ML20248F997
| ML20248F997 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 10/02/1989 |
| From: | Medford M TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 8910100014 | |
| Download: ML20248F997 (9) | |
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7 TENNESSEE VALLEY AUTHORITY.
CH ATTANOOGA, TENNESSEE 37401 i
O 6N 38A Lookout P1 ace
+
OCT 021989-1
,U.S._ Nuclear Regulatory Commission.
.j ATTN:- Document Control Desk e Washington, D.C..20555
. Gentlemen o
In the Matter of.
)-
Docket Nos. 50-327..
.50-328
- Tennessee Valley Authority
.).
~SEQUOYAH NUCLEAR PLANT (SQN) - NRC INSPECTION REPORT NOS.' 50-327/89-19 AND a
50-328/89 ' Enclosed is TVA's-response to.B. Ai Wilson's letter to 0. D. Kingsley, Jr.,
u dated August 25, 1989, which transmitted the subject notice of violation.' An-
-l extension'of the due date for;this response to October.2, 1989, was verbally.
-l approved by NRC in a telephone conversation held between M. A. Cooper and L. J. Watson on September 26, 1989.
If you have'any questions concerning this submittal, please telephone d
M. A. Cooper.at (615) 843-6651.
Very truly yours, 1
1 TENNESSEE VALLEY AUTHORITY
$]%nl'7 0 h
/
i Mark 0. Medford, Vice President and Nuclear Technical Director Enclosures cc (Enclosures):
Ms. S. C. Black, Assistant Director
.for Projects l
TVA Projects Division U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Mr. B. A. Wilson, Assistant Director for_ Inspection Programs TVA Projects Division L'
U.S. Nuclear Regulatory Commission gp[
l Region II T
' t 101 Marietta Street, NW, Suite 2900 l
Atlanta, Georgia 30323
.NRC Resident Inspector p
Sequoyah Nuclear Plant 8910100014 891002 2o00 Igou Ferry Road PDR ADOCK 05000327 Soddy Daisy, Tennessee 37379 0
PNU l
An Equal opportunity Err.aloyer O
ENCLOSURE 1 RESPONSE TO NRC INSPECTION REPORT NOS. 50-327/89-19 AND 50-328/89-19 B. A. WILSON'S LETTER TO 0. D. KINGSLEY, JR.,
DATED AUGUST 25, 1989 Violation 50-327, 328/89-19-05 "A.
Technical Specification 6.8.1 requires that procedures recommended in Arpendix A of Regulatory Guide 1.33, Revision 2, be established, implemented and maintained.
This includes operating and abnormal operating procedures.
This requirement is implemented for failures of source range reactor trip system instrumentation by Abnormal Operating Instruction (AOI)-4, Nuclear Instrumentation Malfunctions. A0I-4, states that operators shall place the failed detector trip switch to bypass on panel M-13.
Contrary to the above, when channel N-31 exhibited severe spiking and was declared inoperable, the licensee did not place the level trip switch in the bypass position.
This is a Severity Level IV violation (Supplement I)."
Admission or Denial of the Alleged Violation TVA admits the violation.
Reason for the Violation During the recovery from the Unit 2 reactor trip from 100 percent power, the 1
source range channels were placed in service, and N31 was noted to have erratic readings and was declared inoperable. Because of the high level of activity resulting from the reactor trip, Operations personnel overlooked placing the switch in bypass as required by Abnormal Operating Instruction (AOI) 4.
Instrument Maintenance (IM) personnel subsequently placed the source range in bypass to perform Surveillance Instruction (SI) 603, dHigh Flux Adjustment After Shutdown (Source Range Drawer)." Following the performance, IMs returned N31 to the "as found" condition as required by procedures. A spike subsequently occurred resulting in generation of a reactor trip signal.
It should be noted that the intent of A0I-4 for placing the trip switch to bypass is to avoid unneeded reactor protection system (RPS) actuations.
Leaving the inoperable channel in a nonbypassed condition provided a more conservative condition, i.e., spiking or channel failure could only and did result in the performance of the RPS function. The root cause of this violation is considered to be personnel error. Details concerning this event are provided in Licensee Event Report (LER) 328/89008 dated August 9, 1989.
Corrective Steps That Have Been Taken and Results Achieved A training letter was issued to all licensed personnel and shift technical advisors on July 21, 1989, addressing the failure to comply with AOI-4 when the N31 source range monitor was declared inoperable.
l Corrective Steps That Will Be Taken to Avoid Further Violations There is no further corrective action planned.
Date When Full Compliance Will Be Achieved TVA is in full compliance.
