ML20155F663
| ML20155F663 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 06/13/1988 |
| From: | TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML20155F659 | List: |
| References | |
| NUDOCS 8806170007 | |
| Download: ML20155F663 (15) | |
Text
{{#Wiki_filter:- TABLE 3.3-5 (Continued) ENGINEERED SAFETY FEATURES RESPONSE TIMES INITIATING SIGNAL AND FUNCTION RESPONSE TIME IN SECONOS 6. Steam Flow in Two Steam Lin?s-Mich Coincident with Steam Line Pressure-Low a. Safety Injection (ECCS) 1 28.0(7)/28.0(1) b. Reactor Trip (from SI) s '3. 0 c. Feedwater Isolation < 8.0(2) d. Containment Isolation-Phase "A"I ) 18.0(8)/28.0(9) e. Containment Ventilation Isolation Not Applicable f. Auxiliary Feedwater Pumos 1 60 g. Essential Raw Cooling Water System 1 65.0(8)/75.00) h. Steam Line Isolation < 8.0 i. Emergency Gas Treatment System 38.0(9) 7. Containment Pressure--Hich-Hiah R63 a. Containment Spray < 208(9) b. Containment Isolation-Phase "B" 65(8)/75(9) c. Steam Line Isolation 17.0 R16 d. Containment Air Return Fan ., 540.0 and 1 660 8. Steam Generator Water Level--Hich-Hioh a. Turbine Trip 1 2.5 lR67 i b. Feedwater Isolation 1 11.0(2) 9. Main Steam Generator Water Level - Low-Low a. Motor-driven Auxiliary < 60.0 feedwater Pumps (4) b. Turbine-driven Auxiliary -< 60.0 Feedwater Pumps (5) 4 SEQUOYAH - UNIT 1 3/4 3 '1 "n;nd Cnt N:. 5 % 63 Deren 21. !?S? 8806170007 880613 hDR ADOCK 05000327 DCD
INSTRUMENTATION TABLE 3.3-5 (Continued) TABLE NOTATION (10) The response time for loss of voltage is measured from the time voltage is lost until the time full voltage is restored by the diesel. The response time for degraded voltage is measured from the time the load R33 shedding signal is generated, either from the degraded voltage or the SI enable timer, to the time full voltage is restored by the diesel. The response time of the timers is covered by the requirements on their setpoints. b go-{e ll sk/ec/ by TJ 8738' ru$m' *l Sef ** l /Y /987 ^ D.?) We k//owbr yalves d exeep ow '/o k upon.re bnes k %//e are r4wn Ar s-,/ w,w 6a
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3 %lves : FC V-O-99, ~ @ -fog -/o4 dr'ywe 7%a : 74. 75 85 %lve : FC V-70-/Y/ b u.1-1%na : 2d. 7 0 ( t) (!) y 80 i j
- NOTE: This tech'nical specification to be implementeif at the startup following the second refueling outage or following completion of the.
