ML20064K864
| ML20064K864 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 03/15/1994 |
| From: | Powers K TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-90-001, IEB-90-1, TAC-M85442, TAC-M85443, NUDOCS 9403230325 | |
| Download: ML20064K864 (4) | |
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March 15, 1994 U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C. 20555 Centlemen:
In the Matter of
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Docket Nos. 50-327 Tennessee Valley Authority
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50-328 SEQUOYAH NUCLEAR PLANT (SQN) - NRC BULLETIN 90-01, SUPPLEMENT 1 - LOSS OF FILL-01L IN TRANSMITTERS MANUFACTURED BY ROSEMOUNT, VERBAL REQUEST FOR ADDITIONAL INFORMATION (TAC NOS. 85442 AND 85443)
References:
1.
TVA letter to N9r' dated March 4,1993, "Sequoyah Nuclear Plant (SQN) - N'.: Bulletin 90-01, Suppicn:ent 1 - Loss of F111-011 in Transmitters Manufactured by Rosemount" 2.
TVA letter to NRC dated December 4, 1992, "Sequoyah i
Nuclear Plant (SQN) - NRC Bulletin 90 Loss of F111-011 in Transnsitters Manufactured by Rosemount -
Updated Response" 3.
'IVA letter to NRC dated July 13, 1990, "Sequoyah Nuclear Plant (SQN) - NRC Bulletin 90 Loss of F111-011 in Transmitters Manufactured by Rosemount" The purpose of this letter is to provide a detailed description of the SQN Rosemount transmitter trending program as requested by NRC during a February 2, 1994, telephone conversation. The attached enclosure provider the requested program description.
In addition, as a result of further evaluation of the merits of continuing to trend certain Rosemount transmitters, TVA will no longer trend Flow Transmitters 1-FT-3-155 -163; I and.2-FT-72-13, -34.
Flow Transmitter 1-FT-3-155 was replaced during the Unit 1 Cycle 6 refueling outage with a post-1989 transmitter.
Flow Transmitter 1-FT-3-163 has I
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'7 DR. ADOCK 05000327 '
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U.S. Nuclear Regulatory Commission Page 2 March 15, 1994 surpassed its pound per square inch (psi) per month criteria with acceptable trend data; and in accordance with NRC Bulletin 90-01, Supplement 1, Section 1.e guidance, further trending is not required.
Flow Transmitters 1 and 2-FT-72-13, -34 are in the containment sprap i
system that is only pressurized during testing.
The normal system operating pressure is less than 500 psi.
Based on NRC Bulletin 90-(41, Supplement 1, Section 1.f guidance, these transmitters will no longer be trended. Three transmitters will remain in the trending program:
1 and 2-FT-3-142 and 1-FT-3-147.
i Please direct questions concerning this issue to W. C. Ludwig at (615) 843-7460.
Sincerely) i
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f Ken Powers Site Vice President Sequoyah Nuclear Plant t
Enclosure cc (Enclosure):
Mr. D. E. LaBarge, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852-2739 NRC Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy-Daisy, Tennessee 37379-3624 Regional Administrator U.S. Nucicar Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323-2711 4
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ENCLOSURE SEQUOYAH NUCLEAR PLANT (SQN) UNITS 1 AND 2 RESPONSE TO NRC BULLETIN 90-01, SUPPLEMENT 1 -
i LOSS OF FILL-0IL IN TRANSMITTERS MANUFACTURED BY ROSEMOUNT, VERBAL REQUEST FOR ADDITIONAL INFORMATION i
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Enclosure The purpose of this enclosure is to provide a description of SQN's trending program for Rosemount Model 1153 transmitters.
The trending process used by SQN consists of baselining the transmitters to calibration data taken ir alender year 1985. This data was plotted as zero on the y axis being L 'eled " Deviation from Nominal Output." The i
calibration cycle (each calibration of transmitter) was plotted on the x l
axis. At the next calibration, the "as-found" calibration data was algebraically added to the baseline value and plotted as deviation from nominal output. This stsp was repeated for each of the five calibration values (4.00, 8.00, 12.00, 16.00, and 20.00 mil 11 ampere [mA]).
l Successive calibration cycles were plotted by factoring in the calibration adjustments so that each calibration value was referenced back to the baseline zero values. This resulted in a trend that showed I
absolute change of the transmitters after each calibration referenced to the 1985 baseline. The criteria used to determine when a transmit <r should be changed out was three consecutive out of calibrations in tne same direction of a magnitude that required readjustment of the trar.smitter to meet the as-Icft calibration acceptance criteria. As-left acceptance criteria contained in the surveillance instruction (SI) is 4.00 +/
.04 mA.
Additionally, the as-found acceptance criteria found in the SI is 4.00 +/
.46 mA.
At no time was the out of calibration ns-found acceptance criteria violated.
The range code 5 transmitters used in the auxiliary feedwater system have a calibration range of 0 to 300 inches of water.
Based on the Rosemount Technical Bulletin (TB) No. 4, the range down factor (RDF) equals 750 inches of water divided by 300 inches of water or 2.5.
The published zero-drift limits in TB No. 4 are -0.8 percent and +1.45 percent upper range limit (URL). The true zero drift limit is then computed to be
-2.0 percent and +3.63 percent. The most conservative case for these transmitters is the -2.0 percent zero drift limit. Since the data supplied in the TB No. 4 is for a 12-month cycle, the -2.0 percent zero drift limit must be multiplied by 1.5 as SQN uses an 18-month calibration cycle (18 months /12 months = 1.5).
Therefore, for SQN, the zero drift rate computes to be -3.0 percent. The calibrated span for the SQN transmitters is 16 mA (20 - 4 mA). The acceptance criteria in engineering units for zero drift of calibrated span equate to 3.52 mA (4.0 - [.03 x 16 ]).
The acceptance criteria in the SI for the as-found low limit at the zero point are 3.54 mA (4.00 +/
.46 mA). A review of the calibration data for the auxiliary feedwater flow transmitters in question indicates that none of the transmitters exceeded the zero drift as-found acceptance criteria. The method of trending'that SQN applies is j
more conservative than the method described in Rosemount's TB No. 4.
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should be noted that if SQN had used the Rosemount methodology. Flow Transmitter 1-FT-3-155 would not have been replaced during the Unit 1 Cycle 6 refueling outage.
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