ML20024G784
| ML20024G784 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 04/24/1991 |
| From: | Cross J PORTLAND GENERAL ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML20024G783 | List: |
| References | |
| NUDOCS 9104300298 | |
| Download: ML20024G784 (9) | |
Text
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PORTLAND CENERAL ELECTRIC COMPANY EUGENE WATER & ELECTRIC BOARD I
AND PACIFIC POWER & LICHT COMPANY Operating License NPF-1 Docket 50-344 License Change Application 205 This License Change Application requests modifications to Operating Licenso NPF-1 fer the Trojan Nucicar Plant to revise the Trojan Technical l
Specifications to modify the Resistance Temperature Detector element locations which may be used in determining the average Containment i
temperature.
l PORTLAND CENERAL ELECTRIC COMPANY By _
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James E. Cross Vice President Nuclear l
Subscribed and sworn to before me this 2 hay of Apell 1991.
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9104300298 910424 PDR ADOCK 05000344 P
LCA 205 i
Attachment A Page 1 of 8 De.ggription_nf Change A revision to the Surveillance Requirements for Trojan Technical Specification (TTS) 4.6.1.5, " Containment Systems Air Temperature", is proposed.
Five of the eight Containment Air Cooler (CAC) inlet Air Resistance Temperature Detector (RTD) elements are required to determine the primary Containment average air temperature.
The change proposes to use any five of the eight RTD elements (four located at the nominal 205-foot elevation and four located at the nominal 210-foot elevation) rather than requiring four of the eight to be from the nominal 210-foot elevation. A phrase "to be within the above limits" is also added to clarify that comparison of average Containment temperature to the established temper 3ture limit is required.
Renton for Change There are only four RTD elements which are located at the nominal 210-foot elevation.
Failure of any one of these four elements would result in noncompliance with the present TTS 4.6.1.5 regardless of the number of RTD elements available f rom the nominal 205-foot elevation.
The elevation levels for the RTD elements are shown in Figure 1.
The four RTD elements (i.e., Points 3, 7, 11, and 15 in Figure 2) discussed above are located between each pair of CACs and the center of Containment at the 211-foot-2-inch elevation (nominal 210-foot elevation). They are referred to as inboard RTDs in the referenced figures. The remaining four RTD elements (i.e., Points 1, 5, 9, and 13 in Figure 2), referred to as outboard RTDs, are located between each pair of CACs and the Containment wall at the 206-foot-6-inch elevation (nominal 205-foot elevation). Because acceptable Containment average air temperatures can be determined from any five of these eight RTD elements, the present TTS requirement to have four RTDs from the nominal 210-foot elevation is unnecessary.
Significant Hazards Consideration Determination In accordance with the requirements of Title 10 of the Code of Federal Regulations, Part 50.92 (10 CFR 50.92), this License Change Application (LCA) is judged to involve no significant hazards based upon the following considerations:
1.
Does the proposed license amendment involve a significent increase in the probability or consequences of an accident?
'The proposed changes provide an equivalent means for verifying Containment air temperatures. The verification ensures that the average Containment air temperature does not exceed the initial temperature condition assumed in the Loss of Coolant Accident (LOCA)
LCA 205 Attachment A Page 2 of 8 analysis nor the maximum allowable continuous duty temperature for equipment and instrumentation located within Containment.
Temperature readings recorded during full-power operation between September 1 and December 31, 1989 were analyzed. A comparison was then made between readings taken by inboard RDT elements versus outboard RTD elements for the same CAC.
This comparison is shown in Figure 3.
This figure shows that the temperature diff.cence for the CAC No. VC-204 location is significantly larger than the differences shown for the other locations.
The cause of this abnormality is thet RTD Element No. 13 is reading 5'F too low. That determination was made from computing the performance of CAC No. VC-204A using the cold air RTD Element No.14 and the RTD Element No.13.
Figure 4 shows the apparent reduced performance of CAC No. VC-204A.
Further evidence that RTD Element No. 13 is not functioning properly is shown in Figure 5,-which shows the average deviation of individual RTDs from the average inboard or outboard reading.
Until RTD Element No. 13 is replaced, administrative controls will be established not to use this element in determining the Containment average air temperature.
With the data from CAC No. VC-204 removed from Figure 3, excellent agreement is shown between the inboard and outboard temperature readings.
Since the Containment temperature limits remain the same and the equivalency of temperature readings between the inboard and outbcard RTDs have been established via review of actual temperature data, there will not be any increase in either the probability or-consequences of an accident due to the proposed change.
2.
Does the proposed licenso amendment create the possibility of a new or different kind of accident from any previously evaluated?
As discussed above, the propcsed changes provide a technically equivalent means for verifying Containment air temperature.
Consequently, a new or different type of accident will not be created.
3.
Does the proposed license amendment involve a significant reduction in a margin of safety?
Because the proposed changes meet the intent of the bases of the TTS, a margin of safety will not be reduced.
Safetv/ Environmental Evaluation Safsty and environmental evaluations were performed as required by 10 CFR 50 and the TTS. The review determined that the proposed changes do not create an unreviewed safety question, nor does it create an unreviewed environmental question.
LCA 205 i
Attachment A Page 3 of 8 Schedule _Conaldexations It is requested that the effective date of the amendment be 30 days after issuance by the Nuclear Regulatory Commission.
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SUPPORT BEAM cOf(Tall { MENT WALL TYP:CA _ CAC COOLil10 COILS
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.g DNIATION : OF1NDIVIDUAL RTD FOR AVERAGE LIKE RTDS Dally readings from 9/1/89 thru 12/31/89 3
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