ML20046C559
| ML20046C559 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 08/05/1993 |
| From: | Barkhurst R ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20046C560 | List: |
| References | |
| RTR-NUREG-1366, RTR-NUREG-1432 W3F1-93-0065, W3F1-93-65, NUDOCS 9308110150 | |
| Download: ML20046C559 (8) | |
Text
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August 5, 1993 U.S. Nuclear Regulatory Commission Attn:
Document Control Desk Washington, D.C.
20555
Subject:
Waterford 3 SES Docket No. 50-382 License No. NPF-38 Technical Specification Change Request NPF-38-136 Gentlemen:
The attached description and safety analysis support a change to the Waterford 3 Technical Specifications.
The proposed ~ amendment ~ revises Surveillance Requirement 4.1.3.1.2 for Control Element Assembly (CEA) freedom of movement
~ testing to decrease the frequency of testing from once per 31 days to once'per 92 days. The proposed change is consistent with the recommendations of NUREG-1366 " Improvements to Tec'.nical Specifications Surveillance Requirements" and NUREG-1432 " Standard Technical Specifications Combustion Engineering Plants".
The proposed change has been evaluated in accordance with 10CFR50.91(a)(1)'
using criteria in 10CFR50.92(c) and it has been determined that the proposed change involves no significant hazards considerations.
The circumstances surrounding this proposed amendment do not meet the NRC's
. criteria for exigent or emergency review. However, the current monthly surveillance imposes an increased potential:for unnecessary challenges to safety systems; therefore, an expeditious review is respectfully requested.
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m Technical Specification Change Request NPF-38-136 W3F1-93-0065 Page 2 August 5, 1993 Should you have any questions or comments concerning this request, please contact Paul Caropino at (504) 739-6692.
Very truly yours,
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JS R.P. Barkhurst Vice President, Operations Waterford 3 RPB/PLC/dc
Attachment:
-NPF-38-136 cc:
J.L. Milhoan, NRC Region IV D.L. Wigginton, NRC-NRR R.B. McGehee N.S. Reynolds NRC Resident Inspectors Office Administrator Radiation Protection Division (State of Louisiana)
American Nuclear Insurers
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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the matter of
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Entergy Operations, Incorporated
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Docket No. 50-382 Waterford 3 Steam Electric Station
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AFFIDAJ_II R.P. Barkhurst, being duly sworn, hereby deposes and says that he is Vice President Operations - Waterford 3 of Entergy Operations, Incorporated; that he is duly authorized to sign and file with the Nuclear Regulatory Commission the attached Technical Specification Change Request NPF-38-136; that he is 4
familiar with the content thereof; and that the matters set forth therein are
.i true and correct to the best of his knowledge, information and belief.
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Ak R.P. Barkhurst Vice President Operations - Waterford 3 STATE OF LOUISIANA
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) ss PARISH OF ST. CHARLES
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Subscribed and sworn to before me, a Notary Public in and for the Parish and State above named this -
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day of MvGv5 F
, 1993.
l w~ S lN Notary Public My Commission expires 6v e " ' ' r' c
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I DESCRIPTION AND SAFETY ANALYSIS
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0F PROPOSED CHANGE NPF-38-136 This proposed change modifies the frequency associated with Control Element 1
Assembly (CEA) operability testing. Specifically,.the Technical Specification (TS) requirement that each full-length CEA not fully inserted and each part-length CEA which is inserted in the core below 145 inches shall be moved a short distance in any direction "at least once per 31 days", would be changed to "at least once per 92 days".
Existina Specification See Attachment A Proposed Specification i
See Attachment B Descriotion The current Waterford 3 TS for CEA operability (TS 3/4.1.3) assures that acceptable power distribution limits are maintained, the minimum shutdown margin is maintained, and the potential affects of CEA misalignments are limited. The surveillance requirements for the movable CEAs include verifying that each full-length CEA not fully inserted and each part-length CEA which is inserted in the core below 145 inches is operable by movement of at least 5 inches in any one direction. This surveillance (TS 4.1.3.1.2) is designed to verify the ability of each CEA to insert on a reactor trip. Verifying each CEA is trippable would require that each CEA be tripped.
In modes 1 and 2, tripping a CEA would result in radial or axial power tilts or oscillations.
Therefore, demonstrating that the CEA can move freely within a small range (i.e. 5 inches) is adequate to demonstrate freedom of movement without exceeding the alignment limit (i.e. 7 inches when one CEA is being moved), and when combined with other surveillances, provides increased confidence that all CEAs continue to be trippable even if they are not regularly tripped.
The major concern with the performance of this test is that it creates the patential for dropped CEAs and/or reactor trips. CEAs are designed to be moved and the subject test does not involve moving the control assemblies in any way that differs from the way the CEAs are moved when controlling power or power distribution. However, the control element drive mechanism (CEDM) and the CEDM control system are complex and their mechanical movements and timing requirements are exacting. Due to the increased potential for unnecessary.
I challenges to safety systems, the proposed amendment increases the current j
surveillance interval from 31 days to 92 days.
The proposed change is consistent with the Technical Specification Improvement Program and supported in NUREG-1432 " Standard Technical Specifications Combustion Engineering Plants" and NUREG-1366 " Improvements to Technical Specification Surveillance Requirements".