Violation 50-327, 328/89-19-07 l
"B.
Technical Specification 3.0.1 states that upon failure to meet a Limiting Condition for Operation, the associated Action requirements shall be met. Technical Specification 3.3.1 states that as a minimum, the reactor trip system instrumentation channels and interlocks of Table 3.3-1 shall be operable with response times as shown in Table 3.3-2.
Action Statement 2, of TS 3.3.1, states that with the number of operable channels one less than the total number of channels, startup and power operation may proceed provided conditions 2a through 2d are met.
Action 2d states that the quadrant power tilt ratio (QPTR), as indicated by the remaining three detectors, shall be verified consistent with the normalized symmetric power distribution obtained by using the movable i
incore detectors in the four pairs of symmetric thimble locations at i
least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> when thermal power is greater than 75% of rated thermal power.
On July 22, 1989, the Unit I reactor trip system power range channel N43 failed. The licensee entered Action Statement 2.d.
Contrary to the above, the licensee failed to reduce power to less than or equal to 75% of rated thermal power to meet Action Statement 2.d when an incore flux map to verify the QPTR could not be completed within the 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> required by Action Statement 2.d.
This is a Severity Level IV violation (Supplement I)."
Admission or bonini of the Alleged Violation TVA denies the violation.
Reason for the Dental I.
Background
At 0258 on July 22, 1989, with Unit 1 operating at 100 percent power, power range excore Detector N-43 on Unit 1 failed during operation and was declared inoperable. Action 2 of Limiting Condition for Operation (LCO) 3.3.1.1 was entered, which required, in part, that:
"c.
Either, THERMAL POWER is restricted to less than or equal to 75% of RATED THERMAL and the Power Range, Neutron Flux high trip reduced to less than or equal to 85% of RATED THERMAL POWER within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />; or, the QUADRANT POWER TILT RATIO is monitored at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />."
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"d.
The QUADRANT POWER TILT RATIO, as indicated by the remaining three
. detectors is verified consistent with the normalized symmetric power distribution obtained by using the movable incore detectors in the four pairs of symmetric thimble locations at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> when THERMAL POWER is greater than 751. of RATED THERMAL POWER."
The first requirement, Item c above, can be satisfied by performance of SI-133, " Quadrant Power Tilt Ratio." The second requirement,' Item d above, can be satisfied by performance of SI-178, " Moveable Detector Determination of Quadrant Power Tilt Ratio." This SI could typically be expected to be completed within 2-4 hours.
TVA reviewed the action statements and initiated efforts to meet the requirements.
It was fully anticipated that performance of both SI-133 and SI-178 would be completed well within the 12-hour timeframe, and a reduction in power was not considered at that time.
The duty reactor engineer arrived onsite at 0430 on July 22, 1989. A review of procedures conducted by th_e reactor engineer verified that performance of SI-133 and SI-178 was required.
At 0600, working copies of the procedures were ordered from the document center.
The Unit 1 assistant shift operations supervisor (AS0S) and the radiological control supervisor were requested to remove the hold order from the Unit I traveling incore monitor (TIM) system.
The duty reactor engineer arrived in the main control room at 0730 and began setting up the TIM system.
By 0815, preparations were complete, and flux mapping commenced. The duty reactor engineer completed taking flux map data at 1030 and, after securing the TIM system, started reviewing the data.
The performance of SI-133 commenced at 1100 and was completed by 1130.
At 1145, the duty reactor engineer began data reduction for SI-178, and at 1223, the hold order was reinstated on the Unit 1 TIM system.
By 1300, the duty reactor engineer determined that an apparent problem existed with the calculation method that had been used to perform in SI-178. After discussing the problem with the reactor engineering supervisor, the duty reactor engineer decided to try the second method prescribed in SI-178.
By 1345, this method had also failed to produce usable results. After consulting again with the reactor engineering supervisor, it was determined that the third method specified in SI-178 should be used because of several inoperable TIM detectors, which had failed two days earlier. At 1402, the duty reactor engineer notified the ASOS that an additional flux map would be required. At 1419, the hold order was again removed from the TIM system, and at 1430, flux map data collection was started.
At approximately 1433 (nearing the end of the initial 12-hour action timeframe), the Operations superintendent was contacted to discuss the situation. The Operations superintendent reviewed the associated j
technical specifications (TSs) and considered the possibility of l
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reducing power within the remaining 25 minutes of the initial 12-hour action statement.
