ML20052A587
| ML20052A587 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/21/1982 |
| From: | J. J. Barton GENERAL PUBLIC UTILITIES CORP. |
| To: | Barrett L Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20052A588 | List: |
| References | |
| 4400-82-L-0052, 4400-82-L-52, NUDOCS 8204280483 | |
| Download: ML20052A587 (8) | |
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o' pril 21,1982 cy 4400-82-L-0052 TMI Program Office Attn:
Mr. L. II. Barrett, Deputy Program Director U. S. Nuclear Regulatory Commission c/o Three Mile Island Nuclear Station Middletown, Pennsylvania 17057
Dear Sir:
Three Mile Island Nuclear Station, Unit (TMI-2)
Operating License No. DPR-73 Docket No. 50-320 Recovery Operations Plan Change Request No. 12 Modifications to Air Cleanup System Surveillances Attached please find the subject document.
This submittal is made to request changes in various surveillances performed on the Fuel llandling Building, Auxiliary Building and Control Room Emergency Air Cleanup Systems. This change will clarify various surveillance requirements and supplements the change requested by Technical Specification Change Request No. 35.
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Recovery Operations Plan Chance Request No.12 The licensee requests that the attached pages 4.7-4, 4. 7-5, 4.9-1 and 4.9-2, be substituted for the existing Recovery Operations Plan.
Reason for Change This change is being requested in order to clarify the surve111ance require-ments affecting the various Air Cleanup Systems specified in the TMI-2 Recovery Operations Plan.
With respect to the Control Room Emergency Air Cleanup System the changes requested for surveillance requirements 4.7.7.1.b and 4.7.7.1.f institute more stringent requirements which will improve the surveillance performed on the system.
The change requested for 4.7.7.1.c.2 and 4.7.7.1.d specifies testing criteria for the carbon in the control room charcoal adsorber which is equivalent to that in Regulatory Position C.6.b of Regulatory Guide 1.52, j
Revision 2, March 1978. The reason for this change to an equivalent testing i
criteria is that the TMI-2 system was not designed with an air heater in line l
with the charcoal adsorber to reduce relative humidity, thus testing at a reduced relative humidity does not reflect actual conditions, and there is no t
test in Regulatory Guide 1.52 which fits our system. Other changes to 4.7.7.1.c.3, 4.7.7.1.f and 4.7.7.1.g are administrative in nature and specify the particular section of ANSI N510-1975 invoked for the surveillance.
The change requested for surveillance requirement 4.7.7.1.c modifies the existing requirement by the addition of the adjective significant so that this The determination of testing need not be performed following minor events.
wnether an event is significant will be made on a case by case basis by the appropriate management personnel.
With respect to the Auxiliary Building and the Fuel Handling Building Air Cleanup Systems the increased movement of radioactive materials in and through tne affected buildings has emphasized the need to maintain these air cleanup systems in a continuing operable status.
Additionally we have reformatted the Surveillance Requirements in an attempt to make them more easily understood.
Tne following is a cross reference between the existing and the proposed Recovery Operations Plan Section 4.9.12.
Existing Proposed 4.9.12.a 4.9.12.a 4.9.12.b.1&2 4.9.12.c.1 4.9.12.c.1&2 4.9.12.a 4.9.12.c.3&4 4.9.12.a 4.9.12.c.5&6 4.9.12.a & 4.9.12.0.4 4.9.12.c.7&8 4.9.12.b.1, 2 & 3 4.9.12.d & c 4.9.12.d The surveillances performed every 31 days have been increased in order to insure the system is operating satisfactorily. The existing 4.9.12.b (proposed 4.9.12.c) has been changed to eliminate installation testing because this was completed with original system testing.
The 18 month periodic testing has been consolidated in new 4.9.12.a and b, and the testing following _ _ _ - _ _ _ _ -
paintirg has been eliminated. Present retest requirements following painting consists of verifying flow rate through the HEPA filters which we now propose to do once every 31 days. Also, before and after painting DOP tests have demonstrated no deleterious effects on the HEPA filters, and we no longer take credit for the charcoal adsorbers in these systems. Several surveillances performed every 18 months pursuant to existing Sections 4.9.12.c 1 through 4 will now be performed every 31 days and other 18 month surveillances perfonned pursuant to existing Section 4.9.12.c 5 through 8 further describe test conditions for additional clarity.
Additionally air flow rate surveillance requirements are revised based on the reviews we committed to in Recovery Operations Plan Change Request No. 9.
Safety Evaluation Justifying Change Tne changes requested for surveillance requirements 4.7.7.1.b and 4.7.7.1.f for the Control Room Emergency Air Cleanup System institute niore stringent requirements which will improve the surveillances performed on the system and therefore enhance safety.
l The change requested for surveillance requirement 4.7.7.1.d changes the testing criteria for the carbon in the control room charcoal aosorber from that specified in Regulatory Position C.6.b of Regulatory Guide 1.52 Revision 2, March 1978 to an equivalent testing criteria. This change is !
requested because the Control Room Emergency Air Cleanup System does not have in line air heaters to control relative humidity to the charcoal adsorbers and thus does not fall into any of the categories specified in Regulatory Guide 1.52.
