ML20235B832

Proposed Tech Specs,Consisting of Changes to Control Room Technical Support Ctr Essential Filtering Sys

ML20235B832
Person / Time
Site:	Rancho Seco
Issue date:	06/29/1987
From:	SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:
Shared Package
ML20235B802	List: ML20235B801 ML20235B832
References
TAC-65732, NUDOCS 8707090216
Download: ML20235B832 (14)

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ATTACHMENT I RANCHO SECO TECHNICAL SPECIFICATIONS (Pages affected by Proposed Amendment No. 161) 8707090216 070629 PDR P

ADDCK 05000312 PDR

RANCHO SECO UNIT 1 TECHNICAL SPECIFICATIONS Surveillance Standards 4.10 CONTROL ROOM / TECHNICAL SUPPORT CENTER EMERGENCY FILTERING SYSTEM Applicability Applies to the Contral Room /TSC Emergency Filtering System and related

-components.

Objective To verify that this system and its components will'be able to perform their design functions.

Specification I

'4.10.1 The Control Room /TSC Emergency Filtering System shall be:

A. Demonstrated operable at least once per 31 days by initiating flow through the HEPA filters and charcoal adsorbers.

B. Demonstrated operable at least once per refueling interval, or once every 18 months, whichever occurs first, or after each partial ~ or complete replacement of the HEPA filter bank or charcoal adsorber bank, or following painting, fire, or chemical release in the operating air makeup system, or af ter any structural maintenance on the HEPA filter or charcoal adsorber housings, by:

1. Verifying that the charcoal adsorbers remove > 99.5 percent of a halogenated hydrocarbon refrigerant test gas when they are tested in-place in accordance with ANSI N510 while 161> operating the filter train at a stabilized flow rate of at least 2880 CFM but no greater than 3520 CFM (Make up air

< flow rate shall not exceed 1760 CFM). 1

2. Verifying that the HEPA filter banks remove > 99.9 percent of the DOP when they are tested in-place in accUrdance with ANSI 161> N510 while operating the filter train at stabilized flow rate l of at least 2880 CFM but no greater than 3520 CFM (Make

< up air flow rate shall not exceed 1760 CFM).

3. Verifying within 31 days after removal that a laboratory analysis of a carbon sample from either at least one test canister or carbon sample removed from one of the charcoal adsorbers demonstrates a removal efficiency of >95 percent for radioactive methyl iodide when the sample is tested in accordance with ASTM D3803 (30*C, 95% R.H.). The carbon samples not obtained from test canisters shall be prepared by either:

Proposed Amendment No. 161 4-41 1

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RANCHO SECO UNIT 1 TECHNICAL SPECIFICATIONS

-Specification -(Continued) Surveillance Standards 4.10.1 B. 3. (a) Emptying one entire bed from a removed-adsorber tray, mixing the adsorbent thoroughly, and obtaining samples at least two inches in diameter and with a length equal to the thickness of the bed.

(b) Emptying a longitudinal sample from an adsorber tray, mixing the adsorbent thoroughly, and obtaining samples at least two inches in diameter and with a length equal to the thickness of the bed.

4. Verifying that the pressure drop across the combined HEPA filters, and charcoal adsorber banks is <6 inches Water 161> Gauge while operating the filter train at a stabilized flow rate of at least 2880 CFM but no greater than 3520 CFM (Make up air flow rate shall not exceed 1760 CFM).

5. Verifying the air makeup system maintains the Control .

Room /TSC at a positive pressure of >0.125 inches W.G.  !

relative to the outside atmosphere with a stabilized make up 1 air flow rate no greater than 1760 CFM.

