ML20197J893
| ML20197J893 | |
| Person / Time | |
|---|---|
| Site: | 05000000, Diablo Canyon |
| Issue date: | 06/21/1985 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML082840462 | List:
|
| References | |
| FOIA-86-197 NUDOCS 8506270790 | |
| Download: ML20197J893 (4) | |
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Enclosura SAFETY EVALUATION REPORT TECHNICAL SPECIFICATIONS CHANGES BASED ON THE WESTINGHOUSE OWNERS GROUP TECHNICAL SPECIFICATION OPTIMI7ATION PROGRAM RACKGROUND On February 21, 1985, the NRC issued its Safety Evaluation Report on the Westinghcuse Technical Specification Optimization Program for increased surveillance intervals and out-of-service times for testing and maintenance of the Reactor Trip System (RTS). The Optimization Program proposal was set forth in kCAP-10271, " Evaluation of Surveillance Frequencies and Out-0f-Service Times for the Reactor Protection Instrumentation System" Supplement 1.
By letter dated May 20, 1985, Pacific Gas and Electric Company submitted proposed Technical Specifications for Diablo Canyon Units 1 and for the Full Power License for Unit 2 based on the Optimization Program.
EVALUATION The proposed Technical Specification chances include an increase in the sur-veillance interval of reactor trip system channels from monthly to quarterly.
The proposed quarterly surveillance intervals are annotated to indicate that the quarterly tests are to be performed on a staggered test basis.
In addition the surveillance intervals for those reactor trip sytem channels which also provide signals to the Engineered Safeguards Actuation System (ESFAS) have been annotated to indicate that the more restrictive ESFAS surveillance requirements apply to these channels. These changes are consistent with the staff's generic evaluation of the Optimization Program and are, therefore, acceptable.
The surveillance frequency for channels which would be tested prior to plant startup was noted as prior to startup in lieu of quarterly as recommended under the Optimization Program. Also, the startup surveillance was annotated to indicate that it is to be performed prior to startup if not performed in the previous 31 days.
The channels for which testing prior to startup applies are:
1.
Power Range, Neutron Flux, low Setpoint.
The low setpoint channels are required to be tested prior to entry into Mode 2 and for operation in Mode 1 below the P-10 interlock setpoint.
For these transitional operating modes, the surveillance test would be conducted prior to startup and not on a routine basis as would be implied by specifying a quarterly test frequency. Thus, the surveillance frequency is noted as prior tostartup,S/U(1).
In the Table 4.3-1 Notation, note (1) is revised to in-dicate if not performed in the previous 31 days, instead of 7 days.
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Intermediate Range, Neutron Flux.
The intermediate range channels are required to be tested for the same transi-tional modes as the power range low setpoint channels. On the same basis the surveillance frequency is noted as prior to startup, rather than quarterly.
3.
Source Range, Neutron Flux The source range channels are required to be tested in Mode 2 below the P-6 interlock setpoint and in Modes 3, 4, and 5.
The source range channels, in addition to initiating reactor trip, provide the high flux at shutdown alarms which alert the operator of reactivity changes caused by a boron dilution event.
Therefore, the surveillance requirements for the source range channels apply to Modes 3, 4, and 5.
The surveillance frecuency is noted as prior to startup and as quarterly.
o 4.
Reactor Trip System Interlock (pTSI),
Intermediate Range Neutron Flux, P-6 The P-6 interlock channels are required to be tested prior to entry into Mode 2 and for operation in this mode below the P-6 interlock setooint. For this transitional operating mode, the surveillance test would be conducted prior to startup and not on a routine basis as would be implied by specifying a cuarterly test frequency. Thus, the surveillance frequency is noted as i
prior to startup.
5.
RTSI, low Power Reactor Trips, Plock, p-7 The surveillance frequency is noted as prior to startup, consistent with that specified for the P-10 and P-13 channels as noted below.
6.
RTSi, Power Range Neutron Flux, P-8 The currently specified monthly test interval is annotated to indicate that when the plant is at power level greater than the channel trip setpoint, the surveillance requirement is satisfied by verifying that the interlock permissive logic is in its required state. This provision was included in the Technical Specifications such that power reductions below the channel setpoint would not be required for the sole purpose of meeting the surveillance requirement. For example,'the previous monthly surveillance requirement for the P-8 channels would require a power reduction below its setpoint had this annotation to the surveillance requirement not been included. Likewise, this same annotation is used for the P-10 channels and precludes the necessity of power reductions for testing.
This annotation to the surveillance requirement only verifies the status of the permissive logic and does not address verification of channel setting or operability. Those aspects would be verified following a refueling shutdown and prior to startup. With a monthly surveillance interval the annotated surveillance at power would in all likelihood have expired during a refueling shutdown (i.e., exceeded 31 days) and testing would be required prior to entry into Modes 2 or 1, as applicable to the permissive channels. However, this
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j situation may not be true if a quarterly surveillance interval is specified,
'i.e., the annotated surveillance performed at power may not have exceeded a 92 day surveillance interval _ during a refueling shutdown. Therefore, since the only comprehensive tests are actually performed prior to startup, the surveil-lance interval is stated as prior to startup.
The status of interlock pennissives at the logic and channel level are indivi-
-dually indicated on status monitoring displays in the control room. As-such they are routinely checked and particular attentien is given _to this information during operational mode changes. The fact that the permissive status indication is readily available and can be routinely vnrified constitutes a different consideration with respect to the availabilp.y of trip channels which must change state on the occurrence of an event and for which the function unavail-ability is dependent on the surveillance interval.
It is concluded that maintaining the requirement for the verification of the permissive logic status is not safety significant. Therefore, since the surveillance frequency has been noted a prior to startup, note (8) is no longer applicable to these channels.
7 RTSI, low Setpoint Power Range Neutron Flux, P-10 The surveillance frequency is noted as prior to startup, on the same buis as for the power range P-8 channels noted above.
8.
RTSi, Turbine impulse Chamber Pressure, P-13 The surveillance frequency is noted as prior to startup. The bases with regard to note (8) is the same as for the power range interlock channels noted above. However, unlike the power range channels which can only be tested when the measurement signal is below the setpoint, the turbine impulse chamber pressure channels include features which would permit them to be tested without reducing reactor power. However, since the P-13 channels and herce P-13 logic only provide inputs to the P-7 logic which are diverse to the P-10 inputs to the P-7 logic, it is concluded that there is sufficient,iusti-fication for excluding testing as currently noted by the provision on note (8) when operating above the P-13 setootnt. Further, since the channel state is indicated, its state can be readily determined. Thus, it is concluded that the additional surveillance as would occur by noting a quarterly (8) is no surveillance frequency annotated with note (8) is not warranted. Since note longer used, it is deleted from the Table 4.3-1 notation.
With regard to the inclusion of the startup test requirement, wherein channels would be tested prior to plant startup if not tested in the previous 31 days, the staff concludes that this is appropriate in view of the increase in the surveillance frequency from that currently required for startup tests if not performed in the previous 7 days.
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6 9.
Out of Service Times for Testina and Maintenance For those RTS channels which provide input signals to ESFAS, the ACTION column of Table 3.3-1 is annotated, as applicable, with note (1) and the Table 3.3-1 Notation includes note (1) to indicate that the Applicable Modes and ACTION statement for these channels under the ESFAS specification requirements are applicable. This is consistent with the staff's evaluation for the Optimization Program and is, therefore, acceptable.
CONCLUSION The staff concludes that the proposed Technical Specifications are acceptable.
Principal contributor: Thomas Dunning Dated: June 21, 1985 e
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