ML20234D759

Proposed Tech Spec 4.7.6 Changing Control Room Area Ventilation Sys Surveillance Requirements to Extend Carbon Adsorber Sampling Frequency from 720 H to 1,440 H

ML20234D759
Person / Time
Site:	Catawba
Issue date:	12/21/1987
From:	DUKE POWER CO.
To:
Shared Package
ML20234D758	List: ML20234D756 ML20234D759
References
NUDOCS 8801070181
Download: ML20234D759 (5)

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ATTACHMENT I I

PLANT SYSTEMS ,

SURVEILLANCE REQUIREMENT $ (Continued) .

c. At least once per 18 months or (1) after any structural maintenance on the HEPA filter or carbon 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 1% (Unit 1), 0.05% (Unit 2) and uses the test proce-  ;

dure guidance in Regulatory Position C.5.a. C.S.c, and C.5.c a of i Regulatory Guide 1.52, Revisions 2, March 1978, and the sytem flow rate is 6000 cfm 2 10%; l

2) Verifying, within 31 days after removal, that a laboratory analysis of a representative carbon sample ootained in accor-dance with Regulatory Position C 6.b of Regulatory Guide 1.52, Revision 2, March 1978, meets the laboratory testing criteria of Regulatory Position C.6.4 of Regulatory Guide 1.52. Revi-sion 2. March 1978, for a methyl iodide penetration of~1ess than 1%; and

3) Verifying a system flow rate of 6000 cfm + 10% dur.ng system opera n wnen tested in accordance with XNSI 1G10-1980.

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d. After every % hours of carbon adsorber oceration, by verifying, within 31 days after removal, that a laboratory analysis of a repre-sentative 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 j penetration of less than 1%;

e. At least once per 18 months by:

1) Verifying that tne pressure drop across the ccmbined HEPA filters, i caroon adsorber banks, and moisture separators is less than 8 inches Water Gauge while operating the system at a flow rate of 6000 cfm + 10%;  ;

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J$ 2) Verifying that on a High Radition-Air Intake, or Smoke Density- l goA High test signal, the system automatically isolates'tne affected

-o intake from outside air with recirculating flow through the HEPA.

EE filters and carbon adsorber banks; g 3) Verifying that the system maintains the control room at a positive  ;

-o pressure of greater than or equal to 1/8 inch Water Gauge relative

$ to adjacent areas at less than or equal to pressurization flow o,

of 4000 cfm to the control room during system operation;

4) Verifying that the heaters dissipate 25 2.5 kW, and f

'TIIe7 equirement for reducing refrigerant concentration.to 0.01 ppe may be satisfied by operating the system for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> with neaters on and operating.

CATAWBA - UNITS-1 & 2 3/4 7-15

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l ATTACHMENT II TECHNICAL JUSTIFICATION AND. SAFETY ANALYSIS l The OPERABILITY of the Control Room Area Ventilation System ensures that: (1) the l ambient air temperature does not exceed the allowable temperature for continuous-duty rating for the equipment and instrumentation cooled by this system, and (2) l the control room will remain habitable for operations personnel during and following all credible accident conditions. Technical Specification 4.7.6, Control Room Area Ventilation System Surveillance Requirements, ensures that the System remains operable as required.

Proposed Technical Specification 4.7.6.d seeks to extend the Control Room Ventilation System Carbon adsorber sample time interval from 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> to 1440 hours0.0167 days <br />0.4 hours <br />0.00238 weeks <br />5.4792e-4 months <br /> because existing requirements are overly restrictive. Catawba Nuclear Station is equipped with state-of-the-art Control Room Ventilation System Carbon adsorbers which retain very high efficiencies over prolonged intervals of j operation. Laboratory data supports the high efficiency of the Carbon adsorbers.

Therefore, it is reasonable and justifiable to extend the carbon adsorber sample time interval as indicated in the proposed Technical Specification.

