CNL-15-108, Technical Specification (TS) Change - Reactor Coolant Temperature Indicator Inoperable - Exigent Amendment (WBN-TS-2015-12)
| ML15149A511 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 05/29/2015 |
| From: | James Shea Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| CNL-15-108, WBN-TS-2015-12 | |
| Download: ML15149A511 (17) | |
Text
CNL-15-108 May 29, 2015 10 CFR 50.90 10 CFR 50.91 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Watts Bar Nuclear Plant, Unit 1 Facility Operating License No. NPF-90 NRC Docket No. 50-390
Subject:
Watts Bar Nuclear Plant (WBN) Unit 1 -Technical Specification (TS)
Change - Reactor Coolant Temperature Indicator Inoperable - Exigent Amendment (WBN-TS-2015-12)
References : 1. TVA Letter to NRC dated October 29, 2004, "Watts Bar Nuclear Plant (WBN)
Unit 1 -Technical Specification (TS) Change TS-04 Reactor Coolant Temperature Indicator Inoperable- Exigent Amendment" (ML043080416)
- 2. NRC Letter to TVA dated November 19, 2004, "Watts Bar Unit 1 -Issuance of Exigent Technical Specification Amendment Concerning Inoperable Reactor Coolant System Temperature Indicator (TAC No. MC4979)" (ML043140476)
Pursuant to 10 CFR 50.90 and 10 CFR 50.91 (a)(6), Tennessee Valley Authority (TVA) requests an Exigent Technical Specification (TS) Change to License No. NPF-90 for WBN Unit 1. The proposed Exigent TS change will provide a one time change toTS Table 3.3.4-1, Function 4a, "RCS Hot Leg Temperature Indication," to permit the temperature indication for Reactor Coolant System (RCS) Loop 4 to be inoperable for the remainder of WBN Unit 1 Operating Cycle 13.
The request is necessary because on May 16, 2015, TVA discovered that Temperature Indicator (TI), 1-TI-68-65C, was not operable. The 30-day completion time for Condition A of TS 3.3.4 will expire on June 15, 2015, at approximately 0448 EDT which requires a plant shutdown . Accordingly, TVA requests approval of the TS change by June 14,2015 and that the implementation of the revised TS be effective immediately to avoid the required shutdown . This device is one of four instruments that provides indication in the Auxiliary Control Room (ACR) for the hot leg temperature of RCS Loop 4. The remaining three instruments remain operable.
U.S. Nuclear Regulatory Commission CNL-15-108 Page2 May 29,2015 Upon discovery of this condition, TVA entered TS 3.3.4, "Remote Shutdown System,"
Condition A. Condition A requires restoration of the Loop 4 temperature indication within 30 days. The problem has been isolated to components (modifier circuit or thermocouple) both located inside the Reactor Building Polar Crane Wall.
While the plant is operating, the radiological and environmental conditions inside this area would impose significant burden on plant staff attempting to repair the components. WBN Unit 1 is scheduled to start the Cycle 13 refueling outage in September 2015. TVA has evaluated the opportunity to repair the Loop 4 hot leg temperature indication and concluded that the safety significance of operating with the Loop 4 hot leg temperature indication inoperable for the remainder of the cycle does not outweigh the potential consequences to personnel safety and the radiological doses required to affect the repair. In addition, the LAR is being submitted as a deterministic LAR with risk insights using the WBN Probabilistic Risk Assessment (PRA). TVA concluded that the risk of continued plant operation with the Loop 4 hot leg temperature function inoperable is qualitatively assessed to be very low compared to the incremental risks associated with a plant shutdown.
Therefore, relief is requested from the requirements of TS 3.3.4, Condition A forTS Table 3.3.4-1, Function 4a. If the request is not granted, Condition A will require the restoration of the Loop 4 temperature indicator within 30 days or the plant must be shutdown in accordance with Condition B. The shutdown of the plant would result in an operational transient that is not necessary because the remaining temperature indications available in the ACR are adequate to safely shutdown the unit should an emergency arise. Considering this and the unanticipated failure of the instrumentation, TVA could not reasonably have avoided this exigency.
