ML20195D993
| ML20195D993 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 11/09/1998 |
| From: | Dacimo F COMMONWEALTH EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20195D999 | List: |
| References | |
| NUDOCS 9811180214 | |
| Download: ML20195D993 (29) | |
Text
Commonwealth litison Company 1.aSalle Generating Station 2001 North 219,1 Road Marseilles. IL 6iM i 9757 Tel 815d57-6761 November 9,1998 United States Nuclear Regulatory Commission Attention: Document ControlDesk Washington, D.C. 20555
Subject:
Application for Amendment to Appendix A, Technical Specifications, to Facility Operating Licenses LaSalle County Nuclear Power Station, Units 1 and 2 Facility Operating License NPF-11 and NPF-18 NRC Docket Nos. 50-373 and 50-374 Proposed Changes to Leak and Break Detection Isolation Instrumentation Technical Specification Requirements
References:
- 1. Letter dated November 24,1997 from W. T. Subalusky to the U.S. ;
NRC, Request for Technical Specification Amendment to Facility l Operating License NPF-11 for Irak and Break Detection Isolation I instrumentation.
- 2. January 6 and 15,1998 Telephone conferences between Comed and NRR involving RWCU Irak and Break Detection. 1
- 3. Letter dated April 16,1998 from F. R. Dacimo to the U.S. NRC, i Comed Response to NRC Staff Request for Additional Information (RAI) and Supplemental Request for Technical Specification Amendment to Facility Operating License NPF-11 for Leak and Break Detection Isolation Instrumentation.
- 4. Letter datedJuly 6,1998 from D. M. Skay to O. D. Kingsley, Issuance of amendment 129 to Facility Operating License No. NPF-11 for LaSalle County Station Unit 1. (FAC No. MA0178) l i
c\-
. . .; 1 q 2 4
\
9811100214 981109 "[
DR ADOCK 050003
__ m,,
i November 10,1998 )
Page 2 ;
U.S. Nuclear Regtdatory Commission l Pursuant to 10 CFR 50.90, Commonwealth Edison Company (Comed) proposes to amend Appendix A, Technical Specifications, of Facility Operating License NPF-18, LaSalle County Station Unit 2. The proposed amendment requests a change to the Technical Specifications which:
+
adds automatic primary containment isolation on Ambient and Differential Temperature (AT)- liigh for the Reactor Water Cleanup System (RWCU) Pump, Pump Valve, Holdup Pipe, and Filter /Demineralizer (F/D) Valve Rooms;
+
adds automatic primary containment isolation on RWCU Pump Suction Flow -
liigh; revises the ambient and differential temperature isolation setpoints in the RWCU Heat Exchanger Rooms;
+
eliminates the Residual Heat Removal (RHR) System steam condensing mode isolation actuation instrumentation; and
+
eliminates the ambient and differential temperature alarm and isolation functions for the IUIR System shutdown cooling mode.
Currently, the Unit 2 RWCU pump rooms have no temperature monitoring because they contain " cold" piping. A design modification that restores " hot" suction to the RWCU pumps determined that the RWCU pump rooms and associated new pump valve room require leak detection isolation instrumentation. The setpoints for the heat exchanger rooms are being changed as a result of new design basis calculations. The new ambient and differential temperature leak detection for the RWCU holdup pipe area and the F/D valve room and the RWCU pump suction high flow switch are being added to minimize the impact ofline breaks in these areas. The steam condensing mode of the RHR system is no longer utilized. Area temperature monitoring of the RHR shutdown cooling mode lines is being deleted because the system mode has been recognized as a moderate energy line and because area temperature monitoringis not effective since the energy in these lines is not sufficient to increase the area temperatures to detectable levels. These lines are in service in Cold Shutdown or at low reactor pressures in Hot Shutdown.
The proposed leak detection changes for LaSalle County Station (LaSalle) Unit 2 are the same, except for minor differences, as the LaSalle Unit 1 changes proposed in Reference 1
. and approved by Reference 4. Reference 3 supplemented Reference 1 and answered NRC l questions raised in two conferences calls listed in Reference 2.
a l
l Comed requests approval of this license amendment request prior to startup of LaSalle Unit 2 from its present refuel outage, L2R07, currently scheduled for May 1999. The amendment should be made effective upon issuance for Unit 2. Comed will implement the amendment prior to startup of LaSalle, Unit 2, from the current outage.
I l
l l
November 10,1998 Page 3 U.S. Nuclear Regulatory Commission This proposed amendment request is subdivided as follows:
L ~ Attachment A gives a description and safety analysis of the proposed changes in this amendment.
- 2. Attachment B includes'the marked-up License / Technical Specification pages for l LaSalle Unit 2 with the requested changes indicated.
- 3. Attachment C describes Comed's evaluation performed in accordance with 10 CFR 50.92 (c), which confirms that no significant hazard consideration is involved.
- 4. Attachment D provides an Environmental Assessment Statement Applicability Review per 10 CFR 51.21.
- 5. Attachment E is the Summary of Sargent and Lundy (S&L) Calculations For.
Revised Heat Loads For the RWCU Areas Affected By the Modification That ;
Changes the RWCU System From a Cold Suction To a Hot Suction.
- 6. ' . Attachment F is the Summary of S&L Calculation No.1,001281, RWCU Areas
- l. Temperature Response Due To High Energy RWCU Fluid Leakage.
l 7. Attachment G is the Summary of S&L Calculation No. I,001324, Area Ambient .
and Differential Temperature Design Basis Calculations for Reactor Coolant leak Detection.
- 8. Attachment H is the Summary of S&L Calculation No. 3C7-1184-001, ECCS l Room Leak Detection Setpoints. I
- 9. Attachment I is the Summary of S&L Calculation No. I,001384, Reactor Building l Environmental Transient Conditions Following RWCU and RCIC High Energy Line Breaks (HELBs).
- 10. AttachmentJ is the Summary of S&L Calculation No.1,001420, Unit 2 RWCU Room Setpoint Margin Analysis and Loop Accuracy.
- 11. Attachment K is the Summaries of S&L Calculation No. L-001443, Reactor Water Cleanup High Flow Isolation Error Analysis.
This proposed amendment has been reviewed and approved by Comed Onsite and Offsite l Review in accordance with Comed procedures.-
l Comed is notifying the State ofIllinois of this application for amendment by transmitting a copy of this letter and its attachments to the designated state official.
l 4 i
I L .
, , . . .. .-. . . - - - . . _ . . ~ . - _ . - . - . . . .-..- .. -. .
c j i - November 10,1998
. Page 4 '
U.S. Nuclear Regulatory Commission I affirm that the content of this transmittalis true and correct to the best of my knowledge, information and belief.