The specific test substituted comes from an approved standard (ANSI /ASME N509-1980) and specifies testing at 95% relative humidity which more accurately reflects actual conditions. The 5% penetration limit varies from that listed in the standard because it is based on the decontamination factor of 10 (90% removal efficiency) derived from the original testing discussed in Section 9.4.1 of the TMI-2 FSAR and accepted by the NRC in Section 11.3 of the TMI-2 Safety Evaluation Report, Supplement 1 and thus is consistent with the system's original design bases.
Other changes to 4.7.7.1.c.3, 4.7.7.1.f and 4.7.7.1.g are aoministrative in nature and have no effect on safety.
The changes requested for Fuel Handling Building and Auxiliary Building Air Cleanup System flow rates are based on a review of the design of these systems. The subject systems are designed to control pressure in their respective building relative to atmospheric pressure, which results in flow as a variable over a relatively wide operating range. The number of HEPA filters existing in the system, 60 for the Auxiliary Building Air Cleanup System (ABACS) and 40 for the Fuel Handling Building Air Cleanup System (FWACS), is determined by the design flow of the respective system. Design flow per filter element usually ranges from 1000 CFM to as high as 1500 CFM, however fan capacities and normal system losses limit actual system flow to ap-proximately 1400 CFM per filter in the subject systems. The minimum proposed system flow rates, 54,000 CFM for the ABACS and 36,000 for the FFBACS, were determined based on a nominal design capacity of 1000 CFM/ filter with an allowance of 10%. Maximum flowrates of 80,000 CFM for the ABACS and 54,000 for the FH3ACS are based on a capacity of 1333 CFM/ filter which is 67 CFM below the actual system design values, and 167 CFM/ filter below the 1500 CFM/ filter design limit utilized in similar systems. This wide range of normal system flow is required to avoid entering the action statement under normal conditions such as when a door is opened to the outside atmosphere, which causes an increase in building air flow to compensate for the decrease in building differential pressure, or when a Unit #1 supply fan (in the shared Fuel Handling Building) is temporarily shutoff causing a decrease in, normal flow. Single exhaust filter train flowrates (1 tem 4.9.12.b.2) have been revised correspondingly. The revised system and single train flowrates are consistent with the original design of the subject systems as discussed in Section 9.4 of the TMI-2 FSAR and will provide reasonable assurance that adequate ventilation will be provided and that exhaust air will be filtered by HEPA filters prior to release.
Other changes requested for Section 4.9.12 of the Recovery Operations Plan are discussed below, a)
The additional changes requested for surveillance requirements in existing 4.9.12.a & b (proposed 4.9.12 a & c) will enhance surveillance of the Auxiliary Building and Fuel Handling Building Air Cleanup Systems and thus improve overall reliability.
The specific requirement in -
existing 4.9.12.b (proposed 4.9.12.c) for testing following painting, fire or chemical releases has been modified by eliminating the re-quirement to test after painting. DOP and filter pressure drop testing is most indicative of possible damage or derangement resulting from structural repairs.
Painting has not caused any noticable degradation of the HEPA filters, based on before and after DOP and flow testing.
(Credit is no longer being taken for the charcoal adsorbers in the subject systems.) It is expected that substantial spray painting could cause filter loading however, which would be most noticable on the filter D/P. Therefore the filter D/P surveillance is stepped up to once per 31 days versus the present once per 18 months.
Additional changes to existing 4.9.12.b (new 4.9.12.c) were made to eliminate the initial test requirement, because this has been done and to eliminate the 18 month retest because it would be redundant in view of the remainder of the changes proposed herein.
b)
The additional changes requested for existing surveillance requirement 4.9.12.c (proposed 4.9.12.b), 4.9.12.d (proposed 4.9.12.d), and 4.9.12.e (proposed 4.9.12.d) do not adversely impact safety.
Items 4.9.12.c.3 &
4 of the present Recovery Operations Plan have been added to item 4.9.12.a and thus will be performed more often, therefore safety is not impacted.
Items 4.9.12.c.1 & 2 of the existing Recovery Operations Plan which require measuring Auxiliary Building and Fuel Handling Building Air Cleanup Systen air flowrates have been incorporated into 4.9.12.a and thus will be performed every 31 days vice every 18 months.
Surveillances performed by 4.9.12.c 7&8 (proposed 4.9.12.o.1, 2 & 3) have oeen reworded for additional clarity with no change in the tests intent.
Changes in existing 4.9.12.c.5 & 6 (proposed 4.9.12.b.4) specify test conditions to be established while measuring building pressure. Existing Recovery Operations Plan Sections 4.9.12.d & e have been incorporated into new 4.9.12.d and the changes made to the surveillances now specify the pertinent section of ANSI N510-1975 to be followed when performing these tests and its relationship to Regulatory Guide 1.52.
These changes are administrative in nature and have been made to further clarify these surveillance requirements and do not affect safety.
In sunmary the changes to the surveillance requirements discussed above will improve the surveillance of the subject air cleanup systems therefore les-sening the probability of an accident or malfunction of equipment important to safety. In so doing the possibility of a different type of accident than previously considered has not been introduced. This change redefines the required flow rates for the subject air cleanup systems but does not reduce tne margin of safety as defined in the basis for the technical specification accompanying this surveillance requirement because' adequate ventilation will continue to be provided and exhaust air will continue to be filtered through tne HEPA filters prior to release to the atmosphere.