He concluded that a rapid reduction in power was not the most prudent course of action; however, entry into LCO 3.0.3 at 1458 would be unavoidable. From review of LCOs 3.3.1.1 and 3.0.3, the Operations superintendent concluded that continuing to follow LCO 3.0.3 o
upon expiration of the 12-hour action statement was an acceptable course provided by TSs. Action 2.c was being met through the performance of l
SI-133. Action 2.d could not be met.
LC0 3.0.2 governs operation when an action statement cannot be met.
The Operations superintendent was familiar with the SI that needed to be performed to verify QPTR and knew it should take approximately three hours to complete.
The Operations superintendent was aware that a full flux map had verified expected core performance two days earlier and that no indication of abnormalities existed from review of reactor parameters. The decision was made that entry into LCO 3.0.3 at 1458 and subsequent compliance with 3.0.3 was the appropriate action based on compliance with TSs, safety of the plant, reactor stability, and inability to comply with the Action Statement 2.d within the 12-hour time limit. At 1458, the 12-hour time limit in LC0 3.3.1.1, Action 2.d, was exceeded, and LCO 3.0.3 was entered. Actions continued to expedite completion of SI-178. This determination was discussed with senior nuclear power management and received their full concurrence.
Senior management categorically ruled out any requests for enforcement discretion as an option if the requirements of TS 3.0.3 could not be met. At no time id TVA personnel attempt to misinterpret TSs to maximin the per.od of time before a power reduction would be required.
The reactor engineering supervisor had arrived in the control room at about 1430, and at 1600, he summoned an off-duty reactor engineer to assist onsite. The off-duty reactor engineer arrived onsite at 1630 and i
began a review of the data obtained from the performances of SI-178.
By 1730, the off-duty reactor engineer verified that the first two methods of SI-178 would not work if any incore detectors were inoperable. After examining the flawed flux map data in some detail, another set of flux map data was collected at about 1840.
The data was downloaded from the P-250 process computer onto a magnetic tape and uploaded onto the PRIME computer. The INCORE computer code was run, and the results were used to complete SI-178. At 1930, on July 22, 1989, the SI-178 acceptance criteria were satisfied, resulting in compliance with the action statements of LC0 3.3.1.1; and LCO 3.0.3 was exited (additional details concerning this event are provided in LER 327/89022 dated August 21, 1989).
II. Analysis TVA denies that its failure to reduce power to less than 75 percent of rated thermal power constitutes a violation.
TVA believes a condition existed that was not provided for in the action statements of LCO 3.3.1.1 and that entry into and compliance with LC0 3.0.3 were correct from both a regulatory compliance and reactor safety standpoint.
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' TS 3.3;1.1, Action Statement 2.c, provided two options whereby compliance could be achieved:
(1). operation at less than 75 percent power with:bistables. set to less than 85 percent, or (2) monitoring of QPTR every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. Option 2.was logically selected and was always
<J complied with-by calculation using the three remaining detectors (SI-133).. All further contention focuses on Action Statement 2.d, which'
. unlike Action Statement 2.c, did not p ovide two options to meet the action statement.. Instead, Action Statement 2.d simply required verification of-QPTR once every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> if operating at greater than 75 percent power.- TVA fully expected to be able to complete the required surveillance, SI-178, within the required 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
It was not until~the final hour and minutes that TVA determined the latest attempt had.again resulted in data collection problems and that additional flux mapping would be required.
From the point of failure of the power range
' channel to the end of the first 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, TVA was operating as provided
. in the. action statement of LCO 3.3.1'.1.
At the end of the first 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, TVA was fully complying with-Action 2 c but did-not comply with Action 2.d because of complications 1n completing verification of QPTR in accordance with SI-178.
Thus, TVA entered-LC0 3.0.3, which provides di_rection for operation when neither 4
an LCO nor its action statements are satisfied.
LCO 3.0.3 provides the timeframe for placing the unit in a mode (condition) where the specification no longer applies..LCO 3.0.2 states that if the LCO is-l
' restored' prior to expiration of the specified time intervals, complet' of,the action requirement is not required. Therefore, in this case, reduction to less than 75 percent power. would have resulted in LCO 3.3.1.1 Action Statement 2.d no longer being applicable. As a.
result, LCO 3.0.3 would also no longer be applicable because all other remaining LCO 3.3.1.1 action statements were also being complied with.
Immediately upon entering LC0 3.0.3, actions were initiated to achieve a condition where the specifications could be complied with, i.e., TVA efforts continued to expedite completion of SI-178. Management was promptly informed of the situation and shift personnel were made aware that upon lack of success in such completion of SI-178, the unit would
_ require power reduction to be completed within the timeframe specified 1_
in'LCO 3.0.3.