'If there are any questions or comments concerning this letter, please refer them to Perry L Barnes, Regulatory Assurance Manager, at (815) 357-6761, extension 2383.
r
)
l c , Yk :
l Fred R. Dacimo j Site Vice President j LaSalle County Station j Subscribed and sworn to before me, a Notary Public in and g/4 '
8 for the State ofIllinois, this _ / day of DEB Y NOTARY PUBUC, STATE OFILLINOIS stumtAto ]99 7 MY COMMISS10N EXPIRES 1012000 i
l O >la n (1 N a r< n Attachments Notary $)ublic
(
cc: J. L Caldwell, Acting NRC Region III Administrator :
D. M. Skay, NRC Project Manger - NRR - LaSalle M. P. Huber, NRC Senior Resident Inspector - LaSalle Office of Nuclear Facility Safety, IDNS L-i I
l l
l h
I.
\ , .,
! ATTACHMENT A I
DESCRIPTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES i A.
SUMMARY
OF THE PROPOSED CHANGES l
(
l Commonwealth Edison Company (Comed) proposes to revise Appendix A, Technical Speci6 cations of Facility Operating License NPF-18, LaSalle County Station (LaSalle) Unit 2.
He proposed changes include changes to the Technical Specifications which: ;
add automatic primary containment isolation on Ambient and Differential Temperature (NI)- High for the Reactor Water Cleanup System (RWCU) Pump, Pump Valve, Holdup Pipe, and Filter /Demineralizer (F/D) Valve Rooms; i
add automatic primary containment isolation on RWCU Pump Suction Flow - High; revise the ambient and differential temperature isolation setpoints in the RWCU Heat Exchanger Rooms; eliminate the Residual Heat Removal (RHR) System steam condensing mode isolation actuation instrumentation; and i 1
eliminate the ambient and differential temperature alarm and isolation functions for the l RHR System shutdown cooling mode.
Currently, the RWCU pump rooms have no temperature monitoring because they contain " cold" piping. A design modification that restores " hot" suction to the RWCU pumps determined that the RWCU pump rooms and associated new pump valve room require leak detection isolation instrumentation. The setpoints for the heat exchanger rooms are being changed as a result of new design basis calculations. The new ambient and differential temperature leak detection for the RWCU holdup pipe area and the F/D valve room and the RWCU pump suction high flow instrumentation are being added to minimize the impact ofline breaks in these areas.
He steam condensing mode of RHR system is no longer utilized. Area temperature monitoring of the RHR shutdown cooling mode lines is being deleted because the system mode has been recognized as a moderate energy line and because area temperature monitoring is not effective since the energy in these lines is not sufficient to increase the area temperatures to detectable levels. These lines are in service in Cold Shutdown or at low reactor pressures in Hot Shutdown.
The proposed leak detection changes for LaSalle Unit 2 are the same, except for minor differences, as the LaSalle Unit 1 changes proposed in Reference 1 and approved by Reference 4.
Reference 3 supplemented Reference 1 and answered NRC questions raised in two conferences calls listed in Reference 2.
( A-1 l
ATTACHMENT A DESCRIPTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES B. DESCRIPTION OF THE CURRENT REQUIREMENTS Technical Specification Table 3.3.2-1 requires the following Automatic Primary Containment Isolation Instrument trip functions to be OPERABLE, with setpoints as listed in Table 3.3.2-2:
A.3 Reactor Water Cleanup System Isolation
- b. Heat Exchanger Area Temperature - High, with a setpoint of s 181*F and an allowable value of s 187'F. The Minimum Operable Channels Per Trip System is "1/ heat exchanger".
- c. Heat Exchanger Area Ventilation AT - High, with a setpoint of s 85'F with an allowable value of s 91*F. The Minimum Operable Channels Per Trip System is "1/ heat exchanger" A.5 RHR System Steam Condensing Mode Isolation
- a. RHR Equipment Area A Temperature - High, with a setpoint of s 50*F and an allowable value of s 56*F. The Minimum Operable Channels Per Trip System is "1/RHR uea".
- b. RHR Area Temperature - High, with a setpoint of s 200'F and an allowable value of s 206*F. Tables 3.3.2-2,3.3.2-3, and 4.3.2.1-1 state this Trip Function as "RHR Area Cooler Temperature - High". He Minimum Operable Channels Per Trip System is "1/RHR area".
- c. RHR Heat Exchanger Steam Supply Flow - High, with a serpoint of s 123" H 2O and an allowable value of s 128" H20. The Minimum Operable Channels Per Trip System is "1".
A.6 RHR System Shutdown Cooling Mode Isolation
- d. RHR Area Temperature - High, with a setpoint of s 200 F and an allowable value of s 206'F. Tables 3.3.2 2 and 3.3.2-3 state this Trip Function as "RHR Area Cooler Temperature - High" he Minimum Operable Channels Per Trip System is "1/RHR area",
- e. RHR Equipment Area AT - High, with a setpoint of s 50 F and an allowable value of s 56'F. The Minimum Operable Channels Per Trip System is "1/RHR area".
A-2 l .
ATTACHMENT A DESCRIPTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES he Applicable Operational Conditions for the instrumentation channels, are listed in Table 3.3.2 1 as Conditions 1,2, and 3.
The Technical Specification Surveillance Requirements for each of the above trip functions are as follows:
Channel Checks are "NA" (Not Applicable),
Channel Functional Tests are "Q" (quarterly), and a
Channel Calibrations are "Q" (quarterly).
%ese Technical Specification requirements pertain to the area temperature and differential temperature leak detection monitors which are located in equipment areas of systems outside primary containment that carry hot reactor coolant. When these monitors sense a leakage of hot reactor coolant in excess of the established leakage rate limit, by sensing an increase in the equipment area temperature or area ventilation differential temperature, an isolation of the system containment isolation valves is actuated. The established leakage rate limit for isolation is a temperature or differential temperature corresponding to a 25 gpm leak,in accordance with the GE design specification recommendation for the leak detection system.
For each of the above trip functions, the isolation logic consists of two trip systems, one for the inboard containment isolation logic and one for the outboard containment isolation logic. Each of these trip systems contains one channel. A trip of a single channel causes the associated inboard or outboard valve group to isolate as designated in Technical Specification Table 3.3.21.
The RWCU containment isolation valve group is 5 (five).