6. Verifying a stabilized flow rate thru the essential filtration unit of at least 2880 CFM but no greater than 3520 CFM while operating in the radiological mode when

< tested in accordance with ANSI N510 C. Demonstrated operable after every 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> of charcoal adsorber operation by:  ;

1. Verifying within 31 days'after removal that a laboratory analysis of a carbon sample from either at least one test canister or carbon sample removed from one of the charcoal adsorbers demonstrates a. removal efficiency of >95 percent

'for radioactive methyl iodide when the sample is tested in accordance with ASTM D3803 (30*C, 95% R.H.). Carbon samples not obtained from test canisters shall be prepared by either:

(a) Emptying one entire bed from a removed adsorber tray, mixing the adsorbent thoroughly, and obtaining samples at least two inches in diameter and with a length equal to the thickness of the bed or,

[

(b) Emptying a longitudinal sample from an adsorber tray, mixing the adsorbent thoroughly, and obtaining samples at least two inches in diameter and with a length equal to the thickness of the bed.

1 Proposed Amenjment No. 161 l- 4-41a I i

RANCHO SECO UNIT 1 TECHNICAL SPECIFICATIONS Surveillance Standards-Specification (Continued) 4.10.1' C. 2. After reinstallation of the sampled adsorber tray, per C.1:

(a) Verify that the charcoal adsorbers remove >99.5 percent of a halogenated hydrocarbon refrigerant test gas when they are tested in-place in accordance with ANSI N510 161> while operating the filter train at a stabilized flow rate of at least 2880 CFM but no greater than 3520 CFM.

(b) Verify that the HEPA filter bank removes >99.9 percent of the DOP when tested in-place in accordince with ANSI 161> N510 while operating the filter train at a stabilized flow rate of at least 2880 CFM but no greater than 3520

< CFM.

D. Started on a manual signal and operated for 15 minutes in each 31-day period.

161> E. Demonstrated operable at least once per refueling interval or once.every 18 months, whichever occurs first, by:

1. Verifying that on a high radiation signal, the normal system is automatically isolated and that the emergency filtering system operates.

2. Verifying that on a toxic gas (ammonia excluded) isolation signal, the system automatically switche, into the isolation mode of operation with flow through the HEPA filters and charcoal adsorber banks.

3. Verifying that the refrigerant system will maintain the Control Room / Technical Support Center temperature at no more

< than 80 F for at least 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.

Bases The purpose of the Control Room /TSC Emergency Filtering System is to limit the particulate and gaseous fission products and toxic products to which the Control Room area and Technical Support Center would be subjected during an accidental radioactive or chemical release in or near the Auxiliary Building.

The system is designed with two redundant filter trains each of which consists of a moisture separator, a heater, a high efficiency particulate filter, two  :

banks of charcoal filters, a second high efficiency particulate filter and a  ;

booster fan to pressurize the Control Room and Technical Support Center with i 161> outside air. The prestabilized air flow rate will not exceed 3750 CFM during 4 the 15 minutes preceding stabilized air flow.

Proposed Amendment No. 161 4-41b

RANCHO SECO UNIT 1 TECHNICAL SPECIFICATIONS Surveillance Standards Specification (Continued)

Since th'is system is not normally operated, a periodic test is required to l ensure its operability when needed. Monthly testing of this system will i show that the system is available for its designed safety action. During  ;

this test the system will be observed for unusual or excessive noise or i 161>< vibration when the fan motors are running. The flow of 1760 cfm makeup air was selected to limit the maximum radiation dose to occupants of the Control 161> Room /TSC in an accident. For this analysis, each 2-inch charcoal filter was conservatively assumed to provide a DF of 10 for iodine ba' sed on laboratory analysis showing >95 percent removal of radioactive methyl iodide. The aggregate 4-inch charcoal depth of the two beds in series provides an overall fodine DF of 100. The HEPA filter is assumed to provide a DF of 100 for

< particulates.

Refueling interval testing will verify the methyl iodide removal efficiency of the charcoal and the amount of leakage past the charcoal and HEPA filters are at least equal to the design values.

161> The Essential Filtering System is automatically started and the Normal System isolated when the radiation level in the vicinity of the outside air intakes for the Control Room /TSC Normal Air Conditioning System increases to a predetermined level or when chlorine concentration in the tank farm

< atmosphere increases.

The testing required after painting, fire or chemical release, is not to be interpreted to include minor touch-up painting, housekeeping chemicals and detergents, or other routine maintenance or housekeeping activities.

