ML20070G682

Forwards Revised Proposed Changes to Tech Specs Sections 3/4.3.1 & 3/4.3.2 Re Increased Surveillance Test Intervals & Allowed Outage Times for RTS & ESF Actuation Sys Instrumentation,Per NRC 910305 Request

ML20070G682
Person / Time
Site:	Wolf Creek
Issue date:	03/08/1991
From:	Rhodes F WOLF CREEK NUCLEAR OPERATING CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20070G683	List: ML20070G682 ML20070G706
References
ET-91-0053, ET-91-53, NUDOCS 9103120293
Download: ML20070G682 (4)

Text

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W(ELF CREEK NUCLEAR OPERATING CORPORATION Forrest T. F4hodes ve. pre.m March 8, 1991 Egwng & Techn cal swvees g7 91.Oo$3 U. S. Nuclear Regulatory Cotrnission ATTH: Document Control Desk Mail Station P1-137 Washington, D. C. 20555

Reference:

Letter ET 91-0047 dated February 27, 1991 from F. T.

Rhodes, WCNOC to the NRC

Subject:

Docket No. 50-482: Changes to Proposed Revision to Technical Specifications 3/4.3.1 and 3/4.5.2 - Increased Surveillance Test Intervals and Allowed Outaga Times for Reactor Trip System and Engineered Safety Features Actuation System Instrumentation Gentlemen:

In Reference 1 Wolf Creek Nuclear Operating Corporation (WCNOC) submitted proposed Technical Specification changes to Sew .ons 3/4.3.1 and 3/4.3.2. As discussed between Mr. D. V. Pickett, NRC ane Mr. H. K. Chernoff. WCNOC on March 5, 1991, additional information is being provided concerning ESFAS instrument setpoint drift. Additionally, this letter transmits revised marked-up pages for the Technical Specifications.

Revisions to the enclosed pages are identified with a revision bar. The enclosed pages should be inserted into Reference 1.

In accordance with 10 CFR 50.91, a copy of the revised pages is being provided to the designated Kansas State Official. If you have any question concerning this matter, please contact me or Mr. H. K. Chernoff of my staff.

Very truly yours, p.yY Forrest T. Rhodes Vice President Engineering & Technical Services FTR/sgw Enclosures cci G. W. Allen (KDHE), w/e A. T. Howell (NRC), w/e R. D. Martin (NRC), w/e D. V. Pickett (NRC), w/e M. E. Skov (NRC), w/e i 1

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STATE OF KANSAS )

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Forrest T. Rhodes, of lawful age, being first duly sworn upon oath says that he is Vice President Engineering and Technical Services of k'olf Creek Nuclear Operating Corporations that he has read the foregoing document and knows the content thereof: that he has executed that same for and on behalf of said Corporation with full power and authority to do so and that the facts therein stated are true and correct to the best of his knowledge, information and belief.

() {\l ? l By 'V i . N?-

Forrest T. Rhods-Vice President Engineering & Technical Services SUBSCRIBED and sworn to before me this f day of 77744b, 1991.

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l Attachment I to ET 91-0047 Page 8 of 11 A review was performed on the impact of extending the A0Ts for those '

SSPS functions (i.e., steam generator level low-low, phase A containment isolation, safety injection, and SSPS logic) which provide input to plant-specific design features such as BOP ESFAS.

Implementation of the following plant-specific functions is affected by any change in signal availability to or from the BOP ESFAS:

(a) containment purge isolation (Functional Unit 3.c)

(b) auxiliary feedwater initiation (Functional Unit 6.d)

(c) control room ventilation isointion (Functional Unit 9)

No changes are proposed to the technical specification requirements for the BOP ESFA ' actuation logic and relays (i.e., no changes are proposed for Functional Units 3.c.3), 6.c. or 9.c) and the unavailability of the BOP ESPAS itself remains unchanged. For the above functions (a) through (c), overall function unavailability is made up of two ceparate components representing SSPS unavailability and BOP ESFAS unavailability, the latter remaining unchanged. As reported in Tables 3.6-6 and 3.6-9 of WCAP-10271, Supplement 2, Revision 1, typical unavailability for safety injection and auxiliary feedwater pump start increased by a factor of 3 to 6. Given that the BOP ESFAS unavailability does not change, the overall functional unavailability increase would be bounded by the factor of 3 to 6 inctaase in SSPS unavailability, regardless of what value is assigned to the BOP ESPAS unavailability (typical value is SE-04). Similar conclusions can also be drawn for Functional Units 4 and 5 which are implemented via the Main Steam / Main Feedwater Isolation Actuation System.

Therefore, the overall impact of the changes in SSPS unavailability resulting from the generic technical specification changes on the affected plant-specific ESFAS functions remains within the bounds of the generic analysis,

b. SER Condition - Confirm that any increase in instrument drift due to the extended STIs is properly accounted for in the setpoint calculation methodology. '

Response -

From the monthly ACOTs performed on the ESPAS instrumentation, WCNOC collects the 'as found" and 'as left' data including accumulated drift for trending of calibration /setpoint drift. A review of this data confirmed that the setpoint drift which could be expected under the extended STIs remains within the existing allowance in the ESFAS instrument setpoint calculation. To support this conclusion, "as found" and 'as left" data for those ESFAS channels with increased STIs will be collected over a one year period after quarterly testing is begun. WCNOC will review this data to verify that any setpoint drift remains within the existing allowance in the ESFAS instrument setpoint calculation.

l J

Attachment II to ET 91-0047 Page 3 of 3 Standard 2 - Create the Possibility of a New or Different Kind of Accident from any Previously Analyzed.

The proposed changes do not involve hardware changes and do not result in a change in the manner in which the RTS or ESFAS provide plant protection. No change is being made which alters the functioning of the RTS or ESFAS. Rather the likelihood or probability of the RTS or ESFAS functioning properly is affected as described above. Therefore the proposed changes do not create the possibility of a new or different kind of accident.

Standard 3 - Involve a Significant Reduction in a Margin of Safety.

The proposed changes do not alter the manner in which safety limits, limiting safety system settings, or limiting conditions for operation are determined.

The impact of reduced testing, other than as addressed above, is to allow a longer time interval over which instrument uncertainties (e.g., drift) may act. The review of existing monthly calibration /setpoint drift data for ESFAS instrumentation addresses this concern. Implementation of the proposed changes is expected to result in an overall improvement in safety, as follows:

a. Reduced testing will result in fewer inadvertent reactor trips, less frequent actuation of ESFAS components, and less frequent distraction of operations personnel.

b. Improvements in the effectiveness of the operating staff in monitoring and controlling plant operation will be realized. This is due to less frequent distraction of the operators and shift supervisor to attend to instrumentation testing,

c. Longer repair times associated with increased A0Te will lead to higher quality repairs and improved reliability.

Based on the above discussions, it has been determined that the proposed technical specification revisions do not involve a significant increase in the probability or consequences of an accident previously evaluated or create the possibility of a new or different kind of accidents or involve a significant reduction in a margin of safety. Therefore, this amendment application does not involve a significant hazards consideration.

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