The design bases for the temperature and differential temperature leak detection primary containment isolation control instrumentation is set forth in UFSAR Section 7.3.2 and includes appropriate redundancy, electrical and physical separation, and seismic and environmental qualification.
l l A-3 I
L l l
i l ATTACHMENT A i
DESCRIPTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES j C. BASES FOR THE CURRENT REQUIREMENTS The basis for Technical Specification 3/4.3.2 states the following conceming Isolation Actuation I Instrumentabon tnp settmgs. j i
"Some of the trip settings may have tolerances explicitiy stated where both the high and low values are critical and may have a substantial effect on safety. The setpoints of other l instrumentation, where only the high or low end of the setting have a direct bearing on safety, are established at a level away from the normal operating range to prevent inadvertent actuation of the systems involved." l Safety design bases (a), (b), and (d) for the primary containment isolation control system are stated in UFSAR Section 7.3.2.1 as follows:
l "a. To limit the release of radioactive materials to the environs, the primary i containment and reactor vessel isolation control system shall, with precision and i reliability, initiate timely isolation of penetrations through the primary containment whenever the values of monitored variables exceed preselected operational limits."
"b. To provide assurance that important variables are monitored with a precision sufficient to fulfill safety design basis (a), the primary containment and reactor j vessel isolation control system shall respond correctly to the sensed variables over the expected design range of magnitudes and rates of change."
"d. To provide assurance that conditions indicative of a failure of the reactor coolant pressure boundary are detected to fulfill safety design basis (a), primary containment and reactor vessel isolation control system inputs shall be derived from variables that are true, direct measures of operational conditions."
The safety design basis for leakage detection is given in the following excerpt from UFSAR Section 5.2.5.5.4:
"For process lines that are normally open, there are at least two different methods of detecting abnormal leakage from each system within the nuclear system process barrier located in the drywell, reactor building, and auxiliary building, as shown in Table 5.2-8.
The instrumentation is designed so it can be set to provide alarms at established leakage rate limits and isolate the affected system,if necessary. The alarm points are determined analytically or based on measurements of appropriate parameters made during startup and preoperational tests."
A-4
ATTACHMENT A DESCRIPTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES
%e UFSAR states the following in Section 5.4.7.2.2.3 concerning deletion of the steam condensing mode of RHR from use:
"The procedures governing Steam Condensing Mode Operation have been deleted and a review of other procedures that operate the below listed valves, concluded that these valves are not required to operate in plant emergency procedures."
D. NEED FOR REVISION OF THE REQUIREMENTS
- 1. %e original RWCU system design included " hot" pump suction from the Reactor THeirculation System. This " hot suction" presented problems with the pump seal design and therefore the RWCU system was modified per General Electric AID 25-79 to provide the pumps with " cold suction" from downstream of the non-regenerative heat exchangers. As a result of this modification the temperature monitoring function of the leak detection system in the pump rooms became meaningless and so it was eliminated by license amendments NPF-11, No. 20 and NPF-18, No. 7 (TAC Nos. 55773 and 55774).
Although the " cold" suction eliminated several seal issues, it introduced other issues such as fluid flashing / voiding at the regenerative heat exchanger inlet and severe pump vibrations. The current design modification retums the RWCU system to the original configuration with " hot suction" by utilizing improved design pumps that can withstand the " hot suction" and this in tum creates the need to re-establish the temperature monitoring function of the Leak Detection system in the pump and pump valve rooms.
The previous design utilized three 50% capacity RWCU pumps in separate rooms. The current configuration has two 100% capacity pumps in separate rooms, separated by an intervening valve room, which is designated as the Pump Valve Room.
- 2. As a result of a High Energy Line Break (HELB) analysis re-evaluation conducted for LaSalle Unit 1,it was determined that some portions of the " hot" RWCU piping would not isolate in time, after the occurrence of a break, prior to causing Environmental Qualification (EQ) temperatures in adjacent areas to be exceeded. His condition was reported as a condition that was potentially outside the design basis of LaSalle Units 1 and 2 in LaSalle License Event Report (LER)97-033.
o The existing leak detection isolation method for these areas is the RWCU Differential Flow - High, with a setpoint of s 70 gpm and an allowable value of s 87.5 gpm. His method has a 45 second time delay for operational considerations. In order to provide a more rapid response (without the 45 second time delay) to these areas, should a break occur, additional detection will be provided consisting of temperature leak detection in the RWCU Holdup Pipe and F/D Valve Rooms and RWCU Pump Suction High Flow break detection.
A-5
, . . - . ~ . . _ .- -- - -- - . . . . _~ - . . . - -. . . . , _ _ _
8 ATTACHMENT A DESCRIPTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES
- 3. Leak detection monitoring for the RWCU heat exchanger rooms is currently based on
- both ambient temperature and AT. The current setpoints had been based on calculations ,
of the expected bounding summer temperature or AT conditions that would result due to a leak of the highest RWCU process temperature fluid.
The RWCU heat exchanger room alarms and isolation serpoints were established, based on expected summer conditions. A special calculation was done to evaluate the safety analysis for LaSalle LER 97-031, " Leak Detection Area Temperature Calculation Errors Result in Plant Operation Outside Design Basis and Techical Specifications Due to ;
Inadequate Technical Review," with respect to various ambient conditions, including the zero leakage exdition for comparison. The following table compares the current alarm and isolation setpoints to the leakage values obtained from the special calculation:
Summer Nominal Winter Curre T Current AT Setpoint Setpoint Ventilation air 103 94 60 -
3 ,
inle:T
{ _ -- "
i 0 gpm leak 117 104 74 -
exhaust T l &_ ; )
? e Y :_. R$
5 gpm leak 167 124 96 130 34 exhaust T alarm i i
25 gpm leak 198 180 141 181 85 ;
exhaust T l isolation Representative winter values (specially calculated for this purpose) have been included in the table for comparison. The zero gpm leak reflects the equipment produced heat load.
As the table shows, the high temperature serpoint will isolate on less than 25 gpm leakage during summer conditions when the temperature reaches 181 *F, but it will require a leak greater than 25 gpm to actuate isolation during the nominal and winter conditions. 'Ihis condition was reported as operation outside the design basis and Technical Specifications in LER 97-031.
A-6
,._ .-- . ~_ _ _ _- . _ _ __ _ _ _ _ _.- _ _ _ _ _ - _ _ ___ _ .
ATTACHMENT A DESCRIPTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES l
l The current design modification retums the RWCU system to the original configuration l with " hot suction" by utilizing improved design pumps, different pipe sizes, slightly modi 6ed piping configuration, etc., and requires revised design documents. New leak rate and setpoint calculations for the pump and heat exchanger rooms, have been performed.
%e results of these calculations have indicated the need for changing the heat exchanger room setpoints.
- 4. %e steam condensing mode of the RHR while in operating conditions 1,2, or 3, was deleted a reported in the Comed October 20,1992 letter (Reference 5). Le UFSAR was updated accordingly at that time; however, no Technical Specification change was submitted. %e need to have consistent documentation results in this Technical Specification change request to delete the associated isolation actuation trip functions, A.5, from Technical Specification Tables 3.3.2-1, 3.3.2-2, 3.3.2-3, and 4.3.2.1-1,
- 5. Area temperature monitoring of the RHR shutdown cooling mode lines is intended to provide assurance that important variables are monitored with a sufficient precision so i that the isolation control system shall respond correcdy to the sensed variables.
l However, calculations for temperature response show that, the RHR shutdown cooling area temperature and AT sensors are not affected significantly as a result of a leak because the shutdown cooling lines are moderate energy lines. Therefore, these variables are not the important variables that can be monitored with precision to assure correct response of the isolation control system.
