ML20149J577
| ML20149J577 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 07/21/1997 |
| From: | Bajestani M TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 50-327-97-04, 50-327-97-4, NUDOCS 9707280281 | |
| Download: ML20149J577 (8) | |
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'i U.S.! Nuclear Regulatory Commission-10 CFR 2.201
. ATTN:
Document Centrol Desh Washington, D.C. 20555-Gentlemen:
4 In the Matter of-
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Docket Nos.
50-327 7ennessee Valley Authority )
-SEQtfoYAH NUCLEAR PLANT (EQN) - NRC INTEGRATED INSPECTION REPORT'NOS.- 50-327,320/97 REPLY TO NOTICE OF VIOLATIONS
~(HOVa) 50-327/97-04-02.AND 50-327/97-04-03
.This letter provides TVh's reply to NOVs 50-327/97-04-02 and 50-327/97-01-03 which are documented in the subject inspection report dated June 20, 1997.
The NOV identified two violations that are characterized as: 1) failure to meet the technical specifiest:lon (TS) surveillance requirements (SR)f for performance of functional testing of nuclear n
instruments; and 2) failure to follow procedures during-Initial startup for power ramp rate increases.
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-In' TVA's reply to the NOV, TVA is denying Violation A (50-327/97-04-02), " Failure to Meet the Sarveillance Requirements of TS 4.10.3.2, For Performirg Functional Testing of.the riuclear Instruments,"
The ene.l os.. ire contr. ins TVA's reply to the NOV.
?If you ' have enestions regarding this ' recponse, please (423)1843-7001 ct Pedro Salas at contact me 1(423);843-71/u.
Sincerely,:
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Mr.XR.'W. Fernan,; Project Manage j i; '
,,JNuclear Regulatory Commission
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Tone!Whito. Flint,: North-
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n Rodkv111e, Maryland 20857-2739.
E i-NRC' Resident' Inspector L
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Sequoyah Nuclear Plant (y$
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JSoddy-Daisy, Tennessee-37379-3624.
Regional"Ndministrator LO. L ; Nuclear. Regulatory Commission n
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!P.tlanta Federal Center 61 Forsyth Street, SW, Suite 23T85 k:.
Atlanta, Georgia 30303-3415 E-
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ENCLOSURE TEENESSEE VALLEY AUTHORITY l
SEQUOYAH HUCLEAR PLANT (SQN)
UNITS l'AND 2 L
INSPECTION REPORT NUMBER 50-327, 50-328/97-04 REPLY TO NOTICE OF VIOLATION (NOV) 4 I.
RESTATFgNT OP VIDIATION A
" Technical Specification 4.'.0.3.2,
?hysics Tests Surveillance
. Requirements, requires that eacn Intermediate and Power _ Range Channel shall be subjectec to a CHANNEL FUNCTIONAL TEST within 12 he.urs prior to initiating PHYSICS TESTS.
Contrary to the above, on May 11,.1997, each Intermediate and Power Range Channel was not subjected to.a CHANNEL FUNCTIONAL 1
TEST within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> prior to initiating PHYSICS TESTING, in that tho'12-hour.cnannel functional test for Power. Range i
Channal instrument NI-42 and Intermediate Power Range Channel instrument NI-36 expired prior to the initiation of Physics Testing.
This is a Severity Level IV Violation (Supplement 1)."
)
i AUSWEA TO THE VIOLATION TVA respectfully disagrees with NRC that a violation of Technical Specification (TS) Surveillance Requirement 4.10.3.2
- exists, j
The SQN procedure for conducting low power physics testing explicitly defines the start of physics tests as the time.that j
permission'from the Senior Reactor Operctor (SRO) has been obtained to begin the first withdrawal of control bank A.
The procedure also states that this time would stop the clock on j
t Nuc} ear Instrumentation System (NIS) channel testing for startup. -In accordance with the procedure, permission wan obtaintd at OP13 EDT from the SRO te begin low power physics testing and to perform red pulls to critical.
Personnel began j
low power physics test-activities which includes data collection j
to obtain average NIS baseline count rate before pulling control
- banks.
y; TVA. believes.that data collection activities are both necessary j
and essential fro n the standpoint of safety in order to measure j
the'- fundamental nuclear characteristics of the reactor core.
'TVA considers'such activities well within the TS definition of PHYSICS TESTS.
/.
(
It should be noted that discussions had taken place earlier in i
the shift, at approximately midnight, netween the Shift Manager, the Reactor Engineer, and the individual responsible for Management Oversight regarding tne remaining items neceasary for Mode 2 entry and their statua.
