ML20108A650

Responds to NRC Re Violation Noted in Insp Repts 50-327/83-26 & 50-328/83-26.Corrective Actions:Computer Program Corrected & Revised.Violation Denied in Item C of Notice of Violation

ML20108A650
Person / Time
Site:	Sequoyah
Issue date:	01/20/1984
From:	Mills L TENNESSEE VALLEY AUTHORITY
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20108A579	List: ML20108A650
References
NUDOCS 8411150094
Download: ML20108A650 (7)

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. j, TENNESSEE' VALLEY-AUTHORITY.

CH ATTANOOGA TENNESSEE 374ot 400 Chestnut Street Tower II

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January 20,.1984 U.S. Nuclear Regulatory Commission Region II.

Attn:

Mr. James P. O'Reilly, Regional Administrator 101 Marietta Street, NW, Suite 2900' Atlanta, Georgia 30303

Dear Mr. O'Reilly:

SEQUOYAH NUCLEAR PLANT UNITS 1 AND 2 - NRC-0IE REGION II' INSPECTION REPORT 50-327/83-26 AND 50-328/83 ' RESPONSE TO VIOLATION The subject OIE inspection report dated December 21, 1983 from R. C. Lewis to H. G. Parris cited TVA with two Severity Level IV Violations and one Severity Level V violation.

Enclosed is the response to the items of violation specified in the subject inspection report.

If you have any questions, please get in ' ouch with R. H. Shell at c

FTS 858-2688..

i' To the best of my knowledge, I declare the statements contain'ed herein are complete and true.

Very truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills, Anager Nuolear Licensing-Enclosure cc (Enclosure):

Mr. Richard C. DeYoung, Director Office of Inspcotion and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C.

20555 Records Center Institute of Nuclear Power Operations 1100 Circle 75 Parkway, Suite 1500 Atlanta, Georgia 30339 i

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0 An Equal Opportunity Employer m...

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~ ENCLOSURE 7

' eq RESPONSE -- NRC INSPECTION REPORT NOS.

50-327/83-26 AND 50-328/83-26 R. C. LEWIS' LETTER TO H. G. PARRIS

-DATED DECEMBER-21', 1983-Item'A (327/83-26-01)

Technical-Specification 2.2.1, Table 2.2-1, item 7 and Technical Specification 3 3 1.1 require that the reactor' trip systems overtemperature delta T.-(OTAT) instrumentation trip setpoint be less than er equal to the computed trip setpoint values. With a setpoint less conservative than a maximum of 2% in excess of computed setpoint,.the &annel is to be declared inoperable and the action statement of Technical Specification 3 3.1.1 applied. A minimum of three 1

0 TAT channels is mquired to-be operable. Contrary to the above, all four channels of OTAT were degraded beyond the allowed 2% and thus wem inoperable.

An erroneous non-conservative data value existed in the program utilized in calibrating the error signal generating circuitry since Unit 1 cycle 2 restart in January 1983 Upon discovery on October 25, 1983, the licensee immediately.

i complied with Technical Specification 3.0.3 and corrected the calibration error.

This is a Severity Leve'l IV Violation (Supplement I).

This violation applies to Unit 1 only.

1.

Admission or Denial of the Alleged Violation TVA admits the violation occurred as stated.

2.

Reasons for the Violation if Admitted On October 25, 1983, during mealibration of unit 2 reactor. trip instrumentation for overtemperature delta T, it was noted that the calibration procedures contained incorrect values. An immediate review of unit 1 calibration data revealed that all four unit 1 overtempera-j ture delta T channels were less conservative t 'an technical i

specification allowable values.

l-A technical specification change issued in January 1983 revised the values which define the delta I dead band boundaries and the rate at which the overtemperature delta T trip setpoints are reduced as delta I exceeds the dead band limits. These technical specification values are utilized in a cottputer program which calculates the instrumentation setpoints for the dannels. When the new technical specification

. change was issued, personnel updated the computer program to include i

these new values. Investigation revealed that personnel had failed to

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correct two additional values in the program which were dependent upon the technical specification values. Subsequent review of the calibra-tion data during the normal review cycle failed to discover the error.

