ML20059K830
| ML20059K830 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 01/24/1994 |
| From: | Geoffrey Edwards PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9402020286 | |
| Download: ML20059K830 (4) | |
Text
1' Peat.h Bcitam Atomic Pr,wer station.
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January 24,1994 '
U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 Docket No.
50-277 Ucense No.
SUBJECT:
Peach Bottom Atomic Power Station, Unit 2 I
Request for Enforcement Discretion from Technical Specification Section 4.1.A, Table 4.1.1, " Functional Testing of Main Steam Une Radiation Monitors"
Dear Sir:
As discussed with the NRC on January 20,1994, this letter is being submitted to request Enforcement Discretion (ED) to suspend the requirement to perform a weekly functional test of the "B" and *D" Main Steam Une Radiation monitors. This Enforcement Discretion is being -
pursued because the requested relief is temporary and non-recurring. Further, the period for _
which relief is requested is of such short duration that a license amendment cannot be issued.
Enforcement Discretion is requested to apply until 01/22/94 at 1900 hours0.022 days <br />0.528 hours <br />0.00314 weeks <br />7.2295e-4 months <br />, at which time it is forecasted that weather conditions will improve thus reducing the peak load conditions on the d
electrical distribution grid.
In accordance with the guidance contained Part 9900 of the NRC Inspection Manual,'the PECO j
Energy Company (PECO) requests Enforcement Discretion from the requirements of Peach
)
Bottom Atomic Power Station, Unit 2 Technical Specifications (TS) Section 4.1.A Table 4.1.1,
" Functional Testing of Main Steam Line High Radiation Monitors" l
TS 4.1.A details the testing requirements for Reactor Protection System instrumentation. TS 4.1.A states: " Instrumentation systems shall be functionally tested and calibrated as indicated on i
Tables 4.1.1 and 4.1.2 respectively". TS Table 4.1.1 requires that all the Main Steam Line Radiation Monitors be functionally tested at least once per week. PECO Energy Company is i
requesting ED from this TS until weather conditions improvo, thus reducing the peak load i
conditions on the electrical distribution grid.
The following is a discussion of the requested discretion:
1)
A discussion of the reouirements for which a waiver is reauested.
TS Section 4.1.A requires weekly functional testing of the Main Steam Une Radiation -
Monitors. Performance of this test causes a half scram and half Group I isolation. The test procedure specifically states that an inadvertent trip of the other Reactor Protection System (RPS) bus will result in a full reactor scram and subsequent shutdown. A review CCN 94-14009 0
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U. S. Nuclear Regulatory Commission January 24,1994 Document Control Desk Page 2 I
of test data since January 1990 was performed that indicated the trip functions of the Surveillance Test had performed satisfactorily during this period. PECO requests an ED from this TS until January 22,1994 at 1900 hours0.022 days <br />0.528 hours <br />0.00314 weeks <br />7.2295e-4 months <br />.
2)
A discussion of the circumstances surroundino the situation includino the need for oromot action.
Extreme cold accompanied by wind, Ice, and snow have caused power grid load conditions to deteriorate to the point of state of emergency declarations in Pennsylvania and Maryland. All efforts are being made to minimize the probability of an inadvertent plant trip that could result in a loss of power generation to the grid. Although PECO monitors the state of the grid and works to minimize adverse effects of inclement weather, the extreme weather conditions and increased load on the grid have degraded the PJM network and power supplies on the east coast.
I The surveillance test program schedules tests at the appropriate intervals and uses the grace period when necessary. Even with the use of this grace time, the test cannet be delayed without exceeding the TS Surveillance Requirement.
3)
A creliminarv evaluation of the safety sionificance and ootential consecuence of the orocosed reauest.
Based on the review of Main Steam Une Radiation monitor past performance, the probability of failure in the limited time that the monitors will be out of surveillance is negligible. Other plants have removed the TS Surveillance Requirement for testing these radiation monitors as part of Scram Frequency Reduction. The safety assessment for this change is included in General Electric NEDO-31400, " Safety Evaluation for Eliminating the Bolling Water Reactor Main Steam Une Isolation Valve closure function and scram function of the Main Steam Une Radiation Monitor, dated May 1987.
