ML20248B447
| ML20248B447 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 08/02/1989 |
| From: | Schnell D UNION ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20248B453 | List: |
| References | |
| ULNRC-2055, NUDOCS 8908090237 | |
| Download: ML20248B447 (8) | |
Text
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1901 Gratiot Street
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1 UNION
^"9"st 2 r 1989
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N8*8' U. S. Nuclear Regulatory Commission kg Attn: ' Document Control Desk Mail Station F1-137-Washington, DC.'20555'-
D Gentlemen:
ULNRC-2055 DOCKET NUMBER 50-483 CALLAWAY' PLANT REVISION TO. TECHNICAL SPECIFICATION 3/4.1.3 MOVABLE CONTROL ASSEMBLIES UnioneElectric Company herewith transmits an appli-cation for. amendment-to Facility Operating License No.
NPF-30.for Cc11away Plant.
This amendment application revises Technical Speci-fication 3/4.1.3.and its associated Bases to' allow con-tinued operation.for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> with one or more control rod assemblies inoperable due to an electrical problem inithe rod control system provided all affected control rods remain trippable.
It is similar to an amendment recently' approved by the NRC for the Wolf Creek Generating Station.
Attachments 1, 2, and 3 contain'the. Safety Evaluation, t
'the Significant Hazards Evaluation, and the Proposed Technical Specification Changes in support of this amend-ment request.
The proposed changes will become-effective for Union Electric implementation upon'NRC approval.
Very truly our,
Donald F. Schnell JMC/bjs Attachments
, i 8908090237 990802 hDR ADOCK 0300o493 FDC C-
.u_________
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STATE OF MISSOURI )
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l Donald F.
Schnell, of lawful age, being first duly sworn i
upon oath says that he is Senior Vice President-Nuclear and an I
o." Union Electric Company; that he has read the foregoing office's document and knows the content thereof; that he has executed the same for and on behalf of said company with full power and authority to do l
co; and that the facts therein stated are true and correct to the best of his knowledge, information and belief.
1 i
By l
Donald F.
Schnell l
Senior Vice President l
Nuclear l
day of dcy I 198f SUBSCRIBED and sworn to before me this J+A t
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1 f ) }{ e ns /s w.., C. M. dol #,HUC NOTI,ity Frgtic, g;f,gg g7 gg$,ggg, MY COMMIS$10N !.XFil:[S l,cy 13, jg.9 ST. LOUIS COUNTY l 1
j cc: Gerald Charnoff, Esq. Shaw, Pittman, Potts & Trowbridge 2300 N. Street, N.W. ) Washington, D.C. 20037 Dr. J. O. Cermak CPA, Inc. 4 Professional Drive (Suite 110) Gaithersburg, MD 20879 i R. C. Knop Chief, Reactor Project Branch 1 U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, Illinois 60137 Bruce Little Callaway Resident Office U.S. Nuclear Regulatory Commission RR$1 Steedman, Missouri 65077 I Tom Alexion (2) l Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission 1 White Flint, North, Mail Stop 13E21 11555 Rockville Pike I l Rockville, MD 20852 Manager, Electric Department Missouri Public Service Commission f P.O. Box 360 Jefferson City, MO 65102 l' Ron Kucera [ Department of Natural Resources l P.O. Box 176 l Jefferson City, MO 65102 1 l l \\
bec: D. Shafer/A160.761 /QA Record (CA-758) Nuclear Date E210.01 l DFS/ Chrono l D. F. Schnell J. E. Birk J. V. Laux L M. A. Stiller G. L. Randolph R. J. Irwin H. Wuertenbaecher W. R. Campbell A. C. Passwater R. P. Wendling D. E. Shafer D. J. Walker-O. Maynard (WCNOC) N. P. Goel (Bechtel) T. P. Sharkey NSRB (Sandra Auston) i
_ - _ _ _ _ _ _ _. _, Page 1 of 2 ULNRC -2055 SAFETY EVALUATION This amendment request revises Technical Specification 3/4.1.3 and its associated Bases to allow continued operation for 72 hours for diagnosis and repair, with one or more control rod assemblies inoperable due to a rod control urgent failure alarm or other electrical problem in the rod control system provided all affected control rods remain trippable. It is similar to an amendment recently approved by the NRC for the Wolf Creek Generating Station.