modification, whichever is earlier. R33 .s SEQUOYAH - UNIT 1 3/4 3-33a &ne nt ,t. 29 ":y 5, 19S3-e
== w O w ~. e.* ame - eem 6 D e w-
.~ TABLE 3.6-2 (Continued) CONTAINMENT ISOLATION VALVES S E VALVE NUMBER FUNCTION MAXIMUM ISOLATION TIME (Seconds) A. PilASE "A" ISOLATION (Cont.) 63. FCV-43-2 Sample Przr Steam Space 10* 8'a*'len/ 64. FCV-43-3 Sample Frzr Steam Space 10* f 7; gg.oy 65. FCV-43-11 Sample Przr Liquid 10* y 66. FCV-43-12 Sample Przr Liquid 10* 67. FCV-43-34 Accum Sample 5* 68. FCV-43-35 Accum Sample 5* 69. FCV-43-75 Boron Analyzer S* R41 V70s FCV-43-77 Boron Analyzer 5* 8. PilASE "B" ISOLATION R 1. FCV-32-80 Control Air Supply 10 ? 2. FCV-32-102 Control Air Supply 10 y, 3. FCV-32-Il0 Control Air Supply 10 4. FCV-67-83 ERCW - LWR Cmpt. Clrs 60* 5. FCV-67-87 ERCW - LWR Cmpt Clrs 60* FC V-'7'#9 * # ERCW - LWR Cmpt Cirs E4cW-twa ( 7/ 4/<s 70, 6. FCV-67-88<#6V7'f0
- E RCW - LWR Cmp t Cl rs<8AC W-! "4 C, p / 6/'J 60*< 70
- genu,,,f,,
7. FCV-67-91 60* 8. FCV-67-95 ,u ), ERCW - LWR Cmpt Clrs 60* R41 as / 9. FCV-67-96 ERCW - LWR Cmpt Clrs 60* 10. FCV-67-99 ERCW - LWR Cmpt Cirs 60* 11. FCV-67-103 ERCW - LWR Cmpt Clrs 60* 8, jrl;' 12. FCV-67-/05 ERCW - LWR Cmpt Cirs<EKcw-Lwg ( y/ c/r,EtcW-4wf g / d-s 60*(jo. F CV 10g F6V-67-/06* g g 13. FCV-67-107 ERCW - lWR Cmpt Cirs 60* g !; 14. FCV-67-111 ERCW - LWR Cmpt Clrs 60* 15. FCV-67-112 ERCW - LWR Cmpt Clrs 60* g 16. FCV-67-130 ERCW - Up Cmpt Clrs 60* p-17. FCV-67-131 ERCW - Up Cmpt Clrs 60* t; 18. FCV-67-133 FRCW - Up Cmpt Clrs 60* i g 19. FCV-67-134 ERCW - Up Cmpt Clrs 60* V 20. FCV-67-138 ERCW - Up Cmpt Clrs, 60* This yaIve is a,wm/ s 4 e,,y / J ;o, of d s.,,,;.//,, font /2nfan. 3
TABLE 3.6-2 (Continued) N@ CONTAINMENT ISOLATION VALVES S N VALVE NUMBER FUNCTION MAXIMUM ISOLA 1 ION TIME (Seconds) 8. PilASE "B" ISOLATION (Cont.) 21. FCV-67-139 ERCW - Up Cmpt Clrs 60* 22. FCV-67-141 ERCW - Up Cmpt Cirs 60* 2,~ b 23. rCv-67-i42 ERCw - Up Cmpt Cirs 60* ets Nemu, 24. FCV-67-295 ERCW - Up Cmpt Cirs 60* 25. FCV-67-296 ERCW - Up Cmpt Clrs 60* R41 26. FCV-67-297 ERCW - Up Cmpt Cirs 60* 2 7."- FCV-67-298 ERCW - Up Cmpt Cirs 60* 28. FCV-70-87 RCP Thermal Barrier Ret 60 29. FCV-70-89 CCS from RCP Oil Coolers 60 30. FCV-70-90 RCP Thermal Barrier Ret 60 R 31. FCV-70-92 CCS from RCP Oil Coolers 60 32. FCV-70-134 To RCP Thermal Barriers 60 ?, 33. FCV-70-140 CCS to RCP Oil Coolers 60 M V fcV-70-Nr 4 ces 4a A u o d coo /a<, 65 C. PIIASE "A" CONIAINMENT VENT ISOLATION 1. FCV-30-7 Upper Compt Purge Air Supply 4* i 2. FCV-30-8 Upper Compt Purge Air Supply 4* i. 3. FCV-30-9 Upper Compt Purge Air Supply 4* 4. FCV-30-10 Upper