Existing Technical Specification 4.7.6.d indicates that each Control Room Area Ventilation System is to be demonstrated operable after every 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> (30 days) of carbon adsorber operation by verifying within 31 days after removal that a .

laboratory analysis of a representative carbon sample meets the laboratory testing criteria of Regulatory Position C.6.b of Regulatory Guide 1.52, Revision 2, March 1078, for a methyl iodide penetration of less than 1%. The filter units l in service at Catawba Nuclear Station currently have no bypass mode. Therefore, either A train (1CRA-PFT-1) or B train (2CRA-PFT-1) must operate in the filtered mode continuously. This design configuration allows one unit to run continuously for 30 days before a sample must be removed.

Each filter unit is initially provided with six installed sample canisters. If one canister is removed every 30 days (one canister from each unit is removed every 2 months) the samples would be depleted after one year. The removed canisters are to be reloaded and reinstalled in the filter unit. Renoval of the i cover from the carbon bed jeopardizes Unit integrity and a refrigerant penetration leak rate test is required on the carbon bed whenever the cover is removed. This results in the Technical Specification 4.7.6.e surveillance test interval being reduced from the normal 18 canth to one year or less. Therefore the existing sampling interval is overly restrictive and results in excessive sampling of the Control Room pressurizing filter units. Proposed Technical Specification 4.7.6.d would allow for a normal 18 month surveillance test interval (as required by existing Technical Specification 4.7.6.e) by extending the Technical Specification 4.7.6.d sample interval from 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> to 1440 hours0.0167 days <br />0.4 hours <br />0.00238 weeks <br />5.4792e-4 months <br />.

Historical data supports the proposed Technical Specification 4.7.6.d sampling j interval of 1440 hours0.0167 days <br />0.4 hours <br />0.00238 weeks <br />5.4792e-4 months <br />. Laboratory sample analysis results for filter units j 1CRA-PFT-1 and 2CRA-PFT-1 show that over the course of one year and more than '

4,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> of run time per unit covering typical atmospheric and seasonal metheorologica conditions, there was no noticeable degradation in the methyl l iodine efficiency of the carbon. The sample results ranged from 99.98% to 99.95% l efficiency for 1CRA-PFT-1 and from 99.99% to 99.90% efficiency for PCRA-PFT-1. l Therefore, the proposed extension of the Technical Specification 4.7.6.d sample interval is justifiable due to the high efficiency of the carbon in 1CRA-PFT-1 and 2CRA-PFT-1 and their ability to retain their efficiency over the course of L - - --__ _________________ _ _ _

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TECHNICAL JUSTIFICATION AND SAFETY ANALYSIS (Continued) l prolonged operation as shown by the subject laboratory sample results.

The air flow rate through 1CRA-PFT-1 and 2CRA-PFT-2 is 6,000 cubic feet per minute (CFM) of which 4,000 cfm is outside air and 2,000 is recirculated Control Room area air. Since Catawba Nuclear Station is located in a rural environment, away from any major industrial plants, the outside air is essentially clean and free of any industrial pollutants. Therefore, circulation of outside air through the filter units has no detrimental effect on the efficiency of the carbon. This phenomena is demonstrated by Catawba's carbon analyses results from the start of plant operation.

Additionally, the carbon utilized at Catawba Nuclear Station is activated and )

impregnated with Triethylenediamine (TEDA). This type of carboa is a state-of-the-art material which results in high methyl iodide efficiency as shown by laboratory analysis of the samples. The 720 hour0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> run time interval recommended by Regulatory Guide 1.52 is an arbitrary value applying to activated carbon.

Since Catawba's carbon is activated and impregnated with TEDA, the methyl iodide efficiency has been increased substantially. 3 In summary, the control Room Ventilation System carbon adsorbers have been proven

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to maintain very high levels of Methyl Iodide efficiency under extended operation conditions. Laboratory analysis of carbon samples indicate that extending the sampling interval to 1440 hours0.0167 days <br />0.4 hours <br />0.00238 weeks <br />5.4792e-4 months <br /> has an insignificant effect on the efficiency of the adsorbers. Also, outside air circulated through the adsorbers is of high quality and would not impact the efficiency of the adsorbers even if sampling intervals are extended. Therefore, the proposed change to Technical Specification 4.7.6.d is reasonable and technically justifiable.

