ML19344E018
| ML19344E018 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 08/18/1980 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | Schwencer A Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0588, RTR-NUREG-588 NUDOCS 8008260523 | |
| Download: ML19344E018 (9) | |
Text
4 TENNESSEE VALLEY AUTHORITY CH ATT ANCOG A. TENNEGSEE 37401 400 Chestnut Street Tower II August 18, 1980 Director of Nuclear Reactor Regulation Attention:
Mr. A. Schwencer, Chief Licensing Branch No. 2 Division of Licensing U.S. Nuclear Regulatory Commission Washington, DC 20555
Dear Mr. Schwencer:
In the Matter of the Application of
)
Docket Nos. 50-327 Tennessee Valley Authority
)
50-328
Reference:
1.
Letter'from L. M. Mills to A. Schwencer dated June 16, 1980 2.
Letter from L. M. Mills to A. Schwencer dated July 28, 1980 i
3.
Letter from L. M. Mills to A. Schwencer dated August 11, 1980 In TVA's response to NUREG-0588 for Sequoyah Nuclear Plant, references 1 and 2, TVA identified several items which lacked sufficient environ-mental qualification documentation. Enclosed is a revision to the safety justification submittal, reference 3, as requested by the NRC reviewer. The revision provides additional detail concerning the safety review for each item.
Very truly yours, TENNESSEE VALLEY AUTHORITY l\\.
L. M. Mills, Man er Nuclear Regulation and Safety i
Enclosure t
8008260jg pt 3 m:om,.wm
0 ENCLOSURE NCR Equip =ent Affected Action Required for Resolutien SCNEEB8003 Foxboro Pressure Trans-Transmitters have been replaced
=itters in Main Steam with qualified equipment.
Jalve Rec =s SONEEB8004 Miscellaneous Class lE Our evaluation of the equipment covered Equi;=ent in Main Steam by this NCR is listed belew:
Valve Roo=s (valves, trans=itters, switches,
These MOV.'s were criginally found to have inadequate documentation to justify operation in the accident temperature enviren=ent. The vender has new analyzed the subject -
equipment for the higher temperatures and has confir=ed, by letter, that the valves under the postulated accident conditions will perform their intended function.
- 2. Solencid Valves LSV-3-174 & 175. LSV-3-174 and -175 are used for flew centrol to steam generater (SG) No.1 and SG Nc. 4 through turbine-driven auxiliary feedwater (TDAFW) headers.
Failure of these solenoids would result in one of two modes. Either the associated valve would receive air er air would be blocked resulting in valve isolation. Isolation would ce an acceptable failure. If air is being received the valve is modulating and ch sing a less desirable situatica for the faulted SG.
However, manual control of AFW is available and the valve can be isolated from the :nain centrol room.
Isolation to SG 1 and 4 is acceptable since at least TDAFW would be provided to intact SG's 2 and 3 A failure in the mode which would allow an air supply to the FCV is acceptable to take credit for operator action at 10 minutes after the event to remote r.anually close the valve to the faulted SG.
- 3. Trans=itters PT-1-1C, SC, 19C, & 26C.
PT-1-1C, -8C, -19C, and -26C are used for auxiliary centrol of atzcapheric relief valves on the main stea= headers. These PT's are caly
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lined up when control is in the auxiliary mode and are not required to operate for the accident.
- 4. PdIS-1-17 and 18. Case 1 - Failure of the PdIS causes isolation of the associated FCV's.
Consider the high energy line break (EELB) associated with SG No. 4 and a failure of motor-driven auxiliary feedwater (MDAFW) pump 1 A-A.
The result is a total loss of AFW except for the MDAFW pump 1B-B feeding the faulted SG No. 4 and intactSG #3. -
l This is unacceptable feedwater flow.
A similar situation would exist with a faulted SG No. 1 and failure of MDAFW pump 1B-B.
Case 2 - Failure of the PdIS associated does not cause isolation of the associated FCV's. PDIS-1-17 and -18 are not required since they are used to indicate and isolate breaks in the TDAFW pump room or high 1
flow in the TDAFW pump line.
Therefore, TDAFW would be available to all SG's.
Also a failed or faulty indication from the PdIS would not cause the operator to take improper action since it provides location indication only.
So for case 1, TVA is pursuing resolution of the qualification of PdIS-1-17 and -18 for this isolated case. If the "in-situ" instrument cannot be qualified, it will be replaced with a qualified component.
This item will be resolved before the plant exceeds 5 percent power.
- 5. PS-3-160A&B, 165A&B.
Case 1 - Failure of PS's cause associated LXV's to close. TDAFW to SG 1 and 4 is lost but TDAFW to SG 2 and 3 still provided as well as MDAFW to at least SG 2 or 3 Therefore, this mode is considered f
acceptable.