Compt Purge Air Supply 4* 5. FCV-30-14 Lower Compt Purge Air Supply 4* ?k 6. FCV-30-15 Lower Compt Purge Air Supply 4* ga 7. FCV-30-16 Lower Compt Purge Air Supply 4* 8. FCV-30-17 Lower Compt Purge Air Supply 44 R41 g '< 9. FCV-30-19 Inst Room Purge Air Supply 4* " 's 10. FCV-30-20 Inst Room Purge Air Supply 4* g* 11. FCV-30-37 Lower Compt Pressure Relief 4* g 12. FCV-30-40 Lower Compt Pressure Relief-4* M$
- T4h valve a ref,,,yu / s &,. e fb,, of tt: suuA U me.6& &gn, t
TABLE 3.3-5 (Continued) ENGINEERED SAFETY FEATURES RESPONSE TIMES INITIATING SIGNAL AND FUNCTION RESPONSE TIME IN SECONDS 6. Steam Flow in Two Steam Lines-Hich Coincident with Steam Line Pressure-Low a. Safety Injection-(ECCS) 5 28.0(7)/28.0(1) RU b. Reactor Trip (from SI) < 3.0' c. Feedwater Isolation 8.0(2) d. Containment Isolation-Phase "A"( ) 18.0(8)/28.0(9) e. Containment Ventilation Isolation Not Applicable f. Auxiliary Feedwater Pumps <60 g. Essential Raw Cooling Water System 65.0(8)/75.0(9) h. Steam Line Isolation < 8.0 i. Emergency Gas Treatment System 38.0(9) 7. Containment Pressure--Hich-Hioh R51 a. Containment Spray < 208(9) b. Containment Isolation-Phase "B" _ 65(8)/75(9) c. Steam Line Isolation < 7.0 d. Containment Air Return Fan > 540.0 and <660 8. Steam Generator Water Level--High-Hioh lR55 a. Turbine Trip < 2.5 h11.0(2) b. Feedwater Isolation 9. Main Steam Generator Water Level - Low-Low a. Motor-driven Auxiliary < 60.0 Feedwater Pumps (4) b. Turbine-driven Auxiliary ~< 60.0 i Feedwater Pumps (5) .s SEQUOYAH - UNIT 2 3/4 3-31 E N' M' i 0:::25:: 21, 'as' .-.N
f INSTRUMENTATION TABLE 3.3-5 (Continued) ~ TABLE NOTATION (10) The response tirne for loss of voltage is measured from the time ' voltage 'is lost until the time full voltage is restored by the diesel. The response time for degraded voltage is measured from the time the load R18 shedding signal is generated, either from the degraded voltage or the 51 enable timer, to the time full voltage is restored by the diesel. The response time of the timers is covered by the requirements on their setpoints. /Vofe // pod) 7~$ 87-3 9 .tul~,'tYed fy m bt /Y, /fe'? l b O2) 7Ae 4/4w.y ralva eueph,r d rfe m,ome La .r ho w, sie a 7We 4d/e s<d' ws//' dare 7d e,Lu / M. /,:, .s ea a.,4 d t4 /n,4 /y .ryu4 snd 1A: -/]ne 6 in4aSA Valva : R V-O- 89, -10, -/os, -/o6 A'ryoru< ika: 74. 75 f83 N VAlve: Ed V ~ 70 /'// deporue -ha : 24, 70 80 e "NOTE: This technical specification is to be implemented during the startup R18 following the first refueling outage. SEQUOYAH - UNIT 2 3/4 3-33a '- nd -* "a w ~ u p._, e .,v m r. s v.,, w ~. '. es =