TVA has additionally analyzed this event under the QPTR TS 3.2.4 since its SR 4.2.4.2 is identical to the subject TS 3.3.1.1 Action
. Statement 2.d.
For the subject event, QPTR was verified in accordance with TS 3.3.1.1, Action 2.c (SI-133) to be in limits; however, SR 4.2.4.2 was not met.
If SR 4.2.4.2 is not met, TS 4.0.3 indicates this constitutes noncompliance with the operability requirements for the LCO and that the time limits of the action requirements are then applicable. The TS 3.2.4 action statements only address various actions
- and time limits based upon a degree of actual out-of-limit QPTR conditions.
Because out-of-limit conditions did not exist and none of these actions provide for failure to perform monitoring, failure to perform the required SR 4.2.4.2 would result in entry into LC0 3.0.3.
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Therefore, application of the QPTR TS to this same event would have also f
resulted in the action taken by TVA, that is, entry into and compliance with LC0 3.0.3.
The above violation implies-that LCO 3.0.3 cannot be entered if a licensee could have previously taken action including power reduction to prevent it (i.e., TVA should have reduced power before the expiration of the 2.d action statement to less than 75 percent so that Action 2.d would no longer be applicabl~e).
This would appear contrary to the purpose of LCO action statements and specifically LCO 3.0.3.
TVA understands that LCO action statements were written to provide the course allowing continued operation up to a timeframe where power reduction would be indicated by the LCO action statement in a specified period of time or in absence by LCO 3.0.3, which also provides for a reduction within a specified period of time. Action 2.d required QPTR be verified within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> when thermal power level is greater than 75 percent.
It does not require a reduction below 75 percent when this verification cannot be completed.
TVA believes the appropriate action is entry into LCO 3.0.3.
The violation indicates that once LCO 3.0.3 was entered, TVA should have initiated whatever action was necessary to be able to satisfy the LCO 3~.3.1.1 action statements as quickly as possible, i.e., that a power reduction to 75 percent power should have been completed within some unspecified timeframe, but shorter than that provided by LCO 3.0.3.
This calls into question the very basis for action statements (e.g., to allow an appropriate time to remedy expected plantsproblems before introducing a plant transient).
Furthermore, TVA does not believe that l
reducing power as quickly as possible should always be considered the conservative and prudent course of action in consideration of overall I
unit safety and stability.
III. Conclusion As discussed above, TVA does not consider that immediate reduction in j
power was the conservative or required action to take upon expiration of l
the initial 12-hour action statement nor that unnecessarily introducing a plant transient as a result of potential loss of monitoring would have t
been conservative in consideration of all factors.
TVA believes that the decisions made in this situation were technically sound with foremost consideration to safe and prudent plant operation.
TVA additionally believes operations were conducted conservatively and in full compliance with associated TSs. Accordingly, TVA respectfully requests that the subject violation be withdrawn.
4
7 Corrective Steps That Have Been Taken and Results Achieved
'Notwithstanding our belief that the violation as. stated did not occur, TVA has reviewed the interrelated TSs 3.3.1.1, 3.2.4, 3.0.3, and 4.0.3 to determine if clarification is required. Although these SQN TSs generally parallel NRC's standard TSs, TVA believes ambiguities and redundancies exist with the requirements. As a result, TVA is preparing a priority TS change (89-36) for NRC approval to clarify and remove such ambiguities from the applicable.
TS sections.
As a result of recent events involving interpretations of TSs, the site director has met with key site personnel to stress the importance of literal compliance and the escalation process to ensure timely resolution of questionable situations. Additional training is being provided to licensed personnel during ongoing Weeks 5 and 6 of annual requalification training to reemphasize TS compliance from both compliance and safety standpoints.
Recent performance involving questionable issues such as source checking of radiation monitors indicates an aggressive and conservative management approach;is being implemented in resolution of-both technical and compliance-related issues.
Additional corrective actions associated with issues surrounding the event are addressed in LER 327/89022 dated August 21, 1989.
~ Corrective Steps That Will Be Taken-t'o Avoid Further Violations As described above, TSs will be revised.to provide clar.ification. Additional corrective actions associated with issues surrounding the event are addressed in LER 327/89022 dated August 21, 1989.
Date When Full Compliance Will Be Achieved TVA is in full compliance.
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ENCLOSURE 2 List of Commitment TVA will sub'mit a priority TS change by November 1, 1989, to clarify and remove ambiguities.from the applicable TS sections.
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