ML19353B153
| ML19353B153 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 12/05/1989 |
| From: | Berry K CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 8912120052 | |
| Download: ML19353B153 (3) | |
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General Omces: 1946 West Pornou Road. Jackson, MI 49201 e (51M 7881636 I
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December 5, 1989 1
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Document Control Desk 1
Washington, DC 20555 DOCKET 50-155 - LICENSE DPR BIG ROCK POINT PLANT -
RESPONSE TO INSPECTION REPOET 8h-027 - ROUTINE SAFETY INSPECTION NRC Routine Safety Inspectir.a #S0-155/880?7 (DRSS) of the Big Rock Point Emergency Preparedness Program resulted in one open item (155/88027-01).
This letter contains Consumers Power Company's response to that open item.
Open Item 155/88027-01 requested reeveluation of Big Rock Point Emergency Action Levels (EALs) which are not applicable whr a the plant is not at power.
The open item resulted from an NRC concern that Lu,a for Engineered Safeguards, Station Power, Fire, Natural Phenomena, and Misce.1.laneous External Events are not valid when the reactor is not at power (less taan 212 degrees farenheit at Big Rock Point). The open item was issued based on the NRC conclusion that the "not at power" statement is too encompassing.
Consumers Power Company has reevaluated these EAls in light of NRC concerns and has concluded that no modf*1 cation of Big Rock Point EALs is needed at this time-for the following reasonst 1.
At Big Rock Point there are only four modes of plant operation; cold shutdown, shutdown, refueling, and power operation. The plant is considered to be in power operation anytime the primary system temperature is above 212'F.
There are a number of EALs which would be applicable at all times, the most obvious being a " fuel handling accident which causes evacuation of the containment" (page 1-7 of EPIP-1).
Similar19, other Primary Coolant System events on pages 1-4, 5 and 6, the Radiological Barrier events on page 1-5, the Radiological Effluents events on page 1-8, and the Security and Evacuation of the control room events on page 1-13, would be applicable at all times.
2.
Some of the events deal with operating parameters, such as ATWS or low Intake Bay Level, that are only applicable when the plant is "at power".
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Response to Inspection Report 88-027 December 5, 1989 3.
If the plant is not in power operation, then it follows that the shutdown cooling system is in service (if there is fuel in the reactor), the l
primary system temperature is less than 212*F, and/or the fuel is in the fuel pool. In this situation there are only two problems that can lead to core damage. (when combined with containment failure would lead to offsite release); a loss of cooling to the reactor vessel or fuel pool, or draining of the reactor vessel or fuel pool.
a.
Loss of cooling with the primary system intact (reactor vessel head in place) - under these conditions the primary system would begin to heat up and pressurize. The rate of heatup would be dependent on the amount of time after reactor shutdown. It is important to keep in mind that under ideal condition. at Big Rock Point it takes approximately ten hours to reach shutdown conditions after reactor shutdown or trip.
Decay _ heat loads ten hours af ter reactor shutdown are less than two negavatts thermal at Big Rock Point. At Big Rock Point a loss of cooling condition when the plant has already attained the shutdown mode would be a slow transient.
In any case, once the pr! nary system reached a temperature of 212*F the plant would be in power operation and all EALs would then be in effect, b.
Loss of cooling with the head off - the primary system will not pressurir.e but will begin to heat up and eventually boil. The boiling itself could cause airborne radioactivity to increase in the containment, but it would not be expected to cause a threat to the health and. safety of the public.
If the boiling condition were left unattended with no makeup or cooling, the level in the reactor would eventually drop to the low reactor water icvel setpoint. However, there are already EALs covering this situation, such as low reactor water level (page 1-5), which is in effect whenever fuel is in the reactor.
c.
Loss of cooling to the spent fuel pool - this is very similar to the loss of cooling in b. above except that it would take much longer to cause a problem. Assuming a full core was placed in the spent fuel pool and the spent fuel cooling system failed at the same time, L
boiling would occur after_20 hours following the LOCA. Assuming the make-up line also failed, it would require one month for all the water above the fuel to boil away.
1 d.
Draining of the spent fuel pool is not possible below the level af the l
concrete weir. A siphon-breaker is installed in the make-up line to the pool to prevent water from being siphoned as a result of a pipe failure.
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LOCA during shutdown - again in this case, the EALs for LOCAs are still applicable and will cover the situation.
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Nucle:r R:gulct:ry Commission 3
.1 fig Rock Point Plant Response to Inspection Report 88-027 December 5, 1989 4.
The remaining Eats that are currently not applicable, except in power operation, are those dealing with external events (fires, floods, earthquakes. etc). Any external event that leads to either loss of reactor cooling or loss, of primary system level would be eventually covered by EAls that are in effect at all times (as discussed in 2.
above). It is also important to recognir.e that the consequerces of such events are much less severe than during power operation, and the probability of these events leading to core damage is much smaller during plant shutdown.
Based on reevaluation of all Eats that could be affected by tiot being at power.
Consumers Power Company has concluded that there is no need to modify Big Rock Point Eats due to exceptions resulting from the "not at powar" statement, gjl &&~f Kenneth W Berry Director, Nuclear Licensing CC Administrator, Region III, USNRC NRC' Resident Inspector - Big Rock Point DC0989-0199-NLO4 s
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