ML20129F262
| ML20129F262 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 10/23/1996 |
| From: | Matthew Mitchell NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20129F244 | List: |
| References | |
| NUDOCS 9610290080 | |
| Download: ML20129F262 (3) | |
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UNITED STATES j
NUCLEAR REGULATORY COMMISSION c,
f WASHINGTON, D.C. 20%H001
,I' SAFETY EVALUATION R_Y THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO 109 TO FACILITY OPERATING LICENSE NO. NPF-62 ILLIN0IS POWER COMPANY ET AL.
CLINTON POWER STATION. UNIT NO. 1 DOCKET N0. 50-461
1.0 INTRODUCTION
By letter dated February 22, 1996, Illinois Power (IP, the licensee) requested review and approval of its application for amendment of the Clinton Power Station (CPS) Operating License (License No. NPF-62) to incorporate a proposed change to the CPS Technical Specifications (TS) Appendix A.
IP proposed to revise TS 3.4.11, " Reactor Coolant System (RCS) Pressure and Temperature (P/T)
Limits," to incorporate a P/T Limits curve for the bottom head region of the reactor vessel, separate and apart from the core beltline region of the reactor vessel. The new P/T Limits curve will be used during hydrostatic pressure tests and leak rate (HP/LR) testing. The application was supplemented isy letters dated July 22 and September 20, 1996, in response to Requests for Additional Information from the staff.
These subsequent submittals provided clarifying information and did not alter the staff's initial finding that the proposed changes involve no significant hazards consideration.
The staff has reviewed the information provided by the licensee in the documents listed above.
The staff has determined that the licensee used methodologies consistent with or conservative to the requirements of Title 10 of the Code of Federal Reculations Part 50 (10 CFR 50), Appendix G; Appendix G to Section XI of the American Society of Mechanical Engineers (ASME) Code; and Standard Review Plan (SRP, NUREG-0800) Section 5.3.2.
The staff also determined that the methodology proposed by the licensee for monitoring the vessel lower head, beltline, and flange temperatures was acceptable.
2.0 EVALUATION The requirements and guidelines which have been established or endorsed by the NRC concerning pressure vs. temperature limitations on reactor vessel environment provide adequate margins of safety against brittle fracture of the reactor vessel during all modes of operation. As addressed in 10 CFR 50, Appendix G, two regions of the reactor vessel are identified relating to the establishment of these limitations (i.e., the closure flange region and the vessel beltline region).
Each of these regions is currently controlling in different pressure / temperature regimes for the CPS HP/LR testing curve.
9610290080 961023 PDR ADOCK 05000461 P
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The licensee has proposed consideration of a third region of the vessel, the lower head, separately from the two mentioned in 10 CFR 50, Appendix G.
The f
licensee has asserted that this separation is valid due to the therwohydraulic conditions of the water in the vessel during HP/LR testing. The water in the vessel lower head is separated from the water in contact with the vessel beltline and flange regions by the reactor baffle plate. The water in the regions above the baffle plate is heated by decay heat from the reactor core, t
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while the water in the lower head is cooled due to the injection of control i
rod drive water for vessel pressurization. With little or no circulation through the recirculation pump loops, these regions are therefore maintained at different temperatures during the HP/LR testing procedure.
i The licensee has proposed to implement an additional HP/LR testing curve in the CPS TS based upon the nil-ductility transition reference temperature (RT The lic
) for the limiting material of the reactor vessel lower head.
l ensee submitted the proposed lower head HP/LR testing curve in their submittal on February 22, 1996. Additional information on the material j
properties of the lower vessel head materials, the methodology of the licensee's lower head stress analysis, and information to support the i
licensee's ability to accurately monitor the lower head and vessel beltline temperatures was submitted in the letters dated July 22 and September 20, l
1996.
i In addition, the licensee has proposed to modify the Bases for TS 3.4.11 to implement a method for monitoring the vessel lower head, beltline and flange j
temperatures during HP/LR testing. The licensee has proposed to assess the temperature of the vessel lower head by using the lower of the two temperature values given by the external bottom head thermocouple and the bottom head drain temperature. The vessel head flange, vessel shell flange, and the reactor recirculation loop temperature will be used to ensure compliance with the P/T curve applicable to the beltline and flange regions.
i The regulatory guidelines concerning the development of P/T Limits are contained in Appendix G to 10 CFR 50 and provide the general basis for these i
limits.
The requirements of 10 CFR 50, Appendix G specifically state that the P/T Limits for a vessel must be at least as conservative as limits obtained by j
following the methods of analysis and the margins of safety of Appendix G to i
Section XI of the ASME Code. The staff has also established guidance for the development of P/T limits in SRP Section 5.3.2.
The staff has assessed the information provided by the licensee to support the i
i proposed vessel lower head P/T limits curve for HP/LR testing.
Independent i
calculations were performed in a manner consistent with SRP Section 5.3.2 and Appendix G to Section XI of the ASME Code. The staff determined that 1) the licensee's calculated value for the applied stress intensity factor was conservative; 2) the licensee's calculated reference stress intensity factor (K,) for the limiting lower head material (plate heat number C4027-1) was i
consistent with Appendix G of the ASME Code; and 3) the licensee's P/T limits i
curve for the vessel lower head during HP/LR testing was at least as conservative as that which would be generated using the methodologies of SRP
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Section 5.3.2 and Appendix G of the ASME Code.
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l In conclusion, the staff has reviewed the information provided by the licensee and i. s determined that the licensee used methodologies consistent with or conservctive to 10 CFR 50, Appendix G; Appendix G to Section XI of the ASME Code; and OP.P Section 5.3.2.
The staff also determined that the methodology proposed by the licensee for inclusion in the Bases for TS 3.4.11 concerning monitoring the vessel lower head, beltline, and flange temperatures was acceptable. Therefore, the staff finds the licensee's proposed changes acceptable.
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3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Illinois state official was notified of the proposed issuance of the amendment.
The state official i
had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
This amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 or changes a surveillance requirement.
The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration and there has been no public comment on such finding (61 FR 18169). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 4
51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
5.0 CONCLUSION
The staff has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendrent will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: Matthew Mitchell Date:
October 23, 1996
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