Should WBN Unit 1 experience a shutdown prior to the Unit 1 Cycle 13 refueling outage, the instrumentation (modifier circuit or thermocouple) will be repaired prior to startup and entry into Mode 3. to this letter provides the description and evaluation of the proposed change. contains a copy of TS Page 3.3-48 annotated to show the proposed change. contains a copy of TS Page 3.3-48 without the annotation.
TVA has determined that there are no significant hazards considerations associated with the proposed change and that the TS change qualifies for a categorical exclusion from environmental review pursuant to the provisions of 10 CFR 51.22(c)(9). The WBN Plant Operations Review Committee and TVA Nuclear Safety Review Board have reviewed this amendment request and concluded that operation of WBN Unit 1 in accordance with the proposed change will not endanger the health and safety of the public. Additionally, in accordance with 10 CFR 50.91 (b )(1 ), TVA is sending a copy of this letter and enclosure to the Tennessee State Department of Environment and Conservation.
U.S. Nuclear Regulatory Commission CNL-15-108 Page3 May 29,2015 This letter contains no new regulatory commitments; however, compensatory actions are listed in the enclosure. Should you have questions regarding this request, please contact Gordon Arent at (423) 365-2004.
I declare under penalty of perjury that the foregoing is true and correct. Executed on this 29th day of May 2015.
Enclosure:
Evaluation of the Proposed Change cc (Enclosure):
U.S. Nuclear Regulatory Commission, Region II NRC Senior Resident Inspector- Watts Bar Nuclear Plant Unit 1 NRR Project Manager - Watts Bar Nuclear Plant Unit 1 Director, Division of Radiological Health- Tennessee State Department of Environment and Conservation
ENCLOSURE TENNESSEE VALLEY AUTHORITY WATTS BAR NUCLEAR PLANT, UNIT 1 NRC DOCKET NO. 50-390 EVALUATION OF THE PROPOSED CHANGE
Subject:
Watts Bar Nuclear Plant (WBN) Unit 1 -Technical Specification (TS)
Change - Reactor Coolant Temperature Indicator Inoperable - Exigent Amendment (WBN-TS-2015-12)
- 1.
SUMMARY
DESCRIPTION
- 2. DETAILED DESCRIPTION
- 3. TECHNICAL EVALUATION
- 4. REGULATORY EVALUATION 4.1 Applicable Regulatory Requirements/Criteria 4.2 Precedent 4.3 Significant Hazards Consideration 4.4 Conclusions
- 5. ENVIRONMENTAL CONSIDERATION
- 6. REFERENCES ATTACHMENTS:
- 1. Proposed TS Change for WBN Unit 1 (markup)
- 2. Proposed TS Change for WBN Unit 1 (retyped)
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1.0
SUMMARY
DESCRIPTION Pursuant to 10 CFR 50.90 and 10 CFR 50.91(a)(6), TVA requests an Exigent Technical Specification (TS) Change to License No. NPF-90 for Watts Bar Nuclear Plant (WBN)
Unit 1. The proposed Exigent TS change will provide a one time change to TS Table 3.3.4-1, Function 4a, "RCS Hot Leg Temperature Indication," to permit the temperature indication for Reactor Coolant System (RCS) Loop 4 to be inoperable for the remainder of WBN Unit 1 Operating Cycle 13. The request is necessary because on May 16, 2015, TVA discovered that Temperature Indicator (TI), 1-TI-68-65C, was not operable. This device provides indication in the Auxiliary Control Room (ACR) for the hot leg temperature of Reactor Coolant System (RCS) Loop 4 and is located inside the Reactor Building Polar Crane wall.
Accordingly, TVA is requesting this proposed TS change under exigent circumstances, and requests that the Nuclear Regulatory Commission (NRC) expedite the review of the requested change to support approval by June 14, 2015.
2.0 DETAILED DESCRIPTION 2.1 Basis for the Exigent Request As detailed in Section 3.0, "Technical Evaluation," of this enclosure, TVA could not have reasonably avoided this exigent request. The key factors that are the basis for the exigent request include:
A. TVA could not reasonably have anticipated the failure of the instrumentation.
Although WBN did experience a failure of the Loop 4 hot leg instrument in 2004, the issues in the 2004 failure resulted in a full scale reading. The issues associated with the current failure (failing low scale) have been isolated to the modifier circuit or the thermocouple. Nothing in the 2004 failure could have led TVA to reasonably anticipate the current failure.