1 Proposed Amendment No.161 4-41c

ATTACHMENT II FACILITY CHANGE SAFETY ANALYSIS PAGE 1 0F 7 PROPOSED AMENDMENT NO.161 DESCRIPTION:  ;

Proposed Amendment No.161 makes four changes to the Control Room / Technical Support Center Essential Filtering System (Technical Specifications ,

Surveillance Standards Section 4.10) Specifications and two changes to the Bases. These changes include:

1) specify high and low air flow rate limits in cfm for in-place filter leak testing, filter leak pressure drop monitoring, and flow rate measurement of the Essential Air Filtration unit, !I

2) specify the maximum makeup air flow rate in cfm of the Essential Air Filtration unit,

3) modify the requirements for demonstration of system actuation / isolation by "high radiation" or " toxic gas" signals,  ;

4) incorporate a requirement to verify that the system maintains the '{

required temperature in the CR/TSC, j

5) revise the Bases paragraph which describes the decontamination factor of the charcoal filters, and

6) revise the Bases paragraph which describes the automatic initiation of the' system.

REASON FOR CHANGE:

Purpose The first proposed change specifies high and low limits for flow through the Essential Filtering System filter trains for stabilized operating conditions.

The flow rate limits are stated in engineering units (CFM) which are consistent with the units of the specific parameter.

A second change specifies the maximum makeup air flow rate. This limits radiation exposure to personnel and avoids control room /TSC overpressurization caused by greater than necessary air flow rates. Previously, only a nominal flow rate was specified in Technical Specifications.

Previously, Technical Specifications required the demonstration of the operability of the system, and the automatic initiation capability of the system following: 1) replacement of, or maintenance on, the HEPA filter bank or charcoal absorber bank, or 2) a fire, painting, or chemical release in the operating air makeup system. Actuation of the system because of high radiation or toxic gas is not affected by any of these events. The third proposed change deletes the present requirement to test the actuation of the system following any of these listed occurrences.

ATTACHMENT II (Cont.)

FACILITY CHANGE SAFETY ANALYSIS PAGE 2 0F 7 PROPOSED AMENDMENT NO. 161 Purpose (Cont.)

The fourth proposed change introduces a requirement to verify that the system maintains the required temperature in the CR/TSC to ensure a proper thermal environment.

The fifth proposed change is to the Bases and clarifies the discussion on the decontamination factor for the charcoal filters. This change eliminates confusion on the origin of the 95% figure for removal of radioactive iodide.

The final proposed change is to the Bases and provides a description of the radiological and toxic gas events which cause automatic actuation and isolation of the system. The reference to initiation of train B upon receipt of an SFAS signal is removed. This clarifies the conditions that initiate CR/TSC Essential Filtering System operation.

EVALUATION AND BASIS FOR SAFETY FINDINGS:

Systems, Subsystems, Components Affected Proposed Technical Specification Amendment No.161 affects the Control Room / Technical Support Center Essential Filtering System.

The essential HVAC units are environmentally qualified to IEEE 323/344. The air handling units and ducting are Quality Class I and Seismic Category I.

Safety Function of Affected Systems / Components The safety function of the CR/TSC Essential Filtering System is to provide a suitable environment for operating equipment and for personnel comfort and sa fety. The affected areas are the Control Room, Computer Room, and Technical Support Center. The CR/TSC Essential Filtering System was installed to satisfy the habitability requirements outlined in NUREG-0737, " Clarification of TMI Action Plan Requirements," item III.D.3.4, and NUREG-0696, " Functional Criteria for Emergency Response Facilities," item 2.6. The system was designed in accordence with Reg. Guide 1.52, Design, Testing, and Maintenance Criteria for Post-Accident ESF Atmosphere Cleanup System. The CR/TSC Essential Filtering System is required for safe shutdown.

The Control Room is served by two separate and independent, low pressure air-conditioning systems. One system serves under normal operating conditions, while the CR/TSC Essential Filtering System operates under emergency conditions following an accident. The motorized dampers of the normal ventilation system close automatically on indication of high radiation or chlorina gas. The Essential Filtering System isolation dampers automatically open and the system actuates upon a high radiation signal.

