ML20101R787
| ML20101R787 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 07/06/1992 |
| From: | Schrage J COMMONWEALTH EDISON CO. |
| To: | Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19303E902 | List: |
| References | |
| NUDOCS 9207160205 | |
| Download: ML20101R787 (10) | |
Text
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C:mm:nralth Edison
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J Down:rs Grova lilinois 60515 i
July 6, 1992 Dr. Thomas E. Murley, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Hashington, DC 20555 Attn: Document Control Desk
Subject:
Quad Cities Nuclear Power Station Unit 1 Application for Amendment to 1
Facility Operating License DPR-29, Appendix A, Technical Specifications MC_Qorief_N_os. 50-254
Dear Dr. Murley:
Pursuant to 10 CFR 50.90, Commonwealth Edison Company-(CECO) proposes to amend Appendix A, Technical Specifications of Facility Operating License DPR-29.
The proposed amendment reflects a modification to the High Pressure Coolant Injection (HPCI) turbine steam exhaust ilne.
The proposed amendment adds the requirements for the new containment isolation valves which are part of the modification.
The proposed amendment request is provided as follows:
- 1. provides the Safety Evaluation for the amendmert request;
- 2. provides a summary of the proposed changes;
- 3. provides the proposed-Technical Specification pages which reflect the requested changes;
- 4. describes CECO's evaluation pursuant to 10 CFR 50.92(c); and,
- 5. provides the Environmental Assessment for the amendment request.
The information contained in Enclosure 1 is considered to be proprietary information to General Electric, and is supported by an affidavit signed by General Electric, the owners of the information.
contains the affidavit that sets forth the basis on which the information may be withheld from public disclosure by the NRC and addresses the considerations listed in paragraph (b)(4) of 10 CFR 2.790 of the NRC regulations.
Accordingly, CECO requests that the information containN in Enclosure 1 be
,1withheldfrompublicdisclosureinaccordancewith10CFR2.790.
,v
[loutageforUnit1(Q1R12)whichisscheduledto_beginonSeptember5,1992and 2
This modification will to be implemented during the twelfth refut. ling 1
v.,end on December 6, 1992. CECO, therefore, respectfully requests NRC's appioval of this proposed amendment prior to the end of the refueling outage.
CECO will ensure that the Project. Manager is appraised of any schedule changes with respect to the refueling outage.
/Ih g 9207160205 920706 PDR ADOCK 05000254 Q A g- /-
Dr. Thomas E. Hurley 2
July 6, 1992 This proposed amendment has been reviewed and approved by CECO's onsite and off-site review in accordance with Company procedures.
To the best of my knowledge and belief, the statements contained are true and correct.
In some respect, these statements are not based on my personal-knowledge, but obtained information furnished by other Ceco employees, cor4 tract employees and consultants. Such information has been reviewed in acccrdance with company practice, and I believe-it to be reliable.
CECO is notifying.the State of Illinois of this application for amendment by transmitting a copy of tMs lette and its attachmeet to the-designated State Official.
Please direct any questions concerning this submittal to John Schrage at (708) 515-7283.
Verytrulyyoufs, j
4 John L.
chrage Nuc1 a Licensing Administrator Attachments: 1) Safety Evaluation
- 2) Summary of the Proposed Changes
- 3) Proposed Technical Specification Pages
- 4) Evaluation of Significant Hazards Consideration
- 5) Environmental Assessment
Enclosures:
- 1) General Electric Setpoint Calculations, GE-NE-901-013-049'.
Revision 1 dated 6/06/91
- 2) General Electric Company Affidavit
- 3) General Electric Company Service Informatier: Letter SIL 30 Figures:
- 1) HPCI Turbine. Exhaust Line
- 2) HPCI Sparger Conceptual Design
- 3) Isolation Logic for Vacuum Breaker Line cc: A. Bert Davis, Regional' Administrator-RIII F.A. Maura, Inspector-RIII L.N. Olshan, Project Manager-NRR T.E. Taylor, Senior Resident Inspector-QC Stateoff41a1&l1,Countyof2)4'464' f-] ((d 3 [-
Signedbeforemeonth;s__fL(rday h M %RYELLEN Of LONG of Z//e/
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, 1992.
