ML20091B967
| ML20091B967 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 04/25/1984 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| Shared Package | |
| ML20091B878 | List: |
| References | |
| NUDOCS 8405300448 | |
| Download: ML20091B967 (5) | |
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TENNESSEE VAL' LEY AUTHOslTY CH ATTANOOGA. TENNESSEE 374o1 400 Chestnut Street Tower II
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I Pl: 32 April 25, 1984 U.S. Nuclear Regulatory Commission Region II ATTN: James P. O'Reilly, Regional Administrator 101 Marietta St.reet, NW, Suite 2900 Atlanta, Georgia 30303
Dear Mr. O'Reilly:
Enclosed is our response to R. C. Lewis' March 28, 1984, letter to H. G. Parris transmitting Inspection Report Nos.
50-259/84-07, -260/84-07, -296/84-07 regar ding activities at our Browns Ferry Nuclear Plant which appeared to have been in violation of NRC regulations. We have enclosed our response to the Notice of Violation as enclosure 1 and the Notice of Deviation as enclosure 2.
If you have any questions, please call Jim Domer at FTS 858-2725.
To the best of my knowledge, I declare the statements contained herein are complete and true.
Very truly yours, TENNE 3SEE VALLEY AUTHORITY L. M. Mills, Matager Nuolear Licensing Enclosure NK*olQ a
PDR An Equal Opportunity Employer
-1 RESh0NSE - NRC ' INSPECTION ' REPORT NOS. -
t 50-259/84-07, 50-260/84-07, AND 50-296/84-07 RICHARD C. LEWIS'S LETTER TO H. G. PARRIS DATED MARCH 28, 1984 Item 1 - (259/84-07-02) 10 CFR 50, Appendix B, Criterion V requires that activities affecting quality shall be prescribed by documented instructions, procedures, or -
drawings, of a type appropriate to the circumstances and shall be accomplished in accordance with these instructions, procedures, or drawings.
Contrary to the above, this requirement was not met in that Standard i
Practice 23 1 (Nuclear Digital. Computer Software Systems) was not adequately accomplished to control the K, breakpoint factor used in the determination of the Minimum Critical Po9er Ratio (MCPR) correction for red'uced flow. This resulted in nonconservative calculations by the process computer of the MCPR limit from the beginning of. cycle startup on December 29, 1983 until January 30, 1984. A factor of 0 75 was used-instead of 0.80.
MCPR requirements are specified in Technical Specification 3 5.K.
This is a Severity Level IV Violation (Supplement I) applicable to Unit 1.
1.
Admission or Denial of the Alleged Violation TVA. admits the violation occurred as stated.
2.
Reasons For the Violation The problem was caused by a lack of administrative controls governing reinitializing the process computer. This event' was caused by loading a core dump which was generated before correcting K. Inadequate' proceduresallowedthewrongcomputertapetobeuskdtoreinitialize the process computer, thus overlaying the correct K.with a previous' J
g fuel cycle K.
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Corrective Steps-Which Have Been Taken and the Results Achieved A' review of thermal limit calculations for the period-K, in error was conducted.
It was verified core maximum fraction of critical power did not-exceed 0 90 during this period. This would result in a maximum core fraction of critical power of 0 92 it. operating near 75 percent core flow. The~ error would be:much less at' lower flows and no error above 80 percent flow. This leaves at least an 8. percent margin to the
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'ltaiting value of 1.0.
A comparison between the core dump for J.
January 31, 1984, and the beginning of cycle core dump was made. This verified that all other nuclear system steam supply process computer y,
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constants are correct at this time.
4.
Corrective Steps Which Will Be Taken To Avcid Further Violations 4
Since this' event, a plant instruction (BF 23 3) delineating reiniti--
F alizing the process computer has been issued.. BF 23 3 requires documented approval by a plant nuclear engineer and a systems analyst j-any time nuclear system steam supply real time or rod worth minimizer I
sequence data is changed. These changes are reviewed by the reactor-engineering unit supervisor and.the computer unit supervisor when l
completed. A training class was given by the computer unit supervisor i
to all nuclear engineers and computer specialists concerning BF 23 3.on 1
March 8,.1984.