The ambient temperature and AT isolation actuation instrumentation trip functions A.6.d and A.6.e, respectively, have setpoints and allowable values that are non-conservative with respect to design calculations. His was also reported in LER 97-031. %erefore, these trip functions are proposed to be deleted from Technical Specifications.
E. DESCRIPTION OF THE PROPOSED CHANGES The setpoint and allowable values for RWCU items A.3.b and A.3.c are proposed to be changed in Table 3.3.2-2. The new trip functions A.3.f through A.3.1 are being added and require changes to Tables 3.3.2-1, 3.3.2-2, 3.3.2-3, and 4.3.2.1-1.
The applicable operational conditions for the instrumentation channels in Table 3.3.21 are unchanged for the RWCU heat exchanger rooms ambient temperature and AT trip functions and will be the same Operational Conditions for the added trip functions. He Minimum Operable Channels per Trip System are 1 or 1/ area or room as applicable, like the existing similar trip functions. Action 22 also applies to the new RWCU trip functions, because they involve the same valve group i
[
\
A-7
. .. -- ~ -- - - --.
\CIIMENT A DESCRIFTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES Ihe proposed change to the Technical Specifications changes the setpoints for trip functions
- A.3.b. and A.3.c. in Technical Specification Table 3.3.2-2 and adds 'new trip functions A.3.f through A.3.1 to Technical Specification Tables associated with Technical Speci6 cation 3.3.2.
The proposed setpoints are as follows for the following revised or added isolation actuation instrumentation functional units for changes to Technical Specification Table 3.3.2-2:
A.3 Reactor Water Cleanup System Isolation
- b. Heat Exchanger Area Temperature - High, with a setpoint of s 149'F and an allowable value of s 156.8 F.
- c. Heat Exchanger Area Ventilation AT - High, with a setpoint of 5 33 'F and an allowable value of s 40.3 *F.
- f. Pump and Pump Valve Area Temperature - High, with a setpoint of s 201 'F and an allowable value of s 209 'F.
- g. Pump and Pump Valve .Ar' ea Ventilation AT - High, with a serpoint of s 86 *F and an allowable value of 5 92.5 'F.
- h. Holdup Pipe Area Temperature - High, with a setpoint of s 201 *F and an allowable value of s 209 *F.
- i. Holdup Pipe Area Ventilation AT - High, with a setpoint of 5 86 'F and an allowable value of 5 92.5 'F.
- j. Filter /Demineralizer Valve Room Area Temperature - High, with a setpoint of 5 201 'F and an allowable value of 5 209 F.
- k. Filter /Demineralizer Valve Room Area Ventilation AT - High, with a setpoint of
- s 86 'F and an allowable value of s 92.5 'F.
L
- 1. Pump Suction Flow - High, with a setpoint of s 560 ppm and an allowable value of s 610 gpm.
l j' RWCU trip functions A.3.f through A.3.1 are being added to Technical Specification Table 3.3.2-l 3, and likewise do not require response time testing, because the valve group depends on emergency diesel generator start time of 13 seconds for valve movement to begin.
i A-8 l
i l
l' )
l ATTACHMENT A l l
DESCRIPTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES I The proposed Technical Specification Surveillance Requirements for the new RWCU temperature and AT trip functions are as follows:
Channel Checks are "NA" (Not Applicable),
l Channel Functional Tests are "Q" (quarterly), and Channel Calibrations are "Q" (quarterly).
The proposed Technical Specification Surveillance Requirements for the RWCU pump suction flow - high trip function is the same as above, except the instrumentation loops being installed are analog channels which will allow a Channel Check. Therefore this trip function is proposed to have a "S" (shiftly) Channel Check.
The elimination of the RHR steam condensing mode trip functions (A.5) and the deletion of the RHR shutdown cooling mode temperature monitoring trip functions (A.6.d and A.6.e) will require deleting these trip functions from Technical Specification Tables 3.3.2-1, 3.3.2-2, 3.3.2-3, and 4.3.2.1 1.
All of the above changes and the deletions of trip functions A.5, A.6.d. and A.6.e are indicated on the marked-up pertinent Technical Specification pages (Attachment 19 l
Leak detection equipment being installed as a result of this change, will have similar functional performance and surveillance requirements as the currently installed equipment and will meet the ,
existing design bases requirements. In addition, the isolation logic, with I channel per trip system for each of the above trip functions,is the same as that described in the current requirements section. The RWCU pump suction flow - high trip function has the same logic and is consistent with RHR and RCIC high flow isolation actuation instmmentation trip functions.
l l A-9
h_ l l
l l
ATTACHMENT A DESCRIPTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES F. BASES FOR THE PROPOSED CHANGES Le criteria that have been applied to provide an upper and lower limit for isolation after detection ofleakage ue:
- 1. he isolation setpoints must be high enough to provide operational margin for weather changes, loss of ventilation, loss of normal heating of supply air, and other ventilation changes.
- 2. The isolation setpoints must be low enough so that they provide their function before the detected leakage exceeds the established leahage limit (25 gpm equivalent mass at standard conditions).
The approach used to determine a basis for the changes to the leak and break detection system isolation requirements is outlined below:
- 1. Other stations contacted do not utilize both ambient and AT for isolation uniformly:
Two nuclear plants that were contacted isolate on high temperature only; Two nuclear plants that were contacted isolate on both high ambient and AT detection; One nuclear plant that was contacted indicated that as a result of the Improved Technical Specifications effort, they are eliminating the AT isolation function; Two older nuclear plants that were contacted depend on operator action for isolation of the RWCU system; and One nuclear plant that was contacted has automatic isolation on system differential process flow only.
Other plants utilize water served fan coolers or have common areas for the pumps and heat exchangers. LaSalle's RWCU area rooms are ventilated with 100% outside air, which is tempered by the supply heating coils and staged through the general areas of the reactor building, prior to entering these rooms. This ventilation is the only cooling media for the RWCU areas.
