ML19343B934
| ML19343B934 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 02/12/1981 |
| From: | Trimble D ARKANSAS POWER & LIGHT CO. |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| IR-0281-05, IR-281-5, NUDOCS 8102180312 | |
| Download: ML19343B934 (3) | |
Text
l' ARKANSAS POWER & LIGHT COMPANY i
POST OFFICE BOX 551 UTTLE ROCK. ARKANSAS 72203 (501) 371-.*.000 February 12, 1981 1R-0281-05 Director of Nuclear Reactor Pegulation ATTN:
Mr. Robert W. Reid, Chief Operating Reactors Branch #4 Division of Licensing U. S. Nuclear Regulatory Commission Washington, D. C.
20555
Subject:
Arkansas Nuclear One - Unit 1 Docket No. 50-313 License No. OPR-51 Cycle 5 Reload Report Responses to Verbal Questions (File:
1510.5)
Gentlemen:
On February 5, 1981, we received verbal requests for additional information and clarification on the January 30, 1981, submittal of the ANO-1 Cycle 5 Reload Report.
This letter will document AP&L's reply to the questions as described below:
Concern 1 Will AP&L supply review criteria on the startup test section along with the present acceptance criteria in the Cycle 5 Reload Report?
Response 1 AP&L has a review philosophy that is variable from test to test and potentially varies from refueling to refueling, dependent on many conditions.
The existing acceptance criteria have been set up to ensure the safety of plant operations.
The flexibility of review below the acceptance criteria limits cust be maintained for the practical completion'of startup testing w.ith adequate tolerance for variances during that testing.
It is impractical for AP&L to include review criteria with the reload report section covering startup testing due to the necessarily flexible nature of such testing.
It should be pointed out that the request for such review criteria is not a part of the NRC requested information for inclusion in reload reports.
AP&L was not required to respond to a similar request on the ANO-1 Cycle 4 Reload Report, and this was approved.
MEMBEA MtOOLE SOUTH UTIUTIES SYSTEM
Mr. Robert W. Reid February 12, 1981 We understand that other utility reload reports have recently been approved without this information. We trust the above reasoning and past precedents will resolve this issue now and for future reload reports.
Concern 2 Concern w:s expressed regarding the power level at which the core symmetry test is performed.
Response 2 AP&L will perform a core symmetry check at 15% full power using the in-core detectors.
Core asymmetry of any conceivable magnitude at core power levels up to 15% would not result in violation of any thermal criteria.
At the power kvel (15-20% FP) when the plant computer alarms package be-comes operational, any quadrant tilt above the steady state limit (which is power level independent) will cause an alarm.
Operator action is then required per Technical Specifications.
Concern 3 Additional wording is suggested for Section 6 of the Cycle 5 Reload Report per a telecopy from the NRC on February 6, 1981.
Response 3 AP&L submits the following additional wording which is slightly different from the February 6,1981, telecopy from the NRC as follows:
The magnitude of the rod bow penalty applied to each fuel cycle is equal to or greater than the necessary burnup dependent DNBR rod bow penalty for applicable cycle minus a credit of 1% for the flow area reduction factor used in the hot channel analysis.
All plant operating limits are presently based on an original method (1) of calculating rod bow penalties that are more con-servative than those that would be obtained with new approved procedures (2).
For the current cycle of operation, this sub-rogation results in a DNBR in excess of 3.8% margin, which is l
partially used to offset the reduction in DNBR due to fuel rod bowing.
References:
(1)
D. F. Ross and D. G. Eisenhut (NRC). memorandum to D. S.
Vassallo and K. R. Goller (NRC) on " Interim Safety Eval-uation Report on the Effects of Fuel Rod Bowing on Thermal Margin Calculations for Light Water Reactors", December 8, 1976.
(2)
L. S. Rubenstein (NRC). letter to J. H. Taylor (B&W) on
" Evaluation of Interim Procedure for Calculating DNBR Reduction Due to Rod Bow", October 18, 1979.
I
Mr. Rcbert W. Reid February 12, 1981 Concern 4 Can the Lead Test Assemblies (LTA's) meet all of the thermal design criteria using the TAFFY-3 or TACO-1 models?
Response 4 The LTA's meet all of the thermal design criteria for Cycle 5 operation using the TAFFY-3 and/or TACO-3 models.
Concern 5 Discuss procedures to be taken if control rod reactivity worths measurements in Section 9.2.3 do not meet the shutdown margin requirements.
Response 5 The Control Rod Group Reactivity Worth Test procedures for Cycle 5 are similar to those used in Cycle 4.
Each measured control rod group must agree within +15% of the predicted worths and the sum of the measured control rod group worths (Groups 5, 6 and 7) must agree within 110% of the corresponding predicted worth.
The acceptance criteria of 115% on each mea.ured control rod group is for information only and no specific action will be required if the acceptance criteria is not met since no safety limits are associated with this limit.
If the acceptance criteria of +10% of the predicted worth for Groups 5, 6 and 7 is not met, an evaluation by the plant's nuclear engineering group will be performed with involvement of the fu.el vendor a.id the onsite safety committee as needed.
Probable courses of action will be to re perform the test with consid-eration for increasing precision or for measurement of an additional rod group (s) concurrent with re-verification of calculated values and generation of a calculated worth for the additional rod group (s) to be measured.
If after reading and/or reanalaysis involving the fuel vendor, results are still unacceptable, NRC will be notified since the shutdown analysis will be affected.
Very truly yours, DA4rNf f.
David C. Trimble Manager, Licensing DCT: LDY: si l.
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