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$ NOTARY PUBUC. STATE OF ILLIN0IS C MY COMMISSION EXPh. GAV93 Notary Public
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.AUACHMENT_1 DESCPlflION_8MD_ SAFETY AN8 LYSIS _Of PROEQSED__CH8NGES_IQ APPENDIX A; IICHNICAL SPECIFIC 6HOMS QUA0_CIIIES_SIAIloti s
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l-1 IntrodUC.t10!)
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Commonwealth Edison Company'(CECO) proposes to amend the Facil'ty Operating License for Quad Cities Nuclear Power Station tQCNPS) Unit-1 (DPR-29),
i Appendix A, Technical SpecificationsL(TS).
The proposed changes-are-consistent with those that were-recently approved for Unit'2,-DPR-30,-
Amendment No. 130.
The proposed amendment would:
I 1.
Reflect a proposed modification to the HPCI turbine. steam ~ exhaust.
i line vacuum breaker configuration. -This~ modification.js scheduled
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for the upcoming cycle 12 refueling outage.
The proposed modification will create a new primary containment boundary such that i
the steam exhaust line check valve 2301-45 can be removed from:--the 10 CFR 50, Appendix J leak rate testing ~ program. : Revised' testing--
requirements for the 2301-45 valve will be incorporated into the-Inservice-Testing Program according to Section-XI of the-ASME Code per 10 CFR SC.55(g).
2.
Propose Technical Specification changes to correct ar omission of ihs-l HPCI low pressure isolation.setpoint to Table 3.2-1; i
3.
Propose Technical Specification changes 1to add.two new vacuum line j.
primary' containment isolation valves to Table 3.7-1.
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Backgr.ound On June 15, 1990, USNRC Region III issued Inspection Report-50-254(265)/890241 which summarized the.results of their inspection of the Quad Cities 10 CFR 50, Appendix'J test program.
A_ Notice of Violation was issued, which cited ineffective corrective actions to repetitive valve failures. One of-the valves which was cited as a: concern was the High Pressure Coolant Injection-t (HPCI) ste"n exhaust check valve, 2301-45.
The HPCI steam exhaust valve has:
experienced repeated ~ Local Leak Rate (LLRT)-failures.- Cyclical " chugging" loads from unstable steam condensation,__during periods of low HPCI: turbine steam flow, are bt'ieved to be the cause of-the repeated failures. : Previous-f i
attentpts to improve valve performance have-consisted of-redesigning the; 2301-45 valve and/or changing the seating materials.
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In response to the Notice of Violation. CECc committed to accelerate the test-interval for the 2301-45 valve to ensure thatLits sontainment functi_on remained effective.
In' addition, surveillance procedures were~ revised to j
minimize potential damage to the valve _during. low steam flow turbine 1
operations.
4 l
In September, 1990 CECO conceptualized a: proposed modification to the' current-design of the HPCI exhaust system.
This proposed modification providesethe-following_ benefits:
i 1.
Adds the ability to isolate the vacuum breakeriline through-the us_e;
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of motor. operated valves (MOV), thereby avoiding the potential for a containment atmosphere;1eakage path through the HPCI turbine' exhaust;_
f 2.
Improves the reliability of_the vacuum breaker with.a "^ne-out-of-two-l_
twice" check valve conflyuration;--
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3.
Provides improved access for maintenance, since the va d breakers l
are located external to the torus; and,.
i 4.
Improves the steam condensation stability-through the use of a sparger which is designed to: provide for_more stable condensation-
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i over a wide. range of steam flows, thereby minimizing the cyclical' s
" chugging" loads on the 2301-45 valve.
ExistingSovifleuration The existing-configuration and proposed modification 1to the HPCI' steam exhaust line are shown on Figure 1.
The HPCI turbine-exhaust line runs from the i
exhaust of the HPCI turbine through the Core Spray. corner: room, penetrate's-the-torus and discharges:below'the torus water level.
