2CAN048307, Responds to & 830405 Conversation Re CPC Software Discrepancy.Substantial Software Mods,Including Linear Power Density Penalty Factor,To Be Installed Prior to Cycle 5 Evaluation.Schedule Will Be Provided by 830515
| ML20073L632 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 04/14/1983 |
| From: | John Marshall ARKANSAS POWER & LIGHT CO. |
| To: | Clark R Office of Nuclear Reactor Regulation |
| References | |
| 2CAN048307, 2CAN48307, NUDOCS 8304210192 | |
| Download: ML20073L632 (2) | |
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ARKANSAS POWER & LIGHT COMPANY POST OFFICE BOX 551 LITTLE ROCK. ARKANSAS 72203 [5011371-4000 April 14,1983 2CAN048307 Director of Nuclear Reactor Regulation ATTN: Mr. Robert A. Clark, Chief Operating Reactors Branch #3 Division of Licensing U. S. Nuclear Regulatory Commission Washington, DC 20555
SUBJECT:
Arkansas Nuclear One - Unit 2 Docket No. 50-368 License No. NPF-6 CPC Software Discrepancy Gentlemen:
In response to your letter dated March 30,1983,(2CNA038304) and pursuant to my conversation with you on April 5,1983, the following information is provided.
Our letter dated February 25,1983,(2CAN028316) informed you of our
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intention to correct the discrepancy at the next CPC software modificatisr.
and comitted to provide you a schedule for that modification by May 30, 1983.
Prior to receiving your March 30, 1983, letter, we had understood this response to be acceptable; however, we will augment that response with our most current information as follows.
We agree with the desirability of incorporating the Linear Power Density (LPD) penalty factor; however, we do not feel that a safety issue or situation would dictate a CPC software change specifically for this one item. As you are aware, even the most minor software change must go through a lengthy and costly development, verification, implementation, and testing program.
As a result, efforts are made to consolidate as many changes as possible into one modification package thereby reducing the number of times this process must be undertaken and limiting the overall number of software changes.
Although the LPD penalty factor was originally intended to be incorporated into the software, it is not necessary to accomplish the design basis safety function of the CPCs.
In the unusual event of both CEACs failed, or one 8304210192 830414 PDR ADOCK 05000368 MEMBER MIDDLE SOUTH UTIUTIES SYSTEM
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Mr. Robert A. Clark April 14, 1983 failed and tne other declared inoperable a substantial DNBR penalty factor will be generated by the CPCs which will result in an automatic trip under all conditions. As stated in previous correspondence, the CPCs in their current software configuration conform with their design basis safety analysis role as reviewed and approved for ANO-2.
As stated in our February 25,1983' letter, we are continuing to discuss and schedule future CPC modifications.
Currently, we anticipate that no software modifications will be necessary to support restart of A.N0-2 for the next operating cycle (Cycle 4).
We are evaluating a rather substantial software modification to be installed prior to Cycle 5.
It is our intent to add the LPD penalty factor at that time.
An evaluation is currently underway to more specifically define the scope and schedule of this modification.
We expect to complete this evaluation by May 15, 1983, and will provide you a more definitive schedule following that effort.
Very truly yours,
[
John R. Marshall Manager, Licensing JRM:JTE:sl