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7 3.. Corrrctiva Stcp1 Which Havn Bern Teken end tha R culta Achievrd 1The computer program'was corrected upon discovery and new setpoints calculated. Unit 1 complied with LCO 3 0.3 and the overtemperature delta T channels were all recalibrated by 1434 (CST) on October.25,

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1983. The computer program has been revised; to calculate the values that were inadvertently not changed rather than require personnel to hand calculate and change them, display the current technical specifi-1

~ ation values and request user verification, and print the technical c

specification values being -used.on the hard copy printout of the calib-ration data. The calibration procedure Technical Instruction (TI) 36, "Incore-Excore. Calibration," has been revised to reference the technical specification for the values. -

4.

Corrective Steps Which Will be Taken To Avoid Further Violations No further action is required.

5.

Date When Full Compliance Will be Achieved The plant was in fbil compliance on October 25, 1983 f

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Item'B:(327.'328/83-26-0'2) h en

- Technical Specification 3 7 9 requires all carsty-relsted-snubbsra be l

operable when' in Modes.1 through' 4.- Tables 4.7.9.a and. 4.7.9.b list the

' numbers of snubbers mquired by size for various. systems..' Technical Speci-tfication 3 0.4 requires that entry into an operational ~ mode.or other speci :

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fied condition:shall' not:be made unless the conditions for the Limiting iConditions' for ' Operation (LCO) are met without; reliance on provisions.in-

. the action' requirements.

Contrary to the above, Unit'.1:was in Mode 1:and. Unit 2 in Mode 3 'on October 7,1983, with' the Reactor Coolant System (RCS) having.less than the Technical Specification specified number of snubbers on that system. The

' licensee had. implemented an engineering chan6e on' the RCS by installing.

drain lines and valves;on pressurizer safety valve: loop seal' piping:and reconfiguring the-. seismic supports in accordance with the seismic analysis

- without having affected a Technical Specification change before accending

. modes.:- The licensee ' conferred with NRC/NRR and regional management representa-

-tives and submitted.an administrative &ange to the Technical Specification -

p table.as part of its inanediate. corrective actions.

This is.a Severity LeveliV Violation (Supplement'I). This violation.

applies to Unit 1 and Unit'2.

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!1.. Admission or Denial of the Alleged-Violation TVA admits.the violation occurred as stated.

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2.

Reasons for the Violation if Admitted On October 7,1983, the Field Quality Engineering Group was myiewing a :

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Field Services Group' workplan which included a change to Surveillance Instruction (SI)- 162.1, and during this myiew, identified a potential discrepancy between the SI and the technical specification LCO table.

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This prompted a thorough investigation into safety-related snubbers by j

plant management. The investigation revealed two main items,- these i

being -(a) that the technical specification LCO table -did not m flect I

the same number of snubbers by size and system when. compared to

'SI-162.1,' and (b) that neither the LCO table nor SI-162.1 reflected the actual count of safety-related snubbers in the plant. Factors contrib-4 uting to (a) above are that there was approximately one year's differ-ence between the preparation of the LCO table and SI-162.1 (revision 1),

i and that either, during this time, different drawings were used or an -

incorrect count.was made from the drawings. It appears that the LCO

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table and SI did not agree from the date of issuance.

Item (b) was I

most probably caused by the failure to use the latest as-constructed i

drawings during the preparation of the LCO table and the SI-162.1 listing. Contributing to these errors was a misunderstanding of the

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technical specifications such that it was interpreted that the SI-and i

LCO table were -for information and general guidance and that an update would be made as information became available.