Following the status review, the decision was made not to continue lunctional tests of the NIS instruments because it was felt that the other activities would be complete prior to the expiration of the surveillances for the NZS instruments, and therefore the additional tests wcald not be necessary.
It was the deliberate completion of the necessary prerequisite activities for Mode 2 entry that allowed the SRO to give permission to start physics tests in accordance with the procedure.
As part of its examination of the circumstances and events surrounding this proposed violation, TVA baselined its definition of initiation of physics testing with respect to numerces other plants.
This examination indicated there was a wide rcnge of practices.
Some facilities define the initiation of physics testing as the point at which shutdown bank s
withdrawai begins, others define it j ust prior te pulling cor. trol rods when the reactor trip braaker tunction is verified, and yet another facility delines it as the time the reactivity computer is connected.
The varied positions among facilities in
)
establishing the point at which physics testing starts is j
consistent with the lack of specific regulatory guidance on the j
issue.
This conclusion is based upon a review of ANSI /ANS 19.6.1, 1985, " Reload Startup Physics Tests for Pressurized Water Reactors," and Regulatory Guide 1.68, Revision 2,
- 1978,
" Initial Test Programs for Watar-Cooled Nuclear Power Plants,"
which do not address what activities constitute the initiation of physics testing.
TVA is concerned with the negative impact tnat starting physics tests later would have on reactor safety.
If physics tests were j
not started until the reactor.is critical, then the 12-hour clock for functional testing of the NIS channels would not stop J
until the reactor was critical.
Under this scenario, the NIS channels would be required to be removed from service to perform the functional tests at the same time that the control rods were being pulled to reach criticality.
We believe that.this practice is fundamentally unsound, would jeopardize the safe operation of the plant, and would otherwise represent a i
reduction in the margin of safety as defined in the TS Bases.
II.
RESTATEMENT OF VIOIATION B i
" Technical Specifications 6.8.1.a requires, in part, that procedures shall be established, implemented, and maintained
. covering the activities recommended in Appendix A of Regulatory Guide 1.33, Revision 2, February 1978, ' Quality Assurance Program Requirements (Operation).'
Appendix A of 1
Regulatory Guide 1.33, Section 1, includes procedures for 1
2 i
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' Authorities ana Responsibilities for Safe Operation and Shutdown' and Section 2 includes procedures for ' Power Operatice and Process Monitoring.'
General Operating Instruction (GOi, 0-GO-5, Normal Pcwer Operation, Revision 6, Section 5.1, requires that ramp load rate increases shall be within the limits stated in Technical Instruction (TI)-40.
i T1-40, Determination of Preconditioned Reactor Power, Revisicn 8, Section 4.1, requires that for the initial startup after core reload, the ramp rate should be limited to 3 percent of full power in an hour between 20 percent and 100 percent of full power.
Site Standard Practice (SSP)-12.1, Conduct of Operations, Revision 17, Section 3.8.3 C, requires that unit status, load or significant reactivity changes, and initiation and completion of surveillance tests shall be recorded in at least one narrative log.
Site Standard Practice (SSP)-12.1, Conduct of Operations, Revision 17, Section 3.1.5 F, requires the Unit Supervisor (US) coordinate the activities of the Unit Operators (UOs) with other Operations and plant personnel to achieve safe, reliable, and efficient operation or the unit.
Contrary to the above, on May 15, 1997:
1.
Operaters exceeded 3 percent of full power in one-hour ramp rate.
2.
Operators failed to record it, the narrative log an Axial Flux Difference ( AFD) alarm condition, a significant load and reactivity change, and the initiation of a aarveillance test.
3.
The unit supervisor did not coordinate the activities of the unit operators with other Operations and plant personnel when he failed to notify the Shift Manager (SM) of a significant load and reactivity change and of an Axial Flux Difference alarm condition.
This is a Severity Level IV Violation (Supplement 1)."
TVA's REPLY TO THE VIOLATION
===1.
Background===
Procedures impose restrictions on power level increases for initial startups following refueling.
The power increase is limited to approximately 3 percent per hour between 20 percent and 100 percent of full power.
The 3
i procedure allows small deviaticns from the 3 percent rate with the stipulation that the power increase not enceed 3.5 percent in any one hour.
Additionally, procedures establish a preconditioned power level which is the highest power level for which there is an accumulated time of operation of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> during any 7-day operating period.
There are no power level increase restrictions below the preconditioned power level.
Prior to the event in question, a reactor coolant system (RCS) water inventory test was aborted upon determination that the RCS average temperature (Tavg) could not be maintained within the one degree Fahrenbelt test requirement.
