ML20236V237
| ML20236V237 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 07/24/1998 |
| From: | Gordon Peterson DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9808030024 | |
| Download: ML20236V237 (7) | |
Text
- - _ _ _ _ _ - _ _ _ _ _ - - - _ _ _ - - _ - - _ _ _ _ _ _ _ _ _ _ _ - _ _.
hM Duk) Power
[ghy, Catauha Nuclear Station
(
4800 Concord Road
- m. s, c, f,
[
York, SC 29745
' Gary R..Peterson (803) 831-4251 omCE Vice hrsident (803) 831-3426 htx July 24, 1998 i
U.S.
Nuclear Regulatory Commission
. Attention:
Document Control Desk l
Washington, D.C.
20555
Subject:
Duke Energy Corporation Catawba Nuclear Station, Unit 2 Docket Number 50-414 Notice of Enforcement Discretion (NOED) Request Refueling Water Storage Tank Level Attached is the written follow-up documentation of the background and technical information supporting the Catawba Unit 2 Notice of Enforcement Discretion (NOED) request which was approved by the NRC staff in a telephone conference call on July 23, 1998.
As discussed in detail in Attachment 1, an extension of the time limit of Technical Specification 3.0.3 to be shut down is being requested in order to replace one Refueling Water Storage Tank (RWST) level transmitter which was damaged by lightning.
Should you have any questions concerning this information, please call L.J.
Rudy at (803) 831-3084.
Ver t uly yours, l'
'/
fat.
h J ry g. Peterson LJR/s 80 /
Attachment 9008030024 980724 PDR ADOCK 05000414 P
pm w.
U.S.
Nuclear Regulatory Commission Page 2 July 24, 1998 xc (with attachment):
i L.A.
Reyes U.S. Nuclear Regulatory Commission Regional Administrator, Region II Atlanta Federal Center 61 Forsyth St.,
SW, Suite 23T85
-Atlanta, GA 30303 D.J.
Roberts Senior Resident Inspector (CNS)
(-
U.S.
Nuclear Regulatory Commission Catawba Nuclear Station P.S.
Tam l
NRC Senior Project Manager (CNS) l U.S. Nuclear Regulatory Commission Mail Stop O-14H25 Washington, D.C. 20555-0001 i
M.
Batavia, Chief l
Bureau of Radiological Health 2600 Bull St.
Columbia, SC 29207 i
l I
a
Catawba Nuclear Station Request for Enforcement Discretion Refueling Water Storage Tank Level Duke hereby requests that the NRC grant discretion in enforcing shutdown requirement:s of Technical Specification (TS) Limiting Condition for Operation (LCO) 3.0.3 and permit continued operation of Catawba Nuclear Station, Unit 2, until 0035 hours4.050926e-4 days <br />0.00972 hours <br />5.787037e-5 weeks <br />1.33175e-5 months <br /> on July 26, 1998, pending aplacement of the transmitter on one channel of Refueling Water Storage Tank (RWST) level instrumentation.
This would provide an additional 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> to complete the transmitter replacement prior to having to shut down and be in Hot Standby.
I
- 1. Technical Specifications violated Without enforcement discretion, TS LCO 3.0.3 will be violated.
In the present situation, 2 channels of RWST level are inoperable on Unit 2 due to lightning strikes.
TS LCO 3.3.2 - Engineered Safety Features Actuation System Instrumentation, Table 3.3-3, Functional Unit 9b requires a minimum of 3 operable channels.
With only 2 operable channels, TS LCO 3.0.3 must be entered.
2.
Circumstances surrounding the situation On' July 23, 1998 at approximately 1735 hours0.0201 days <br />0.482 hours <br />0.00287 weeks <br />6.601675e-4 months <br />, lightning disabled RWST Level Channels 1 and 3 on Unit 2.
TS 3.3.2, Table 3.3-3, Functional Unit 9b, Action 16a, allows continued operation with 1 inoperable channel provided the inoperable channel is bypassed and the MINIMUM CHANNELS OPERABLE requirement is met.
Since 3 channels are required as a minimum, Action 16a cannot be used with 2 inoperable channels.
Therefore, TS LCO 3.0.3 must be entered.
TS LCO 3.0.3 states in part:
within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> action shall be initia'ted to place the unit in a MODE in which the specification does not apply by placing it, as applicable, in:
j I
- a. At least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />,
- b. At least HOT SHUTDOWN within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, and
- c. At least COLD SHUTDOWN within the subsequent 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />."
Instrument and Electrical (I&E) technicians checked the 2 inoperable channels and discovered that the transmitters had been L-_---_ ---
struck by lightning and could not be calibrated.
To restore gompliance with TS LCO 3.3.2, Action 16a, one of the inoperable level transmitters would have to be replaced and calibrated.
This work could not be done under the time constraints of TS LCO 3.0.3.
- 3. The safety basis for the request, including the evaluation of the safety significance and potential consequences of the proposed action.
