Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
SINNS No.: 9197
IN 83-14
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D.C. 20555
March 21, 1985
Information Notice No. 83-14: DEWATERED SPENT ION EXCHANGE RESIN
SUSCEPTIBILITY TO EXOTHERMIC CHEMICAL ,
REACTION
Addressees:
All nuclear power reactor facilities holding an operating license (OL) or
construction permit (CP).
Purpose:
This information notice is provided as an early notification of a
potentially significant problem pertaining to the apparent susceptibility of
certain spent ion exchange resin to undergo an exothermic chemical reaction.
The Nuclear Regulatory Commission (NRC) staff is reviewing the problem and
its effects. If the evaluation so indicates, the NRC may request further
licensee action. In the interim the NRC recommends that recipients of this
notice review the information herein for applicability to their facilities.
An inadequate knowledge of the characteristics of a waste stream might
result in adverse conditions such as similiar exothermic reactions, poor
waste solidification, or incompatibility of wastes with container materials.
No specific action or response is required at this time.
Description of Circumstances:
Spent ion exchange resin from Arkansas Power and Light's Arkansas Nuclear
One (ANO) Unit 2 evidenced an exothermic chemical reaction on January 15,
1983. Approximately 100 cubic feet of spent resin was stored in a
high-integrity liner mounted in a shipping cask and covered with a tarp to
protect it from inclement weather. The resin had completed its last
dewatering cycle at 12:30 a.m. on January 15, 1983, and was considered
adequately dewatered for shipment to the burial site. Later that same day,
at 8:00 a.m., the oncoming shift of radwaste workers noted steam and smoke
coming from under the tarp. The vapor was noted to be very odorous and sharp
(heavy chemical smell). Licensee personnel immediately sampled, for airborne
radioactivity and toxic gases; both proved negative. The pH of the water
collected during the dewatering process was determined to be 3.5 to 4.0. A
core sample of the resin was obtained and the core temperature was measured
to be 365F. It was noted also that the resin at the top of the liner
had formed a strong crust. The resin was finally cooled at about 11:00 a.m.
when 150 gallons of demineralized water at 50F was added to the liner
and recirculated. The temperature of the water stiblized at 80F and the
pH of the water returned to 7.0. At this point, the licensee began sampling
pH and monitoring temperature every 3 hours.
8212060385
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IN 83-14
March 21, 1983
Page 2 of 2
A second liner full of spent resin from the same source as the resin that
overheated was nearby but had not undergone any changes. The only apparent
difference between the two batches of resin appears to be that the
unaffected resin had only been partially dewatered. The spent resin in
question came from the Unit 2 spent resin holding tank (2T13 tank), where it
is believed to have been "caked" around the sides of the tank for a number
of years. Specifically, since commercial power operation began in 1980,
the,licensee was aware that only about 160 cubic feet of usable volume was
available in this 350 cubic foot spent resin holding tank, indicating that a
large amount of resin was retained in the tank during normal resin sluicing
operations. The licensee's successful efforts to free this caked resin
resulted in the two liners full of resin. Since this resin was used prior to
commercial power operation, it had significantly lower specific
radioactivity than is normal for spent resin; on the other hand, it was most
probably exposed to chemicals and contaminants not normally associated with
power operation.
The licensee has consulted both the Chem-Nuclear Corp. and the Dow Chemical
Corp. concerning this matter. Both companies have provided knowledgeable
personnel to assist on-site. The complete analysis results from resin
samples taken are not available at this time, and the licensee will wait
until this phenomenon is better understood before determining the best means
of final disposal for the affected resin. However, Chem-Nuclear Corp. has
determined that there were oxidizing agents present in the affected resin in
the form of nitrites (0.05 ppm) and nitrates (0.5 ppm) that apparently
contributed to the exothermic reaction. Accordingly, Chem-Nuclear Corp. has
notlfied its cus,tomers that nitric acid and other strong oxidizing agents
can cause exothermic (and possibly explosive) reactions when mixed with
organic material such as ion exchange resins. Chem-Nuclear has further
cautioned its customers to consult with someone knowledgeable before using
strong-oxidizing agents, and the company is placing a label with a suitable
warning on its reusable containers. Additionally, Chem-Nuclear field
personnel were instructed about this potential hazard, and warning/caution
statements have been added to their procedures.
If you have ahy questions regarding these matters, please contact the
Regional Administrator of the appropriate NRC Regional Office.
James M. Taylor, Director
Division of Quality Assurance, Safeguards,
and Inspection Programs
Office of Inspection and Enforcement
Technical Contact: A. W. Grella
492-7746
Attachment:
List of Recently Issued IE Information Notices