Filtered outside air is provided by the Essential Filtering System to maintain a positive pressure. Upon detection of chlorine gas, the Essential Filtering

7 A1TACHMENT II (Cont.)

FACILITY CHANGE SAFETY ANALYSIS PAGE 3 0F 7 ;

PROPOSED AMENDMENT NO. 161 Safety Function of Affected Systems / Components (Conte )

System actuates, but the outside air dampers of both the normal ventilation system and the Essential Filtering System automatically close and the entire <

flow through the Essential HVAC Filtering System consists of recirculation air. The system also auto-actuates on high control room temperature.

Initiation of emergency ventilation provides adequate protection for plant .'

personnel in the Control Room, Computer Room, and TSC.

The Essential Filtering System, as described in USAR Section 9.7.3.1. A and Table 9.7-1, consists of redundant ventilation systems (see figure). One operating essential system recirculates Control Room air at 16,950 cfm.

Approximately 3200 cfm is passed through the CR/TSC Essential Filters Train.

Part of the air passing through the CR/TSC Essential Filters is recirculated control room air, while the remainder (approximately 1600 cfm) is fresh outside air. The addition of outside air maintains a positive pressure of 1/8-inches of water (with respect to adjoining areas) in the Control Room and TSC at all times during radiological events.

The CR/TSC Essential Filtering system is also addressed in Section 3.13 of Rancho Seco Technical Specifications.

Effect on Safety Functions Amendment 70 of the Technical Specifications stated in several places that the flow rate for the CR/TSC Essential Filter Train is 3200 cfm + 10%. Proposed Amendment 161 changes this range of flows to specific high and low limits with the same engineering units. These limits (3520/2880 cfm) are equal to the flow range stated previously (3200 cfm + 10%). This is an administrative change that has no effect on the safety function of the CR/TSC Essential Filtering System.

Amendment 70 of the Technical Specifications stated that the flow rate of 3200 cfm + 10%, which was discussed in the preceding paragraph, is composed of the nominal flowrates of 1600 cfm makeup air plus 1600 cfm recirculated air.

Proposed Amendment No.161 places a maximum limit of 1760 cfm on the makeup flow rate. This figure is equal to the previous 1600 cfm nominal flow rate + {

10%. This maximum permissible flowrate limits the radiation dose to the occupants of the CR/TSC in the event of an accident. It also prevents overpressurization of the Control Room / Technical Support Center. This change {

enhances the ability of the system to prevent overpressurization of the control room, places a specific limit on a nominal parameter, and enhances the safety function of the CR/TSC Essential Filtering System.

Previously, Technical Specifications required the demonstration of the operability of the system, and the automatic initiation capability of the system following: 1) replacement af, or maintenance on, the HEPA filter bank or charcoal absorber bank, or 2) a fire, painting, or chemical release in the operating air mckeup system. None of the listed events affects the capability

ATTACHMENT II (Cont.)

FACILITY CHANGE SAFETY ANALYSIS PAGE 4 0F 7-PROPOSED AMENDMENT NO.161 Effect on Safety Functions (Cont.)

of the Essential Filtering System to automatically initiate or isolate upon receipt of a high radiation or toxic gas signal. Proposed Amendment 161 removes the requirement to unnecessarily test the automatic initiation of the system following any of these events. The proposed amendment does retain the requirement to test the initiation of the system once per refueling cycle or -

every 18 months, whichever comes first. This is an administrative change which has no effect on the safety function of the CR/TSC Essential Filtering

. System.

The fourth change in Proposed Amendment No.161 incorporates a ' requirement for verification that the system will maintain the CR/TSC temperature at no more than 800F for at least 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. 800F is the maximum temperature allowed in the Control Room / Technical Support Center environment, as stated in Section 9.7.1.2, Auxiliary and Administrative Buildings, of the USAR. This is an enhancement to the surveillance standards, 'and the requirement for

. verification of this capability is an operational enhancement to the CR/TSC Essential Filtering System.

The fifth change clarifies the discussion on the DF of the charcoal filters.

