ML17332A641
| ML17332A641 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 03/06/1995 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17332A635 | List: |
| References | |
| NUDOCS 9503150322 | |
| Download: ML17332A641 (5) | |
Text
~PS RE00 Wp.0
++*++
~-
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.
191 TO FACILITY OPERATING LICENSE NO.
DPR-58 AND AMENDMENT NO.
177 TO FACILITY OPERATING LICENSE NO.
DPR-74 INDIANA MICHIGAN POWER COMPANY DONALD C.
COOK NUCLEAR PLANT UNIT NOS.
1 AND 2 DOCKET NOS.
50-315 AND 50-316
- 1. 0 INTRODUCTION By letter dated August 12, 1992 and supplemented April 12, 1993, the Indiana Michigan Power Company (the licensee) requested amendments to the Technical Specifications (TS) appended to Facility Operating License Nos.
DPR-58 and DPR-74 for the Donald C.
Cook Nuclear Plant, Unit Nos.
1 and 2.
The proposed amendments would change the minimum channels operable for the pressurizer safety valve position indicator acoustic monitor to two out of three total from one per valve.
The amendments would also delete certain footnotes which are no longer applicable.
- 2. 0 EVALUATION The D.
C.
Cook Nuclear Plant reactor coolant system is protected against overpressurization by control and protective circuits such as the pressurizer pressure high reactor trip and by the three power-operated relief and three safety valves connected to the top of the pressurizer.
Upon opening, these valves discharge steam into the pressurizer relief tank which condenses and collects the valve effluent.
The purpose of the pressurizer safety valve acoustic monitor is to provide the operator with information regarding safety valve position.
Two independent monitoring systems exist that alert the operator to the passage of steam from the safety valves due to valve lift.
An acoustic flow monitor on the discharge of each safety valve detects acoustic vibrations generated from the steam flowing through the valve, and actuates an alarm in the control room.
Due to the magnitude of the acoustic vibrations and the sensitivity of the instrumentation, all three monitors were added to meet the requirements of NUREG-0578, "TMI-2 Lessons Learned Task Force Status Report and Short Term Recommendations,"
and NUREG-0737, "Clarification of TMI Action Plan Requirements,"
and are environmentally qualified, unlike the downstream temperature sensors.
During normal operation the acoustic monitors are not used to detect valve leakage; A temperature sensor downstream of the acoustic sensor generates a
9503150322 95030b PDR ADQCK 050003i5i i
P PDR
signal that actuates a control room alarm when a temperature increase is experienced in the line, as would be the case if the valve released steam.
The licensee utilizes the temperature sensor installed downstream of the affected pressurizer safety valve as backup indication of flow through this valve.
This sensor provides indication and alarm in the control room and on the plant computer.
The licensee's experience has shown that these sensors perform effectively to detect leakage.
In addition, licensee experience has also shown that when one of the pressurizer safety valves opens, all three safety valve acoustic leak detection channels are actuated.
This is caused by the sensitivity of the accelerometers and the fact that the three safety valves and their associated acoustic monitor sensors are in close proximity to each other.
If the safety valve associated with the inoperable valve position acoustic monitor channel discharges, the remaining two valve acoustic monitor channels would alert the operator.
Further the safety valve discharges into the pressurizer relief tank.
The temperature,
- pressure, and liquid level of the tank are indicated and alarmed in the control room.
A change in these parameters would alarm and alert the operator of a safety valve discharge condition.
- Also, when a
pressurizer safety valve lifts, it can be heard in the control
- room, and would therefore alert the operators.
In a conference call with the NRC staff on January 27,
- 1992, the licensee confirmed that the electronics of the acoustic monitors are sufficiently independent to allow isolation of the affected acoustic monitor without affecting the remaining operable acoustic monitors.
The licensee also committed in that call to perform appropriate surveillance, i.e.,
channel check to determine functionality at an appropriate frequency.
The licensee also conducted a review of emergency and abnormal procedures which reference the acoustic monitors.
In an emergency situation, the operator does not use a signal from the pressurizer safety valve position indicator acoustic monitors as an action initiator.
The operator responds to other indications of loss of reactor coolant inventory.
As the operator does not have direct control of the pressurizer safety valve, "where" the loss of inventory is occurring is of less importance than compensating for the loss of inventory.
In addition, the Cook Nuclear Plant emergency operating procedures do not reference the pressurizer safety valve position indicator acoustic monitors.
Finally, the safety valve position indication is considered Type D, Category 2
instrumentation and is not required to be incorporated in the Post-Accident Monitoring TS at all.
The listing of the safety valve position indication was deleted from the improved "Standard Technical Specifications Westinghouse Plants,"
NUREG-1431, issued September 1992.
The licensee's proposed amendments would change the minimum channels operable for the pressurizer safety valve position indicator acoustic monitor to two out of three total from one per valve.
Hased on the above discussions regarding the existence of backup instrumentation and the staff position that these instruments are not required to be included in the TS, the staff finds the proposed TS change to be acceptable.
0 1
l' The licensee also proposed the deletion of the "*****"footnote for the "Safety Valve Position Indicator Acoustic Monitor" TS.
The "*****"
footnote provided a one time exemption for one acoustic monitor for a specific operating cycle.
This footnote was previously deleted by amendments 186 and 172 for Units 1 and 2, respectively.
- 3. 0 STATE CONSULTATION In accordance with the Commission's regulations, the Michigan State official was notified of the proposed issuance of the amendments.
The State official had no comments.
- 4. 0 ENVIRONMENTAL CONS IDERATION The amendments change the requirements with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
The staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration and there has been no public comment on such finding (60 FR 6302).
Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b),
no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
5.0 CONCLUSION
The staff has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed
- manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
J.
Hickman Date:
March 6, 199$
J