ML20010F853
| ML20010F853 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 09/04/1981 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | Adensam E Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8109110458 | |
| Download: ML20010F853 (2) | |
Text
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,E TENNESSEE VALLEY AUTHORITY CH ATTANOOG A. TENNESSEE 374ot 400 Chestnut Street Tower II September 4, 1981
'I Director of Nuclear Reactor Regulation g
y-5 Attention:
Ms. E. Adensam, Chief
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Licensing Branch No. 4 y
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-4 Division of Licensing g#g*$
N U.S. Nuclear Regulatory Commission f
g Washington, DC 20555 h'$1 fil) \\
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Dear Ms. Adensam:
In the Matter of
)
Docket No. 50-328 Tennessee Valley Authority
)
In section 5.2.2.4 of the Sequoyah Nuclear Plant Final Safety Analysis Report (/SAR), TVA committed to implement a system for control of Reactor Coolant System (RCS) pressure during low temperature operation before unit 2 fuel loading. During preoperational testing of the system, a problem with the response times for the pressurizer relief valves (PRV) was identified (reference nonconformance report SQNNEB8122). TVA determined that corrective action for this condition would be required before initial criticalitv. However, the modifications implemented at this time have not produced the required PRV response time. Therefore, we propose to delay full implementation the RCS Low Temperature Over-pressure Protection System until the first unit 2 refueling outage. The deferral of this system does not represent a reduction in available plant safety margins for the following reasons:
- 1. 'For Sequoyah unit 1, a special alarm was added to notify the operator in the main control room of water solid conditions when RCS pressure 2
exceeds 380 lb/in g. The overpressure protection circuitry installed in unit 2 provides the same alarm capability. It should be noted that unlike the unit 1 al rm, the RCS pressure alarm for unit 2 actuates uhen the pressure rises to within 20 lb/in2 of the programmed setpol' a (which varies as a function of temperature) of the PRV's.
2.
Operator training and administrative procedure changes are the same for units 1 and 2 and have been implemented.
QOY S
Ifl hhCK05000328 458 8309o4 FD p
l PDR An Equal Opportunity Employer
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- Ms. E. Adensam, Chief September 4, 1981 3
The NRC staff, in Supplement No. 1 of the Sequoyah Safety Evaluation report, concluded that since no credible overpressure transient could damage the reactor vessel during the first operating cycle (based on expected minimal neutron damage to the vessel), full implementation of the RCS Low Temperature Overpressure Protection System could be deferred until the first refueling outage. We believe that the same technical justifications can be applied to unit 2.
Very truly yours, TENNESSEE VALLEY AUTHORITY
. M.
ills, Manager Nuclear Regulation and Safety Subscribed and sworn to before me this day of Ln' N6 tar Public My Commission Expires
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TENNESSEE VALLEY AUTHORITY CH ATTANOOGA, TENNESSCE 37401 400 Chestnut Street Tower II September 4, 1981 Director of Nuclear Reactor Regulation Attention:
Ms. E. Adensam, Chief Licensing Branch No. 4 Division of Licensing l
U.S. Nuclear Regulatory Commission Washington, DC 20555 l
Dear Ms. Adensam:
In the Matter of
)
Docket No. 50-328 Tennessee Valley Authority
)
In section 5.2.2.4 of the Sequoyah Nuclear Plant Final Safety Analysis Report (F3AR), TVA committed to implement a system for control of Reactor Coolant System (RCS) pressure during low temperature operation before unit 2 fuel loading. During preoperational testing of the system, a problem with the response times for the pressurizer relief valves (PRV) was identified (reference nonconformance report SQNNEB8122). TVA determined that corrective action for this condition would be required before initial criticality. However, the modifications implemented at this time have not produced the required PRV response time. Therefore, we propose to delay full implementation the RCS Low Temperature Over-pressure Protection System until the first unit 2 refueling outage. The deferral of this system does not represent a reduction in available plant safety margins for the following reasons:
1.
For Sequoyah unit 1, a special alarm was added to notify the operator in the main control room of water solid conditions when RCS pressure 2
exceeds 380 lb/in 8. The overpressure protection circuitry installed in unit 2 provides the same alarm capability. It should be noted that unlike the unit 1 alarm, the RCS pressure alarm for unit 2 actuates when the pressure rises to within 20 lb/in2 of the progratened setpoint (which varies as a function of temperature) of the PRV's.
2.
Operator training and administrative procedure changes are the same for units 1 and 2 and have been implemented.
An Equal Opportunity Employcr
I
-2 Ms. E. Adensam, Chief September 4, 1981 3.
The NRC staff, in Supplement No.1 of the Sequoyah Safety Evaluation report, concluded that since no credible overpressure transient could damage the reactor vessel during the first operating cycle (based on expected minimal neutron damage to the vessel), full implementation of the RCS Low Temperature Overpressure Protection System c c1d be deferred until the first refueling outage. We believe that the same technical justifications can be applied to unit 2.
Very truly yours, TENNESSEE VALLEY AUTHORITY
. M. Mills, Manager Nuclear Regulation and Safety Subscribed and sworn to efore me this day of o R f
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NotapPublic My Comission Expires Y2
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TENNESSEE VALLEY AUTHORITY CHATTANOOG A. TENNESSEE 37401 400 Chestnut Street Tower II September 4, 1981 Director of Nuclear Reactor Regulation Attentiona Ms. E. Adensas, Chier Licensing Branch No. 4 Division of Licensing U.S. Nuclear Regulatory Commission Washington, DC 20555 Dear Ms. Adensam!
In the Matter of
)
Docket No. 50-328 Tennessee Valley Authority
)
In section 5.2.2.4 of the Sequoyah Nuolear Plant Final Safety Analysis Report (FSAR), TVA committed to implement a system for control of Reactor Coolant System (RCS) pressure during low temperature operation before unit 2 fuel loading. During preoperational testing of the system, a problem with the response times for the pressurizer relier valves (PRV) was identified (reference nonconformance report SQNNE38122). TVA determined that corrective action for this condition would be required before initial criticality. However, the modifications implemented at this time have not produced the required PRV response time. Therefore, we propose to delay full implenentation the RCS Low Temperature Over-pressure Protection System until the first unit 2 refueling outage. The deferral of this system does not represent a reduction in available plant safety margins for the following reasons:
1.
For Sequoyah unit 1, a special alarm was added to notify the operator in the main control room of water solid conditions when RCS pressure 2
exceeds 380 lb/in g. The overpressure protection circuitry installed in unit 2 provides the same alarm capability. It should be noted that unlike the unit 1 alsrm, the RCS pressure alarm for unit 2 actuates when the pressure rises to within 20 lb/in2 of the programed setpoint (which varies as a function of temperature) of the PRV's.
2.
Operator training and administrative procedure changes are the same for units 1 and 2 and have been implemented.
An EUM Cpportunity Employer
-2 Ms. E. Adensam, Chief September li, 1981 3.
The NRC staff, in Supplement No.1 of the Sequoyah Safety Evaluation report, concluded that since no credible overpressure transient could damage the reactor vessel during the first operating eyole (based on expected minimal neutron dansEe to the vessel), full implementation of the RCS Low Temperature Overpressure Protection Systes co*11d be deferred tmtil the first refueling outage. We believe that the same technical justific.stions own be applied to unit 2.
Very truly yours, TEMNESSEE VALLET AUTHORITY
. M.' Mills, Hanager Nuolear Regulation and Safety Subscribed and sworn to efore
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