The wording in the original Technical Specifications. ( Amendment 70) promoted confusion as to what the total DF is for radioactive iodide for each HVAC train. The Proposed Amendment states that the DF for each charcoal bed is 10, and that the aggregate depth of 4 inches of charcoal (for each train) provides an overall DF of 100. This is an administrative clarification only, and has no effect on the function of the CR/TSC Essential Filtering System.

The. final change incorporated into Technical Specifications by Proposed Amendment No.161 is a change to the Bases >aragraph which discusses the automatic initiation of the system. TEclange deletes the reference to an .

SFAS-related automatic start. Presently, 'B' train of the CR/TSC Essential I Filtering System is sequenced on its electrical bus and started six minutes after receipt of an SFAS signal. This is performed to ensure that unexpected i bus loading does not exceed the capacity of the bus. With the additional capacity of.the TDI diesels, the necessity of starting one train of the CR/TSC Essential Filtering System will no longer exist. Upon receipt of an SFAS signal, the systems (A and B trains) will be sequenced on their res buses, but will not start until a further permissive start signal (pective high i radiation, toxic gas, CR temperature) is received. This change does not affect the functionality of the CR/TSC Essential Filtering System but reflects the added electrical capacity of the TDI diesels. It has no effect on the I safety function of the Essential HVAC System. Additionally, Proposed I Amendment No.161 specifies the physical areas where a radiation or chlorine increase can be detected and initiate the operation and isolation of the CR/TSC Essential Filtering System. This is a clarification to the Bases and 1 does not affect the safety function of the system. {

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FACILITY CHANGE SAFETY ANALYSIS PAGE 5 0F 7 PROPOSED AMENDMENT NO.161 Analysis of Effects on Safety Functions The conversion of the flowrate "3200 cfm + 10%" into high and low ifmits of 3520 cfm and 2880 cfm, respectively, is an administrative change only, and has no effects on any safety function. The stated high and . low limits are equivalent to the present values of 3200 cfm + 10% and 3200 cfm - 10%. The new limits, however, are for stabilized flow. Testing has shown flow to stabilize within approximately 8 minutes of system initiation. Maximum flow during this period should not exceed 3750 cfm. Using these figures, calculations (Z-ZZZ-M1305) show that this added flow will contribute an additional integrated thyroid dose of 0.4 Rem over the 30-day post-accident period. A Control Room habitability study (Revision 4, April 22,1985) has determined that, with a nominal makeup flowrate, the resultant expnsure received would be 13.4 Rem to the thyroid and 2.4 Rem to the whole body (Table 6-3, Calculated Control Room Operator Radiatfon Exposure from All Sources).

This is well under the maximum permissible dose allowed by 10 CFR 50, Appendix A, Criterion 19 (5 Rem whole body). This unstabilized flow will result in an approximately 3% increased dose received prior to the stabilization of air flow. It is well within regulatory limits and does not affect nuclear safety.

The specification of a maximum makeup air flowrate (1760 cfm) limits the amount of radiation dose to the occupants of the CR/TSC in the event of an accident. 1760 cfm is equivalent to the presently stated nominal flowrate (1600 cfm) plus 10%. Any increased dose received from the maximum flowrate of 1760 cfm in the event of an accident (.8 Rem thyroid, approximately a 6%

increase) is well within regulatory limits (Criterion 19, above) and does not affect nuclear safety (calculation Z-ZZZ-M1305). Makeup air flow maintains a positive pressure within the CR/TSC envelope. This proposed change (which also deletes any lower limit on makeup air flowrate) allows full adjustment of makeup air flowrate to maintain a 1/8" watergauge pressure in the CR/TSC and to avoid overpressurization. The lower level of makeup air flow is bounded by the necessity to maintain this positive pressure as stated in Section 4.10.1.B.7 of Technical Specifications.

Additionally, both CR/TSC Essential HVAC trains could actuate simultaneously on independent high radiation signals from the nonnal HVAC intake radiation monitors R-15701 and R-15702. Operating procedures presently state that if both trains are initiated by automatic signal, one train should be secured.

