ML20012G435
| ML20012G435 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 02/26/1993 |
| From: | Stimac S COMMONWEALTH EDISON CO. |
| To: | Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9303020309 | |
| Download: ML20012G435 (9) | |
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'\\ Commcnwsalth Edison f74 6 1400 Opus Place V
e Downers Grove, Illinois 60515 February 26, 1993 I
Dr. Thomas E. Murley, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555 Attn:
Document Control Desk
Subject:
Zion Station Unit 1 Request for NRR Halver of Compliance to Facility Operating License No. DPR-39 Appendix A, Technical Specification Surveillance Requirement 4.8.9 Containment Recirculation Sump Level Channel Calibration NRC Docket No. 50-295 j
Dear Dr. Murley:
The purpose of this letter is to request a NRR Temporary Halver of Compliance (TH0C) from the requirement to perform the 18 month channel calibration for the Unit I containment recirculation sump level instrumentation channels (item 17 of Table 4.8.9-1) required by Specification 4.8.9.
Unit 1 is currently in Mode 1, Power Operation. The Unit I containment recirculation sump level instrumentation channels have not been calibrated within the required frequency identified in Technical Specification Amendment No. 141 which is to be implemented by February 26, 1993.
In order to perform the calibration, a plant shutdown would be required due to the radiation doses in the area during plant operations.
Therefore, to prevent the shutdown of Unit I required by Action b. of Specification 3.8.9 and creation of an undesirable transient on the unit, a one time waiver of the requirement to perform the channel calibration of the containment recirculation sump level instrumentation channels is proposed. A detailed i
description of the TWOC and its basis is included in the Enclosure.
This request for NRR THOC and its basis were discussed during a teleconference between CECO and NRC (NRR and Region III) personnel on February 25, 1993. At this time, CECO and NRC agreed to the general content of the enclosed material.
To preclude the need to shutdown Zion Unit 1, CECO requests that NRC l
approve this THOC prior to 11:59 PM on February 26, 1993. CECO requests that the THOC be effective from the date and time of approval until June 30, 1993 at 5:00 PM. As agreed to doing the aforementioned teletonference, this will ensure sufficient time is available for NRC to approve a Technical Specification amendment to resolve this issue.
If such an amendment has not
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been approved by 5:00 PM on June 30, 1993, the two Unit 1 containment recirculation sump level instrument channels will be declared inoperable and the applicable actions of Technical Specification 3.8.9 shall be taken.
Additional justification'for this duration is included in the Enclosure.
9303020309 930226 ZNLD/2484/4 hDR g (-
AD3CK 0500 5
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i' Dr. Murley February 26, 1993 The following informatien is provided in the Enclosure in support of this request for TWOC:
Discussion of the requirements for which the THOC is requested; Discussion of the circumstances leading to the request, Description of compensatory actions; Evaluation of safety significance and potential consequences; Discussion which justifies the duration of the request; i
Basis for concluding that the request does not involve a significant hazards consideration; Basis for concluding that the request does not involve irreversible environmental consequences.
This request for NRR THOC has been reviewed and approved by CECO senior management as well as on-site review in accordance with Company procedures.
CECO will submit a request for Technical Specification amendment for NRC l
review which will resolve this issue by March 5, 1993.
This amendment request will propose addition of a footnote to Table 4.8.9-1 to identify the allowance to extend the 18 month surveillance frequency until completion of the next scheduled outage, Z1R13, currently scheduled to begin October 21, 1993. CECO will perform the necessary calibrations prior to expiration of this TWOC, if Unit i experteiites a shutdown to Mode 3, Hot Shutdown.
Please direct any questions you may have to this office.
Very truly Yours,
/
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Stephen F. Stimac Nuclear Licensing Administrator Enclosure cc:
A. Bert Davis, Regional Administrator - RIII C.Y. Shiraki, Project Manager - NRR J.D. Smith, Senior Resident Inspector - Zion Office of Nuclear Facility Safety - IDNS ZNLD/2484/5
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l REQUEST FOR NRR TEMPORARY WAIVER OF COMPLIANCE t
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1.