- 2. A re-evaluation of the IIELB analysis for lines located in the Reactor Building was performed. This evaluation indicated areas where break isolation would not occur within the times utilized to determine the bounding area temperatures for Equipment Qualification (EQ). These areas are the RWCU high energy lines outside the equipment rooms where isolation is currently actuated by a high delta A-10
l l
1 l
i ATTACHMENT A DESCRIPTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES flow signal. This signal has a 45-second actuation delay for operational considerations l (density changes occur in the system during startup and shutdown, and flow surges when j the F/D's are takers in and out of service). i During this time delay, additional mass-energy is released, causing the temperature m adjacent areas to possibly exceed the EQ temperature limits. To prevent this, RWCU pump suction flow detection is being provided with setpoints chosen high enough to avoid spurious isolations during pump and F/D swapping, but low enough so that breaks will be isolated prior to allowing the EQ temperature limits ta be exceeded.
- 3. IIeat load and supply air flowrate calculations were performed to provide input to the leak detection design basis calculation (summarized in Attachment F) and to reflect the new " hot" suction configuration of the RWCU system. A calculation summary is included in Attachment E.
l
- 4. Leakage rate calculations (summarized in Attachments F and G) were perfonned for the areas without room coolers that utilize ambient and differential temperature leak detection isolation. These calculations used steady state conditions in accordance with the GE design specification.
For the isolation actuation point based on the established leak rate limit cases of 25 gpm, bounding initial ventilation values were utilized and analytical limits were chosen so that
+he established leak rate limit was not exceeded except for the heat exchanger room. In this room, the analytical limits are now calculated based on the regenerative heat exchanger feedwater retum temperatures (437' F) instead of the reactor coolant inlet to the regenerative heat exchanger temperature (533' F) . This results in the established leak I rate limit being exceeded for the extreme winter condition based on ambient temperature isolation (i.e., a leakage rate of 36.4 ppm will be necessary to actuate isolation with an inlet ventilation temperature of 65 F). It should be noted that the differential .
l temperature isolation actuation is conservative under these same conditions, actuating at a leakage rate of 17 gpm. Additionally, " hot" leakage (i.e., prior to the regenerative heat exchanger,533' F) will conservatively actuate isolation under all ambient conditions at a leak rate less than the established limit. An ambient temperature serpoint that would actuate isolation for feedwater retum temperatures (437 F) under all ambient conditions would increase the potential for spurious actuations.
For the alarm actuation point based on the established leak rate limit cases of 5 gpm, design ventilation conditions were utilized and analytical limits based on summer conditions were typically chosen to ensure that adequate margin is provided during these conditions so that no spurious alarms are received. This, however, leads to a higher ,
leakage rate being alarmed during the winter design conditions. In all cases, these alarm l values are below the isolation actuation values, with the maximum value being 23.6 gpm.
A-11
_ . _.- _ -.. _ _ _ _ _ _ _ _- . _ _ _ . _ _ - -~ _ .. . _
l l
l l
l i ATTACHMENT A 1
DESCRIPTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES
%erefore, there is still marin between the detection of a small leak with its consequent alarm and the larger leak which results in automatic isolation of the system.
- 5. Leak detection analytical setpoints for the RWCU areas ambient and differential temperature were calculated. See Attachment F for a summary of calculation I 001281.
See attached Figure, "RWCU LD/ Break Modifications" for the relative locations of sensors in the RWCU areas.
- 6. Instrument Setpoint calculations were performed to determine that sufficient available margin exists as defined below, for the instrument loops that initiate a Group 5 isolation upon detection of ambient temperature, differential temperature, and suction flow.
- a. He Technical Specification allowable and the nominal Technical Specification setpoint.
- b. The analytical limit and the nominal Technical Specification serpoint.
The calculations ue valid under normal and accident environmental conditions, and allow for all normal and accident errors. Thus Technical Specification compliance is ensured for the instrument channels. See Attachment J for a summary of calculation I 001420.
- 7. An evaluation of the remaining temperature isolation setpoints in Technical Specification Table 3.3.2-2 was perfor.ned to assess their adequacy. His evaluation indicated that clarification of the temperature leak detection basis was needed but that the setpoints are I
adequate and therefore no change is necessary. Calculations 1001324 and 3C7-1184-001 are summarized in Attachments G and H, respectively.
- 8. A Figure, RWCU LD/ Break Modifications,is provided to show each enclosed compartment and open space through which the RWCU normal flow stream puses outside of the Primary Containment. I The following table describes the leak detection methods available for each of the areas shown ~on the attached figure. All RWCU piping outside containment in the primary flow path is monitored. A secondary flow path, the RWCU Blowdown Line, is not included. The RWCU Blowdown Line branches off of the RWCU retum line from the F/Ds prior to the RWCU Regenerative Heat Exchangers. Therefore, the lines only handle cold water (< 140 'F). In addition, these lines are normally only used during the following conditions to aid in maintaining reactor water level when steam f'ow and feedwater flow are too low for the reactor water level control system:
- a. Cold Shutdown or Refueling, no steam flow or feedwater flow.
l l
A-12 i
l.
l ATTACHMENT A l
DESCRIPTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES
- b. Unit Startup prior to the reactor water level control system functioning in Automatic, at about 10% power.
- c. Unit Hot Shutdown after decay heat drops below the capability of the reactor water level control system due to low feedwater flow / low steam flow.
I The RWCU Blowdown Line consists oflow pressure piping downstream of Motor- l Operated Valves (MOVs),2G33-F034, RWCU Reject to Main Condenser Valve, and 2G33-F035, RWCU Reject to Waste Surge Tank Valve, which form a normally closed )
boundary, isolating the line. The RWCU Blowdown Flow Control Valve,2G33-F033, (normally closed and upstream of the MOVs) closes if the following are true to protect !
the piping downstream of the MOVs, thus isolating the blowdown line:
- b. Either the 2G33-F034 or 2G33-F035 are not full closed (an interlock being added by DCP 9600301). !
The Blowdown Flow Control Valve is designed to fail in the closed position on loss of l power or loss of air. i
'Ihe potentially high pressure portion of the RWCU Blowdown Line piping and valves is in the F/D Valve Room and thus are covered in part (not by T or NI) by leak detection for that area when the Blowdown Flow Control Valve is not fully closed. Any leaks asso-iated with the high energy portion of the blowdown piping within the F/D valve room will be detected by the same leak detection methods listed for the F/D area. In addition, blowdown flow indication is provided in the Main Control Room where it can l be seen when controlling the Blowdown Flow Control Valve.
'Ihe associated piping and valves up to and including the RWCU Blowdown Line downstream MOVs are ASME Section III, Class C,like the rest of the RWCU system downstream of the primary containmen+ outboard isolation valve that is part of the normal flow path / pressure boundary m the RWCU system. The RWCU system, including the blowdown line valves and the associated blowdown line instrumentation are !
non-safety-related and are not single failure proof. Reactor Coolant Pressure Boundary is maintained by the primary containmerit isolation valves in the suction line of the system.
