United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 82-43: Deficiencies in LWR Air Filtration/Ventilation Systems

                                                         SSINS No.:  6835 
                                                         IN 82-43 

                                UNITED STATES
                        NUCLEAR REGULATORY COMMISSION
                    OFFICE OF INSPECTION AND ENFORCEMENT
                           WASHINGTON, D.C. 20555

                              November 16, 1982

Information Notice No. 82-43:    DEFICIENCIES IN LWR AIR FILTRATION/ 
                                    VENTILATION SYSTEMS 

Addressees: 

All nuclear power reactor facilities holding an operating license (OL) or 
construction permit (CP). 

Purpose: 

This information notice is provided as notification of events that had 
actual or potential radiological impact on the plant environs.  It is 
expected that recipients will review the information for applicability to 
their facilities. No specific action or response is required. 

Description of Circumstances: 

Within the past 2-1/2 years, air filtration/ventilation systems at five 
facilities were found to have serious deficiencies, ranging from overloaded 
prefilters to evidence of a wetted high-efficiency particulate air (HEPA) 
filter bank, to penetration of HEPA filter banks by substantive quantities 
of radioactive resin beads.  Deficiencies occurred in both safety-related 
and non-safety-related systems. 

In June 1982, radioactive spent resin was found on the grounds and roof 
areas at Pilgrim 1.  Principal radionuclides were Co-60, Cs-137, Cs-134, and 
Mn-54; contamination ranged from 20,000 dpm/100 cm2 to 100,000 dpm/100 cm2.  
The contamination penetrated damaged filters in a non-safety-grade HEPA 
filter plenum.  The degraded condition of these filters was not detected in 
a timely manner because of a lack of surveillance or testing of the 
filtration system. The HEPA filter failure occurred possibly as an end 
result of a combination of high dust loadings and mechanical damage 
resulting from the impact of disintegrating prefilters, as well as the 
probable warping or distortion of HEPA filter frames under prolonged 
exposure to water and high humidity. 

In December 1980, the SGTS trains at Brunswick 1 were found to be operating 
at close to 100% humidity, and condensation was observed on the interior 
walls. Regulatory Guide 1.52 recommends operation at humidity of 70% or 
less; operation at high humidity is known to cause substantial degradation 
of the iodine-retention capacity of charcoal absorbers.  Also, in December 
1980, both filter trains in the turbine building filter system at Brunswick 
were found to be operating with the upstream HEPA differential pressure 
gauges offscale high.  Also, in the turbine building filter system, 43% of 
the upstream HEPA filters were improperly installed. 
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                                                          IN 82-43 
                                                          November 16, 1982 
                                                          Page 2 of 2 

In August 1980, filters and charcoal adsorbers in the Surry 1 process vent 
exhaust air treatment system were determined to have been half submerged in 
water, and the HEPA filters were caked with dust.  No pressure drop instru-
mentation was provided across the filter banks to ascertain their state of 
loading.  Also, in August 1980, pressure drop gauges across the HEPA filter 
banks in the ventilation exhaust treatment system of the auxiliary building 
at Surry 1 exceeded 5 inches, which is offscale high; this condition had 
existed since May 1980. 

In May 1980, the normal containment building exhaust filters at Turkey Point
were found to be overloaded with dust to such an extent that the filter 
medium was separated from its frame in more than 50% of the filters.  This 
apparently allowed radioactive contamination resulting from explosive 
plugging of steam generator tubes to be transported to the southeast sector 
of the plant site. 

In March 1980, it was determined that HEPA filters in the Big Rock Point 
offgas and chemistry laboratory exhaust treatment systems were not being 
tested for leakage in place.  No records were maintained of pressure 
differential across the laboratory HEPA filters which had not been replaced 
for at least five years. 

In each case described above, licensees initiated programs and procedures to
correct the deficiencies and to prevent or minimize their potential for 
reoccurrence. 

Air treatment systems which incorporate filtration or absorption media are 
provided to reduce the potential release of radioactive materials to the 
environs.  In order to function as designed, such systems should be 
installed, tested, and maintained to a degree consistent with their intended 
function. 

Guidance on installation, maintenance, and testing programs, of a degree and
nature which have been demonstrated to ensure proper system functioning, is 
provided in Regulatory Guides 1.52 and 1.140. 

No written response to this information notice is required.  If you need 
addi-tional information about this matter, please contact the Regional 
Administrator of the appropriate NRC Regional Office or this office. 


                                Edward L. Jordan, Director 
                                Division of Engineering and 
                                  Quality Assurance 
                                Office of Inspection and Enforcement 

Technical Contacts:     L.J. Cunningham, IE
                        301-492-8073

                        P.G. Stoddart, NRR
                        301-492-7633

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