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Date When Full Compliance Was Achieved Full compliance was achieved March 8, 1984, when Standard Practice BF 23 3 was revised and approved by PORC.
Item 2 - (259/260/84-07-04)
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Technical Specification 3 7.G.2 requires that the Containment Atmosphere j-Dilution (CAD) System shall be operable whenever the reactor mode switch is l
in the "RUN" position.
i Contrary to the above, this requirement was not met in that the~two independent CAD systems were inoperable from January 25-27, 1984,'for 40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> due to isolation valves 0-84-506 and 0-84-556 in the CAD tank pressure buildup. circuit being shut contrary to operating requirements.
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Units one and two-were operating in the "RUN" mode during this time.
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i This is a Severity Level IV Violation (Supplement I) applicable to Units 1.
and 2.'
Item'3 - (259/260/84-07-05)
Technical Specification 6 3.A.1 requires that detailed written procedures shall be prepared, approved, and adhered to for normal startup, operation and shutdown of the reactor and of all systems and components involving j
nuclear safety of.the facility.
Contrary.to the above, this requirement was not met in that plant' operating 3
instruction OI-84 for the Containment Atmosphere Dilution (CAD)' system was
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not followed on January 25, 1984, resulting-in two valves (0-84-506 on i
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'A' and 0-84-556 on System 'B') being left misaligned in the shut position after a routine nitrogen addition to the two containment atmosphere dilution tanks. These valves isolated the CAD tank automatic pressure buildup control circuit.
This is a Severity Level IV Violation (Supplement I) applicable to Units 1 and 2.
1.
Admission or Denial of the Alleged Violations TVA admits violations 2 and 3 occurred as stated, f
2.
Reasons for Violations 2 and 3 if Admitted The event occurred because of improper valve lineup by unlicensed operators either after a special test, or after filling the tanks-following the special test, which occurred on January 25, 1984, during the 1500-2300 shift. However, the lineup of these valves after filling the tanks was not specifically addressed in the system operating instruction.
3.
Corrective Steps Which Have Been Taken and the Results Achieved The operating instruction (OI-84) was changed on February 16, 1984, to address the proper operation. A caution order was placed on each valve and an information letter was sent to all operations personnel I
on February 2, 1984, describing the event and expressing the importance of logging abnormal valve l.ineup.
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Corrective Steps Which Will Be Taken To Avoid Further Violations l
No additional corrective steps are planned.
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Date When Full Compliance Was Achieved Full compliance was achieved February 16, 1984, when 01-84 was revised.
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Notice of Deviation (259/260/84-07-01)
Tennessee Valley Authority's letter dated August 4, 1982, in response to Browns Ferry Inspection Report 82-11 of June 16, 1982, stated that, in regard to Appendix "A" violation, an evaluation of the Units-1 and 2 safety-related piping would be conducted to verify piping supports were adequate and the results would be reported to the NRC by January 17, 1984.
~4-Contrary to the above, evaluation results have not been received as of February 25, 1984.
- 1. ~ Corrective Action Regarding this Deviation A supplemental response to item 259/82-11-01 of NRC Inspection Report 82-11 was sent from L. M. Mills to J. P. O'Heilly on March 21, 1984 providing the details of the inspection of suspect safety-related piping in units 1 and 2 for possible inadequately supported test, vent, or drain connections.
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Action Taken to Avoid Further Deviations In order to prevent further deviations of this type, our modification group is placing more emphasis on commitments and has added an additional person to handle their compliance items. To help ensure that all commitments are implemented in a timely manner, the compliance staff is now obtaining weekly an overdue items printout.
3 Date When These Actions Were or Will Be Completed Full compliance was achieved on March 21, 1984, when the supplemental response was transmitted.
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