Case 2 - Failure of PS's do not cause l
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associated LCV's to close. The faulted 53 would receive TDAFW as well as the other SG's.
The operator can isolate flow to the faulted SG at 10 minutes. Therefore, this mode is considered acceptable.
- 6. PS-3-140B and 150B - These PS's are located in the other valve room.
A logic similar to item 5 would apply, i
S&6. The PS's.of items 5 and 6 do not provide any indication or alarm, and therefore their failure would not cause improper operator action.,
- 7. Handswitches: HS1-15B,16B,17B,18B, HS3-33B,47B,873,1003 These handswitches are used for testing purposes and are not required to operate in the accident environment.
- 8. Internal wiring (cables types CPJ, CPJJ, and PJJ) to junction boxes 3042, 3061, 3066, 3063, 3062, 3069, 2890, 2891, 2857, and 2858.
These cables were originally suspected to be not qualified for the recident environment. We have since determined, from review of vendor information, that the cables are adequately qualified.
SCNEEB8006 Wide Range Steam Transmitters have been replaced with Generator Level Trans-qualified equipment.
SQNEEB8007 Miscellaneous HVAC Information received from the equipment and EGTS Solenoid vendor confirmed that exposure to Valves temperatures somewhat higher than the solenoid qualification specifications will not result in tamediate solenoids failure. However, the effective service life of this equipment will be shcrtened.
Prior to initial criticality, TVA reviewed the solenoids identified in this NCR and replaced solenoids in the EGT and HVAC systems inside containment with qualified solenoids for maintenance considerations. The remaining solenoids
are associated with ventilation systems in the auxiliary building. In this location, the solenoids can be maintained without risking undue exposure of personnel to adverse plant conditions.
TVA will be replacing the auxiliary building solenoids with qualified solenoids. However, due to procurement lead times and installation schedules, this cannot be accomplished prior to full-power operation. We expect to have the qualified solenoids installed in the auxiliary building by January 1, 1981.
SQNEEB8008 Local Control Station This equipment was identified as Selection Switches (C-H nonconforming under the criteria type 10250T), located provided in section 2.1.6(b) of NUREG-in the following areas:
0578. The failu'e of this equipment
- 1. Vertical pipe chase EL to function in an adverse environment 653,699,690, and 714.
does not affect any associated or
- 2. Aux feedwater pump related plant safety function.
turbine room EL 690.
The' efore, this equipment, using
- 3. RHR heat exchanger NUREG-0588 guidelines, meets category room EL 690 "C" requirements.
- 4. Gas stripper room EL 669
- 5. RHR pump room EL 653 SQNEEB8009 Pressure Switches (tag Unqualified components have been Nos. PS-30-46A & B, replaced with qualified components.
-47A & B, and -48A & B)
SQNEEB8010 Class 1E motors:
Preliminary vendor test data in addition to analysis by TVA provides Emergency Gas Treatment justification for continued plant Air Handling Unit (AHU) operation until additional vendor Spent Fuel Pit AHU data has been received. Final RHR Pump Cooler verification of equipment qualification SIS Pump Cooler AHU will be accomplished within the time Cent. Charging Pump AHU schedules provided in NUREG-0588.
AFW and Boric Acid Pump The approach which TVA used to establish AHU that the motors are functionally operable CCS Pump and AFW Pump AHU and to determine aging effects for their Pipe Chase AHU given operating and accident environ-Penetration Room Coolers ments combined partial test data with j
480-Volt Board Room AHU information on motor materials to Containment Spray Pumps support analytical assumptions and Containment Spray Pump AHU conclusions reached. The environments Component Cooling Water considered were temperature, humidity, Pumps and radiation.
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Component Cooling Water Booster Pumps Temperature - Tenperature rise test data is available for some motors. For those motors which we did not have temperature rise test data, we assumed a maximum rise as specified by the contract. Using this value and the most severe temperature condition the motor would experience, the maximum operating temperature of,the motor was determined.
This temperatgre was compared to a normal ambient of 40 C at which all motors are 0
rated (NEMA HG-1).
The 10 C rule (an approximation of Aerhenuis's Law as applied to insulatien materials) was used to establish the operating life of the motor.
(We assumed a fivgC ambieng and motor temperature year life for the motors based on 40 rise.) The 10 C rule states that for each 10 C rise in temperature above some reference temperature at which the material is able to operate,without degradation (in our case 40 C plus the allowable temperature rise) the useful life of thg material is halved. There-fore, a 10 C temperature rise above the maximum allowable temperature of the material would reduce the life to 2.5 years. Using this approach we can establish the motor aging due to temperature effects.
