ML19318B682
| ML19318B682 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 06/23/1980 |
| From: | METROPOLITAN EDISON CO. |
| To: | |
| Shared Package | |
| ML19318B678 | List: |
| References | |
| NUDOCS 8006270296 | |
| Download: ML19318B682 (2) | |
Text
pr Three Mile Island Nuclear Station, Unit 11 (TMI-2)
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Operating License No. DPR-73
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D'cket No. 50-320 o
Technical Specification Change No. 25 The licensee requests that the attached changed page, 2-9, of the TMI-II Technical Specifications, Appendix B, be substituted in the existing Technical Specifications.
Reason for Change The proposed change to Appendix B of the TMI-II Technical Specifications deletes the requirement for an operationally functional interlock between HP-R-225 and/or HP-R-226 (The Reactor Building Purge Exhaust radiation monitors) and the purge exhaust dampers D5129 A/D and/or D5129 B/C.
Since the issuance of the NRC Order for Temporary Modification of License on June 12, 1980, the basis for the interlock setpoint has been superseded from the Technical Specifications. Our intent, during the period of the purge, is to place the interlock control switch in the BYPASS position that will cause the interlock to be functionally inoperable.
Safety Evaluation Justifying Change The reactor-building purge exhaust flow is monitored for radioactivity concentration by radiation monitors HP-R-225 and HP-R-226.
These menitors are equipped with actuation circuitry to provide an interlock function for the purge exhaust dampers D5129 A/D and D5129 B/C to cause the dampers to automatically shift position from the OPEN position to the RECIRCULATE position.
One portion of the Appendix B Technical Specifications that have been superseded is that portion that limits the instantaneous release rate of gaseous effluents discharged from the plant vent stack to the atmosphere. The instantaneous release rate limit provided the basis for the setpoint specification as well as the basis for the existence of the interlock. The basis for the setpoint specification no longer exists and the requirement for the interlock functional operability no longer exists.
Furthermore, during purge of the reactor building atmosphere, through the Reactor Building Purge Exhaust System, the indication range of HP-R-225 and/or HP-R-226 may be exceeded.
Therefore, the capability to purge the reactor building atmosphere with the interlock operability functional is not technically feasible.
During the period of purge, the gaseous activity concentration of the purge flow stream will be monitored by HP-R-219A.
Radiation monitor HP-R-219A provides monitoring for all gaseous effluents from the plant vent stack as a backup to HP-R-225 and/or PP-R-226.
In accordance with NRC approved purge procedures, the purge system flowrate will be adjusted ' to ensure that the maximum permissibic activity concentration, as indicated by HP-R-219A, will not be exceeded as allowed by existing meteorological conditions.
In addition, the instantaneous release rate of gaseous activity will not be permitted to exceed 1.5 Ci/sec as a result of the alarm setpoint on HP-R-219A.
This maximum instantaneous release rate is determined by the combination of the activity concentration indicated on HP-R-219A and the plant vent gaseous effluent 800627'Ofg
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.wr 4.q ; q Safety Evaluation Juotifying Change (Con't.)
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flowrate as indicated on HP-R-219A, the plant vent stack flowrate indicator /
recorder.
HP-R-219A will be set to provide an alarm condition when the plant vent stack activity concentration indication reaches,a level of 1.29 x 10-2 pCi/cc.
At this activity concentration, purging at a purge system flowrate of 25,000 cfm will produce an instantaneous relea'se rate of approximately 0.76 Ci/sec. This worst case activity release rate will not be approached because of procedural controls which limit actual flowrates based on meteorological conditions to maintain NRC imposed off-site dose limits.
Amendment Class (10 CFR 170)
The Licensee has determined t. hat because the amendment request involves a pro forma change and not a safety concern, it represents a Class II License Amendment (per 10 CFR 170.22). Therefore, enclosed please find a check in the amount of $1,200.00 a
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