However, even in the event both trains run continuously, the 30 day integrated dose would not exceed 5 Rem whole body and 30 Rem thyroid, as required by 10 CFR 50, Appendix A, Criteria 19.

A demonstration of the capability of the system to automatically initiate is presently required following maintenance, painting, a fire, or chemical release, even though these events do not affect the initiation or isolation of the system due to high radiation or toxic gas. This proposed amendment deletes this requirement but retains the requirement to verify the auto initiation capability every 18 months or fuel load, whichever comes first.

This change does not affect nuclear safety.

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ATTACHMENT II (Cont.)

FACILITY CHANGE SAFETY ANALYSIS PAGE 6 0F 7 PROPOSED AMENDMENT N0.161 ,

Analysis of Effects on Safety Functions (Cont.)

The present Technical Specification does not specify any requirements to verify the system's capability to maintain a suitable thermal environment in the Control Room or TSC. This proposed amendment includes the requirement to demonstrate the capability of the system to maintain the temperature in the control room at no more than 800F for eight hours. This temperature is given in USAR Section 9.7.1.2 as the maximum inside temperature to be maintained in the Control Room /TSC area of the Auxiliary Building by Essential HVAC system.

This addition enhances the verification of the operability of the system.

The proposed change to the Bases for Technical Specifications Section 4.10, addresses the causes of automatic initiation of the CR/TSC Essential Filtering System. In the Bases, the amendment specifies the location of the radiation (vicinity of the outside air intakes for the CR/TSC normal ventilation) or toxic gas (tank farm atmosphere) which initiates or isolates the system. This clarifies the events which initiate / isolate the CR/TSC Essential Filtering System.

Additionally, the proposed amendment deletes the reference to automatic initiation of ventilation train B upon receipt of an SFAS signal and loss of offsite power. Presently, during an SFAS and a loss of offsite power, the 'B' train of the Essential HVAC equipment is sequenced to automatically start six minutes after the SFAS. Train 'A' can be manually started, as necessary, after all essential loads on its electrical bus had automatically started. It is necessary to start the system to ensure that all essential loads are properly sequenced onto the bus; there is not enough electrical capacity to handle an untcheduled start of the Essential Filtration System due to CR temperature, radioactivity, or chlorine gas. With the addition of the TDI diesels, the auto starting of the CR/TSC Essential Filtering System 'B' train will no longer be necessary. Calculations show (Z-EDS-E0648) that in a worst i case situation, in which a train of the Essential Filtering System starts '

concurrently with the last load to be sequenced on its respective bus, sufficient electrical capacity will be available to provide necessary power (ref. calc. L-EDS-E0667). This change meets the requirements of Reg. Guide 1.52, Desi t,n, Terting, and Maintenance Criteria for Atmospheric Cleanup Systems, and has no effect on the safety function of the system. A separate ECN ( A-36602) is developed to remove the SFAS auto-start feature from the system.

Summary Proposed Amendment No.161 makes four changes to the Specification section and two changes to the Bases section of Technical Specification Surveillance Standards section 4.10, Control Room / Technical Support Center Essential Filtering System. The system's air handling units and ducting are Quality Class I and Seismic Category I. The CR/TSC Essential Filtration system is

ATTACHMENT II (Cont.)

FACILITY CHANGE. SAFETY ANALYSIS PAGE 7 0F 7 PROPOSED AMENDMENT NO. 161 Summary - (Cont. )

designed in accordance with Reg. Guide.l.52, Design, Testing, and Maintenance Criteria for Post-Accident ESF Atmospheric Cleanup System. The system satisfies the habitability requirements outlined in NUREG-0696 and NUREG-0737.

The proposed amendment affects the amount of makeup air flow discussed in Section 9.7.3.1. A of the USAR, and thereby is a change to the facility as i described in the USAR. No new failure modes are introduced as a result of these changes, and there are no effects on the safety functions of the CR/TSC Essential Filtering System. The potential increase in dose to the personnel in the Control Room incorporates the " worst-case" situation and results in a i total integrated dose of less than one-half that allowed by the 10 CFR 50, Appendix A, Criterion 19. Therefore, there is no decrease in nuclear safety.