B. The repair of the affected instrumentation precludes repair at power because the affected equipment is located inside the Reactor Building Polar Crane Wall, which is a high dose area during power operations.
C. The shutdown of the plant to implement the repairs is not necessary because the remaining temperature indications available in the ACR are adequate to safely shutdown the unit should an emergency arise.
2.2 Proposed Technical Specification Change This proposed change revises Note A at the bottom of TS Table 3.3.4-1, "Remote Shutdown System Instrumentation and Controls," to state the following:
"For Function 4a, the temperature indicator for RCS hot leg 4 is not required to be operable for the remainder of Cycle 13."
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2.3 Justification for the Change On May 16, 2015, while performing routine surveillance instruction 1-SI-0-4, "Monthly Surveillances," TVA determined that Instrument 1-TI-68-65C was inoperable. After performing trouble shooting, TVA determined that the problem is either with the modifier circuit or with the associated thermocouple. Both the modifier circuit and the thermocouple are located inside the Reactor Building Polar Crane Wall.
TVA has evaluated the plant conditions needed to perform the necessary repairs. While the plant is operating, as discussed in more detail in the Technical Evaluation section, the radiological conditions and environmental conditions inside this area would impose significant burden on plant staff attempting to repair the components. WBN Unit 1 is scheduled to start the Cycle 13 refueling outage in September 2015. TVA has evaluated the opportunity to repair the Loop 4 hot leg temperature indication and concluded that the safety significance of operating with the Loop 4 hot leg temperature indication inoperable for the remainder of the cycle does not outweigh the potential consequences to personnel safety and the radiological doses required to affect the repair. In addition, the LAR is being submitted as a deterministic LAR with risk insights using the WBN Probabilistic Risk Assessment (PRA). TVA concluded that the risk of continued plant operation with the Loop 4 hot leg temperature function inoperable is qualitatively assessed to be very low compared to the incremental risks associated with a plant shutdown. As noted, additional details are provided in the Technical Evaluation section.
3.0 TECHNICAL EVALUATION
3.1 System Description A. Remote Shutdown System The Remote Shutdown System [also referred to as the Auxiliary Control System (ACS)]
provides the control room operator with sufficient instrumentation and controls to place and maintain the unit in a safe shutdown condition from a location other than the MCR.
The ACS is required in the event that the MCR must be evacuated due to some unspecified reason, as well as during a Control Building fire which causes loss of safe shutdown control from the MCR. This system is not required to function for mitigation of any design basis event, other than the fire or evacuation of the MCR or a design basis flood. Portions of the ACS that terminate in the ACR are used during the design basis flood. The ACS meets two separate failure criteria.
- 1. During normal operation, equipment and controls are provided to ensure that a random single failure in the ACS does not affect the corresponding MCR equipment and controls. During MCR evacuation, no single failure of ACS equipment must be assumed per the WBN design.
- 2. ACS equipment and controls are assumed to be damaged if the equipment is not fire protected in the zone of influence of a fire. No equipment failures other than those directly attributed to a fire must be considered.
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The most limiting condition for the events in which the ACS is required is a fire. For a fire, procedures require that the Reactor Coolant Pumps be tripped such that decay heat removal is via natural circulation. Section 7.4, "Safe Shutdown Systems," of NUREG-0800, "Standard Review Plan," establishes the review guidelines for the remote control stations and the equipment used to maintain safe shutdown. Consistent with these guidelines, TVA has developed a safe shutdown logic diagram for an Appendix R fire. This logic defines a sufficient set of equipment and indication to safely shutdown the reactor from the ACR. For each safety function, the equipment required to accomplish the safety function has been divided into groups of functionally related equipment necessary to accomplish the safety function. The RCS hot leg temperature indicators are required for steam generator (SG) level control in redundant shutdown logic paths. If Loop 4 temperature indication (T(hot)) is removed, success for this function can still be achieved via the remaining available ACS T(hot) indicators.