- m=
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I i TABLE 3.6-2 (Continued) m E g CONTAINMENT ISOLATION VALVES 5c VALVE NUMBER FUNCTION MAXIMUM ISOLATION TIME (Seconds) l 8 e A. PilASE "A" ISOLATION (Cont.) 2 i l = 63. FCV-43-2 Sample Przr Steam Space 10* Renu,nf,u,/ 64. FCV-43-3 Sample Przr Steam Space 10* l 4 73 Sp-07 65. FCV-43-11 Sample Przr Liquid 10* 66. FCV-43-12 Sample Przr Liquid 10* R29 67. FCV-43-34 Accum Sample 5* 68. . FCV-43-35 Accum Sample 5* g 69. FCV-43-75 Boron Analyzer 5* 770. FCV-43-77 Boron Analyzer 5* w 8.* PIIASE "B" ISOLATION 2 m 1. FCV-32-81 Control Air Supply 10 4 2. FCV-32-103 Control Air Supply 10 3.- FCV-32-111 Control Air Supply 10 4. FCV-67-83 ERCW - LWR Cmpt Cirs 60* 5. FCV-67-87 ERCW - LWR Cmpt Clrs 60* 4 (V 89" ERCW - LWR Cmpt Clr EW-W4@ O' 70 R29 e F 6. FCV-67-88 FCV-67-91 Ecv 90" ERCW - LWR Cmpt Clr EACW-/ #4 d'*7/ 6/"' 60*< 70* l Reno J<r 7. 60* 4J.A'n<ss=3 8. FCV-67-95 ERCW - LWR Cmpt Clrs 60* 9. FCV-67-96 ERCW - LWR Cmpt Cirs 60* ei' 10. FCV-67-99 ERCW - LWR Cmpt Clrs 60* 11. FCV-67-103 ERCW - LWR Cmpt Clrs 60* i si Y 12. FCV-67-10gM 47-/06 [ERCW - LWR Cmpt C1rs F4 V /c'55 ERCW - LWR Cmpt Cirs E4cw-4M %/ c/-s 60*< 70, $l E 13. z FCV-67-107 E4W - NA d /- 4/ 60* 7C* O j! 14. FCV-67-111 ERCW - LWR Cmpt Clrs 60* 15. FCV-67-112 ERCW - LWR Cmpt Clrs 60* i' S 16. FCV-67-130 ERCW - Up Cmpt Clrs 60* F ', 17. FCV-67-131 ERCW - Up Cmpt Clrs 60*
- g 18.
FCV-67-133 ERCW - Up Cmpt Cirs 60* N 19. FCV-67-134 ERCW - Up Cmpt Clrs 60* 20. FCV-67-133 ERCW - Up Cmpt Cirs 60* v Y OSMS bia Va Nt lJ fcj uire l tt Wv A O M* M O
' TABLE 3.6-2 (Continued) ?, CONTAINMENT ISOLATION VALVES R iE VALVE NUMBER FUNCTION MAXIMUM ISOLATION TIME (Seconds) B. PilASE "B" ISOLATION (Cont. ) N 21. FCV-67-139 ERCW - Up Capt Cirs 60* 22. FCV-67-141 ERCW - Up Cmpt C1rs 60* 8en b 23. FCV-67-142 ERCW - Up Cmpt Clrs 60* 45 A'ceewy 24. FCV-67-295 ERCW - Up Cmpt Cirs 60* R29 25. FCV-67-296. ERCW - Up.Cmpt Cirs 60* 26. FCV-67-297 ERCW - Up Capt Clrs 60* 2 7.. FCV-67-298 ERCW - Up Capt Cirs 60* 28.' FCV-10-87 RCP Thermal Barrier Ret 60 29. FCV-70-89 CCS from RCP Oil Coolers 60 30. FCV-70-90 RCP Thermal Barrier Ret 60 } 31. FCV-70-92 CCS from RCP Oil Coolers 60 32. FCV-70-134 To RCP Thermal Barriers 60 33. FCV-70-140 CCS to RCP Oil Coolers 60 Y' FC V-70 -l'ff ' Cc f k ACP Dil lookrs 65 C. PilASE "A" CONTAINMENT VENT ISOLATION 1. FCV-30-7 Upper Compt Purge Air Supply 4* 2. FCV-30-8 Upper Compt Purge Air Supply 4* 3. FCV-30-9 Upper Compt Purge Air Supply 4* R29 4. FCV-30-10 Upper Compt Purge Air Supply 4* 5. FCV-30-14 Lower Compt Purge Air Supply 4*
- pl 6.