Axial Flux Difference (AFD) was also apprcaching the target bar.d upper-3imit due to increasing xenen.
Following the aborted rest, operators prepared to dilute the RCS to allow repositioning of control rods wnich had been withdrawn while the test was underway.
Operators diluted approximately 1,200 gallons te raise power and RCS Tavg, wh.ile allowing rods to step in and restore AFD i
to program band. The UO and US had anticipated the power rise from the current 64 percent but had incorrectly i
determined that because the core had previously reached 67 percent, an increase to 'id percent would not violate the 3 percent per hour limit.
This determination was incorrect because the unit had not been at the 67 percent power level for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> it. seven days of cperation and l
therefore was not preconditioned for a 67 perceat power level.
Therefore, the 3 percent per hour limit should have been applied from the 64 percent power level instead of applying it to increases above the 70 percent level.
2.
Reason For The Violation B The reason for the violation was inadequate knowledge of tne preconditioned power level limits by the US and the UO.
An additional Instance occurred during the earlier shift en May 15, 1991,
- rom 10:03 a.m.
to 11:03 a.tu.
when the power increased 3.55 percent.
Operations personnel also failed to adhere to procedural requirements for logging the above sequence of evento.
This failure was caused by a lack of sensitivity for properly maintaining logo.
A contributing factor was that procedures did po' allow a simple and quick method for capturing shirt e' ents other than immediately ente 11ng a narrative log entry into tha computar-besed log system.
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During this sequence of events, the SM.was not aware of the difficulties being experienced by the Unit 1 p
operators, (specifically, the AFD alarm and the need for a 1,200 gallon dilution). This was caused by a failure to follow procedural requirements when the US did not coordinate with the SM on changing plant conditions and the SM did not adequately monitor crew activities, c
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3.
' Corrective Steps Taken And Results Achieved TVA immediately evaluated the consequences of the excessive nuclear instrumentation ramp power change.
The indicated reactor power change (which was about 6 percent 4
in 47 minutes) did not challenge any safety limits - the actual core power change was significantly less than this because a portion of the increase in the indicated level was due to increased flux leakage as RCS temperature increased.
Framatome Cogema Fuels was contacted to assess impact on the ner Framatome Cogema fuel loaded in i
the-Unit 1 Cycle 8 (U1CL} refueling outage; an existing Westinghouse memorandum was referred to in order to assess the likely effect on cladding of the older Westinghouse fuel.
It was concluded that this relatively modest power change was unl.ikely to cause fuel cladding j-damage, nor any concern with new fuel integrity.
' 4.
Corrective Steps That Have Been Taken To Prevent Recurrence Mantgement expectations were discussed with the UO and US concerning the 3 percent per hour limit for power level i.
Increase.
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Interviews were conducted with nine licensed operators j
and four inar.ructors regarding the procedural requirements for reactor power ramp rate and U
praconditioned power levsl limits.
As a result of these interviews, it was concluded that the extent of this knowledge based error was limited to a few individuals.
Shift Managers revjewed the event with the operating crews through the Operations Directive Manual U.7,
" Error g
F Awareness Program."
b Appropriate disciplinary action was taken for the
[
invcived personne).
I The on-shift managers.have been making formal N
1 observations of thp' logs of the. previous shift.
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Discrepancies are then turned over to the following shift s
forffeedback and' correction, and the observation is forwarded'to the Operations Managet for review.
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Periodic QA observations of control room logs are being d'
Lused in an ongoing effort to assess the effectiveness-of actions taken to improve logkeeping.
Procedures were revised to permit the use of temporary handwritten. logs, provided that such informal notes are transferred to the official computerized narrative log in S.
a timely manner.
i.
5.
Corrective Steps'That will Be Taken To Prevent Recurrence A standdown will be conducted for Operations department s
personne1' prior to the Unit 2 Cycle 8 (U2C8) refueling outage addressing lessons learned from UIC8 events.
This action will be completed by September 30, 1997.1 J
Two other changes will be instituted to provide additional barriers to this type of occurrence.
Revisions to the appropriate procedures are planned to clarify expectations for proper communication of information through the chain of command from the (R) up through site management. This action is scheduled for completion by September 5, 1997.2 Also 6 method of using the ICS computer features to assist operators in tracking the reactor power rate limit is planned.
The appropriate procedures are scheduled to be revised to specify trending of reactor. power. This action is scheduled for completion by September 26, 1997.3 6.
Date When Full Compliance Will Be Achieved With respect to the cited violation, TVA is in full compliance.
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'TVA does not consider this corrective action a Regulatory Commitme:
TVA' s corrective action program will track completion of the action.
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