Redundancy for SG level control exists in these paths to account for equipment in one of the redundant paths being damaged by any fire in a single area. For the case addressed by this change, the fire must exist in the Control Building, which is considered a single area, to cause an evacuation of the MCR. Because the conduit, cables and equipment that provide T(hot) indication in the ACR are routed outside the Control Building, removal of the Loop 4 T(hot) indication is acceptable due to the redundant paths not being affected by the Control Building fire. Because a redundant path for SG level control is required to remain functional by the TS for the remainder of Cycle 13, the ACS can adequately perform its function to place and maintain the unit in a safe shutdown condition in a location other than the MCR. Therefore, the fire safe shutdown logic is met and adequate indication is present without Loop 4 T(hot) indication.
Design guidance for ACS is provided in ANSI/ANS-58.6-1983, "Criteria for Remote Shutdown for Light Water Reactors." This guidance does not specifically state that RCS hot leg temperature indication is required for all four loops. Item 4(5) states that equipment, instrumentation and controls which are required to monitor, achieve and maintain a hot shutdown condition (following power operation) shall be located in the Auxiliary Shutdown Station wherever practical. Item 4(5)(b) refers to decay heat removal as a minimum requirement for maintaining hot or cold shutdown and references the following to achieve the decay heat removal.
i) Monitor SG parameters for residual heat removal.
ii) Control Auxiliary Feedwater (AFW) flow and monitor AFW supply inventory.
iii) Control steam relieving system.
WBN uses the RCS hot leg temperature indication for compliance with Item 4(5)(b ).
B. Repair Considerations The problem has been isolated to components (modifier circuit or thermocouple) both located inside the Reactor Building Polar Crane Wall. While the plant is operating, the radiological and environmental conditions inside this area as discussed below would impose significant burden on plant staff attempting to repair the components.
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Personnel Safety - Working Conditions If TVA were to attempt to repair the components that are located inside the Reactor Building Polar Crane Wall, under current conditions, the "stay time" would be approximately 35 minutes. The environmental considerations include containment temperature, humidity, and required personnel protective equipment (PPE).
Expected Radiological Dose for Performing the Repair The table below provides dose estimates for the repair effort at various power levels.
Neutron dose contributes approximately 10% of the estimated total dose when at 100%
reactor power.
Reactor Power Level 100% 90% 75% 50% 25%
Task Inside Polar Crane Wall Entry Transit* 130 110 100 60 45 At Site @ 30 min* 450 360 240 180 120 At Site @ 45 min* 675 540 360 270 180 Maintenance Technician 1* 1255 1010 700 510 345 Maintenance Technician 2* 1255 1010 700 510 345 Radiation Protection Technician* 1255 1010 700 510 345 Radiation Protection Support* 75 50 40 30 20 Totals* 3840 3080 2140 1560 1055
- Dose values 1n m1lhrem C. Risk Considerations When redundant and diverse indications are available to provide necessary information to plant operators, the WBN Probabilistic Risk Assessment (PRA) model does not generally model the effect of the loss of a single indication. In addition, the WBN model does not currently credit shutdown from outside of the main control room. Therefore, from a quantitative perspective (as measured by the WBN PRA model), unavailability of RCS Loop 4 Hot leg Temperature in the Auxiliary Control Room (ACR) does not increase risk. Accordingly, this issue was examined qualitatively and it was noted that RCS Loop 4 hot leg temperature indication is used to ensure decay heat removal via the associated SG. Loop 4 hot leg temperature is only one of at least five parameters used to ensure decay heat removal via the SGs. The remaining indications are sufficient that operators can ensure adequate decay heat removal. Therefore, the risk increase associated with this issue is negligible.
The WBN PRA model does not explicitly address risk associated with a downpower and/or return to full power. However, any significant plant maneuver increases the likelihood of complications which could induce or require a plant trip. As a sensitivity, the risk associated with a down power was assumed to be equal to 10% of the risk associated with a plant trip (%1Turbine Trip Initiating Event (TTl E)). Increasing PRA initiator %1TTIE from 0.241/yr to 0.2651/yr results in an Incremental Conditional Core Damage Probability (ICCDP) estimate of approximately 4E-8.