The proposed amendment does not increase the probability of occurrence or consequences of a previously evaluated accident since the functionality of the system, and'11miting flowrates, have not been altered, merely restated in engineering terms.

The probability of 'an accident of a different type than previously evaluated is not created since the functions of the system have not been changed. The auto-start signal in the event of an SFAS and loss of offsite power was an electrical consideration which is no longer a necessity.

The proposed amendment does not reduce the margin of safety as defined in Technical Specifications since the amendment adds a surveillance requirement which ensures the capability of the system to maintain a suitable thermal environment.  ;

1 Therefore, an Unreviewed Safety QuestioJ) is not involved. l j

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AiTACHMENT III NO SIGNIFICANT HAZARDS CONSIDERATIONS PAGE 1 0F 2 Proposed. Amendment No.161 consists of four changes to the Control Room / Technical Support Center Essential filtering System (Technical Specifications Surveillance Standards Section 4.10) Specifications and one change to the Bases. -These changes include:

1. specifying high and low air flow rate limits in cfm for in-place filter i leak testing,' filter leak pressure drop monitoring, and flow rate I measurement of the Essential Air filtration unit,

2. specifying the maximum makeup flow rate in cfm of the Essential Air j

. Filtration unit, 1

3. ' modifying the. requirements for demonstration of system actuation / isolation  ;

by "high radiation" or " toxic gas" signals, j I

4. incorporating a requirement to verify that the system maintains the l required temperature in the CR/TSC, and

.l S. revising the Bases paragraph which describes the automatic initiation of the system.

Amendment.70 of the Technical Specifications stated in several piaces that the flow rate for the CR/TSC Essential Filter Train is 3200 cfm i 10%. Proposed Amendment 161 changes this range of flows to specific high and lcw limits with the_same engineering units. The limitt (3520/2880 cfm) are equal:to the flow range stated-previously (3200 cfm i 10%). This is an administrative change that has no effect on the safety function of the CR/TSC Essential Filtering System. 4 Amendment 70 of the Technical Specifications stated that the flow rate of 3200 CFM i 10%, which was discussed in the preceding paragraph, is composed of the nominal flowrates of 1600 cfm makeup air plus 1600 cfm recirculate air.

Proposed Amendment No.161 places a maximum limit of 1760 cfm on the makeup flow rate. This figure is equal ~to the previous 1600 cfm nominal' flow rate +

10%.. This maximum permissible flowrate limits the radiation dose to the occupants of the CR/TSC in the event of an accident. It also prevents overpressurization of the Control Room / Technical Support Center. This change enhances the ability of the system to prevent overpressurization of the control room, places a specific limit on a nominal parameter, and enhances the safety function of the CR/TSC Essential filtering System.

Proposed Amendment 161 also removes the requirement to unnecessarily test the automatic initiation of the system following any of these events. The proposed amendment.does retain the requirement to test the initiation of the system once per refueling cycle or every 18 months, whichever comes first. This is an administrative change which has no effect on the safety function of the CR/TSC Essential Filtering system.

PAGE 2 of 2 The District has reviewed the above proposed changes against each of the criterion of 10 CFR 50.92 and concluded that the changes to the Technical Specifications would not:

a. involve a significant increase in the probability or consequences of an accident previously evaluated. The proposed amendment does not increase the probability of occurrence of consequences of a previously evaluated accident since the functionality of the system, and limiting flowrates, have not been altered, merely restated in engineering terms.

b. create the possibility of a new or different kind of accident from any previously analyzed since the functions of the system have not changed.

The auto-start signal in the event of a Safety Features Actuation signal and loss of offsite power was an electrical consideration that no longer applies.

c. involve a significant reduction in a margin of safety. The proposed amendment does not reduce the margin of safety as defined in Technical Specifications since the amendment adds a surveillance requirement which ensures the capability of the system to maintain a suitable thermal environment.

On the basis of the above, the District concludes that the proposed changes do not constitute any significant hazards to the public, and in no way endangers the public's health and safety.