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3. LCorrectiva Stcon Which Hava Be n Tnk'n rnd tha Herults Achicv-d Upon discovery ' of the discrepancies, a complete review was initiated of safety-related snubbers at the. plant. This review included a detailed comparison of the SI to the LCO table and a walkthrough of the latest as-constructed piping and hanger drawings to identify all snubbers. The tabulation made from the drawing review has been used to update the surveillance instruction, and all technical specification safety-related snubbers are now included in.the SI.

Persons involved in the misunder-standing of the technical specifications were instructed to use proper plant channels to obtain interpretations. Also, a technical specification revision was initiated and submitted to NRC/NRR for approval to resolve the discrepancy between the SI and the LCO.

A totally independent review of snubb'er drawings and comparison to the SI has been conducted because of.the large numbers of drawings and snubbers involved. This independent review was completed on November 21, 1983, and the minor discrepancies found between the two reviews were resolved.

4.

Corrective Steps Which Will Be Taken To Avoid Further Violations Until approval by NRC/NRR of the technical specification change, there will not be any snubbers added or deleted from the, newly corrected SI.

5.

Date When Full Compliance Will Be Achieved The plant was in full compliance on November 21, 1983

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' Item'C (328/83-26 01)'

ITechnical' Specification 3.3.3.7, LTablA 3 3-10, items' 12, '13, and 14.

requires thatt each pressurizer power operated relief. valve (PORV),. block f

, valve and safety valve have.two channels of positioniindication' operable.:

Of these 'tworchamels -per valve to provide adequate position indication,-

one tannel';fori the PORVs and safety. valves shall be the' acoustic monitors.

Technical Specification 3 0.4 mquires that entry into an Operational Mode or other specified condition shall not be made unless. the conditions for.

the LCO are met without reliance on provisions contained in the action :

requirements. -

Contrary tto the above, Unit 2 entered-Mode 2 at 11:50 p.m. CST, on-October 12, 1983,:.with all. acoustic monitors : inoperable. in that : the control room panel was ^ removed to the shop for _mpairs. The conditions-for

'LCO 3.3 3 7 wem not met without~ mliance on provisions. contained in the action requimments. The acoustic monitors were restored to service on

' October 13, 198 3.

3 This is a Severity Level IV Violation (Supplement I).

This' violation applies to Unit 2 only.

1.

Admission or' Denial of the~Aileged Violation

. TVA denies this violation.

-2.

Reasons for the Denial

' As stated in letters to NRC dated September 7,1979, December 10, 1980, y

and February 16,-1982, in response to NUREG 0578 and 0737, Sequoyah has four separate means of determining safety valve position (i.e.,- open er closed).

Temperature sensors downstream of each safety valve (one per a.

valve). Temperature indication and alarm are provided in the main control room.

b.

Pressurizer relief tank has temperature, pressure, and level indication and alarm in the main control room.

Acoustic flow monitors are mounted downstream of each safety valve c.

(one per valve). A flow indicating module in the main control room is calibrated to detect failure of a valve to reclose. An alarm in the main control room will actuate when any valve is not fully closed.

d.

Pressurizer pressure indicator and alarm in the main control room.

-In supplement 1 to the Sequoyah SER, NRC acknowledges these four means as providing indication of valve position. The bases for technical specifica-tion 3 3.3.7 (B 3/4 3 3.7) which provides the reasoning behind and the l

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' Cintent* cf th2 specific tion stat;e, ".... ths op;rability of tho accident monittring in;trumentation ensures thit cufficient information is available... to monitor and assess... an accident." Thus, the intent of requiring two indications per valve is to ensure " sufficient information is available" to assess whether.a safety valve has failed to reclose.

TVA design provides four separate means of position indication fbr the pressurizer safety relief valves, and thus, we will take reasonable measures to ensure all four indications are operable during modes 1, 2, and-3 Only two indications, however, are required to meet the limiting condition for operation in the technical specifications, and the acoustic monitors are not specifically identified as being required operable.

Sequoyah was, therefore, in compliance with LCO 3 3.3 7 at all times during the event described in the violation.

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