ML17325B150
| ML17325B150 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 02/23/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17325B151 | List: |
| References | |
| NUDOCS 8903010096 | |
| Download: ML17325B150 (4) | |
Text
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t UNITED STATES NUCLEAR REGULATORY COMMISSION WASHIWGTOM,D. C. 20555 SAFETY EVALUATION BY. THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT N0.121 TO FACILITY OPERATING LICENSE NO.
DPR-58 INDIANA'ICHIGANPOWER COMPANY DONALD C.
COOK NUCLEAR PLANT UNIT NO.
1 DOCKET NO.
50"315
- 1. 0 INTRODUCTION By letter dated August 9, 1988, as revised January 10, 1989, the Indiana Michigan Power Company (the licensee) requested an amendment to the Technical Specifications (TSs) appended to Facility Operating License No.
DPR-58 for
, the Donald C.
Cook Nuclear Plant, Unit No. 1.
The proposed amendment would allow a one-time extension of the surveillance intervals of certain surveillances required to be performed at 9-or'18-month intervals.
The extensions involve the following four groups of TS surveillances:
l.
2.
3.
Ice basket weighing; Resistance temperature detector (RTD) calibrations; Ice condenser flow passage inspections; and Ice condenser inlet door testing.
The proposed extensions associated with the latter two categories were withdrawn by the licensee via a letter dated January 10, 1989.
This was because an unanticipated outage allowed the licensee to perform the necessary survei llances.
The outage was not of sufficient duration to permit performance of the survei llances associated with the first two categories.
Accordingly, the specific survei llances 'considered in this evaluation are as follows:
Technical S ecification 1.
4.6.5.1.b.2 2a.
Table 4.3-1, Item 7 2b.
Table 4.3-1, Item 8 Descri tion Ice basket weighing Overtemperature QT channel calibration Overpower OT channel calibration 2c.
- 4. 3. 2. 1. 2 Total interlock function test for P-12 8903010096 S90223 PDR AQOCK 05000315 P
2d.
Table 4.3-2, Items 1.f and 4.d Low-low Tavg channel calibrations 2e.
Table 4.3-7, I tern 2
2f.
Table 4.3-7, Item 3 Reactor coolant outlet temperature
- T channe1 ca1ibra6hn Reactor coolant inlet temperature
- T~~I channel calibra 2g.
Table 4.3-7, Item 11 Reactor coolant system subcooling margin monitor
-channel calibration These extensions are being sought because the length of the current fuel cycle has been extended beyond an 18-month duration due to 1) operation of the unit at 90K power for most of the cycle length to lessen potential stress corrosion cracking of steam generator
- tubes, and 2) power co'ast down of the unit to avoid a dual unit refueling outage.
In addition, the licensee's August 9, 1988 application proposed an editorial change to Table 4.3-2.
This change is being handled separately.
2.0 EVALUATION Grou 1:
Ice Basket Hei hin The licensee requests extension of the 9-month ice basket weighing required by TS 4.6.5.1.b.2.
Th'e current TS requires these survei llances to be performed by February 26, 1989.
The licensee proposes to extend the surveillance interval to allow the surveillance to be performed during the Cycle 10-11 refueling outage which is scheduled to begin in March, 1989.
The ice basket weighing can be partially performed at power, with personnel access limited to upper containment.
Baskets in Rows 1 and 9, however, often cannot be weighed without first freeing the baskets due to their tendency to become frozen in place.
This additioral operation requir'es personnel to enter lower containment which raises ALARA concerns.
The licensee has evaluated past ice basket weights and the effect of sublimation to determine the impact of the proposed extension on the ability of the ice condenser to perform its safety function.
TS 4.6.5.1.b.2, which requires weighing of ice'askets at 9-month intervals, also requires a minimum weight of 1220 pounds of ice per basket with a total ice condenser weight of 2,371,450 pounds.
"The minimum weight of 1220 pounds per basket contains.
a 10% conservative allowance for ice loss through sublimation with the intent to assure a minimum ice weight of 1098 pounds at the end of the surveillance interval.
The licensee, using data from past survei llances, has performed calculations to estimate the amount of ice that will be present in each basket at the end of the current surveillance interval including an extension period.
Specifically, calculations were performed to estimate ice weights on April 1, 1989.
The calculations were performed per basket for each ice condenser bay and each row group; this distinction being required by the TSs.
The first set of calculations estimated ice losses using data from the last seven surveillance intervals.
The ice loss rate calculations were performed using average expected values and values at the lower 95K confidence level.
These ice loss rates, both average rates and rates at the lower 95K confidence level, were then applied to the "as-left" ice weight of the latest surveillance, March 1988.
The results of the licensee's calculations performed at the lower 95% confidence level indicate that all bays except bay 24 are expected to have average basket weights above 1220 pounds.
Importantly, bay.- 24 is expected to have a lower 95%
confidence level, weight of 1200 pounds, significantly above the 1098 minimum acceptable ice weight.
Estimates of'asket weights for row groups resulted in the prediction that all row groups except 8-3 and 9-3 are expected to have weights above 1220 pounds.
Again, it is important to note that the exceptions are expected to have lower 95K confidence level weights of 1206 pounds and 1166
- pounds, also significantly above 1098 pounds.
The NRC staff has considered the arguments provided by the licensee and concurs that the proposed change to TS 4.6.5.1.b.2 to allow a one time extension of the surveillance interval for weighing the ice baskets is warranted and does not present a significant safety impact.
The surveillance interval extension proposed by the licensee involves a relatively brief time period of operation at power, and analysis indicates that the ice condenser, over that time period, will contain sufficient ice, adequately distributed, to perform its safety function.
Grou 2:
RTD Calibrations The licensee requests extension of surveillance intervals associated with calibration of RTDs.
The affected TSs are listed as Items 2.a through 2.g of Section I of this Safety Evaluation.
The licensee indicates that the current TSs require these surveillances to be performed by tlarch 26, 1989.
The licensee*
proposes to perform the testing during the Cycle 10-Ig refueling outage, which is expected to begin the same month.
The licensee requests relief for calibration of the RTDs only.
The licensee has indicated that the calibration cannot be performed at power since the calibration requires temperature data to be taken with the reactor coolant system at temperatures from the operating range (approximately 568 F) down to approximately 250 F.
The licensee has reviewed past RTD performance and has -found the devices to be very stable, with no significant drift.
The channels involved with the RTDs undergo channel checks and channel functional tests during power operation, which would be expected to alert plant operators to drift.
Since the extension period is brief and since the equipment is subject to periodic surveillance
- checks, there is not likely to be any impact on safety, and therefore the NRC staff finds the one-time extension request acceptable.
-4
- 3. 0 ENVIRONMENTAL CONS IDERATiON This amendment involves changes in surveillarce requirements..
We have determined that the amendment involves no sigrificant increase in the
- amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Coranission has previously issued'a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding.
Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b),
no environmental impact statement or environmental assessment need be prepared in connection with the issuance of this amendment.
4.0 CONCLUSION
We have concluded, based on the=considerations discussed above, that (I) there.
is reasonable assurance that the health and safety of the public will not be endangered by operation in the -proposed
- manner, and (2) such activities will be conducted in compliance with the Commission's'egulations, and the issuance of the amendment will not be inimical to the common defense and security or to the health and,safety of the public.
pate February 23,.19d9 Principal Contributor:
John Stang