FCV-30-15 Lower Compt Purge Air Supply 4* i E 7. FCV-30-16 Lower Compt Purge Air Supply 4* !llji 8. FCV-30-17 Lower Compt Purge Air Supply 4* b 9. FCV-30-19 Inst Room Purge Air Supply 4* N 14 10. FCV-30-20 Inst Room Purge Air Supply 4* n' 11. FCV-30-37 Lower Compt Pressure Relief 4* I G 12. FCV-30-40 Lower Compt Pressure Relief 4* r.. 9 bE3 VQ Ve lJ ftfu!re d tt her tho*f1bb' ors ofOg gjjotla b/ Mo/ikta b' Ort. __i
ENCLOSURE 2 PROPOSED TECHNICAL SPECIFICATION CHANGE SEQJ0YAH NUCLEAR PLANT UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 (TVA-SQN-TS-88-01) DESCRIPTION AND JUSTIFICATION FOR AMENDING TABLE 3.6-2, "CONTAINMENT ISOLATION VALVES," AND TABLE 3.3-5, "ENGINEERED SAFETY FEATURES RESPONSE TIMES" w--
ENCLOSURE 2 Description of Change Tennessee Valley Authority proposes to modify the Sequoyah Nuclear Plant Units 1 and 2 Technical Specifications to revise Table 3.6-2, "Containment Isolation Valves." The change adds five motor-operated butterfly valves (M0Vs) to the table. These valves are replacing check valves that have been used as containment isolation valves. The proposed change also adds a note to Table 3.3-5, "Engineered Safety Features Response Times," item 7.b to reflect the response times for the new valves when actuated by a phase B containment isolation signal. R_eason for Change Check valves 67-562A, -B, -C, and -D are the inboard containment isolation valves for the essential raw cooling water (ERCW) supply headers to lower containment. The lower compartment coolers, the reactor coolant pump (RCP) motor coolers, and the control rod drive ventilation coolers are supplied by these headers. The flow diagram for these headers is Final Safety Analysis Report (FSAR) figure 9.2.2-3. Check valve 70-692 is the inboard containment isolation valve for the component cooling system (CCS) supply header to the RCP oil coolers. The flow diagram for this header is FSAR figures 9.2.2-1 (unit 1) and 9.2.1-3 (unit 2). The check valves identified above have repeatedly failed containment leak rate testing in the "as-found" condition. The repetitive failures of the ERCW and CCS check valves are documented in Condition Adverse to Quality Reports (CAQRs) SQP 870142 and SQP 870143, respectively. The failures have been attributed to the physical location of the check valves in system low points. This location exposes the check valves to a buildup of fine corrosion products and other material, preventing adequate seating of the check valves. To better ensure the ability to isolate containment at these locations, the check valves are being replaced with motor-operated butterfly valves. .iustification for Change The unit 2 ERCW valves will be replaced by engineering change notice (ECN) 7329. The unit 2 CCS valve will be replaced by ECN 7331. The unit 1 ERCW and CCS valves will be repla:ed under ECNs 7378 and 7361, respectively. The modifications on both systems will replace certain inboard containment isolation check valves with motor-operated butterfly valves. The MOVs will provide more reliable isolation capability than the check valves. Bypass lines with pressure-relieving piston check valves will be installed around the new inboard MOVs. This is intended to relieve pressure between the inboard and outboard MOVs while the penetration is isolated. The piping and valves within the isolation envelope will meet the requirements i of TVA class B. The requirements of TVA class B piping are described in FSAR section 3.2.2.2. The components will be seismically supported, and all components will be qualified to seismic category I requirements. The isolation configuration will conform to explicit requirements of 10 CFR 50, r. ~~ ~ ~ ~
. Appendix A, criteria 54 and 56. This is consistent with the evaluation presented in the January 2, 1987 submittal on SQN containment isolation design, except the inbcard barrier will now consist of the MOVs and their associated pressure relief check valves, instead of the previously identified check valves. The motor operators for the new inboard valves will be environmentally qualified for harsh environment conditions. The valve operators will receive class lE trained power from the 480-V reactor MOV boards. Calculations have been performed to demonstrate that the addition of these valve operators to the onsite power system will not have a detrimental impact on diesel generator loading. Because the new MOVs perform an active safety-related function, the intent of Regulatory Guide (RG) 1.106, "Thermal Overload Protection for Electric Motors on Motor-Operated Valves," must be met. Fcr these