ML20046C326
| ML20046C326 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 08/05/1993 |
| From: | Rhodes F WOLF CREEK NUCLEAR OPERATING CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| ET-93-0094, ET-93-94, GL-93-04, GL-93-4, NUDOCS 9308100143 | |
| Download: ML20046C326 (5) | |
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W4pLF CREEK NUCLEAR OPERATING CORPORATION August 5, 1993 Forrest T. Rhodes ET 93-0094 Vice President Engineering U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Station P1-137 l
Washington, D.C. 20555
Reference:
NRC letter dated June 21, 1993, " Rod Control System Failure and Withdrawal of. Rod Control Cluster Assemblies, (Generic Letter 93-04)"
)
Subject:
Docket No. 50-482:
Response To NRC Generic Letter 93-04 Gent l err.:n :
Thi's letter provides Wolf Creek Nuclear Operating Corporation's (WCNOC) reJponse to the reference.
Pursuant to the requirements of 10 CFR i
50.54 (f), the -NRC issued Generic Letter 93-04,
" Rod Control System Failure and Withdrawal of Rod Control Cluster Assemblies,"
on June 21, 1993.
The generic letter requires each addressee to provide an assessment of whether or not the licensing basis for its facility is still satisfied with regard to the requirements for system response to a single failure in the Rod Control System (GDC 25 or equivalent).
If the assessment (Required Response
- 1. (a) ) indicates that the - licensing basis is not satisfied, then the licensee must describe compensatory short-term actions consistent with the guidelines contained in the generic letter, and provide a plan and schedule for long-term resolution- (Required Response 1.(b)).
Subsequent correspondence between the Westinghouse Owners Group and the NRC resulted in scheduler relief for Required f
Response 1. (a) (NRC Letter to Mr. Roger Newton dated July 26, 1993).
In accordance with the granted schedular relief, WCNOC will provide a response to Required Response 1. (a) by September 20, 1993.
The attachment provides the compensatory actions taken by WCNOC - in response to the Salem Rod Control System Failure Event.
.I t also provides a summary of the preliminary results of the generic safety i
analysis program conducted by the Westinghouse Owners Group and its applicability to The Wolf Creek Generating Station.
WCNOC considers this action to be complete with respect to the 45 day required response j
to Generic Letter 93-04 (as amended by the July 26,.1993 NRC letter to l
Mr. Roger Newton).
090059 i
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'N PO. Box 411/ Burlington. KS 66839 / Phone: (316) 364-8831
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Page 2.of 2
.l If you have any questions concerning this matter,.please contact me at (316) 364-8831 Ext. 4002 or Mr. Kevin J. Moles of my-staff at' Ext. 4565.
I Very truly yours, t
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l Forrest T. Rhodes Vice President Engineering l[
FTR/jra Attachment
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cc:
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D. Johnson (NRC), w/a.
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L. Milhoan (NRC), w/a l
G. A.
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1 Forrest T. Rhodes, of lawful age, being first duly sworn upon oath says that he is Vice President Engineering of Wolf Creek Nuclear Operating Corporation; that he has read the foregoing document and knows the content thereof; that he has executed that same for and on behalf of said Corporation with full power and authority to do so; and that the facts therein stated are true and correct to the best of his knowledge, information and belief.
By Forrest T. Rhodes' Vice President Engineering SUBSCRIBED and sworn to before me this [
day of dug
, 1993.
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Attachment to ET 93-0094 Page 1 of 2 l
1 RESPONSE TO NRC GENERIC LETTER 93-04 Comoensatory Actions The purpose of this discussion is to provide a response to the three areas of compensatory short-term actions identified by the.NRC (Required Response 1.(b)) and any additional compensatory actions judged to be j
appropriate, per the NRC Letter t'o Mr. Roger Newton' dated July 26, 1993.
I The second part of Generic Letter (GL) 93-04 Required Response
~1. '(b) states " describe any compensatory short-term actions taken or that will be taken to address any actual or potential degraded or nonconforming conditions, such as".
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" Additional cautions or modifications to surveillance and preventive l
maintenance procedures":
Wolf Creek Generating Station (WCGS) personnel have reviewed
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applicable (WCGS) surveillance and preventive maintenance procedures I
in light of the Salem Rod Control System Failure Event, and have determined that no additional cautions or modifications are required.
Rod Control System serveillances currently performed per WCGS Technical Specifications include comparisons between indicated and
'j demand rod positions and verify operability of the system.
In addition, the operation of each Control Rod Drive Mechanism is checked during startup following refueling by recording and examining Control Rod Drive Mechanism timing traces.
l 2.
" Additional administrative controls for plant startup and power operation"-
Additional instructions to verify agreement between indicated and demand rod positions were added to procedures SYS SF-120,
" Rod Control System Operation;" GEN 00-003, " Hot Standby to Minimum Load;"
GEN 00-004, " Power Operation;" and GEN 00-005, " Plant Shutdown from 20% Minimum Load to Hot Standby."
In addition, the operability of the computer functions which initiate the rod position deviation alarm are currently verified once per week. and following computer
. outages, per procedure STN RJ-001, " Verification of Operebility of Computer Points."
3.
" Additional instructions and training to heighten operator awareness of potential rod control system failures and to guide operator response in the event of a rod control system malfunction":
Generic Letter 93-04, " Rod Control System Failure and Withdrawal of Rod Control Cluster Assemblies," was placed on the required reading list for WCGS Operations Department Personnel.
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' Attachment to ET 93-0094 Page 2 of 2 t
It is WCNOC's position that the above actions are sufficient to address I
the Rod Control System issue at the present time WCNOC will continue to monitor the progress of Westinghouse and WOG efforts to resolve this l
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- issue, and evaluate any future corrective action recommendations resulting from the WOG program for applicability to WCGS.
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Summary of the Westinchouse Generic Safety Analysis Procram The Westinghouse Owners Group (WOG) Analysis Subcommittee is currently l
performing a generic safety analysis intended to demonstrate that all i
Westinghouse plants still satisfy GDC 25 (or its equivalent) for the i'
Salem Rod Control System Failure Event.
The purpose of the program is to analyze a series of asymmetric rod withdrawal cases to demonstrate I
that the condition II Departure from Nuclear Boiling (DNB) design basis is met.
This analysis utilizes a 3-D transient analysis approach to a plant-specific DNB sssessment for the United Kingdom's Sizewell B reactor, using conservative reactivity assumptions. The Sizewell B is a 4-loop 3411 Mwt plant with 17x17 standard fuel, and is a replica of the original SNUPPS plant design (such as USA plants Callaway Plant and WCGS).
J According to the preliminary information WCNOC received from the l
Westinghouse Owners Group (WOG), the majority of the rod withdrawal l
cases analyzed either did not generate a reactor trip or tripped on a l
high neutron flux trip.
For those few cases that tripped on. the Overtemperature Delta-T (OTDT) reactor trip, no credit was assumed for the F Delta-I reset f unct ion.,
This ensures that the statepoints i
generated for those cases that trip on OTDT are conservative for all j
Westinghouse plants.
Uncertainties on the initial conditions were accounted for in the DNB design limit.
l Using this approach, the preliminary analyses indicates that the DNB design basis would remain s at.is f ied for the worst-case asymmetric rod l
withdrawal.
Based on available information, it is WCNOC's positi'n that o
the WOG generic analysis is applicable to WCGS.
However, WCNOC will review the WOG final report and program results and provide a final response to this issue as part of our response to Required Response 1.(a).
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