2CAN049102, Application for Amend to License NPF-6,changing Tech Spec 3.1.3.1 & Associated Bases to Allow Continued Operation,For Up to 72 H,W/More than One Full Length or Part Length Control Element Assembly Inoperable
| ML20072S331 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 04/09/1991 |
| From: | Carns N ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20072S334 | List: |
| References | |
| 2CAN049102, 2CAN49102, TAC-77600, NUDOCS 9104150117 | |
| Download: ML20072S331 (7) | |
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Entergy Operations,Inc.
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E Route 3 Dox 1370 Operations-ne seava'e. ^a 72ao' Telb01964 8888 1
1 Neil S.
- Bun" Carna -
Wce Present Operabons ANO April 9, 1991 2CAN049102 U. S. Nuclear Regulatory Commission Document Control Desk Ha31 Station P1-137-Washington, DC 20555
SUBJECT:
Arkansas Nuclear Ono - Unit 2 Docket No. 50-368 Licenso No. NPF-6 Proposed Technical Spoclfication Changns'-
Movablo Control Assemblies (TAC No. 77600) t Gentlemen:
Entergy Operations has' identiflod. changes to the Arkansas Nuclear One,
. Unit 2 (ANO-2) Technical Specification 3.1.3.1 and its associated Basos.
These proposed changes will allow continued operation for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> with-moro than ono full' longth or part length Control Element Assembly (CEA)
Anoperable duo to.an electronic or electrical problem in the Control
' Element Drive Mechanism Control System'(CEDMCS), provided that all affected CEAs romain trippable. This request is similar to Technical.
Specification change requests approved by the NRC for the Wolf Creek Gorerating Station and.thn Callaway Plant, Unit 1.
o Tho. proposed. change has.boen evaluated in accordance with a 100FR50.91(a)(1), using the critoria' in.10CFR50.92(c) and it has boon.
determined-that thisirequest involves no significant hazards consideration.. The basis for this determination -is : Included; in the Lonclosed submittal'for your review.
The circumstances of this request are not exigent or emergency. However, i.'
wo sequest that NRC Staff's promp attention to preclude an._ unnecessary
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shutoown should more than one CEA oecomo inoperativo'due to electronle or electrical problems in CEDMCS.
.We.rsquest that the changes becoco effectivo upon issuanco.
l-Vory truly, curs, t
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t NSC/agw Attachment 91041501D 910409 ADOCK0SOOg8 gg/
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U. S. NRC April 9, 1991 5 age 2 cc:
Mr. Robert Martin U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 1000 Arlington, TX 76011 NRC Senior Roaldent Inspector Arkansas Nuclear One - ANO-1 & 2 Number 1, Nuclear Plant Road Russellville, AR 72801 Mr. Thomas W. Alexion NRR Project Manager, Region IV/ANO-1 U. S. Nuclear Regulatory Commission NRR Mail Stop 11-D-23 One White Flint North 11555 Rockville Pike Rockville, Maryland 20852 Ms. Sheri R. Peterson NRR Project Manager, Region IV/ANO-2 U. S. Nuclear Regulatory Commission NRR Mail Stop 11-D-23 One White Flint North 11555 Rockville Pike Rockville, Maryland '0852 Ms. Greta Dicus, Director Division of Radiation Control and Emergency Management Arkansas Department of floalth 4815 West Markham Street Little Rock, AR 72201 l
8 STATE OF ARKANSAS
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SS COUNTY OF I,0GAN
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0ATil I, N. S. Carns, being duly sworn, subscribe to and say that I am Vice President, Operations ANO for Entergy Operations, Inc.; that I have full authority to execute this octh; that I have read the document numbered 2CAN049102 and know the contents thereof; and that to the best of my knowledge,.information and belief, the statements in it are true, iW -
N. S. Chrns SUBSCRIBED AND SWORN T0 before me, a Notary Public in and for the County and State above named, this ktI_, day of f
1991.
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L4fMGidbru
((' ' Notary Public//
My Comraission Expires:
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d PROPOSED TECilNICAL SPECIFICATION AND RESPECTIVE SAFETY ANALYSIS IN lilE MATTER OF AMENDING LICENSE NO. NPF-6 ENTER 3Y OPERATIONS, INC.
ARKANSAS NUCLEAR ONE, UNIT 2 DOCKET NO. 50-368
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PROPOSED CilANGE The proposed changes to Technical Specification 3.1.3.1 and its associated Bases are to allow continued plant operation for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> for diagnosic and repair, with more than one full length or part length Control Element Assembly (CEA) inoperable due to electronic or electrical problems in the Control Element Drive Mechanism Control System, providing that all affected CEAs remain trippable.
With tbs proposed addition of the ACTION statement for more than one inoperable but trippablv CEAs, several minor editorial changes (f.e.,
renumbering action statements, correcting typogtaphical errors) were made.
DISCUSSION As described in the ANO-2 Safety Analysis Report, the CEAn provide short term reactivity control (long term reactivity control is accomplished by the use of soluble poison) and insert a large imm"..t of negative reactivity upon a reactor trip signal fro-no Plant Protective System (PPS). The CEAs are also used to contral the power distribution shape of the core.
The Control Element Drive Mechanism Control System (CEDMCS) is made up of the magnetic Jack Drive (Control Element Driva Mechanism (CEDM)), two motor generator sets, reactor trip switchgear, coil power switch (which controls the sequence in which the CEDM coils energize and doenergize),
and the CEDhCS operating consola. This consolo acts as the interface between the operatec and the system by directing the control logic for pror.x sequencing of the CEA coils, which in turn determines the direction of CEA motion.