new MOVs, the thermal overload heater elements will be permanently bypassed. MOV degradation will be detected by the inclusion of the new MOVs in periodic maintenance programs, including MOV analysis and test system (M0 VATS) programs. This approach to meeting the intent of RG 1.106 was found to be acceptable as documented in the supporting safety evaluation for license amendments 61 and 53 for SQN units 1 and 2, respectively. These amendments were transmitted to TVA by letter dated October 22, 1987. The new inboard MOVs will receive both automatic and remote-manual signals. The valves will automatically isolate on a phase B containment isolation signal. This is consistent with the other ERCW and CCS containment isolation MOVs already installed in these lines. Remote-manual control will be available in the main control room. Handswitc'es and valve position indicating lights will be located on panel n 0-M-27A (ERCW panel) for the ERCW MOVs and on panel 0-M-27B (CCS panel) for the CCS MOV. Backup control and transfer switches will be located at the 480-V reactor MOV boacds. An additional change made by ECNs 7329 and 7378 will rearrange the valve numbers on the outboard isolation valves for the ERCW lower containment supply headers. This is done to provide both train A and train B isolation valves for each containment penetration with the inboard valve powered from the same train as its associated lower compartment cooler. By utilizing this configuration, a postulated loss of one train of power will leave two lower compartment coolers and their associated inboard isolation valves available for remote operation. The outboard valves are accessible in the annulus and can be opened manually. The valves procured for the ERCW system have a maximum allowable stroke time of 70 seconds. This is 10 seconds longer than the neximum allowable stroke times for the other ERCW containment isolation valves listed in Table 3.6-2. Similarly, the valve procured for CCS has a maximum stroke tice of 65 seconds, which is 5 seconds longer than the other CCS valves receiving the phase B isolation signal. It is the additienal few seconds of closure time for these specifi; valves that lead to the addition of l i i e l )
I o I the note to Table 3.3-5, item 7.b, "Containment Isolation-- Phase B." -For i both the ERCW and CCS valves, 5 seconds for signal generation is added to the maximum valve closure time to obtain the response time for these valves when diesel generator starting and sequence loading delays are not included. LAn additional 10 seconds is added to this value to obtain the i response time when diesel generator delays are included, j l It has been determined that the few additional seconds of valve closure I time will not-significantly increase the probability of releasing radioactive material from containment during a postulated loss of coolant [ accident (LOCA). Radioactivity could only be released to the environment if all of the following conditions occur: j 1. A LOCA has occurred and progressed to'the point of fuel damage, with fission products released to the containment atmosphere. l 2. The cooling water piping has broken and drained. The draining of the piping would require the degradatton of the water supply because these. valves are located on supply headers to containment. 4 3. The outboard containment isolation MOV fails to isolate. 4. Radioactive material migrates into and escapes through the water f system. r The footnote concerning the applicability of specification 3.0.4 is l applied to the ERCW valves. This is consistent with other containment isolation valves on these lines and other ERCW lines that penetrate containment. t The installation of the new valves is currently scheduled before restart for unit 1 and during the next refueling outage for unit 2. Because the new valves are being added as an enhancement, the schedules for l installation may be revised because of scheduling conflicts. The addition of the footnote (indicatit.g that the new valves are no-required until i their associated modifications are completed) will prevent an unplanned outage if the license amendment is approved before the valves are added during an outage of sufficient duration. I t In summatica, the proposed technical specification change is made because { containment isolation check valves are being replaced with MOVs. The MOVs t f are being installed to provide a more reliable containment isolation mechanism with respect to leakage. The design, configuration, and control i of these MOVs are consistent with that used for similar containment isolation valves. Inclusion of the valves in Table 3.6-2 properly reflects the automatic isolation valves used in the containment isolation design and ensures that the valves are tested in accordance with surveillances 4.6.3.1, 4.6.3.2.6, and 4.6.3.3. The note added to Table f 3.3-5 clarifies that the response time for these valves is slightly longer j than other phase B isolation valves because the maximum closure time of these valves is 5 to 10 seconds longer than the other phase 3 isolation valves of Table 3.6-2. i j
