses the decision making process
The LSP is located in Coevorden, The Netherlands. Centrally
located, it is able to service many European nuclear facilities while minimizing
transport distances. Coevorden offers a friendly regulatory environment and
reliable, educated employees.
The LSP has a broad scope nuclear materials license, meaning it can accept almost
any radionuclide providing the quantities do not exceed license limits. The
framework for transport of radioactive materials is defined in European ADR
regulations, German GGVS (Gefahrengutverordnung Strasse), and laws governing
health physics in each European country where the LSP provides services. Permits
are obtained in each country through which a shipment passes as required.
Waste is generated as sludge from the wastewater processing system and drying
lint. Dutch regulators consider laundering as a value added process taking place
in the Netherlands. Therefore waste is generated in the Netherlands in accordance
with the Dutch Nuclear Power Act and transported off site to the COVRA –
the Netherlands’ radioactive waste disposal site.
Key factors for going off-site were cost and the fact that the company shut
down its fuel fabrication facility which involved decommissioning the on-site
laundry.
Customers are provided clean, folded, and sorted clothing in the LSP’s special transport container (see Fig. 1). The containers are on wheels and can be delivered directly to the point of use, eliminating extra handling.
|
Bags containing dirty laundry are sealed
and then placed into the open top of the lined LSP’s containers.
When a container is full, the liner is sealed and the container is checked
for radioactivity in preparation for return to the LSP. |
special plastic scintillator detector to monitor incoming containers (see Fig.2). The monitor alarms if radiation levels are exceeded.
Fig. 2 Container entrance monitor
A crane lifts the sling bag out of the container to a downdraft
sorting table. The table rotates and workers stationed around the perimeter
sort items into like types. Integrated ventilation systems avoid any need for
worker respiratory protection.
The laundry is placed into 250 kg capacity washing machines. These industrial
washers generate considerably more agitation and “fall” than smaller
washers in use at nuclear facilities. Washing large loads improves economy and
is one reason why the LSP is able to do laundry at less cost. After washing,
laundry is dried in industrial dryers sized to match washing capacity.
Clean clothing is placed on an Automatic Laundry Monitor (“ALM”).
The LSP has designed world-class belt-driven gas flow proportional ALMs capable
of detecting very low levels of alpha and beta-gamma contamination (see Fig.
3). Each ALM has 88 individual detectors arranged to fully monitor every square
centimetre of an item. This gives Siemens confidence that 100% of the clothing
is being directly measured for radioactivity in a repeatable and reliable manner
that outperforms human inspection method.
Finally, clean laundry is sorted and packed by item, size and color and packed
into the transport containers for return to the customer.
Fig. 3: Alpha/beta gas flow monitor ALM
The quantities processed in one calendar year are as follows:
24 Total Shipments
2,1 E8 Bq Total Activity
6 Bq/g Specific Activity
24,463 kg Laundered Clothing
27,211 Coveralls
15,277 Gloves
57,181 Overshoes
318 Containers Of Soiled Laundry
Fig.4: Transport container with clean coveralls
The LSP is periodically audited by Siemens and others. Audits confirm that the off-site laundry is operating according to its design specification, procedures, and governmental requirements.
In addition to logistical considerations Siemens wanted to
provide laundry service at the lowest possible cost. Siemens evaluated four
different LSP offerings.
The LSP offers lease clothing and disposable clothing. A key factor was that
Siemens already owned sufficient protective clothing inventory. Figure 5 depicts
the savings attributed to having the LSP launder the existing clothing inventory.
Fig. 5: Cost comparison
The Siemens project demonstrates that off-site laundry service
offers a number of advantages to managing an on-site laundry. The LSP is better
equipped to do the job with high-volume throughput using efficient, high-performance
equipment. Outsourcing eliminates the need to hire permanent and peak-need
temporary laundry workers. Off-site service eliminates management of laundry
wastewater and other health physics tasks – daily radiation checks,
air sampling, etc., that are part of operating a laundry.
The LSP worked together with Siemens to ensure service was satisfactory and
the LSP was willing to help whenever problems arose. There have been no problems
with transporting radioactive material during the course of the project. In
summary, the process has saved Siemens money while providing laundry service
better than Siemens could have done on its own.
© European Nuclear Society, 2005