' REQUIREMENTS FOR HHICH THE TEMPORARY HAIVER OF COMPLIANCE IS REQUESTED Commonwealth Edison Company (CECO) is requesting a NRR Temporary Halver of Compliance (THOC) from the Zion Technical Specifications in order to avoid placing Zion Unit 1 in an unnecessary shutdown condition, and cycling Unit 1 through an unnecessary thermal transient. The integrity of the reactor vessel and other components of the primary system of a nuclear plant can be adversely affected by the number of thermal transients that they are subjected to during their lifetime. As each additional thermal transient can affect this integrity, it is prudent to avoid such transients as long as the health and safety of the public is preserved.
CECO is requesting a NRR THOC from the CHANNEL CALIBRATION requirements per Specification 4.8.9 for the two Containment Recirculation Sump Level (CRSL) instrument channels on Unit 1.
The two Unit 1 CRSL channels have not been calibrated within the Technical Specification surveillance frequency of 18 months. Unit 1 is currently in Mode 1, Power Operation.
Unit 2 is also in Mode 1 but is unaffected by this request since the CHANNEL CALIBRATION Surveillance Requirements for the Unit 2 CRSL channels were satisfied in December 1992.
In order to perform the calibration, a Unit I shutdown would be required due to the radiation dose rates in the area during plant operations.
The containment recirculation sump is located on the 568' level of containment inside the missi'e barricr.
In crder to calibrate the CRSL channels, personnel must enter this area.
Radiation dose rates in this area are approximately:
1.
4 to 5 R/hr at 60% Rated Thermal Power, 2.
200 mR/hr at 5% Rated Thermal Power, 3.
100 mR/hr during Mode 3, and 4.
100 mR/hr during Mode 5.
Approximately 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> is required in this area in order to complete calibrations of these instrument channels. Therefore, in the interest of maintaining dose rates As low As Reasonably Achievable (ALARA), it is not considered prudent to perform these calibrations during power operation.
However, failure to perform the CHANNEL CALIBRATION within the required frequency will result in the channels being declared inoperable per Specification 4.0.3.
Therefore, to prevent the subsequent shutdown of Unit 1 required by Action b. of Specification 3.8.9 and creation of an undesirable transient on the unit, a one time waiver of the requirement to perform the CHANNEL CALIBRATION of the CRSL channels is proposed.
2.
CIRCUMSTANCES LEADING TO THE REQUEST On November 22, 1991, CECO submitted a Technical Specification Change Request (TSCR) to amend the Zion Accident Monitoring Instrumentation Specification (3.8.9) to reflect Zion's compliance with Regulatory Guide 1.97.
A copy of the TSCR was forwarded to the affected departments within Zion requesting the departments review the TSCR and identify the l
procedures affected by the change request, and if necessary develop new procedures.
In addition to the review, it was noted that procedure changes would have to be in place prior to the amendment being implemented.
ZNLD/2518/2
1 A review of the TSCR was completed on February 27, 1992 for the calibration procedures associated with the Unit 1 CRSL channels. At that time, these instruments were within the 18 month calibration frequency specified by the TSCR.
However, the calibration interval was specified as 1099 days (3 years) in the surveillance scheduling program and not the 550 day (18 months) interval required by the proposed Technical Specification. The last calibration of the Unit 1 CRSL channels was completed on March 2, 1991 and as such, the channels would remain within the calibration frequency specified by the TSCR only until January 17, 1993. At the time the CRSL channel surveillances were reviewed to support the TSCR, the calibration frequency of the instrumentation was not changed in the surveillance scheduling program from the existing 1099 day frequency to the required 550 day frequency.
Since the CRSL channels were within the frequency specified in the surveillance scheduling program and would remain within the frequency prior to the next Unit 1 refueling outage (ZlR13), these instruments were not calibrated during the last Unit 1 refueling (ZlR12) in the spring of 1992.