The design bases of the Main Steam Une Radiation Monitoring system at Peach Bottom Atomic Power Station is to provide prompt indication of gross release of fission products from the fuel under any operating combinations of the Main Steam Unes. In addition, the system will initiate a scram signal upon detection of gross leakage and will take actions necessary to minimize the release. The Main Steam isolation Valves will close and the Mechanical Vacuum Pump will trip and isolate. The system is intended to mitigate the consequence of a Rod Drop Accident. It should be noted that several assumptions are required for a Rod Drop Accident to occur. They are,1) the failure of a Rod to Drive coupling,2) Control Rod fully stuck in,3) a full withdraw of the Rod,4) failure of the operator to notice lack of response of the neutron monitoring equipment l
during Rod movement, and 5) the failure to perform an overtravel check of the Rod.
I The worse case Rod Drop Accident is during very low power operating conditions when the Rod has its maximum worth. Currently Unit 2 is operating or approximately 100 % -
reactor power. All Rods were verified to be coupled during the last plant startup via -
response of the neutron monitoring system as specified in item 4 and by the
_3 performance of an overtravel check in item 5. In addition, the Rod overtravel check in item 5 is performed weekly during the Rod Stroking Surveillance Test. Therefore, based on this safety assessment on the Main Steam Une Radiation monitors, the probability of I
a Rod Drop Accident is extremely low with the existing controls and the consequences are significantly reduced at the current power level.
CCN 94-14009
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l 4)
A discussion of esmoensatory actions.
4 All operating crews will be notified of the TS ED and that the TS Surveillance Requirement has not been satisfied. Instructions currently exist in approved procedures to address Main Steam Line High Radiation conditions if the monitors fall to perform as expected.
5)
A discussion which lustifies the duration of the recuest.
This ED is requested to apply until January 22,1994 at 1900 hours0.022 days <br />0.528 hours <br />0.00314 weeks <br />7.2295e-4 months <br />. This is based on weather forecasts that indicate significantly higher temperatures by that time. In addition, the significant load reduction which occurs during the weekend should allow -
grid recovery so that testing would be acceptable. The Surveillance Test was completed satisfactorily on January 22,1994 at 0906 hours0.0105 days <br />0.252 hours <br />0.0015 weeks <br />3.44733e-4 months <br />.
6)
The basis for the licensee's conclusion that the reauest does not involve sianificant hazards consideration.'
The proposed ED to TS 4.1.A Table 4.1.1 does not involve a significant hazards consideration because operation of Peach Bottom Atomic Power Station with this change does not:
(1) involve a significant increase in the probability or consequences of an accident previously analyzed. The probability of fuel failure is not affected by the failure to perform the required Surveillance Test or failure of the Main Steam Line Radiation monitors. Based on the past performance of the monitors, the probability of failure for the time specified is rninimal and does not represent a significant increase in the consequences. Should a fuel failure occur and the "B"
.l and *D" Main Steam Radiation monitors fail, the "A" and *C" monitors are available and operable to initiate alarms to alert the operators to the condition to take appropriate actions.
(2) create the possibility of a new or different type of accident from any accident previously evaluated. The requested ED does not involve any changes to plant equipment or affect any accident precursors.
(3) involve a significant reduction in a margin of safety. Past performance of the Main Steam Line High Radiation monitors indi.:ates that for the time specified, there is minimal probability of failure.
7)
The basis for the licensee's conclusion that the regypst does not involve irreversible environmental consecuences, The requested ED to the TS does not have an adverse environmental impact because failure to perform the test does not increase the probability of fuel failure. Catastrophic fuel failure can be caused by the drop of an uncoupled rod. All rods have been demonstrated to be coupled, therefore, catastrophic failure will not occur. Other fuel failures are addressed by operational transient procedures that have the Main Steam isolation Valves closed prior to reaching the trip set point.
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U. S. Nuclear Regulatory Commission January 24,1994 j
Document Control Desk-Page 4
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l The Plant Operational Review Committee has reviewed this proposed ED and has concluded -
.l
. that it does not involve a significant hazards consideration and will not endanger the health and
.i safety of the public.
Sincerely
.j G.D. Edwards Plant Manager l
GDE/AJW:gaj cc:
T.T. Martin, Administrator, Region I, USNRC
-l W.LSchmidt, Senior Resident inspector, USNRC
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