A-13
ATTACHMENT A DESCRIPTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES l
. \
AREAS TIIROUGH WilICH RWCU LEAK DETECTION METHODS PASSES AVAILABLE* i Hold-up Pipe Area' 1, 2 (new), 5, 6, 7 ;
Pump / Valve Rooms 1, 2 (new), 5, 6, 7 ;
Heat Exchanger / Valve Rooms 1,2,5,6,7 RWCU Pipe Tunnel 1 (between flow elements),4 (heat exchanger room AT - isolation actuation at approximately i 165 gpm leak),5,6,7 Filter /Demineralizer (F/D) Valve Room 1, 2 (new), 5, 6, 7 F/D Area 1,5,6,7 Radwaste Pipe Tunnel 5,6,7 Main Steam (MS) Tunnel 4 (MS isolation),6,7
- %c numbers represent the following means ofleak/ break detection:
1 - High Differential Flow 2 - High Temperature / Differential Temperature 3 - High Temperature only 4 - High Differential Temperature only 5 - Floor Drain Sump Alarms 6 - Area Radiation Monitors Alarms 7 - High Flow (new) he following provides a summary of the results of the analyses performed for the changes to the detection isolation Technical Specifications:
- 1. A 4-inch line is the smallest line size which is postulated to break in UFSAR Appendix C, Section C.2. 700 gpm is conservatively calculated to be the lowest flow rate that would result from a 4-inch guillotine break. When considering the high flow break detection instrumentation response time, the break flow rate is reduced to 650 gpm. EQ zone temperature limits are not exceeded as a result of a break flowrate of this magnitude.
The analytical value of 650 gpm is based on calculation No. L-001384, which is summarized in Attachment I. %is calculation was performed to establish operational margin to avoid spurious isolations due to the new RWCU Suction Flow - High isolation A-14
1 ATTACHMENT A l
DESCRIPTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES i l
i instrumentation setpoints and to validate that EQ temperature limits for affected areu l will be maintained within limits for RWCU piping design basis breaks outside of the.
Flowrates less than the design basis break flowrate, and leak flowrates, we detected by the leak detection system. For the RWCU system, this consists of the high delta-flow sensor (between the flow elements), ambient temperature and differential temperature (T&AT) sensors, floor drain sump monitors and radiation monitors . T&AT sensors have been added to the plant such that areas containing hot RWCU pipe that could affect safety related equipment necessary to mitigate the consequences of a IIELB ue protected.
RWCU areas, with the exception of the RWCU Filter-Demineralizer (F/D) valve room, are all HELB aren with the ambient temperature isolation setpoint less than the short.
term EQ temperature limit. The F/D valve room, where a short portion of hot piping containing the 2G33-F042, RWCU Retum Upstream Stop Valve, a throttle valve,is located, contains no safety-related equipment other than the temperature sensors, which are qualified to the associated IIELB environments.
'Ihe summary of serpoint calculation 1 001443 (Attschment K) provides the basis for the different.c between the analytical, setpoint and allowable value. The calculation ,
determined the setpoint to be 560 gpm, with an allowable value of 610 gpm, for the l' suction line flow isolation, which ensures a high level of confidence that the analytical limit will not be exceeded under normal or accident operating condi6ons. A 0.5 second ,
time delay is included in the instrument circuitry for operational ccasiderations. 'Ihe j delay is designed to reduce the potential for spurious actuations reculting from fluid flow ;
transient conditions that occur, such as RWCU pump starts and pu.up changes. The time delay is bounded by the isolation response time for the IIELB analysis performed for RWCU piping outside containment that is summarized in Attachment I (Calculation 1,001384).
- 2. Calculation I 001281, which is summarized in Attachment F, determined the changes in AT in response to a leak. Based on the changes in AT,it was determined that with an established leak rate limit of 25 gpm or less, the AT analytical value will be 41.8 'F for the heat exchanger room,94 'F for the pump and pump valve rooms,94 'F for the holdup pipe room, and 94 'F for the F/D valve rooms. Setpoint calculation I 001420, which is summarized in Attachment J, provides the basis for the difference between the setpoints and allowable values. The calculation determined nominal setpoints for the differential temperature isolation setpoints, which ensure a high level of confidence that the analytical limit will not be exceeded under normal or accident operating conditions.
A-15
l l
l J
l ATTACHMENT A DESCRIPTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES l 3. Calculation 1 001281, which is summarized in Attachment F, determined the changes in j temperature (I) in response to a leak. Based on the changes in AT, it was determined that with an established leak rate limit of 25 gpm or less, the temperature analytical value will be 159.8 *F for the heat exchanger room,212 'F for the pump and pump valve l rooms,212 'F for the holdup pipe roorn, and 212 'F for the F/D valve rooms. %e l summary of setpoint calculation 1 001420 (Attachment J) provides the basis for the l difference between the setpoints and allowable values. %e calculation determined i nominal setpoints for the temperature isolation serpoints, which ensure a high level of confidence that the analytical limit will not be exceeded under normal or accident i operating conditions.
l 4. %e results of the room temperature responses and the summary of serpoint calculation 1 001420 (Attachment J) for the RWCU pump, heat exchanger (IIx), holdup pipe, and ,
F/D valve rooms are shown in the following tables: l 1
I l
l l
A-16
'I ATTACHMENT A !
DESCRIPTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES l
1 l
AT ;
RWCU Leakage Analytical Allowable Isolation Alarm Rooms gpm Limit Value Setpoint (* Setpoint f6 f6 0 CO Pump Nonnal 0 18.0 . . -
Room Alarm 5 32.4 - -
28 ,
Isolation 25 94.0 92.5 86 - I Pump Normal 0 17.6 - - - !
Valve Alarm 5 41.0 - -
37 Room Isolation 25 94.0 92.5 86 -
Hx Room Normal 0 17.6 - - -
Alarm 5 24.6 - - 20 Isolation 25 41.8 40.3 33 -
Holdup Normal 0 17.3 - - -
Pipe Area Alarm 5 40.8 - -
37 Isolation 25 94.0 92.5 86 -
F/D Valve Normal 0 19.6 - - -
Room Alarm 5 44.5 - - 40 Isolation 25 94.0 92.5 86 -
l A-17
! ATTACHMENT A DESCRIPTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES Ambient T l
1 RWCU Leakage Analytical Allowable Isolation Alarm l Rooms gpm Limit Value Setpoint f Setpoint i
CO f6 O CO Pump Normal 0 122.0 - - -
Room Alarm 5 136.4 - -
131 Isolation 25 212.0 209 201 -
Pump Normal 0 121.6 - - -
Valve Alarm 5 145.0 - -
140 Room Isolation 25 212.0 209 201 -
IIx Room Normal 0 121.6 - - -
Alarm 5 128.6 - -
124 Isolation 25 159.8 156.8 149 -
IIoldup Normal 0 121.3 - - -
Pipe Area Alarm 5 144.8 - -
140 Isolation 25 212.0 209 201 -
F/D Valve Normal 0 123.6 - - -
Room Alarm 5 148.5 - -
143 Isolation 25 212.0 209 201 -
'Ihe following is the primary basis for the proposed changes to the detection isolation Technical Specifications:
- 1. 'Ihe proposed Technical Specifications add new trip functions A.3.f, A.3.g, A.3.h, A.3.i, A.3.j, and A.3.k, for Area Temperature - High and Area Ventilation AT - liigh in RWCU pump, pump valve, holdup pipe, and F/D valve rooms, and new trip function A.3.1 for the RWCU Pump Suction Flow - liigh, with associated requirements for Tables 3.3.2-1, 3.3.2-2,3.3.2-3, and 4.3.2.1-1. 'Ihe basis for the addition is the safety design basis for the primary containment isolation control system of UFSAR section 7.3.2.1, which has been quoted above in " Bases for the Current Requirements".