The line.contains two largel turbine exhaust check valves, 2301-45 and;2301-74, which arel designed to prevent. water from backing up into the turbine.
Inside the Torus, a: vacuum breaker line, equipned with two:small check valves, ties ~1nto the HPCI steam exhaustiline downstream of.the two exhaust check U
l valves.
The vacuum' breaker line communicates with-the containment atmosphere,.
therebj providing a potential leakage path to areas outside-the containment boundary.
To address ~this potential leakage path, current containment testing provisions require'10 CFR 50, Appendix J, Type C: testing:of the-2301-45 valve.
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Current automatic HPCI isolation is provided by. turbine steam supply valves, 2301-4 and 2301-5.
These containment isolation valves will isolate on a Group IV isolation signal.
The current signals for Group IV are high HPCI steam flow, high HPCI room temperature, or low reactor pressure.
The basis _for the high steam flow and high room temperature isolations is to assure system isolation in the event offa steam lint break.
While the basis for the low steam line pressure l',olation is to assure that steam and radioactive gases will net escape from the HPCI turbine shaft seals into the-reactor building after steam pressure has decreased to such a low value that the turbine cannot be operated.
PIODQ39d_tiodif1Citt10D The proposed modification (Figure 1) eliminates the existing air leakage path created by the current vacuum breaker line and addresses the cause of the 2301-45 valve deterioration.
The existing vacuum breaker line which is located inside the torus will be removed.
The HPCI exhaust line terminates below the minimum water level of the suppression pool; therefore, the line will not communicate directly with the containment atmosphere.
The suppression pool' water inventory provides an effective w.'n-seal for the exhaust line during the post-accident period.
To provide the vacuum r lief function and create a new containment boundary, i new 4-inch vacuum breaker line (reference figure 1), located external to the torus, will be installed.
The new vacuum breaker line will be an isolable air leakage path containing two HOVs; four 4-inch check valves; and the necessary blocking valves and test taps for LLRT.
The outboard isciation valve will be powered from a 250-volt D.C., Division II power source.
The inboard MOV will be fed from a 480-volt A.C. Division II power source.
Both MOVs will be procured to safety-related and environmental qualification standards.
To protect the HPCI turbine e>haust line from unstable steam condensation loads, a sparger will be installed on the end of the HPCI turbine exhaust line inside of the torus.
The first row of holes on the sparger will be located at or below the current HPCI exhaust line-submergence (reference Figure 2).
The valves and piping will be qualified for all applicable loads, including seismic and Mark I containment considerations.
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The-logic for theivacuum breaker isolation > valves has!been developed in accordance with the recommendations contained in General Electric Service:
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- Information Letter (SIL),- No. 30 (Enclosure 3), and isLconsistent withLthe
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design of later operating plants-(e.g., LaSalle RCIC system)( The vacuum linei i
isolation valves will'be normally open to assure'the operational readiness of i-hPCI Automatic isolation will occur during corJitions__ indicative of a-large:
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break inside of the drywell concurrent 1with los reactor: pressure conditions.
The--high drywell pressure signal ensurts that the vacuum breaker function will.
not isolate unless HPCI. operation is inhibited under conditions indicative a large break loss-of-coolant accident.
The low pressure isolation' condition will ensure that the HPCI system will not.be isolated.until steam ~ pressure has decreased to the point where._the HPCI cah no longer perform its_ design a
j function.
The isolation signal is initiated.by a one-out-of-two taken twice-
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j arrangement (reference Figure 3), with a signal _ seal-in feature that must be reset to allow manual'_revpening of the isolation valves.
The-isolation signal-l to each valve is supported by separate. control divisions to ensure that--no
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single physical failure will prevent isolation, The new vacuum breaker isolation valves will_have no greater than a 50-second:
closure time.
The maximum closure time will assure that any_ potential radiological release, during a design basis loss-of-coolant accident,+will-not1 exceed regulatory and TS limits..The closure time was determined on the-ability of the valve to close. Since less than 47. of the. assumed maximum-j number of damaged rods experience cladding damage in_the first 125-seconds 5
after the postulated accident occurs, a maximum closure time of 50-seconds is sufficient.