The RWST level channels provide indication to the operators of the water inventory in the RWST.
These channels also provide the automatic swapover of the Residual Heat Removal pumps (RHR) suction source from the RWST to the containment sump on low level in the RWST.
Normally, there are 4 channels available to perform these functions.
The swapover occurs when 2 out of 4 (2/4) level channels reach the low level setpoint.
With only two operable channels, the redundancy of the system is reduced.
Instead of the normal 2/4. logic, automatic swapover would occur on a 2/2 logic scheme.
This reduction in the number of channels does not create an unsafe condition but does reduce the reliability of the system.
This reduction in reliability can be offset by compensatory measures which are described in Item 6.
- 4. The basis for the licensee's conclusion that noncompliance will not be of potential detriment to the public health and safety and that neither an unreviewed safety question nor a significant. hazard consideration is involved.
NRC granting of this request for enforcement discretion will not have any adverse consequences from the standpoint of public hecith and safety.
The function provided by the system is still availdhle.
The remaining channels are fully operable and will perform the safety function of the system.
There are no significant hazards considerations associated with this request for enforcement discretion.
This is demonstrated as follows:
1 This request for enforcement discretion does not involve a significant increase in the probability or consequences of an accident previously evaluated.
Extending the required time to be l
shut down in Mode 3 by an additional 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> will have no effect l
on accident probabilities or consequences.
The two operable RWST level channels are fully capable of meeting their design basis accident mitigating function.
L-This request for enforcement discretion does not create the possibility of a new or different kind of accident from any accident previously evaluated.
No new accident causal mechanisms are created as a result of the NRC granting of this request for j
This request for enforcement discretion does not impact any plant systems that are accident initiators, since the RWST level channels provide an accident mitigation function as well as a monitoring function.
l This request for enforcement discretion does not involve a significant reduction in a margin of safety.
Margin of safety is related to the confidence in the ability of the fission product barriers to perform their design functions during and following an accident situation.
These barriers include the fuel cladding, the reactor coolant system, and the containment system.
The l
performance of these fission product barriers will not be impacted by the NRC's granting of this request since the design function of the system can still be performed.
No safety margins will be impacted.
l S.
The basis for the licensee's conclusion that the noncompliance will not involve adverse consequences to the environment.
This request for enforcement discretion will not result in any changes in the types, or increase in the amounts, of any J
effluents that may be released offsite.
In addition, no increase in individual or cumulative occupational radiation exposures will be involved.
Therefore, it can be concluded that the NRC's granting of this request for enforcement discretion will not involve any adverse consequences to the environment.
l 6.
Proposed compensatory measures l
Although the 2 operable channels will still provide their safety function, compensatory measures will be implemented to provide assurance that the automatic swapover function will occur.
A dedicated operator will be available to monitor level on the 2 operable channels upon receipt of a Safety Injection Signal.
This operator will monitor the RWST level channels for proper tracking by monitoring RWST level decrease and corresponding containment sump level increase during the injection phase of a loss of coolant accident.
If automatic swapover does not occur, the dedicated operator will direct the Balance of Plant (BOP) operator to manually perform the swapover.
This dedicated operator will also direct the BOP operator to perform a manual
0 A
9 swapover if containment sump level reaches 4.5 feet, regardless Qf RWST level (only necessary if both of the operable RWST level channels were to fail).
Additionally, if for any reason one of the ECCS components, trains, or systems requires planned or unplanned removal from service during this time, Station Management must contact the NRC to reevaluate the enforcement discretion request.
- 7. Justification for the duration of the non-compliance The' noncompliance will last until a third channel of RWST level is restored to operable status.
This is expected to take less than 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />.
A replacement transmitter has been located and work is underway to install this transmitter into one of the inoperable level channels.
In the event that one transmitter cannot be replaced within the 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> extension period, Unit 2 will be shut down per TS LCO 3.0.3.
8.
Statement that the request has been approved by the facility organization that normally reviews safety issues.
This request was reviewed and approved by the Catawba Plant Operations Review Committee in a special meeting on July 23, 1998.
- 9. How one of the NOED criteria for appropriate plant conditions specified in Section B is satisfied.
This request is intended to avoid undesirable transients as a result of forcing compliance with the Technical Specifications l
and, thus, minimize potential safety consequences and operational risks.
Approval of this NOED will avoid a shutdown of Catawba, Unit 2, by allowing continued operation during replacement and testing of one channel of RWST level instrumentation.
- 10. If a follow-up license amendment is required, the NOED request must include marked-up TS pages showing the proposed TS changes.
I No follow-up license amendment is required in conjunction with this NOED request.
- O
- 11. A statement that prior adoption of approved line-item improvements to the TS or the ITS would not have obviated the need for the NOED request.
Prior adoption of approved line-item improvements to the TS or the ITS would not have obviated the need for this NOED request.
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