I l
A-18 i
L l
l l
ATTACHMENT A
! DESCRIPTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES l
l
- 2. %e proposed Technical Specification setpoint for Table 3.3.2-2, for the RWCU Pump Suction Flow - High, will be 560 gpm with an allowable value of 610 gpm based on the results of setpoint calculation 1 001443, which is summarized in Attachment K, and the analytical value (from Calculation No. LOO 1384, which is summarized in Attachment I) for the process flow rate resulting from a pipe break.
r
- 3. The proposed Technical Specification setpoints for Table 3.3.2 2, for the RWCU Pump and Pump Valve Area Temperature - High will be 201 *F with allowable values of 209
'F. %e proposed Technical Specification serpoints for Table 3.3.2-2, for the RWCU Pump and Valve Area Ventilation AT - High will be 86 *F with an allowable value of 92.5 *F. %e setpoints and allowable values are based on the results of serpoint calculation 1401420, which is summarized in Attachment J. The analytical values of the area temperature and differential temperature resulting from an established leak rate limit of 25 gpm are determined by calculation L-001281, which is summarized in Attachment F.
- 4. He proposed Technical Specification setpoints for Table 3.3.2-2, for the RWCU Holdup Pipe Area Temperature - High, will be 201 *F with an allowable value of 209 F. The proposed Technical Specification serpoints for Table 3.3.2-2, for the RWCU Holdup Pipe Area Ventilation AT - High, will be 86 'F with an allowable value of 92.5 *F. The setpoints and allowable values are based on the results of setpoint calculation L001420, l which is summarized in Attachment J. %e analytical values of the ares temperature and differential temperature resulting from an established leak rate limit of 25 gpm are determined by calculation 1,001281, which is summarized in Attachment F.
'5. %e proposed Technical Specification serpoints for Table 3.3.2-2, for the RWCU F/D l Valve Area Temperature - Iligh will be 201 'F with an allowable value of 209 *F. %e l proposed Technical Specification setpoints for Table 3.3.2-2, for the RWCU F/D Valve Area Ventilation AT - Iligh will be 86 *F with an allowable value of 92.5 'F. he setpoints and allowable values are based on the results of setpoint calculation L001420, which is summarized in Attachment J. The analytical values of the area temperature and differential temperature resulting from an established leak rate limit of 25 gpm are determined by calculation 1 001281, which is summarized in Attachment F.
l.
i l 6. The proposed Technical Specification setpoints for Table 3.3.2-2, for the Heat Exchanger Area Temperature - High will be 149 'F with an allowable value of 156.8 'F. he proposed Technical Specification setpoints for Table 3.3.2-2, for the Heat Exchanger Area Ventilation AT - High will be 33 F with an allowable value of 40.3 'F. The setpoints and allowable values are based on the results of setpoint calculation L001420, l which is summarized in Attachment J. The analytical values of the area temperature and differential temperature resulting from an established leak rate limit of 25 gpm are determined by calculation 1 001281, which is summarized in Attachment F.
l' A-19 L _ _ _ _ _
- - . _ -. . .- ..--- --~ . - - -....- - ~ - - - - . -.- -.-
ATTACHMENT A DESCRIPTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES l
- 7. The proposed Technical Specification setpoints are based on controlled room thermal response to a leak as predicted by thermal steady state calculation from the extreme expected room ambient conditions. (Calculation I 001281 is summarized in Attachment F.) he setpoints provide sufficient margin above operating temperature to preclude inadvertent isolations and detect leakage equivalent to 25 gpm water at these room l conditions, which is consistent with the GE design specifications and the basis used at
- other BWR's.
i
- 8. The isolation instrumentation channels for the existing and new RWCU areas ne being ,
modified to locate the inlet sensor for AT trip function instrumentation channels outside of the area being monitored for leakage. ne inlet sensor location assures that the AT
- trip function instrumentation channels remain Operable for loss of normal ventilation.
%e basis for the proposed deletion of trip function A.5 in Technical Specification 3/4.3.2 for the RHR system steam condensing mode isolation is the non-utilization of this mode of operation at LaSalle in the applicable Operational Conditions.
%e following provides the bases for the proposed deletion of the temperature initiated trip functions in the RHR system shutdown cooling mode isolation:
i
- 1. %e safety design bases for the primary containment isolation control system in UFSAR Section 7.3.2.1(a), (b) and (d), quoted previously above in " Basis for Current Requirements", intends the temperature monitoring of the RHR shutdown cooling mode
]
areas to provide assurance that important variables are monitored with a sufficient 6 precision so that the isolation control system shall respond correctly to the sensed !
variables. The Calculation for temperature response shows that, for a 25 gpm leak from the RHR shutdown cooling lines at their highest possible process temperature, the resultant analytical room temperature is less than 130 'F. (Calculation L-001281 is summarized in Attachment F.) Leaks at lower process temperatures result in lower room temperatures. %e design temperature of the RHR rooms is 148 F. Summer room temperatures may reach 110 *F. The required isolation serpoint for a 25 gpm RHR l shutdown cooling mode leak is sufficiently close to operating room conditions such that '
l the possibility for spurious isolation actuations would be greatly increased. The relatively low heat input to the room from the leak and room cooler operation, when the equipment is operating, limits the effectiveness of the differential temperature monitors. f Additionally, the RHR shutdown cooling process temperatures are not detectable (i.e., i
<212 'F) by ues temperature leak detection for over 99% of shutdown cooling operating time. Therefore, temperature is not the appropriate parameter for leak detection, as it does not provide meaningful indication and will not provide setpoints that would be sufficiently above the normal range of ambient conditions to avoid spurious isolations.
f A-20 o
iy y- y- ry w -ra m.a m-e-'- u -m - -
9w-- e ei+w+e re -r w e
i ATTACHMENT A ,
DESCRIPTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES i
! 2. There are two other methods of detecting abnonnal leakage and isolating the system in l
l Technical Specification trip function A.6, which are A.6.a, Reactor Vessel Water Level - ;
low,Ievel 3 and A.6.c, RHR Pump Suction Flow - High. In addition, other means to j detect leakage from the RHR system, such as sump monitoring and area radiation L monitoring, are also available. Therefore, the safety design buis for the leak detection system in UFSAR Section 5.2.5.5.4, which was quoted previously in " basis for the current requirements",is not compromised. t l
In accordance with Technical Specification Administrative Requirement 6.2.F.1, LaSalle has a leakage reduction program to reduce leakage from those portions of systems outside primary containment that contain radioactive fluids. RHR, including piping and !
components associated with the shutdown cooling mode, is part of this program, which includes periodic visual inspection of the system for leakage. The sump monitoring, radiation monitoring and periodic inspections for system leakage makes the probability of a leak of 5 gpm going undetected for more than a day very low.