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3.2 Technical Specification Change Evaluation The basis for continued operation with the RCS Loop 4 hot leg temperature indicator inoperable is acceptable because this parameter is only one of five parameters used to ensure decay heat removal via the SGs. The other parameters will be available in the ACR during the remainder of Cycle 13. Relaxing the requirement for one loop of T(hot) indication while maintaining the requirements for the remaining three loops of T(hot) indication, AFW Controls, SG pressure indication and control, SG level indication, AFW flow indication and SG T(sat) indication, will not adversely affect the unit's ability to remove decay heat. If the operable three loops are consistent relative to T(hot), SG T(sat) and SG level, and the other parameters for the inoperable loop are not contradictory to plant conditions indicated by the operable loops (i.e., SG level and SG T(sat) for loop 4), then it is reasonable to consider that Loop 4 is performing its function to remove decay heat via its SG.
T(hot) is also used to set the reactor cooldown rate during safe shutdown from a location other than the MCR. The absence of one out of the four T(hot) indications does not adversely affect this function because the other three operable indications may be used.
Further, Abnormal Operating Instruction (AOI) 27, "Main Control Room Inaccessibility,"
and AOI-30.2, "Fire Safe Shutdown," are the procedures used for MCR abandonment for non-Appendix Rand Appendix R fire conditions, respectively. AOI-27 and AOI-30.2 both require the unit to be tripped before the MCR is abandoned. The indication for Loop 4 is used in these procedures to monitor the plant cooldown rate in the ACR. The probability of having to abandon the MCR is low and remains the same, whether the plant continues to operate or is shut down. Therefore, the change proposed in this amendment request is considered to be risk neutral with regard to initiating events.
The inoperable RCS loop 4 hot leg temperature indication is only displayed in the ACR.
It is not part of the Reactor Protection System (RPS) and does not provide input to any safety related shutdown system. The only component adversely affected by the inoperable RCS loop four hot leg temperature indicator is the corresponding recorder. In addition, during a shutdown where the Residual Heat Removal (RHR) system is activated to remove decay heat from the reactor, the plant operator can choose one of the remaining three loops (Loops 1 through 3) to achieve the intended goal. Therefore, the out of service temperature indicator has no effect on the safe operation and shutdown of the reactor.
3.3 Additional Considerations TVA evaluated the impact should any failures of additional hot leg temperature indicators occur during the period that the Loop 4 hot leg temperature instrument is out of service.
Should the temperature indicator for another hot leg loop fail while the Loop 4 indicator is inoperable, TVA will evaluate the impact of the inoperable components in accordance with the TVA Corrective Action Program. The evaluation will provide site management with the necessary information to decide if the unit must be shutdown to implement the needed repairs or whether adequate remote shutdown information is available to the operating staff for safe operation of the unit. Any decision to continue plant operation beyond the 30 day allowed outage time (AOT) will require NRC approval under a license amendment.
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Should WBN Unit 1 experience a shutdown prior to the Unit 1 Cycle 13 refueling outage, the instrumentation (modifier circuit or thermocouple) will be repaired prior to startup and entry into Mode 3.
Finally, to ensure operating personnel are fully cognizant of the out-of-service instrument, WBN plans to take the following actions during the time the subject instrument is out of service.
- 1. Operating procedures affected by the inoperable instrument will be revised in accordance with established practice.
- 2. The inoperable instrument will be appropriately tagged.
- 3. The inoperable instrument will be incorporated in the re-qualification training and the required reading (i.e., Night Orders) for licensed operators.
Considering the preceding, TVA proposes to revise TS Table 3.3.4-1, Function 4a, "RCS Hot Leg Temperature Indication," to allow operation until a time not to exceed the end of Cycle 13 with the Loop 4 remote shutdown indicator for RCS hot leg temperature inoperable.
4.0 REGULATORY EVALUATION
4.1 Applicable Regulatory Requirements/Criteria The Bases forTS 3.3.4 states that the operability of the remote shutdown control and instrumentation functions ensures there is sufficient information available on selected unit parameters to place and maintain the unit in MODE 3 should the MCR become inaccessible. Should it be necessary to go to MODE 4 or MODE 5, decay heat removal via the RHR system is available to support the transition.
