ML18153B973

Proposed Tech Specs Re Inoperable Control Rod

ML18153B973
Person / Time
Site:	Surry
Issue date:	11/03/1989
From:	VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
Shared Package
ML18153B972	List: ML18153B971 ML18153B973
References
NUDOCS 8911140228
Download: ML18153B973 (5)

Text

ATTACHMENT 1 SURRY POWER STATION PROPOSED TECHNICAL SPECIFICATION CHANGE INOPERABLE CONTROL ROD

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fDR ADUCK 05000280 PDC

TS 3.12-8 8 T and Overtemperature 8 T trip settings shall be reduced by the equivalent of 2% power for every 1% quadrant to average power tilt.

C. Inoperable control rod

1. A control rod assembly shall be considered inoperable if the assembly cannot be moved by the drive mechanism or the assembly remains misaligned from its group step demand position by more than +24 steps during the "Thermal Soak" period, as defined in Section 3.12.E.1.b, or+/-12 steps otherwise during power operation. No tolerance limit is required in the shutdown modes, but a rod shall be considered inoperable if the rod position indicators do not verify rod movement upon demand. Additionally, a full-length control rod shall be considered inoperable if its rod drop time is greater than 2.4 seconds to dashpot entry.

2. With more than one inoperable control rod assembly as defined in 3.12.C.1 the reactor shall b*e in Hot Shutdown within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. *

3. If more than one control rod assembly in a given bank is out of service because of a single failure external to the individual rod drive mechanism but remain trippable (i.e., programming circuitry),

the provisions of Specification 3.12.C.1 and 3.12.C.2 shall not apply. Either restore the affected assemblies to operable status in the next 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> or be in Hot Shutdown within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

4.. The provisions of Specification 3.12.C.1 and 3.12.C.2 shall not apply during reactor physics tests in which the assemblies are intentionally misaligned.

5. Power operation may continue with one rod inoperable provided that within one hour either:

a. the rod is no longer inoperable as defined in Specification 3.12.C.1, or

e e ATTACHMENT 2 SURRY POWER STATION SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION

DISCUSSION OF CHANGE To eliminate confusion with the existing inoperable control rod Technical Specification and bring it more in line with the Standard Technical Specifications (3 I 4.1.3) several changes are being proposed to 3.12.C.

TS 3.12.C.2 A reference to Section 3.12.C.1 to define inoperable control rods is being included as well as the required action statement (6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> to Hot Shutdown) if the T S requirement is exceeded.

TS 3.12.C.3 The intent of the "out-of-service" in this section is based on a rod control system problem ( e.g., programming circuit) which would not prevent the rod from tripping, therefore as in Standard Technical Specifications the words "remain trippable" are being included.

To clarify the intent of this section we are replacing the existing action requirements with words that are similar with the Standard Technical Specifications. The current interpretation 3.12.C.3 allows 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> of critical operation and then requires a plant shutdown. However, no time limit is given to complete the shutdown (Hot Shutdown). Consistent with Section 3.0 of the Standard Technical Specifications and our interpretation of the requirement, we are proposing that after 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> if the control rod problem _cannot be resolved, the plant be required to "be in Hot Shutdown within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />." This 6 hour6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> period provides adequate time to complete an orderly shutdown with the out-of-service control rods.

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e SIGNIFICANT HAZARDS CONSIDERATION Virginia Electric and Power Company has reviewed the proposed changes against the criteria of 10 CFR 50.92 and has concluded that the changes as proposed do not pose a significant hazards consideration. Specifically, the proposed change clarifies the Technical Specifications to reflect existing practice/interputation by specifying when to commence a shutdown and the required completion time. Thus, operation of the Surry Power Station in accordance with the proposed changes will not:

1. Involve a significant increase in the probability of occurrence or consequences of any accident or malfunction of equipment which is important to safety and which has been evaluated in the UFSAR.

Operation of the Rod Control system has not changed and therefore the probability or consequences of an accident or malfunction have not increased. There is no adverse impact on the safety analysis since the rods remain trippable.

2. Create the possibility of a new or different type of accident from those previously evaluated in the safety analysis report. Physical plant modifications are not being made and plant operations are not being changed consequently new accident precursors are not being generated.

Therefore no new or different kind of accident is created.

3. Involve a significant reduction in the margin of safety. Plant operations are not being changed nor are any of the accident analysis assumptions being modified or exceed by this change. Therefore, the accident analysis assumptions remain bounding and safety margins remain unchanged.