ML14183A661
| ML14183A661 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 05/16/1995 |
| From: | Mozafari B Office of Nuclear Reactor Regulation |
| To: | Hinnant C Carolina Power & Light Co |
| References | |
| TAC-M91970 NUDOCS 9505220243 | |
| Download: ML14183A661 (3) | |
Text
0 May 16, 1995 Mr. C. S. Hinnant, Vice President Carolina Power & Light Company H. B. Robinson Steam Electric Plant, Unit No. 2 3581 West Entrance Road Hartsville, South Carolina 29550
SUBJECT:
CHANGE TO TECHNICAL SPECIFICATION BASIS SECTION 3.1.2 REGARDING PNEUMATIC SYSTEM FOR POWER OPERATED RELIEF VALVES (TAC NO. M91970)
Dear Mr. Hinnant:
By letter dated March 28, 1995, Carolina Power & Light Company (CP&L) proposed a change to the H. B. Robinson Steam Electric Plant, Unit No. 2 (HBR),
Technical Specifications (TS) Bases section 3.1.2. On May 11, 1995, CP&L submitted an update to the basis page reflecting a recent amendment. For consistency with a plant modification, the basis would be revised to indicate that the power operated relief valve (PORV) pneumatic system is now normally supplied from the nitrogen supply system, rather than from instrument air.
Further, the proposed basis change reflects that, as the result of the modification, the nitrogen accumulators have been maintained as a backup supply and the station instrument air provides a secondary backup.
The NRC staff has reviewed the proposed basis change regarding the power supply to the PORVs and has no objection to your proposed change.
Enclosed is a copy of the revised Bases page.
Sincerely, (Original Signed By)
Brenda Mozafari, Project Manager Project Directorate II-1 Division of Reactor Projects -
I/II Office of Nuclear Reactor Regulation Docket No. 50-261 Distribution Docket File DVerrelli, RII
Enclosure:
Basis page 3.1-6a PUBLIC PD2-1 RF cc w/enclosure: See next page SVarga JZwolinski OGC FILENAME -
H:\\DRPE\\PD2-1\\ROBINSON\\ROB91970.LTR ACRS (4)
OFFICE LA:PDII-1 PMfJJ-D:PDII-1 NAME Dunning n0
-M ozafari DMatthew DATE Of/A/95 9 547/95 COPY Yes No Yes/No Yes/No_
OFFICIAL RECORD COPY 9505220243 950518 PDR ADOCK 05000281CO P-~b
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Mr. C. S. Hinnant H. B. Robinson Steam Electric Carolina Power & Light Company Plant, Unit No. 2 cc:
Mr. R. E. Jones Mr. Dayne H. Brown, Director General Counsel - Legal Department Department of Environmental, Carolina Power & Light Company Health and Natural Resources Post Office Box 1551 Division of Radiation Protection Raleigh, North Carolina 27602 Post Office Box 27687 Raleigh, North Carolina 27611-7687 Karen E. Long Assistant Attorney General Mr. Robert P. Gruber State of North Carolina Executive Director Post Office Box 629 Public Staff - NCUC Raleigh, North Carolina 27602 Post Office Box 29520 Raleigh, North Carolina 27626-0520 U.S. Nuclear Regulatory Commission Resident Inspector's Office Mr. Max Batavia, Chief H. B. Robinson Steam Electric Plant South Carolina Department of Health 2112 Old Camden Road Bureau of Radiological Health Hartsville, South Carolina 29550 and Environmental Control 2600 Bull Street Regional Administrator, Region II Columbia, South Carolina 29201 U.S. Nuclear Regulatory Commission 101 Marietta St., N.W., Ste. 2900 Mr. H. W. Habermeyer, Jr.
Atlanta, Georgia 30323 Vice President Nuclear Services Department Mr. Dale E. Young Carolina Power & Light Company Plant General Manager Post Office Box 1551 Carolina Power & Light Company Raleigh, North Carolina 27602 H. B. Robinson Steam Electric Plant 3581 West Entrance Road Hartsville, South Carolina 29550 Public Service Commission State of South Carolina Post Office Drawer 11649 Columbia, South Carolina 29211 Mr. R. M. Krich Manager -
Regulatory Affairs Carolina Power & Light Company H. B. Robinson Steam Electric Plant, Unit No. 2 3581 West Entrance Road Hartsville, South Carolina 29550
point-by-point compar A of the steady state and fini heatup rate data. At any given temperature, the allowable pressure is taken to be the lesser of the I two values taken from the curves under consideration. The composite curve is then adjusted to allow for possible errors in the pressure and temperature sensing instruments.
The use of the composite curve is mandatory in setting heatup limitations because it is possible for conditions to exist such that over the course of the heatup ramp the controlling analysis switches from the O.D. to the I.D.
location; and the pressure limit must, at all times, be based on the most conservative case. The cooldown analysis proceeds in the same fashion as that for heatup, with the exception that the controlling location is always at the I.D. position. The thermal gradients induced during cooldown tend to produce tensile stresses at the I.D. location and compressive stresses at the O.D.
position. Thus, the I.D. flaw is clearly the worst case.
As in the case of heatup, allowable pressure temperature relations are generated for both steady state and finite cooldown rate situations.
Composite limit curves are then constructed for each cooldown rate of interest. Again adjustments are made to account for pressure and temperature instrumentation error.
The overpressure protection system consists of two operable pressurizer Power Operated Relief Valves (PORVs) connected to the nitrogen supply system, backup nitrogen accumulators, the station instrument air system, and the associated electronics.
The TS requirements for low-temperature overpressure protection (LTOP) apply when T is less than 350OF and the RCS is not vented to the containment.
During these conditions, one train (or channel) of the LTOP system is capable of mitigating an LTOP event that is bounded by the largest mass addition to the RCS or by the largest increase in RCS temperature that can occur. The largest mass addition to the RCS is limited based upon the assumption that no more than a fixed number of pumps are capable of providing makeup or injection into the RCS. Hence, this is a matter important to safety that pumps in excess of this design basis assumption for LTOP not be capable of providing makeup or injection to the 3.1-6a Amendment No. 91, 162 1
REVISED BY NRC LETTER DATED May 16, 1995