NUREG-1432 requires full-length CEAs to be subjected to freedom of movement testing every 92 days.
The specified 92 day frequency is based on other information available to the operator in the control room and other surveillances being performed more frequently, which add to the determination of operability of the CEAs. Other requirements for CEA operability in NUREG-1432 do not provide operational constraints more restrictive than the Waterford 3 TS.
In fact, NUREG-1432 requirements are less restrictive. The Waterford 3 TS requires inoperable CEAs to be restored to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> when more than one CEA is discovered to be immovable yet i
trippable. NUREG-1432 allows these CEAs to be considered operable.
The Staff has previously reviewed and approved a similar amendment request by Florida Power & Light Company (FPL). The FPL submittal (letter dated February 12, 1990) evaluated CEA testing and CEA failures at Combustion Engineering designed facilities. The evaluation concluded the following:
(1) the extension of this surveillance interval (i.e. 31 days to 92 days) will result in an insignificant contribution to the risk of core melt, and (2) operating experience has verified that frictional and/or mechanical binding of CEAs are i
not probable events at Combustion Engineering plants. The Staff in its review and approval of FPL's amendment request (letter dated December 2,1992) provided the results of their independent review of plant trip data from 1986 through July 1988 which supported the Staff's ultimate conclusion that l
reducing the frequency of CEA testing from once per 31 days to once per 92 days is acceptable. This information was reiterated by the Staff in NUREG-1366 which recommends a change in frequency of CEA movement tests to i
quarterly.
The Waterford 3 control element assembly drive system contains magnetic jack control element drive mechanisms. When electrical power is removed from the coils of the CEDM, the armature springs automatically cause the driving and holding catches to be withdrawn from the CEDM drive shafts, allowing insertion of the CEAs by gravity.
Both NUREG-1366 (item 4.2.1) and NUREG-1432 (SR 3.1.5.5) suggest a 92 day interval for CEA exercising.
Previous testing results at Waterford 3 support this extended test interval.
In cases where problems have occurred during rod movement testing at Waterford 3, it has been electrical problems, which have prevented CEA movement. These types of problems would not prevent the CEAs from being inserted into the core once the Reactor Trip Breakers open.
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Safety Analysis The proposed change described above shall be deemed to involve a significant hazards consideration if there is a positive finding in any of the following areas:
1 Will operation of the facility in accordance with this proposed l
change involve a significant increase in the probability or consequences of any accident previously evaluated?
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Response
No The intent of the CEA movement surveillance test is to detect CEAs which are stuck out of the core, and to demonstrate that each CEA can move freely within a small range.
The current Waterford 3 Technical Specification 31 day surveillance interval was based on
" Standard Technical Specifications for Combustion Engineering Pressurized Water Reactors", NUREG-0212, which in turn established the interval based on engineering judgment. Operating experience l
has demonstrated that this surveillance is not a principal method for detecting stuck CEAs. As indicated in NUREG-1366, in most instances where control rods (CEAs) were found to be mechanically inoperable they were discovered during control rod. drop timing tests performed during startup physics testing or when the rods were withdrawn from the core during plant startup.
Industry data on control rod drive system reliability indicates an extremely low mechanical failure rate.
Electrical problems with these systems, l
in general, do not prevent insertion of a control rod into the core when the reactor trip breakers are open. The Waterford 3 l
Updated Final Safety Analysis Report (UFSAR), Chapter 15 Accident Analysis assumes the most reactive CEA is stuck in the fully I
withdrawn position on a reactor trip. As discussed above, other l
means of detecting stuck CEAs in normal use make operation with an undetected stuck CEA improbable. Therefore, this proposed change does not involve a significant increase in the probability of or consequences of any accident previously evaluated.
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2.
Will operation of the facility in accordance with this proposed change create the possibility of a new or different type of accident from any accident previously evaluated?
Response
No l
No new accident initiators are created by the extended test interval. A single CEA stuck in the fully withdrawn position and CEA misoperation events have been previously analyzed in the Waterford 3 UFSAR Chapter 15 Accident Analysis. Additionally, the change will not alter operation of the plant or the manner in which it is operated. Therefore, the proposed change will not create the possibility of a new or different kind of accident from any accident previously evaluated.
3.
Will operation of the facility in accordance with this proposed change involve a significant reduction in a margin of safety?
Response
No The proposed change does not significantly affect the probability of a CEA failing to perform its safety function assumed in the safety analysis (i.e. insertion into the core). - The change is in agreement with the CEA exercising frequency required by the
" Standard Technical Specifications Combustion Engineering Plants",
NUREG-1432 Revision 0 and with the recommendations of
" Improvements of Technical Specifications Surveillance Requirements", NUREG-1366. Therefore, the proposed change will not involve a significant reduction in a margin of safety.
" Based on the above safety analysis, it is concluded that:
(1) the proposed change does not constitute a significant hazards consideration as defined by 10CFR50.92; and (2) there is a reasonable assurance that the health and safety of the public will not be endangered by the proposed change; and (3) this action will not result in a condition which significantly alters the impact of the station on the environment as described in the NRC final environmental statement."
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