2CAN038803, Submits Addl Info Re Tech Spec 3/4.7.1.1 Change Request Concerning Operability of Main Steam Line Code Safety Valves
| ML20196K483 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 03/07/1988 |
| From: | Howard D ARKANSAS POWER & LIGHT CO. |
| To: | Calvo J NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM), Office of Nuclear Reactor Regulation |
| References | |
| 2CAN038803, 2CAN38803, NUDOCS 8803150336 | |
| Download: ML20196K483 (2) | |
Text
4 ARKANSAS POWER & LIGHT COMPANY March 7, 1988 2CAN038803 U. S. Nuclear Regulatory Commission l
Document Control Desk l
Washington, DC 20555 ATTN:
Mr. Jose A. Calvo, Director Project Directorate IV Division of Reactor Projects III, IV, V and Special Projects
SUBJECT:
Arkansas Nuclear One - Unit 2 Docket No. 50-368 License No. NPF-6 Additional Information Regarding Technical Specification 3/4.7.1.1 Change Request
Dear Mr. Calvo:
Our letter dated November 30, 1987 (2CAN118702) transmitted an amendment request to TS 3/4.7.1.1, regarding the operability of the main steam line code safety valves, for the purpose of allowing performance of the required hydrotest of the Main Steam System during the upcoming 2k6 refueling outage, Due to scheduling considerations, we find it necessary to conduct this test during startup at the end of 2R6, rather than during shutdown at the beginning of the outage as discussed in our original submittal.
The significant hazards determination of our original submittal is valid for any time during an outage, and the following information is provided as a specific example in support of this determination for performance of the hydrotest at the different time during the 2R6 outage.
I An evaluation was performed by AP&L to verify the acceptability of performing the main steam system hydrotest at the end of the 2R6 outage (beginning of Cycle 7 core conditions) as compared to performing the test at the start of the outage (end of Cycle 6 cure conditions).
The probability or consequences of previously evaluated accidents (SAR Chapter 15) are not increased by changing the time of test performance from end of Cycle 6 (EOC-6) to beginning of Cycle 7 (80C-7).
The consequences of a postulated main steam line break (MSLB) accident are not increased as a result of the change in test schedule since the moderator temperature coefficient of reactivity (MTC) is more positive at BOC-7 than at E0C-6.
The TS limits on MTC (3/4.1.1.4) assure that the assumptions used in the accident and transient analysis remain valid throughout each fuel cycle.
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The negative net reactivity during the test is much greater than the positive i
reactivity feedback which would result from a postulated MSLB at the elevated
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primary system temperature necessary to achieve the required secondary system test pressure.
The conclusions drawn in our original submittal for the postulated u? controlled control element assembly (CEA) withdrawal from a subcritical condition are as valid at BOC-7 as at E0C-6.
As discussed in our original submittal, the reactor trip breakers will be required to be open during the test which will effectively prevent CEA withdrawal.
The ejected CEA accident was also evaluated at the elevated primary system temperature.
The worth of the postulated ejected CEA at 80C-7 is less than the shutdown margin required in this mode of operation.
The TS limit on shutdown margin (3/4.1.1.2) assures that the reactor will be maintained sufficiently subcritical to prevent inadvertent criticality in the shutdown condition.
The determination of shutdown margin conservatively considers the ejection of the highest worth CEA.
Therefore, a postulated CEA ejection will not result in high fuel pin power peaking since the core will remain subcritical throughout the event.
The change in time of performance of the hydrotest will not change the evaluation and conclusions from our original submittal with respect to the possibility of creation of a new or different kind of accident, or with respect to a change in the margin of safety as defined in the ANO-2 Technical Specifications.
Therefore, based on the above discussion, the no significant hazards consideration conclusions, with respect to the three criteria (10CFR50.92) in our original submittal, are valid for performance of the hydrotest at BOC-7 as well as at EOC-6.
We began 2R6 on February 12, 1988.
The outage is presently scheduled for a duration of 78 days.
We will require the proposed amendment request to be effective within 45 days to allow time for associated administrative changes and completion of the necessary procedures for the hydrotest.
Very truly yours, l
Dan R. Howard Manager, Licensing ORH:RBT w