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ATYACRIENT III ANALYSIS OF NO SIGNIFICANT HAZARDS 1 'i pursuant to 10 CFR 50.92, this analyses provides a determination that the-proposed amendment to the Technical Specifications involves no significant ,

i hazards considerations if operation in accordance with the proposed amendment '

would not:

(1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) Create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) Involve a significant reduction in a margin of safety.

The proposed amendment does not involve a significant increase in the probability i or consequences of any previously evaluated accident. Catawba Nuclear Station is equipped with state-of-the-art Control Room Ventilation System Carbon adsorbers which retain very high Methyl Iodide efficiencies over prolonged intervals of operation. previous laboratory analysis results indicate that over the course of

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one year and more than 4,000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> of runtime covering typical atmospheric and seasonal conditions, there is no noticeable degradation in the methyl iodide efficiency of the adsorber and that the carbon is perfectly capable of extended operation. Increasing the Technical Specification 4.7.6.4 sample time intervals I to 1440 hours0.0167 days <br />0.4 hours <br />0.00238 weeks <br />5.4792e-4 months <br /> has no significant impact to the efficiency of the carbon adsorbers J and Control Room Area Ventilation System operability. Therefore, the. proposed 1 change cannot increase the probability or consequences of any previously evaluated accident.

The proposed amendment.does-not create the possibility of a new or different kind of accident from any accident previously evaluated. The proposed increase cf Tecnnical Specification 4.7.6.d sample time intervals to 1440 hours0.0167 days <br />0.4 hours <br />0.00238 weeks <br />5.4792e-4 months <br /> has no effect on the function, operation, or efficiency of the Control Room Area Ventilation l

System. Therefore the proposed Technical Specification change cannot create the  !

possibility of a new or different kind of accident from any accident previously  !

evaluated.

1 The proposed amendment does not involve a significant reduction in a margin of safety. As it was previously indicated, the Catawba Nuclear Station Control Room Ventilation System Carbon adsorbers are capable of extended operation without any significant reduction in their Methyl Iodide removal efficiency. previous laboratory carbon sample analysis results indicate that the proposed carbon adsorber sampling interval of 1440 hours0.0167 days <br />0.4 hours <br />0.00238 weeks <br />5.4792e-4 months <br /> will not reduce the efficiency of the Control Room Ventilation System in any significant manner. Thorefore, the proposed Technical Specification does not involve a significant reduction in a margin of safety.

The commission has provided guidance concerning the application of the standards for determining whether a significant hazards consideration exists by providing examples of amendments that are considered not likely to involve a-significant hazards consideration (Federal Register, Vol. 48, No. 67, pg 14870). Example (iv) involves "A relief granted upon demonstration of acceptable operation from an operating restriction that was imposed because acceptable operation was not yet demonstrated". The proposed extension of the Technical Specification 4.7.6.d

ANALYSIS OF NO SIGNIFICANT HAZARDS (Continued)

I carbon adsorber sampling interval to 1440 hours0.0167 days <br />0.4 hours <br />0.00238 weeks <br />5.4792e-4 months <br /> is similar to Commission Example (iv). The proposed extension in the sampling interval is justifiable because previous operation of the Control Room Ventilation System indicates that the 1440 hours0.0167 days <br />0.4 hours <br />0.00238 weeks <br />5.4792e-4 months <br /> sampling frequency is reasonable and acceptable. Similarly, Example (vi) involves "a change which either may result in some increase to the probability or consequences of a previously-analyzed accident or may reduce in some way a safety margin but where the results of the change are clearly within all acceptable criteria with respect to the system or component...". The proposed increase of the sampling interval to 1440 hours0.0167 days <br />0.4 hours <br />0.00238 weeks <br />5.4792e-4 months <br /> will not significantly increase the probability or consequences of a previously-analyzed accident. The proposed change will result in an insignificant decrease in the Methyl Iodine efficiency of the carbon adsorbers. Any reduction in a margin of safety will be j insignificant as well. Therefore, the proposed Technical Specification change l clearly resembles commission examples (iv) and (vi) and does not involve significant hazards considerations.

Based on the preceding analysis, Duke Power Company has concluded that the proposed amendment does not involve significant hazards considerations.

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