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PTt0pOltd_IRChnical Specificttlons i
l Table 3.2-l' Current Technical Specification Table 4.2-1, " Minimum (Test and Cal!bration Frequency for Core and Containment Cooling System-Instrumentation, Rod Blocks, and Isolations," requires that the HPCI isolation-instruments be periodically; calibrated and tested.
The low pressure isolation functi.on: surveillance requirements are included as part of these-periodic tests. : Technical:
4 Specification Thble 3.2-1, " Instrumentation thatl Initiates Primary 1 Containment-l Isoleton Functions," does not contain.a_ corresponding l limiting.. condition for operation _ requirement.
To-correct this-omission, the requirementsifor the-HPCI low reactor' pressure isolation are proposed.
]
The uasis for the HPCI turbine steam.line low-pressureLisolation is to-assure F
that steam and radioactive gases will not escape from the HPCI turbine' shaft-i-
seals into the reactor building after steam pressure has decreased to a: level j
where the.HPCI turbino cannot operate.
2.
The low pressure l instruments are currently set such that the isolation _does not occur. prior-to reactor pressure decreasing to 90 psig.
Prior to the j
approval of-Technical Specification Amendment No. 130-(DPR-29)'and 124
[f '
(DPR-30), HPCI was required:to be operable at a reattor pressure greater than 90 psig.
The SAFER /GESTR' Analysts for' Quad C) ties-w?s used'to support.
i changing the operability requirements such that HPCI c ration is require,l'to a decreasing reactor pressure of'150 osig.
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CECO contracted General Electric to calculate.a new isolation setpoint based-on the SAFER /GESTR Analysis inputs.
The calculation was performed utilizing methodology contained in NEDC-31336 " General Electric Instrument Setpoint Methodology," dated October, 1986.
The upper bounding limit for the low pressure isolation signal was 150 psig, based on the SAFER /GESTR Analysis inputs.
The lower bounding limit of 95 psig was chosen based on General Electric experience with the stall pressures of HPCI turbines.
The lower bounding limit is conservative in that the anticipated stall pressure for the HPCI turbine is well below a reactor pressure of 95 psig.
The recommended licensing setpoint value is 100 psig.
The calculation is provided in.
~
Table 3.7-1 The proposed changes to Technical Specification Table 3.7-1, " Primary Containment Isolation," adds the vacuum breaker isolation valves. As discussed previously, these valves will be part of the Group IV Isolation which affects the HPCI system.
The vacuum breaker isolation valves will close within a maximum specified time of 50-seconds.
The automatic closure will i
occur during high drywell pressure concurrent with low reactor pressure.
The isolation logic is consistent with_ General Electric recommendations contained-in SIL 30 and also with later designs for the system.
This isolation scheme-assures that the system will be maintained in operational readiness except under conditions where HPCI can no longer operate, concurrent with indication of a break inside of the drywell. As previously discussed, the HPCI steam supply valves isolate during conditions which are indicative of a steam line break or uader pressure conditions when HPCI can no longer perform its design function.
The closure time of 50-seconds is sufficient to limit the assumed radiological release, during a design basis loss-of-coolant-accident, below regulatory and license limits.
The proposed design provides a more reliable containment isolation function.
A more effective means of containment isolation is provided through the use of small, motor-operated valves in place of the turbine exhaust check valves.
The vacuum breaker isolation valves can be closed through remote or local operation in the unlikely event of a failure of the automatic isolation.
The current SAFER /GESTR Analysis for Quad Cities Station-credits HPCI operation during decreasing reactor pressure up to 150 psig.- As such, i
Commonwealth Edison contracted General Electric-to calculate-a new isolation l
setpoint based on the current SAFER /GESTR Analysis inputs.
The calculation was performed utilizing methohlogy contained in NEDC-31336,
" General Electric Instrument Setpoint Mcthodology" dated October, 1986.
