United States Nuclear Regulatory Commission - Protecting People and the Environment

Clarification of Surveillance Requirements for HEPA Filters and Charcoal Adsorber Units in Standard Technical Specifications on ESF Cleanup Systems (Generic Letter No. 83-13)


                               UNITED STATES 
                       NUCLEAR REGULATORY COMMISSION 
                          WASHINGTON, D. C. 20555 

                               March 2, 1983 

TO ALL APPLICANTS FOR OPERATING LICENSES AND HOLDERS OF CONSTRUCTION PERMITS
FOR POWER REACTORS 

Gentlemen: 

SUBJECT:  CLARIFICATION OF SURVEILLANCE REQUIREMENTS FOR HEPA FILTERS AND 
          CHARCOAL ADSORBER UNITS IN STANDARD TECHNICAL SPECIFICATIONS ON 
          ESF CLEANUP SYSTEMS (Generic Letter No. 83-13) 

It has come to our attention that the Surveillance Requirements for HEPA 
filters and charcoal adsorber units in ESF atmospheric cleanup systems as 
stated in the Standard Technical Specifications (STS) in use by applicants 
for operating licenses require clarification. The current revisions of the 
STS for all power reactors do not clearly reflect the required relationship 
between the guidance provided in Regulatory Guide 1.52, Revision 2, and ANSI
N510-1975; the testing requirements of the HEPA filters and charcoal 
adsorbers units; and the NRC staff assumptions used in its safety 
evaluations for the ESF atmospheric cleanup systems. In order to clarify 
this relationship, the wording in the Surveillance Requirements for testing 
the HEPA filters and charcoal adsorber units has been modified. 

We have enclosed the revised testing requirements for HEPA filters and 
charcoal adsorber units in ESF atmospheric cleanup systems that are to be 
used in your submittal of proposed Technical Specifications, or, if your 
proposed Technical Specifications have already been submitted, the staff 
will make the necessary revisions. These changes will also be incorporated 
in the next revision of the STS. The generic changes are indicated by a line 
in the margin of the Surveillance Requirement. Specific ESF atmospheric 
cleanup systems have not been indicated since the changes apply only to the 
testing of HEPA filters and charcoal adsorber units in every ESF atmospheric 
cleanup system. 

This request has been approved by OMB Clearance Number 3150-0011, which 
expires April 30, 1985. 

                                   Sincerely, 


                                   Darrell G. Eisenhut, Director 
                                   Division of Licensing 

Enclosure: 
"Revised Surveillance Requirements 
     for Testing of HEPA Filters and 
     Charcoal Adsorber Units" 



8303020321 
.

                                 ENCLOSURE 

             Revised Surveillance Requirements for Testing of 
                HEPA Filters and Charcoal Adsorbers Units 

1.   At least once per 18 months, or (1) after any structural maintenance on
     the HEPA filter or charcoal adsorber housings, or (2) following 
     painting, fire, or chemical release in any ventilation zone 
     communicating with the system, by: 

     1)   Verifying that the cleanup system satisfies the in-place 
          penetration and bypass leakage testing acceptance criteria of less
          than (*)% and uses the test procedure guidance in Regulatory 
          Positions C.5.a, C.5.c, and C.5.d of Regulatory Guide 1.52, 
          Revision 2, March 1978, and the system flow rate is cfm +- 10%. 

     2)   Verifying, within 31 days after removal, that a laboratory 
          analysis of a representative carbon sample obtained in accordance 
          with Regulatory Position C.6.b of Regulatory Guide 1.52, Revision 
          2, March 1978, meets the laboratory testing criteria of Regulatory 
          Position C.6.a of Regulatory Guide 1.52, Revision 2, March 1978, 
          for a methyl iodide penetration of less than (**)%; and 

     3)   No change 

2.   After every 720 hours of charcoal adsorber operation, by verifying, 
     within 31 days after removal, that a laboratory analysis of a 
     representative carbon sample obtained in accordance, with Regulatory 
     Position C.6 b of Regulatory Guide 1.52, Revision 2, March 1978, meets 
     the laboratory testing criteria of Regulatory Position C.6.a of 
     Regulatory Guide 1.52, Revision 2, March 1978, for a methyl iodide 
     penetration of less than (**)%. 

3.   After each complete or partial replacement of a HEPA filter bank, by 
     verifying that the HEPA filter bank satisfies the in-place penetration 
     and bypass leakage testing acceptance criteria of less than (*)% in 
     accordance with ANSI N510-1975 for a DOP test aerosol while operating 
     the system at a flow rate of cfm +- 10%. 

4.   After each complete or partial replacement of a charcoal adsorber bank,
     by verifying that the charcoal adsorber bank satisfies the in-place 
     penetration and bypass leakage testing acceptance criteria of less than
     (*)% in accordance with ANSI N510-1975 for a halogenated hydrocarbon 
     refrigerant test gas while operating the system at a flow rate of cfm 
     +- 10%. 

*    0.05% value applicable when a HEPA filter or charcoal adsorber 
     efficiency of 99% is assumed, or 1% when a HEPA filter or charcoal 
     adsorber efficiency of 95% or less is assumed in the NRC staff's safety
     evaluation. (Use the value assumed for the charcoal adsorber efficiency
     if the value for the HEPA filter is different from the charcoal 
     adsorber efficiency in the NRC staff's safety evaluation). 

**   0.175% value applicable when a charcoal adsorber efficiency of 99% is 
     assumed, or 1% value applicable when a charcoal adsorber efficiency of 
     95% is assumed, or 10% value applicable when a charcoal adsorber 
     efficiency of 90% is assumed in the NRC staff's safety evaluation. 
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