Humidity - All the motors listed on NCR SQNEEB8010 operate in environments of 80 percent humidity or less. Years of motor operating experience ar.d assurances from motor manufacturers attest to the fact humidity at these low levels will not cause the motors to be functionally inoperable nor degrade motor performance. The one motor addressed on NCR SQNEEB8015 must operate in a 100 percent humidity environment.
Since this motor is of open dripproof construction, measures must be taken to ensure that moisture is not absorbed into the winding insulation. No problem exists when the motor is operating.
However, to prevent moisture absorption when the motor stands idle for long periods an administrative procedure will
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6 be established that causes the motor to be operated at regular intervals to drive out excess moisture.
Radiation - The materials for agl motors in environments greater than 10 rads were identified and their radiation i
damage threshold compared to the operating and accident environments.
In all cases the radiation damage threshold of the materials was higher than the combined 40 years norcal dose and the integrated accident dose. The motors were 'therefore considered acceptable for the radiation environ--
ments in which they were to operate.
Aux Building Gas Treatment TVA has analyzed this equipment and Fan determined that, as a minimum, they will Emergency Gas Treatment perform the required safety functions Fan under the postulated harsh environments through the first fuel cycle (see above discussion on analysis). Additional i
vendor data is being obtained to verify the actual equiment service life. By 1
November 1, 1980, TVA will determine the actual equipment service life and, if required, a schedule for replacement.
Lower Compartment AHU See response to NRC SQNEEB8008.
CRD Nkchanism AHU SQNEEB8011 Solenoid Valve FSV-70-85 See response to' NRC'SQNEEB8008.
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SCNEEB8012 Solenoid Valves PSV Valves have been replaced with qualified 81 and -83 solenoids.
SQNEEB8013 I/P Transducers PSM-Equipment will be relocated in nonhostile 65-80 and -82 environment. This work is presently in progress and has a milestone completion requirement to be finished before the plant prepares to exceed 55 power. Present schedules require completion by August 20, 1980.
SGNNEB8014 Hydrogen Monitoring The radiation environment for tnis System (Annulus Area equipment has been evaluated to Only) consider plant-specific equipment locations. The radiation environdelt
- was calculated using assumptions and methodologies which encompass current NRC guidelines, including NUREG-0588.
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d Using this data, we have determined that the "in situ" equipment is qualified for the environment. However, autoclave testing on similar ccmponents is being pursued to further verify acceptability of equipment. It should be noted that this equipment is qualified for the other environmental parameters (pressure, temeratures, etc.) addressed by NUREG-0588.
SQNEEB8015 Components
- 1. DC Vent Fan Motor See response to NRC SQNEEB8008.
and Starter
- 2. Auxiliary Air The equipment vendor has confirmed that Compressor Motor and that the components are designed to Instrument Rack perform their intended function in the hostile environment. Vendor confirmation was based on comparison of this equipment with similar components that are qualified for the subject environment.
In addition, TVA is pursuing equipment testing to further verify acceptability of equipment.
- 4. Pressurizer Heater See response to NRC SQNEEE8008.
Transformers S. Pressurizer Heater Distribution Cabinet CVRL J.
- 6. Turbine-Driven Auxiliary See response to NRC SQNEEB8008 Feedwater Instrument Panel
- 7. EL734 A/C Circulation Preliminary vendor test data in addition Pump Motors' to analysis by TVA provides justification for continued plant operation until additional vendor data has been received (see response to NCR 20NEEB8010 for discussion on analysis). Final verification of equipment qualification will be accomplished within the time schedules provided in NUREG-0588.
- 8. FSV-81-12 (Solenoid See respone to NRC SQNEEB8008.
Valve)
- 9. Rotork MOB Model This component has been determined to 7A/1RP be a "Limitorqua" operator. Adequate
qualificatien documentation exists for this equipment. Therefore, this component is qualified for the plant environment.
SQNCEB8002 Exposed Safety-Related When reviewing Table 3 11.2 of SQNP FSAR Cables Inside TVA decided to recalculate doses to be Containment expected inside primary containment and to extend the calculations to post-accident times up to two years. The post-accident environment corresponds to the assumptions of Reg. Guide 1.4 which result in the most severe radiation environment'of all design basis accidents. Therefore, this work meets or exceeds the requirements of NUREG-0588. The integrated gamme dose to uncovered cables was calculated taking account of the finite space. The beta dose is based en a very conservative average beta energy of 2 MeV. The additional shielding provided for the cables (1/16" of lead) is sufficient to prevent 2 MeV betas from reaching the cable; the calculated gamma dose is less than that for which the cable was qualified. Accordingly, this modification to the exposed safety-reJated cables results in the cables being qualified for the subject accident environments.
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