The upper bounding limit for the isolation signal was 150 psig which is based on the SAFER /GESTR Analysis inputs.
A lower bound of 95 psig was chosen based on scl:1849:7
GE experience to assure equipment protection.
The lower bound 1s-conservative in that the anticipated stall pressure for the HPCI turbine is well below a reactor tressure of 95 psig. The recommended value for-the nominal isolation
~setpoint (Licensing) is 100 psig.
The calculation is provided i
'nclosure 1.
The proposed changes to the QCNPS Technical Specification have been reviewed and approved by the On-Site Review in acccrdance with controlled Station Procedures. We have review these proposed these proposed amendments in accordance with 10 CFR 50.92(c) and cletermined that no significant hazards-consideration exist.
This evaluation is documented in Attachment 4.-
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AUACHMEHLZ SUttMRLDf_IHE_EBQEOSED_CHAEL10_AEEEJtolL8 -
1 IECMICALSEEC1flCAIIONS Que9_C111ELSIAUDN llMLI_1-fACIL11LDEERAII!KLLICENSLDPR.29
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EAge_ LZ/4.2-8 and -9 1.
Revise the fifth paragraph of the bases to read:
'"A-trip of this. instrumentation results in closure of the RCIC or HPCI steam supply isolation valves. The trip logic for this function is similar to that for the main steam isolation valves 2.
Add.the following to the fifth paragraph:
"In addition,' the steam supply valves'for each system are closed on low steamline-pressure to provide primary containment isolation when the reactor pressure, as sensed in the system steamlines', is below the required pressure for turbine operations."
3.
Add the following to create a new sixth paragraph:
" Operation of the HPCI turbine will continue as long as reactor?
pressure is above.150 psig. When the reactor pressure falls below:
150 psig, the speed of the turbine-pump unit will decrease and gradually be slowed due to stop friction and-.windags Icss a at' low-reactor pressures.
The low reactor pressure' isolation setpoint was developed in accordance with NEDC-31336, " General Electric-Instrument Setpoint Methodology," dated October, 1986. The trip setpoint of-greater than or-equalito 100 psig~was-calculated such that the isolation will occur on decreasing reactor pressure _to provide primary cuntainment isolation when the reactor-pressure, as ' sensed -in
_i the system steamlines,.is below the required pressure for turbine operation.
The external vacuum breaker line_for the HPCI turbine will.1solate on low steamline pressure concurrent with high drywell-pressure signals.
The instrumentation and controls ensure the proper HPCI and primary _ containment response-to a HPCI steamline break-i sc1:1849:9
i (isolation of the steamline supply valves only).-a large break inside the containment (closure of the steam supply!and vacuum relief 1 solation valves) and a small or intermediate size bruak inside containment (steam supply and vacuum breaker isolation valves remain open for HPCI operation)."
Eage_322LL2-15 1.
Add the HPCI steam line pressure low isolation requirements to Table 3.2-1.
The minimum number of operable or tripped instrument channels as "4" and a trip level setting of greater than or equal to 100 psig.
? age 3.7/4.7-3Z 1.
Add the vacuum breaker isolation valves to Table 3.7-1 to include the following information: Group 4 Isolation: Vacuum breater isolation M0-2399-40, H0-2399-41; Number of Power Operated Valves Outboard:
(H0-2399-41) and Inboard: 1 (M0-2399-40); Haximum Operating T!me:
150; Normal Operating Position: 0; Action on Initiating Signal: GC.
Ease 3.7/411-38 1.
Change the description of Group 4, as follows:
"The steam supply isolation valves in the high..."
2.
Add the following to the description of the Group 4 isolation:
"The turbine exhaust vacuum breaker isolation valves close when both of the following signals are present (simultaneously):
1.
High Drywell pressure 2.
Low reactor pressure" 3.
Review Group 5 isolation description as follows:
" Isolation valves in the reactor core isolation cooling system (RCIC) are closed upon any one of the followirg signals:
1.
RCIC steamline high flow 2.
High temperatute in the vicinity of the RCIC steamline 3.
Low reactor pressure."
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