The ACS is required to provide equipment at appropriate locations outside the MCR with a capability to promptly shut down and maintain the unit in a safe condition in MODE 3. The criteria governing the design and specific system requirements of the ACS are located in 10 CFR 50, Appendix A, General Design Criteria (GDC) 19, "Control Room." WBN's compliance with GDC 19 is discussed in UFSAR Section 3.1, "Conformance with NRC General Design Criteria." NRC's review of UFSAR Section 3.1, is documented in Section 3.1.1, "Conformance with General Design Criteria," of the Safety Evaluation Report (SER), dated June 1982.
The instrumentation functions required for the ACR are discussed in Section 7.4, "Systems Required for Safe Shutdown," of the UFSAR. NRC's review of this portion of the UFSAR and other relevant UFSAR sections related to the ACR or the function of the hot leg temperature indication are provided in the following sections of the SER or in Supplements to the SER:
SER June 1982- Section 7.4 SER Supplement 5- Section 1.7 E-7
SER Supplement 7- Section 7.4 SER Supplement 8 - Section 4.4.3.4 SER Supplement 18- Appendix FF, Section 3.4 4.2 Precedent The following license amendments approved by the NRC for Watts Bar and Catawba Nuclear Plants provide clear precedence for the TS change proposed in this submittal.
Watts Bar Unit 1 -Issuance Of Exigent Technical Specification Amendment Concerning Inoperable Reactor Coolant System Temperature Indicator (TAG No. MC4979), dated November 19, 2004 Catawba Nuclear Station, Units 1 and 2 - Issuance of Amendments Regarding Exigent License Amendment Request to Revise Technical Specification 3.3.4, Remote Shutdown System (TAG Nos. MF3473 and MF3474), dated February 27, 2014 4.3 Significant Hazards Consideration The proposed change will revise the Remote Shutdown System Technical Specification Table 3.3.4-1, Function 4a, "RCS Hot Leg Temperature Indication,"
to allow operation with only three of four loop remote shutdown indications for Reactor Coolant System (RCS) hot leg temperature until the Cycle 13 refueling outage. TVA has evaluated whether or not a significant hazards consideration is involved with the proposed amendment by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below.
- 1. Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?
Response: No.
The proposed TS change to allow operation with only three of four loop remote shutdown indications for RCS hot leg temperature until the Cycle 13 refueling outage is only applicable to the following conditions:
A. Fire or smoke in the Main Control Room (MCR).
B. An evacuation of the MCR due to some other (non-fire) unspecified reason C. The design basis flood.
The inoperability of the one T(hot) indicator does not change the probability of occurrence for these events because the indicator is not an accident initiator.
The T(hot) indicators on the four loops are used for indication only and have no automatic control functions. During safe shutdown for an MCR evacuation event, design basis flood or fire related event, no fuel damage is postulated to E-8
occur, nor is the integrity of the reactor coolant pressure boundary or containment barriers postulated to be lost. Sufficient redundancy exists with the operational instrumentation to ensure that decay heat removal functions are not adversely affected by this change. Therefore, the proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
- 2. Does the proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?
Response: No.
The proposed TS change does not alter the function of the Remote Shutdown System which is to achieve and maintain safe reactor shutdown from outside the MCR. The TS instrumentation and controls required are such that sufficient capability is retained for decay heat removal via the Steam Generators (SGs) to provide the indication required for safe shutdown capabilities. The change will not result in the installation of any new equipment or system. The T(hot) instrument is used for indication only and has no automatic control functions. No new operations procedures will be created by this change. Appropriate operational procedures will be updated to clarify that the Loop 4 T(hot) indication in the Auxiliary Control Room (ACR) is not available during the remainder of Cycle 13. No new operating conditions or modes will be created by this proposed change. Therefore, the proposed change does not create the possibility of a new or different kind of accident from any previously evaluated.
- 3. Does the proposed change involve a significant reduction in a margin of safety?
Response: No.
The radiological dose consequences are not affected, because this change is only applicable to the following conditions.
A. Fire or smoke in the MCR.
B An evacuation of the MCR due to some other (non-fire) unspecified reason.
C. The design basis flood.
During safe shutdown for an MCR evacuation event, design basis flood or fire related event, no fuel damage is postulated to occur, nor is the integrity of the reactor coolant pressure boundary or containment barriers postulated to be lost. Sufficient redundancy exists with the operational instrumentation to ensure that decay heat removal functions are not adversely affected by this change. Because the conduit, cables and equipment that provide T(hot) indication in the ACR are routed outside the Control Building, removal of the Loop 4 T(hot) indication is acceptable due to the redundant paths not being E-9
affected by the Control Building fire. Therefore, the proposed change does not involve a significant reduction in a margin of safety.