Discovery that the Unit 1 CRSL channel calibrations were not within the requirad calibration frequency was made during an implementation review prior to the implementation date (February 26, 1993) of the amendment.
3.
DISCUSSION OF 00MPENSATORY ACTIONS l
l During the period of time that this NRR TWOC is in effect, Zion Station will take the following compensatory actions to ensure that Unit 1 is maintained in a safe and stable condition:
a.
Containment water level (wide range) instrument channels and f
refueling water storage tank (RWST) level instrument channels shall be maintained OPERABLE in accordance with specification 3.8.9.
l b.
Appropriate operating personnel will be notified to ensure these actions are maintained.
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- 4. ' EVALUATION OF SAFETY SIGNIFICANCE AND POTENTIAL CONSEQUENCES In order to ensure adequate core cooling is maintained after a design basis loss of coolant accident, spilled reactor coolant and injection water, which would be collected in the containment recirculation sump following the injection phase, would be retirculated back to the RCS by the residual heat removal (RHR). centrifugal charging, and safety injection pumps. The recirculation phase begins before the Refueling Water Storage Tank (RWST) is completely emptied such that all pipes are kept filled with water.
Water level indication and alarms on the RWST are i
provided to inform the operator that sufficient water has been injected into the containment to allow manual initiation of recirculation with the RHR pumps and to provide ample warning to terminate the injection phase while the operating pumps still have adequate net positive suction head.
Two level indicators are provided in the recirculation sump to provide l
backup indication that injection can be terminated and recirculation l
initiated. As a result, the two CRSL channels help cnsure core cooling I
can continue to mitigate the accident consequences during the I
recirculation phase.
However, these channels do not provide a safety function actuation.
The calibration of the Unit 1 CRSL channels was last performed on March 2, 1991. As such, the new 18 month CHANNEL CALIBRATION frequency requirement has not been satisfied.
The calibration of these instruments was performed in the past on a 3 year interval.
The past 3 year interval would have expired in F. arch 1994. A hi:;torical review of calibration data and work requests for the past surveillance intervals since 1977 for both the Unit 1 and Unit 2 CRSL channels showed only 2 failures.
These failures were associated with the Unit 2 instruments and were determined to be the result of failed light bulbs.
These light bulb failures would have been detected during the monthly CHANNEL CHECK requirements of Specification 4.8.9.
The monthly CHANNEL CHECK for the CRSL channels will be performed as required by Specification 4.8.9.
These CHANNEL CHECKS provide a periodic qualitative assessment regarding the OPERABILITY of these channels during the interval until the calibrations can be performed. As a result, calibrations performed at the 3 year interval are considered to be acceptable for maintaining these instruments OPERABLE.
l The RWST level instrument channels and the containment water level (wide range) instrument channels, required to be OPERABLE per Specification 3.8.9, are also available to provide alternate indication of the status of containment water level until the 18 month calibrations of the Unit 1 CRSL channels can be performed.
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5.
A DISCUSSION WHICH JUSTIFIES THE DURATION OF THE REQUEST This change allows a delay in the performance of the CHANNEL CALIBRATION requirements of Specification 4.8.9 for the two Unit 1 CRSL channels until such time as a Technical Specification amendment can be issued granting a one time extension to the CRSL instrument CHANNEL CALIBRATION requirements.
It would be overly conservative to assume the two CRSL channels are inoperable when the CHANNEL CALIBRATION has not been performed within the required frequency.
The opposite is in fact the case; the majority of the calibrations have demonstrated the CRSL channels arc OPERABLE.
Since the CHANNEL CALIBRATIONS have been successfully performed on the two Unit 1 CRSL channels within the previous interval, it is primarily a question of OPERABILITY that has not been verified within the new 18 month interval.
In this case, the two Unit 1 CRSL channels would be considered OPERABLE unless it is known that the CHANNEL CALIBRATION can not be satisfactorily performed (then the associated CRSL channel will be considered inoperable).
