United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 91-40: Contamination of Nonradioactive System and Resulting Possibility for Unmonitored, Uncontrolled Release to the Environment

                                UNITED STATES
                        NUCLEAR REGULATORY COMMISSION
                    OFFICE OF NUCLEAR REACTOR REGULATION
                           WASHINGTON, D.C.  20555

                                June 19, 1991


Information Notice No. 91-40:  CONTAMINATION OF NONRADIOACTIVE SYSTEM 
                                   AND RESULTING POSSIBILITY FOR 
                                   UNMONITORED, UNCONTROLLED RELEASE TO THE 
                                   ENVIRONMENT


Addressees:

All holders of operating licenses or construction permits for nuclear power 
reactors.

Purpose:  

This information notice is intended to alert addressees to the continuing 
possibility for unmonitored, uncontrolled releases of radioactive material.  
The staff had previously addressed these concerns in NRC IE Bulletin 80-10, 
"Contamination of Nonradioactive System and Resulting Potential for 
Unmonitored, Uncontrolled Release of Radioactivity to the Environment," 
dated May 6, 1980.  However, two recent incidents involving the operation of 
radioactive waste concentrators resulted in the radioactive contamination of 
the auxiliary boiler system and subsequently, unmonitored, uncontrolled 
release offsite.  It is expected that recipients will review the information 
for applicability to their facilities and consider actions, as appropriate, 
to avoid similar problems.  However, suggestions contained in this 
information notice do not constitute NRC requirements; therefore, no 
specific action or written response is required.

Description of Circumstances:

Oyster Creek (NRC Inspection Report No. 50-219/90-06)

During early 1990, at the Oyster Creek Nuclear Generating Station, an 
auxiliary boiler was being operated with radioactively contaminated boiler 
water because of a leak in the "A" radioactive waste concentrator.  On March 
10, 1990, the deaerating feed tank associated with the auxiliary boiler 
overflowed onto the boiler house floor.  The water that spilled in the 
boiler house was treated as radioactive, and actions were initiated by the 
licensee to monitor and clean up the spill.  Because of standing water in 
the floor drains (which were clogged) and the negative results of the 
initial surveys of the catch basin, the licensee originally concluded that 
no radioactive material had been transported outside the radiologically 
controlled area.  However, subsequent monitoring at a different location 
indicated that a small amount of radioactive water had been released into 
the site storm drain.  The storm drain system ultimately discharges into 
Barnegat Bay.


9106130344
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                                                            IN 91-40
                                                            June 19, 1991
                                                            Page 2 of 3


FitzPatrick (NRC Augmented Inspection Team Inspection Report No. 50-333/91-
80)

On March 18, 1991, at the James A. FitzPatrick Nuclear Power Plant, an 
unmonitored release of radioactively contaminated steam occurred through an 
atmospheric vent of the auxiliary boiler  for approximately 3 hours.  The 
radioactive materials were inadvertently drawn from the waste concentrator 
into the auxiliary boiler system, released to the atmosphere, and resulted 
in contamination of site buildings and grounds within the protected area.  
Subsequently, some of the contamination was washed by rainfall into site 
storm sewers and through the drain system into Lake Ontario. 

Before the event on March 18, 1991, the auxiliary boiler had been operating 
without detectable activity in the boiler water.  The licensee was venting 
the auxiliary boiler to the atmosphere (at approximately 9000 pounds per 
hour) to increase its load, since operation at low loads made burner 
operation difficult.  The boiler became contaminated from the "B" 
radioactive waste concentrator because operators failed to follow 
administrative and radioactive waste concentrator operating procedures, and 
a side stream steam supply line (steam agitation line) to the concentrator 
had been installed contrary to the system design.  While reducing the liquid 
waste level in the waste concentrator, operators inadvertently left the 
steam agitation valve FCV-02 open (see at-tached drawing).  On the indication 
of low concentrator level, the steam supply valve FCV-106 automatically 
closed, as designed.  Because FCV-02 was open and the steam agitation line 
was installed downstream of FCV-106 rather than upstream as specified in the 
design drawings, a flow path was established from the concentrated 
radioactive liquid side to the steam side of the waste concentrator.  The 
motive force was the vacuum created as the steam condensed on the steam 
side.  When steam was readmitted to the waste concentrator, the 
contamination was flushed to the condensate supply for the auxiliary boiler.  
The licensee took samples of the boiler water 1 hour after the release was 
terminated and found residual contamination at 3.4 E-2 micro-curies per 
milliliter.  

The licensee recognized the potential for the unmonitored release through 
the storm sewer and took samples which indicated radioactive material 
concentrations above the limits for release from the site.  The licensee 
effectively isolated the storm sewer system with inflatable plugs, securing 
the release from the site.  The licensee used plastic sheets on horizontal, 
flat surfaces to prevent the spread of contamination by runoff or wind 
action or by penetration into the soil as a result of the rains.  
Contaminated building vertical surfaces were painted with a strippable 
coating to temporarily fix the radioactive material on the surfaces.  The 
strippable coating was later removed and handled as solid radwaste. 

Discussion:

In NRC IE Bulletin 80-10, the staff stated that the auxiliary boiler could 
become contaminated from the radioactive waste evaporator concentrate tank.  
The bulletin recommended that licensees take appropriate action to identify 
non-radioactive systems that could become radioactive through system 
interfaces and establish sampling and monitoring programs to prevent an 
unmonitored, 
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                                                            IN 91-40
                                                            June 19, 1991
                                                            Page 3 of 3


uncontrolled release.  The events at Oyster Creek and FitzPatrick indicate 
that not all licensees took effective actions in response to the bulletin. 

The event at FitzPatrick emphasizes the potential for unmonitored, 
uncontrolled releases from various sources, including the storm drain 
system.  The circumstances associated with this release were fortuitous in 
that only a small fraction of the radioactive material released to the 
atmosphere was released offsite.  The small offsite release was attributed 
to the high rate of deposition with condensed steam caused by the cold 
ambient temperature which occurred during the release and also to the 
effective corrective actions taken by the licensee once the release was 
identified.  If these conditions did not exist, offsite releases (and thus 
radiological consequences) would likely have been substantially higher.

This information notice requires no specific action or written response.  If 
you have any questions about the information in this notice, please contact 
one of the technical contacts listed below or the appropriate NRR project 
manager.




                                   Charles E. Rossi, Director
                                   Division of Operational Events Assessment
                                   Office of Nuclear Reactor Regulation


Technical Contacts:  Richard Plasse, RI
                     (315) 342-4907

                     Robert Temps, RI
                     (315) 342-4041

                     Kenneth T. Eccleston, NRR
                     (301) 492-1081


Attachments:
1.  Waste Concentrator (WC) B Flow Schematic
2.  List of Recently Issued NRC Information Notices  

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