ML20099C491
| ML20099C491 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 11/09/1984 |
| From: | Fay C WISCONSIN ELECTRIC POWER CO. |
| To: | Harold Denton, John Miller Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20099C493 | List: |
| References | |
| NUDOCS 8411190560 | |
| Download: ML20099C491 (4) | |
Text
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Wisconsin Electnc eom coumr 231 W. MICHIGAN, P.O. BOX 2046. MILWAUKEE, WI 53201 November 9, 1984 CERTIFIED MAIL Mr.
H. R.
Denton, Director Office of Nuclear Reactor Regulation U.
S. NUCLEAR REGULATORY COMMISSION Washington, D. C.
20555 Attention:
Mr.
J.
R. Miller, Chief Operating Reactors, Branch 3 Gentlemen:
DOCKET NOS. 50-266 AND 50-301 TECHNICAL SPECIFICATION CHANGE REQUEST NO. 102 OVERPOWER AND OVERTEMPERATURE AT LAG COMPENSATION POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 In accordance with the requirements of 10 CFR Sections 50.59, 50.90, and 50.91(a) (6), Wisconsin Electric Power Company (Licensee) hereby submits an application for amendments to Facility Operating Licenses DPR-24 and DPR-27 for the Point Beach Nuclear Plant, Units 1 and 2.
The purpose of these amendments is to incorporate additions to Specifications 15. 2. 3.1.B (4), "Overtemperature AT", and 15. 2. 3.1. B (5), " Overpower AT",
to specify the time constants utilized in the measured AT and average temperature lag compensations which are part of the instrumentation for the overtemperature and overpower AT sensing circuitry.
Ne request that these amendments be issued by November 16, 1984 for Point Beach Unit 2 in accordance with the provisions of 10 CFR 50.91(a) (6).
An explanation regarding the exigent circumstances which necessitate this expedited treatment is provided below.
On October 5, 1981 the NRC issued to Wisconsin Electric License Amendments 86 and 90 to Facility Operating Licenses DPR-24 and DPR-27, respectively.
These license amendments include Technical Specification revisions to allow the use of Westinghouse optimized fuel assemblies (OFA' s) at Point Beach Nuclear Plant, Units 1 and 2.
The safety evaluation provided with these amendments also approved several changes to the analysis and operating procedures for the reactors, including use of the Wcstinghouse improved thermal design 8411190060 841109 PDR ADOCK 05000266 j
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procedures (ITDP' s) for the OFA fuel along with the WRB-1 DNB correlations.
Presently, Point Beach. Unit 2 is shut down for a maintenance and refueling outage which includes loading 'a region of OFA reactor fuel.
4 1
i In preparation for use of OFA fuel and the ITDP's, we observed that the primary system resistance temperature detectors (RTD' s) are required to satisfy an enhanced calibration accuracy.
Approximately two weeks ago' we discovered that electrical noise associated with switching between a calibration standard RTD and the Sostman RTD's installed at Point Beach interfered with the calibration procedure.
The noise was only generated when the Sostman RTD's were used.in the calibration circuit.
This problem precluded accurate calibration of the Sostman RTD's.
We determined that replacing the Sostman RTD's with Rosemont RTD's would satisfy i
+the calibration requirements.
We, therefore, expedited procurement 3
of appropriate Rosemont RTD's and informed Westinghouse of our actions.
i About one week ago, Westinghouse informed us that they recommend that a two-second filter be used with the Rosemont RTD's.
l The circuitry to provide this two-second filter is a part of the original reactor protection instrumentation installed at Point j
Beach.
Westinghouse noted that in their modeling of the over-temperature' and overpower AT trip functions an allowance has been made for a filter constant of up to two seconds.
From an analytical and electrical point of view, there is no difference between use j
of a Sostman RTD with no filter or a Rosemont RTD with a two-second i
filter.
Indeed, the change to the over temperature AT and overpower AT equations requested in this application does no more than add a mathematical term (1/1 + t) which was always implicit in the equations in the existing Technical Specifications, but was never explicitly stated because, with the Sostman RTD's incorporating a built-in filter, t was equal to 0 and 1/1 + 0 was equal to'l.
Thus, the term had no math'ematical significance.
The entire system response does not change with the use of a two-second filter in the instrumentation and processing equipment rather than within the RTD itself.
I In subsequent discussions with Westinghouse, the NRC l
Resident Inspector, and Mr. Tim Colburn of your staff, it was determined that the Point Beach Technical Specifications should l
be modified to reflect the mathematical equivalent of the entire circuit.
The NRC staff personnel furthermore indicated that this change should be issued prior to returning Point Beach Unit 2 to power.
Mr.
H. R.
Denton November 9, 1984 We have considered the alternative of utilizing the Rosemont RTD's without a two-second lag compensation factor.
Indeed, in reality, there is no change to the system function at all.
However, with the f aster time response of the Rosemont RTD's it is possible that the overtemperature and overpower trip circuitry could be actuated during normal thermal transients not requiring protection system actuation.
This could result in spurious turbine runbacks or reactor trips.
We believe that it is appropriate to avoid to the greatest extent possible unnecessary challenges to the reactor protection circuits.
Therefore, to ensure the most reliable operation of Point Beach Unit 2 during the next cycle of operation we would prefer returning to power with the two-second filter in the circuit.
In accordance with the requirements of 10 CFR 50.92, we have examined these changes and determined that these additions to the Specifications do not constitute a significant hazards consideration.
In making this determination, we observed that the guidance previously provided by the Commission in 48 Federal Register 14864 states that changes that constitute additional limitations, restrictions, or controls not presently in the specification are not likely to involve significant hazards consideration.
In addition, as noted above, Westinghouse modeling includes an allowance for this filter constant, and the safety analysis is not affected by this change.
Accordingly, the three criteria for no significant hazards concideration in 10 CFR 50.92 (c) are also satisfied.
We were unaware of the calibration problems which necessitated changing the RTD's until two weeks ago.
We did not learn about the recommendation of the vendor to utilize a two-second filter with the replacement RTD's until one week ago.
It is only within the last several days that we were informed of the desirability to change the Technical Specifications to more explicitly reflect the lag compen-sation factor prior to Unit 2 startup.
Therefore, we believe that sufficient exigent circumstances exist for the Commission to issue these changes under the provisions of 10 CFR 50. 91(a) (6).
As noted previously, our planned return to power date for Point Beach Unit 2 is November 16, 1984.
Approval of this mmendments application for Unit 2 by that date is requested.
These changes are not required for Point Beach Unit 1 operation until the end of the spring 1985 refueling outage.
Enclosed with this request is a check in the amount of
$150 for the application fee required by 10 CFR 170.
Mr. H.
R. Denton November 9, 1984 In accordance with Commission regulations, enclosed are three originals and erty copies of.this amendments application.
Your prompt consi ~
tion and approval of this request will certainly be ap' ated.
Very truly your,
6d i
Vice President-Nuclear Power C. W. Fay Enclosure (Check No. 815696)
Copies to NRC Resident Inspector R.
S.
Cullen, PSCW Subscribqd and sworn to before me this 9 *'l day of November 1984.
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