An olectronic or electrical malfunction may occur in the CEDMCS that does not affect the ability of the CEAs to trip but may result in a situation where the CEAs cannot be electrically moved. The CEAs, however, remain trippable and-capable of performing their primary safety functics of shutting 'own the reactor upon initiation of a reactor trip signal.
A CEA is considered trippable if the CEA was demonst roted operable during the last performance of Surveillance Requirement 4.1.3.1.2 and met the CEA drop time criteria.
A CEA can be assumed to be trippatie until CEA traces indicate otherwise.
The current Technical Specification *9eognizes the greater significance of a single CEA being immovable or b wn to be untrippable versus being inoperable due to an electronic or electrical malfunction but yet trippablu. Technical Specification 3.1.3.1(a) addresses one or more full length CEAs being immovable as a result of excessive friction or mechanical interference or known to be untrippable and requires the plant to be in hot standby within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. Technical Specification 3.1.3.1(b) addresses one full length CEA being inoperable due to causes oth.: than that specified in 3.1.3.l(a) and allows continued operations provided other specified Technical Specification requirements are met.
The current Technical Specification also addresses multiple CEAs being immovable as a result af excessive friction or mechanical interference or known to be untrippable (Specification 3.1.3.1.a).
However, the current Technical Specifications do not address more than one CEA being elo:.tronically inoperable dua to CEDMCS malfunct.lon but trippable.
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The proposed changes provido a distinct ACTION statement for more than one inoperable CEA consistent with the significance of the malfunction.
CEAs that are inoperable due to being untrippable is a condition more significant than CEAs which remain trippable but cannot be moved due to an electronic or electrical malfunction.
Distinguishing between these types of malfunctions will allow an appropriate time period to complete corrective action commensurate with the significav.w of the malfunction.
The proposed changes to the existing Technical Specificatios uuld allow continued operation for 72. hours for diagnosis and repair with more than one CEA inoperable due to an electronic or cloctrical problem in the CEDMCS, provided all af fected CEAs remain trippable and CEA alignment and Insertion limits and surveillance requirements remain acceptable.
The use of this time would allow the following to be accomplished:
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Allow sufficient time to evaluate the nature of the failure and to develop a systematic work plan.
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Allow suf ficient time to perform troubleshooting activities in a deliberate aed. systematic manner.
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In the event of parts unavailability, sufficient time to obtain the necessary parts for the repair of the malfunction.
BASIS FOR PROPOSED NO SIGNIFICANT HAZARDS CONSIDEE* TION DETPtlNATION The proposed changes to Technical Specification 3.1.3.1 and _cs associated Bases will allow continued operation for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> for diagnosis and repair, with more than one full leagth or part length Cor. trol Element Assembly (CEA) Inoperable due to electronic or _ electrical.
problems in the Control Element Drive Mechanism Control System (CEDMCS),
provided all affected CEAs remain trippable, in accordance with 10 CFR 50.92, Entergy Operations has evaluated whether
-the proposed: changes Involve a significant safety hazards consideration.
Entergy Operations has concluded that the proposed changes to Technical Specification 3.1.3.1 and its associated Bases does not involve a significant hazards consideration because the operation e f Arkansas
' Nuclear One, Unit 2-in accordance with these changes would not:
f(1) Involve a significant increase in the probability or consequences of I
an accident previously evaluated.
L Allowing 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> for diagnosis and repair associated with -
b electronic or electrical malfunctions of the CEDMCS is acceptable, L
oince_the primary safety function of these CEAs (reactor trip) l' remains.una f f ected.
The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> allowance is considered justifiable in order to provide adequate time to effect repairs without undue exposure'to any operational requirement to move the affected CEA group.-
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m The proposed. changes maintain the original requirements for CEA position, insertion limits, and surveillance requirements so that power and peaking distributions used in the safety analysis will remain unaffected. -The proposed. changes do not affect the ability of the" CEAs to perform their intended safety function when a saf
- .y system setting is reached. Thorofore, the consequences of accidents related to or dependent upon CEA-operation will remain unaffected.
(2) Create the possibility of a new or dif ferent kind of accident from any previously. evaluated.
There are no new failure modes or mechanisms associated with the proposed changes. These changes do not involve any m>dification in the operational limits or physical design of the inve-Ived systems.
These changes will reduce the burden on the control room staff by allowing sufficient time for system repair, (3). Involve.a significant reduction in the marg n of safety.
d These chaages do not-affect any Technica1 Specificatien margin of safety.
These chtngce allcw appropriate ACTION commensurato with the significance of the CEDMCS melfunction, while not subjecting the plant to a transient in response to malfunctions that do not affect the capability of the CEAs to perform Gielr pri aary safety function.'
Other Technical Specification limits -for teactivity related items, such as ' shutdown margin and CEA insertion limits, will remain in effect to ensure that the safety margins are maintained.
CONCLUSION Therefore, based on the evaluation discussed above, Entergy Operations han concluded that the proposed changes do not involve a significant
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- Increase in the probability or consequences of an accident or other
. adverse condition over previous evaluations; or create the possibility of a newlor-different. ktnd of accident or condition over previous eva]uations; or involve a significant reduction in a margf u of safety.
- Therefore, the proposed changes do not involve a significant hazards consideration.
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