Based on the above, TVA concludes that the proposed amendment does not involve a significant hazards consideration under the standards set forth in 10 CFR 50.92(c), and accordingly, a finding of "no significant hazards consideration" is justified.
- 4.4 Conclusions In conclusion, based on the considerations discussed above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
5.0 ENVIRONMENTAL CONSIDERATION
A review has determined that the proposed amendment would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20. However, the proposed amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluents that may be released offsite, or (iii) a significant increase in individual or cumulative occupatiooal radiation exposure. Accordingly, the proposed amendment meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed amendment. *
6.0 REFERENCES
The references are as described in the text.
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ATTACHMENT 1 PROPOSED TS CHANGE FOR WBN UNIT 1 (MARKUP)
Remote S hutdown System 33.4 Table 3.3.4-1 (page 1 of 1)
Remote Shutdown System Instrumentation and Controls FUN CTION/INSTRUMENT REQUIRED OR CONTROL PARAME TER NUMBER OF FUNCTIONS React1v1 ty Control a Source Range Neu tron Flux b Reactor Tnp Breaker Pos111on lnd,callon 1 per lnp breaker 2 Reactor Coolant System (RCS) Pressure Control a Pressunzer Pressure lnd1cat1on or RCS W1de Ra nge Pressure lnd1ca11on
- b. Pressunzer Power Opera ted Rel1el Valve 1 each per relief pa lh (PORV) Control and Pressunzer Block Valve Control c Pressunzer Healer Con trol 3 RCS Inven tory Control a Pressunzer Level lnd1ca t1on b Chargmg and Le tdown Flow Control and lnd1callon 4 Decay Heat Re moval v1a Steam Generators (SGs) a RCS Hot Leg Temperature lnd1cat1on 1 per loop (Refer to Note A below )
b AFW Con trols c SG Pressure lnd1ca t1on and Control 1 per SG d SG Level lnd1cat1on 1 per SG and AFW Flow lnd1callon e SG T,". lnd1cat1on 1 pe r SG 5 Decay Heat Removal v1a RHR System a RHR Flow Control I
~otes A For Funct1on 4a the tempera ture 'ndlcd tor for RCS l1ot leg 4 15 not requ1red to llc operable for the rerna*nder Iof Cycle 6 W<J:ts B<1r-Un1t 1 Replace with
\ 3 3 48 "For function 4a , the temperature indicator for RCS hot leg 4 is not Amendment 53 required to be operable for the remainder of Cyc le 13 ."
ATTACHMENT 2 PROPOSED TS CHANGE FOR WBN UNIT 1 (RETYPED PAGES)
Remote Shutdown System 3.3.4 Table 3.3.4-1 (page 1 of 1)
Rem ote Shutdown System Instrumentation and Controls FUNCTION/INSTRUMENT REQU IRED OR CONTROL PARAM ETER NU MBER OF FUNCTIONS
- 1. Reactivity Control
- a. Source Range Neutron Flux
- b. Reactor Trip Breaker Position Indication 1 per tri p breaker
- 2. Reactor Coolant System (RC S) Pressure Control
- a. Pressurizer Pressure Indication or RCS Wide Range Pressure Indication
- b. Pressurizer Power Operated Relief Valve 1 each per relief path (PORV) Control and Pressurizer Block Val ve Control
- c. Pressurizer Heater Control
- 3. RCS Inventory Control
- a. Pressurizer Level Ind ication
- b. Charging and Letdown Flow Control and Indication
- 4. Decay Heat Removal via Steam Generators (SGs)
- a. RCS Hot Leg Temperature Indication 1 per loop (Refer to Note A below)
- b. AFW Controls
- 5. Decay Heat Removal vi a RHR System
- a. RH R Flow Control
- b. RHR Temperature Indication Notes:
A. For Function 4a, the te mperat ure indicator for RCS hot leg 4 is not requ ired to be operable for the remainder of Cycl e 13.
Watts Bar-Unit 1 3.3-48 Am endment 53