ML18053A692
| ML18053A692 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 12/06/1988 |
| From: | Smedley R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.K.3.05, TASK-TM TAC-49700, NUDOCS 8812120076 | |
| Download: ML18053A692 (2) | |
Text
consumers Power POWERING MICHIGAN'S PROGRESS General Offices: 1945 West Parnell Road, Jackson, Ml 49201 * (517) 788-0550 December 6, 1988 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE.OPR PALISADES PLANT -
NUREG-0737, ITEM II.K.3.5 - REACTOR COOLANT PUMP TRIP (TAC NO. 49700) ~ ADDITIONAL INFORMATION -
CORRECTED PAGE Page 2 of Consumers Power Company letter dated December 1, 1988 states "The nominal post-trip steam generator pressure is expected.to be in the range of 700 psia to 900 psia (reference Enclosure 1, Step 9c)".
This is incorrect.
The correct statement is "The nominal post-trip steam generator pressure is expected in the range of 800 psia to 980 p$ia (reference Enclosure 1, Step 9c)".
A corrected page 2 is enclosed.
Richard W Smedley Staff Licensing Engineer CC Administrator, Region III, NRC NRC Resident Inspector - Palisades Enclosure
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- .** ":*4 Nuclear Regulatory Commission Palisades Plant Rx Coolant Pump Additional Info December 1, 1988 the 91 psia error of Enclosure 2 (for PI-0104) is included this results in:
1210 psia + 91 1300 psia.
The error for PI-0104 is used since this is the digital readout instrument which is most visible to the operators in the Control Room and is most frequently used.
The other pressurizer pressure instrument errors are only 29 psia higher than PI-0104.
Since the calculation for these errors are conservative, it is felt that the 1300 psia is a valid setpoint regardless of which pres-surizer pressure instrument is used.
Palisades Technical Specification 3.1.7 requires secondary steam safety valve maximum relief setting of 1040 psia.
Assuming a 3% relief setpoint accuracy results in:
1040 psia + (0.03 x 1040) = 1071.2 psia.
Hence, as required by CEN-268, the small.break LOCA pressure plateau is below the 1300 psia trip setpoint for the first two PCPs.
The second two PCPs may be tripped in EOP 1.0 if pressurizer pressure falls below the "minimum pressure for PCP operation" curve (ref er to Attach-ment 2 of Enclosure 1).
This curve is primarily based on net positive suction head for PCP operation.
For large break LOCA events this curve would obviously be exceeded and the second two PCPs would be tripped.
In other events (e.g. steam generator tube rupture) the tripping of the second two PCPs would be performed if pressurizer pressure fell below the curve (based on existing PCS temperature).
LOCA VS. NON-LOCA EVENT A principle decision for tripping the second two PCPs outside of EOP 1.0 is the diagnosis of the event (i.e. LOCA versus non-LOCA events).
In the Palisades EOPs the operators perform this diagnosis using the "Event Diagnostic Flow Chart" (refer to Attach-ment 1 of Enclosure 1). As can be seen on this attachment (Page 4 of 8), the diagnosis of LOCA events is initially determined by the trending of pressurizer level and pressurizer pressure.
If either of these parameters is trending in the non-conservative direction, then a LOCA event may be in progress.
The value of 1650 psia is above the automatic safety injection actuation system setpoint of 1605 psia.
On page 6 in Attachment 1 to EOP 1.0, the operators are asked if PCS subcooling is rising or if either steam generator is less than 700 psia.
An affirmative answer to either of these questions indicates an excess steam demand event is in progress (as opposed to a LOCA event).
The value of 700 psia is based upon recent analysis (reference Enclosure 2) which indicates that the accuracy of the steam generator (S/G) pressure instruments is 90 psia during small break LOCA events.
The nominal 2
post-trip steam generator pressure is exp~cted in the range of 800 psia to I
980 psia (reference Enclosure 1, Step 9c).
/
If a LOCA event was in progress, a negative response should have occurred OC1288-0228-NL04