ML20148L796
| ML20148L796 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 11/07/1978 |
| From: | Reid R Office of Nuclear Reactor Regulation |
| To: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| References | |
| NUDOCS 7811200346 | |
| Download: ML20148L796 (5) | |
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November 7, 1978 Docket No. 50-312 i
Mr. J. J. Mattimoe Assistant General Manager and Chief Engineer Sacramento Municipal Utility District 6201 5 Street P. O. Box 15830 Sacramento, California 95813
Dear Mr. Mattimoe:
By letter dated September 13, 1978, you requested amendment of the Rancho Seco Nuclear Generating Station Technical Specifications to permit operation with the fuel loading planned for Cycle 3.
In order to continue our review of this matter we have determined that additional information is needed. The specific information needed is listed in the enclosure.
In order to complete our review on a time scale consistent with your projected schedule for operation in Cycle 3, you should provide fully responsive answers to the enclosed questions by November 17, 1978.
To assist you in meeting this schedule, a draft of the enclosed questions was transmitted to you by facsimile on November 2,1978.
Sincerely,
.h
' hYt Robert W. Reid, Chief Operating Reactors Branch #4 Division of Operating Reactors
Enclosure:
Request for Additional Information cc w/ enclosure:
See next page b
r/ 8 '.12 0 0
9 Sacramento Municipal Utility District cc:
David S. Kaplan, Secretary and General Counsel 6201 $ Street Post Of fice Box 15830 Sacramento, California 95813 Business and flunicipal Department Sacramento City-County Library 828 I Street Sacramento, Californis 95814 a
v 4
4 9
RE_ QUEST FOR ADDITIONAL INFORMATION RANCHO SEC0 NUCLEAR GENERATING STATION OPERATING CYCLE NO. 3 DOCKET NO. 50-312 1.
Provide the maximum ejected rod worths at the 10-3 power level and 100% power level for B0C and E0C conditions and state whether these are bounded by the values used in the FSAR.
If these values are not bounded by previous analysis provide the peak enthalpy for the hottest fuel rod considering rod ejection at each of the above mentioned power levels.
2.
Provide the post ejection maximum peaking factors and compare these to what was used in the FSAR.
3.
State the reason for withdrawal of the APSR during the last 20 days of Cycle 3.
4.
Define the axial stability index and describe how the numerical values presented on Page 5-2 were obtained.
5.
State whether the axial stability index wat calculated with NRC approved models.
6.
What is the maximum vclua of FAH predicted for this fuel cycle?
7.
What is the basis for the selection of 1.71 for F3g?
8.
In determining the flux / flow trip setpoint it is stated that an assumed one pump coast down was analyzed. Justify that this is the worst event of this class when compared with a total loss of flow.
9.
a.
It is noted that in the Technical Specifications reactor coolant system flows previously stated in 1bm/hr have been changed to gpm.
Explain the need for this change and verify that the new
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flows were calculated using the reactor coolant density corresponding to the identified power levels, b.
Explain why the title of Figure 2.3-2 was changed from that specified by the reactor vendor or restore it to its original wording.
If the intent of this change in wording is to allow maximum trip setpoints above Curves 1, 2 and 3 for the indicated pump configurations, provide analyses to justify such higher setpoints.
l
t 10.
Figure 2.1 Identify the specific credits taken in perce-
'o allow the reactor power imbalance tent to change as indicat '
For example, what credits were taken to allow a 10% increase in puwer at +50% and -50% axial imbalance.
- 11. Quadrant '
_r Tilt - Justify the use of the values of 4.92%, 11.07%
and 20% ior quadrant tilt on this reload.
These values have been used in the Standard T/S as typical.
- 12. Verify that the consequences of all the accidents and transients analyzed in the SAR are acceptable considering:
(a) 4.92% tilt as an initial condition; and (b) 20% tilt at 60% rated power as an initial condition.
- 13. Justify the changes to the core imbalance vs power level trip tents (Figures 8-11, 8-12 and 8-13 of BAW-1499) and explain why the per-missible operating region falls outside the maximum setpoint values for reactor power imbalance shown in Figure 8-2.
- 14. Your description of the ejected control rod reactivity worth test in BAW-1499 does not state that four symmetric control rods will be measured. As stated in BAW-1477 "0conee 1 Cycle 4 Quadrant Flux Tilt", page 12, this test "has proven to be an indicator of core symne try".
Please indicate if the measurement of ejected rod worth at four symmetric location (s part of your test program for the Cycle 3 core.
15.
In Section 9.4 you describe actions to be taken if the Acceptance Criteria are not met. This description is too general for the measurement of rod worth. The usual action to be taken if the sum of the worth of groups 5, 6 and 7 differs from predicted by more than +10%, is to measure group 4 by dilution and take additional measurerents and make an evaluation of the discrepancies.
Indicate your comnitment to these corrective actions if the acceptance criteria for measurement of control bank reactivity worth are not met.
i 16.
Indicate your commitment to submit a physics startup test report within 45 days of completion of the tests.
- 17. With regard to your request to modify T/S 3.3.3, the statement that the proposed provision is like the Standard Technical Speci-fications (STS) is not sufficient justification for the change.
The reason this is insufficient is because the STS are based on a number of interrelated provisions. Thus the adoption of a single provision without including all of the related provisions may not
f be technically justified. Accordingly, if you desire to make this change, you should revise your submittal as necessary to incorporate all STS operability and surveillance requirements for engineered safety features in the Rancho Seco T/S, or propose a lesser revision supported by a detailed evaluation which demonstrates the safety of the new provisions relative to the safety of the present provisions.
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