Expiration of this NRR THOC will occur at 5:00 PM on June 30, 1993.
At that time, should a Technical Specification amendment not be issued granting a one time extension to the CRSL CHANNEL CALIBRATION requirements, the two Unit 1 CRSL channels shall be declared inoperable and the applicable actions of Technical Specification 3.8.9 shall be taken.
Should the Technical Specification amendment be granted prior to the expiration date, or if Unit 1 experiences a shutdown to Mode 3 (Hot Shutdown) 6110 10g ccmpletion of these surveillance requirements, this TWOC will be terminated and the Technical Specification requirements for these channels shall become effective.
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6.
BASIS FOR CONCLUDING THAT THE REQUEST DOES NOT INVOLVE A SIGNIFICANT
- HAZARDS CONSIDERATION Commonwealth Edison has evaluated this proposed temporary waiver and has determined that it involves no significant hazards considerations.
According to 10CFR 50.92(c), a proposed change to an operating license involves no significant hazards considerations if operation of the facility in accordance with the proposed change would not:
1)
Involve a significant increase in the probability or consequences of an accident previously evaluated; or 2)
Create the possibility of a new or different kind of accident from any accident previously evaluated; or 3)
Involve a significant reduction in a margin of safety.
The proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
The proposed change does not result in any hardware or operating procedure changes.
The frequencies for surveillances are not assumed in the initiation of any analyzed events.
This change will allow a delay in the performance of the CHANNEL CALIBRATION required by Specification 4.8.9 for the CRSL channels until such time as a Technical Specification amencment can be granted providing a one time extension to this surveillance frequency.
It would be overly conservative to assume the two Unit 1 CRSL channels are inoperable when the CHANNEL CALIBRATION has not been performed within the 18 month frequency.
Since the CHANNEL CALIBRATIONS for these instrument channels have been successfully performed within the i
previous interval, it is primarily a question of OPERABILITY that has not been verified by performance of the surveillance within the new required frequency.
In addition, alternate indication of containment water level is available from the RHST level instrument channels and the containment water level (wide range) instrument channels.
Therefore, the consequences of an accident previously evaluated are not significantly increased since the most likely outcome of performing the CHANNEL CALIBRATION would demonstrate the CRSL channels are OPERABLE.
The proposed change does not create the possibility of a new or different kind of accident from any previously analyzed.
The proposed change does not result in plant operations or configurations that could create a new or different type of accident. Any compensatory measures which have been implemented have been evaluated to ensure they do not result in any component or system being placed in an unanalyzed configuration.
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The proposed change does not involve a significant reduction in a
' margin of safety. The increased time allowed for the performance of the CHANNEL CALIBRATION of the CRSL channels is acceptable based on the small probability of an event requiring these instrument channels.
The required allowance will provide sufficient delay time to obtain a Technical Specification amendment granting a one time extension to the 18 month CHANNEL CALIBRATION for the Unit 1 containment sump recirculation instrument channels and is acceptable considering the historical reliability of these instrument channels. Without this delay, a unit shutdown would be required to perform the surveillance or to comply with the actions for inoperable instrument channels which cannot be restored.
As so..h, any reduction in a margin of safety will be insignificant and offset by the benefit gained in plant safety due to the avoidance of a plant shutdown transient.
7.
BASIS FOR CONCLUDING THAT THE REQUEST DOES NOT INVOLVE IRREVERSIBLE i
ENVIRONMENTAL CONSEQUENCES This proposed THOC does not involve a change in the installation or use of the facilities or components located within the restricted areas as defined in 10CFR20. Commonwealth Edison has determined that this proposed THOC does not involve a significant increase in the amount, or a significant change in the types, of any effluent that may be released off-site, and that there is no significant increase in individual or cumulative occupational radiation exposure. Accordingly, this proposed THOC meets the eligibility criteria for categorical exclusion set forth in 10CFR Section 51.22(c)(9).
Pursuant to 10CFR51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with granting of this proposed THOC.
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