ENCLOSURE 3 PROPOSED TECHNICAL SPECIFICATION CHANGE SEQUOYAH NUCLEAR PLANT UNIT 1 AND LWIT 2 DOCKET NOS. 50-327 AND 50-328 (TVA-SQN-TS-88-01) DETERMINATION OF NO SIGNIFICANT HAZARDS CONSIDERATIONS I e G = w W e M =d 4 m-w w g g g s. _m-
ENCLOSURE 3 Page 1 of 2 Significant Harards Evaluation TVA has evaluated the proposed technical specification change and determined that it does not represent a significant hazards consideration based ot. criteria established in 10 CFR 50.92(c). Operation of SQN in accordance with the proposed amendment will not: (1) involve a significant increase in the probability or consequences of an accident previously evaluated. Containment isolation provides the means of isolating fluid systems that pass through containment penettations so as to confine to the containment any radioactivity that may be released in the containment following a postulated accident. Containment isolation is required following a postulated accident to isolate various fluid systems penetrating containment. SQN does not have a particular system for contairment isolation, but isolation design is achieved by applying common criteria to penetration in many different fluid systems and by using engineered safety feature signals to actuate appropriate valves. The proposed change in the containment isolation scheme will not affect any components capable of initiating any accident as evaluated in the FSAR. The installation of the additional MOV in the CCS supply line to the RCP motor oil coolers could increase the probability of a spurious isolation of the CCS supply. Plant instructions require the RCPs to be shut down if CCS flow is lost to the RCP motor oil coolers. This would result in a complete loss of forced reactor coolant flow, which is evaluated in section 15.3.4 of the FbAR. The FSAR analysis assumes a simultaneous loss of the power supplies to the RCPs initiates the event. It is concluded that the small increase in the probability of a spurious isolation will not significantly increase the probability of the complete loss of forced RCS flow as evaluated in the FSAR. The incressed reliability of the isolation mechanism can potentially reduce the consequences of evaluated accidents. (2) create the possibility of t iew or different kind of accident from any previously analyzed. The loss of CCS flow to the RCP oil coolers has been previously identified as a condition that would require shutdovn of the affected RCP because of high motor-bearing temperatures. This condition is addressed in plant instructions. The resulting loss of forced reactor coolant flow, either partial or total, has been analyzed in the FSAR. The ERCW supplies to lower containment ere evaluated when the lower compartment coolers were upgraded to ensure r eliability under postaccident conditions. All safety system inter' aces wera evaluated to ensure that the use of these surnly Perdsrs will not degrade other safety systems used to mitigate ostulated accide.its. n
ENCLOSURE 3 Page 2 of 2 (3) involve a significant reduction in a margin.of safety. The proposed' change is made as the result of replacing containment isolation check valves with MOVs. This was done to provide a more reliable isolation mechanism for the associated penetrations. This in turn provides a better assurance of meeting the leakage limits of 10 CFR 50, Appendix J, and specification 3.6.1.2. Inclusion of the valves in Table 3.6-2 properly reflects tae automatic isolation valves used in the SQN containment isolation design. The addition of the note to Table 3.3-5, item 7.b reflects i: hat the new containment isclation MOVs have slightly longer respons.e times associated with a phase B isolation signal because their closcre times are slightly longer'than other phase B isolation valves presently installed.' This ensures that the appropriate testing for these valves'is performed. Because of these enhancements, the margin of saf ety will not be reduced, but increased. ) 1 1 'l ) 4 i l 1 i ++
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