Also, due to the low reactor pressures (less than 135 psig) at which RHR shutdown cooling mode is able to operate, reactor coolant makeup and outflow is very low compared to normal plant operation. A change in flow balance due to a leak is thus more readily detectable with reactor coolant water level changes and makeup flow rate, and thus precludes a significant leak going undetected before break detection instrumentation would cause automatic isolation.
I The following provides clarification of the temperature leak detection basis for the T and AT isolation setpoints of Technical Specification Table 3.3.2-2 that do not require changes to the Technical Specifications.
- 1. %e RCIC Equipment Area monitors will only isolate at an established leakage rate limit of 25 gpm when the RCIC pump is not operating. %is is considered the r rmal room )
environment, and is therefore consistent with the GE design specification wtuch states that the setpoints should be calculated by doing a heat balance for the normal room environment. The RCIC equipment area room cooler operates when the pump is running, and its operation controls the room temperature. This occurs during infrequent j
. testing periods, or during postulated accident conditions. During these times, other means ofleak detection are available, such as high steam flow or sump indications. Area temperature and differential temperature will be available for detection and isolation, but at a higher established leak rate limit (approximately 40-50 gpm).
%e isolation instrumentation channels for the RCIC areas are being modified to locate the inlet sensor for AT trip function instrumentation channels outside of the area being monitored for leakage. %e inlet sensor location assures that the AT trip function l instrumentation channels remain Operable for loss of normal ventilation.
A-21
ATTACHMENT A DESCRIPTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES
- 2. Not all areas with systi ms containing reactor coolant outside primary containment are provided with temperature and differential temperature leak detection monitors. This is indicated in UFSAR Table 5.2-8. %e systemt must regularly carry hot coolant in order l for the temperature based system to be effective. The temperature monitors are provided in equipment area rooms, since open piping areas are typically expansive, rendering ambient temperature detection ineffective. The open piping areas also usually contain piping from many systems that would be subject to isolation from leakage from one ,
system.
- 3. The leak detection methods which actuate containment isolation are indicated in UFSAR Table 5.2-8. %e established leakage rate limit for the different isolation methods are also different depending upon operational considerations. His is consistent with the leakage detection safety design basis provided in UFSAR Section 5.2.5.5.4. Additionally, as indicated in UFSAR Table 5.2-8, some areas have leak detection that may not result in automatic isolation. This is consistent with General Design Criteria (GDC) 54, so long as there are redundant means of detection.
- 4. The area temperature and differential temperature detection and isolation sensors are affected by varying ambient temperature conditions. He established leak rate limit setpoints are calculated at design conditions. (Calculation 1 001281 is summarized in Attachment F.) When actual conditions vary, the leakage rates correlating with the detector setpoints may also vary.
G. IMPACT ON PREVIOUS SUBMITTALS his submittal does not impact on LaSalle County Station submittals currently under review by the NRC. This submittal is essentially the same as referenced Unit 1 submittals approved by Reference 4.
H. SCHEDULE REQUIREMENTS Comed requests approval of this license amendment request prior to startup of LaSalle Unit 2 from its current forced outage, L2R07, currently scheduled for May 1999. He amendment should be made effective upon issuance for Unit 2. Comed willimplement the amendment prior to startup of LaSalle Unit 2 from the current outage.
A-22
i ATTACHMENT A DESCRIPTION OF SAFETY ANALYSIS OF THE PROPOSED CHANGES I. REFERENCES
- 1. Letter dated November 24,1997 from W. T. Subalusky to the U.S. NRC, Request for Technical Specification Amendment to Facility Operating License NPF 11 for Leak and Break Detection Isolation Instrumentation.
- 2. January 6 and 15,1998 Telephone conferences between Comed and NRR involving RWCU Leak and Break Detection.
- 3. Letter dated April 16,1998 from F. R. Dacimo to the U.S. NRC, Comed Response to NRC Staff Request for Additional Information (RAI) and Supplemental Request for Technical Specification Amendment to Facility Operating License NPF-11 for Leak and Break Detection Isolation Instrumentation.
- 4. Letter dated July 6,1998 from D. M. Skay to O. D. Kingsley, Issuance of amendment 129 to Facility Operating License No. NPF-11 for LaSalle County Station Unit 1. (TAC No. MA0178)
- 5. letter dated October 20,1992 from J. M. Shields to T. E. Murley, NRC, Deletion of the Steam Condensing Mode of the Residual IIeat Removal (RHR) System.
A-23
RWCU LD/ Break Modifications u FWSystem g _ _ . iso
"------~~~~
437'F
- @ ,l l l @ @ .' e l I O"TE MS Tunnel "I '
I m m L- ________
-* p__.____ ___J e & e M Tunnel l ,
gg: g{ w- l_,_j---g l g;
, 533*F
@. I h @ ;h~ I Floors 2
.__@___-- [ _I lr ,
i 120*F if I
, ! n g ns ag I %
i m
@is
- : -4yp - . -
g D; L _ ______
- I i N TE y contanm.n, RQu ,
g ---
--g yl ,, ,
g,,,,
- - - ~
@ @j @ -
D_ D_ O, ,
e,. Oa
=@
=
-@- : _v a -
i_ _ _ _ _ _ _ _ _ _' --
RWCU Pump g
- High a Flow Signals
l ATTACHMENT B MARKED-UP PAGES FOR PROPOSED CHANGES NPF - 18 3/4 3-11*
3/4 3-12 Insert A 3/4 3-13 3/4 3-14' 3/4 3-14a*
3/4 3-15 Insert B 3/4 3-16 3/4317 3/4 3-18 Insert C 3/4 3-19 3/4 3-20 Insert D 3/4 3-21 3/4 3-22
- These pages are provided for continuity only and have no proposed changes.
l t
{
l B-1 I
l.