Background
As described in the Callaway Final Safety Analysis Report (FSAR) the Control Rod Drive System (CRDS) serves to insert or withdraw rod cluster control assemblies within the reactor core to control average core temperature and to shut down the reactor. The CRDS performs its intended safety function, reactor trip, by putting the reactor in a subcritical condition when a safety system setting is reached, with any assumed credible failure of a single active component. The essential elements of the CRDS (those required to ensure reactor trip) are isolated from nonessential portions of the CRDS (the rod control system). The CRDS provides a Rod Control Urgent Failure alarm, which indicates that an electronic / electrical malfunction has occurred within the CRDS. The conditions that can cause this alarm do not affect the ability to trip any control rods. This may result in a situation where the control rods cannot be stepped in or or out of the reactor, however, the rods remain trippable and therefore capable of performing their safety function. Technical Specification 3.1.3.1 ACTION b, currently requires that, "with more than one full-length rod inoperable or misaligned from the group step counter demand position by more than i 12 steps (indicated position), be in HOT STANDBY within 6 hours". Although the current Technical Specification recognizes the greater significance of rods being immovable or known to be untrippable, acknowledgement of the lesser significance of electrically inoperable rods would allow additional time for diagnosis and repair of malfunctioning equipment while maintaining safe operation of Callaway Plant. The proposed amendment request provides a distinct ACTION statement for an inoperable rod consistent with the significance of the malfunction. A rod that is inoperable due to being untrippable is more significant than a rod that cannot be stepped due to an electrical malfunction, but remains trippable. Distinguishing between these types of malfunctions will allow an appropriate time period to complete corrective action commensurate with the significance of the malfunction. The proposed change to the existing Technical Specification would allow continued operation for 72 hours for diagnosis and repair, with one or more
i, Page 2 of 2 ULNRC -2055 control rod assemblies inoperable due to a rod control urgent failure alarm or other electrical problem in the rod control system provided all affected control rods remain trippable. Evaluation The proposed change to allow 72 hours rather than 6 hours to restore electrically inoperable control rods to operable status will not affect the probability of occurrence or the consequences of an accident or malfunction of equipment important to safety previously evaluated in the Safety Analysis Report. The inoperable control rod (s) can still be tripped and therefore is available to perform its safety function. The 72 hour allowance is based on engineering judgement considering the safety significance of the malfunction. Since the safety function (reactor trip) of the CRDS system is not impaired, the 72 hour time allowance was determined to be appropriate. This change would not create the possibility for an accident or malfunction of a different type than any previously evaluated in the FSAR. This change reduces the burden on the control room staff, by allowing sufficient time for system repair without the concurrent task of condacting an orderly plant shutdown. This change also minimices the potential for a hurried diagnosis which could result in human error and unnecessary transients. This change does not affect the margin of safety as defined in the basis for any technical specifiertion. The Control rods remain trippable and are available to assure adequate shutdown margin. Conclusion Based on the above discussions and the considerations presented in Attachment 2, the proposed revisions to Technical Specification 3/4.1.3 and its associated Bases do not increase the probability of occurrence or the consequences of an accident of me.1 function of equipment important to safety previously evaluated in the safety analysis report; or create a possibility for an accident or malfunction of a different type than any evaluated previously in the safety analysis report; or reduce the margin of safety as defined in the basis for any technical specification. Therefore, the proposed revisions do not I adversely affect or endanger the health or safety of the general public or involve a significant safety hazard. i l l
T i ~ Attachment-2, Page l'of 2-ULNRC -2055 1 SIGNIFICANT FAZARDS CONSIDERATION ) This acaendment request revises Technical Specification 3/4.1.3, and its associated Bases to allow continued operation for172 hours,for diagnosis and repair, with one or more control rod assemblies inoperable due to a rod control urgent failure alarm or other electrical problem in the rod control system provided all affected control rods remt'.n trippable. 1. The proposed change does not involve a significant increase in the probability or consequences of'an accident previously eva.1 tated. Increasing the allowed outage time associated w.:h electronic / electrical-malfunctions of the Control Rod Drive System (CRDS) is acceptable, since the safety function of the CRDS-(reactor trip) remainr unaffected. The conclusions in the Final Safety Analysis Report (FSAR) remain valid. The' proposed change does not affect the ability of the CRDS to perform its intended safety function, when a safety. system setting is reached. The design of the CRDS assures isolation of essential elements of the CRDS (those required to insure reactor trip) from nonessential portions of the CRDS. 2. The proposed changes do not create the possibility of a new or different kind of accident from any previous 3y evaluated. There are no new failure modes or mechanisms associated with the proposed change. This change does not involve any modification in the operational limits or physical design of the involved l systems. The change merely allows tut extended time L period for the diagnosis and repair of portions of the CRDS, thus reducing the probability of a plant transient because of insufficient time for proper ( corrective action or a hurried diagnosis. 3. The proposed change does not involve a significant reduction in a margin of safety. This change does not l affect any Technical Specification margin of safety. This change allows appropriate ACTIONS commensurate with the significance of the CRDS malfunction, while not requiring plant transients in response to malfunctions that do not affect the capability of the CRDS to perform its safety function. Based on the above discussions and those presented in Attachment 1, it has been determined that the requested Technical Specification revisions do not involve a significant increase in the probability or consequences of an accident or other adverse condition over previous evaluations; or create the possibility of a new or different kind of accident or condition over previous
~, Page. 2 of 2' ULNRC-2055-I evaluations; or involve a significant reduction in a margin of safety. Therefore, the requested license amendment does not l involve a.significant hazards consideration'. .i i b I. =- -.}}