ML20237G766
| ML20237G766 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 08/21/1987 |
| From: | NRC OFFICE OF SPECIAL PROJECTS |
| To: | |
| Shared Package | |
| ML20237G751 | List: |
| References | |
| TAC-64314, TAC-64315, TAC-64316, NUDOCS 8709020401 | |
| Download: ML20237G766 (3) | |
Text
- pn nao UNITED STATES E"
i NUCLEAR REGULATORY COMMISSION 7,,
'Lj WASHINGTON,0. C. 20555
\\...../
SAFETY EVALUATION BY THE OFFICE OF SPECIAL PROJECTS SUPPORTING AMENDMENT NO.136 TO FACILITY OPERATING LICENSE NO. DPR-33 AMENDMENT N0.132 TO FACILITY OPERATING LICENSE N0. DPR-52 AMENDMENT NO.107 TO FACILITY OPERATING LICENSE NO. DPR-68 TENNESSEE VALLEY AUTHORITY Bk0hNS FERRY NUCLEAR PLANT, UNITS 1, 2 AND 3 00CKETS NOS. 50-259, 50-260 AND 50-296
1.0 INTRODUCTION
By letter o'ated December 23, 1986 Tennessee Valley Authority, the licensee for Browns Ferry Nuclear (BFN) Plant, Units 1, 2 and 3, proposed changes to plant Technical Specification Surveillance Rewirement (SR) 4.4.A.2.b and provided justification for the same.
The SR deals with testing requirements for ensuring the operability of the Standby Liquid'Contral System (SLCS) for the BFN units.
Specifically, the proposed SR changes the requirement that at least once per each operating cycle, the system be verifico coerable by (1) visually verifying the flow by pumping boron solution through the recirculation path and back to the SLCS solution tank and (2) verifying a minimum pump flow rate of 39 gpm aga.nst the system head of 1275 psig by pumping demineralized water through the SLCS test tank.
The above changes have been proposed in lieu of the existing SR which do not spell out (1) visual verification of the flow during recirculation of the boron solution and (2) the test method for veritying the minimum pump i
flow rate. The staff's evaluation cf the proposed SR changes is given below.
I 2.0 EVALUATION The SLCS is intended to provide the capability for bringing the reactor from full power to a cold, xenon-free shutdown condition, assuming that none of the l
withdrawn control rods can be inserted.
The system accomplishes this purpose by l
injecting sufficient quantity of borated water of proper concentration into the j
reactor vessel in less than 125 minutes. The system consists of a boron solution tank, a test tank containing demineralized water, two positive-displacement pumps, two explosive-actuated valves, other associated valves and controls. The operability of the system is ensured by a number of periodic surveillance tests listed in the plant Technical Specifications for the three BFN units. The licensee has proposed changes to two of these tests which have been identified above (See Section 1.0).
In the description of the first change, the licensee stated that when the boron solution is pumped from solution tank via a recir-culation path back to the solution tank the flow can be visually verified by observing the turbulence throuet a sample opening in the. top of the solution tank. Regarding the second change, i.e., method of verifying minimum pump flow rate, the test requires aligning the pump with the demineralized water test tank such that demineralized water may be recirculated into and from O
1 B70821 P
K 050002 9 P
1
the tank.
For a brief period (a couple of minuter) the discharge from the pump is routed to a floor drain, and the change in water level in the test tank is measured. The valves are then returned to the recirculation flow mode, and the pump is kept running for the remainder of the test period.
In the justification, the licensee stated that the purpose of the pump f!ow rate test is to monitor the pump performance and that it could be achieved by cither pumping the borated water using the solution tank as the source of water or by nmping demineralized water using the test tank as the source of water. The licensee stated that the proposed utilization of the demineralized water and the test tank as the water source for performing the pump flow rate test is the same as what is being currently followed at the BFN units. The licensee added that the above clarification of the flow rate test contained in the proposed SR change conforms with the current practice and is further required since the SR as currently worded implies that the pump flow rate is determined during boron solution recirculation back to the SLCS solution tank. The licensee further stated that the proposed flow rate determination test method is consistent with Standard Technical Specifications and ASME Section XI. During its discussions with the staff, the licensee further stated that the test procedures require verification of at least 48 gpm punp flow rate for the S. R. 4.4.A.1 operability test.
Based on the above, the staff finds the proposed technical specifications changes are acceptable. The bases for staff's acceptance are listed below:
(1) The operational testing of the system specified in the proposed SR char.ges, along with the other tests specified under SR for the system in the existing plant Technical Specifications, will demonstrate the availability of a flow path from the SLC system solution tank to the reactor vessel. These changes will further limit the utilization of borated water for testing
)
purposes and consequently reduce the potential for blocking the piping between 1
the solution tank and the reactor vessel.
l 1
(2) The proposed visual verification of the flow path when the boron solutien is pumped from the solution tank through a recirculation path back I
to the tank will demonstrate that sufficient Net Positive Suction Head (NPSH)
)
is available at the solution tank.
J (3) The proposed utilization of the test tank and demineralized water for testing purposes is consistent with NRC's General Electric Standard Technical l
Specifications (NUREG-0123) for the SLC system.
l l
(4) The proposed SR changes along with the other SR in the existing plant l
Technical Specifications, the test procedures which require verifying that at least a minimum of 48 gpm pump flow rate is available, and the use of a positive displacement pump, provide reasonable assurance that the pump can inject borated water from the SLC system solution trJ F at a flow rate of at least 39 gpm against e system head of 127E psig, whr.n required.
l
I -
i (5l The technical specifications include the SR to flush the system with demineralized water after borated water recirculation test. Additionally, as indicated in the BFN Final Sefety Analysis Report (FSAR), an electric immersion coil is provided for the solution tank, and heating coils are wrapped around l
the pipe lines from the tank to the pump suctions.
These measures maintain the solution temperature in the range 80 F-85 F.
The above assure that the piping between the solution tank and the vessel will remain unblocked.
(6) As indicated in the FSAR, after the functional tests, the valves to and from the solution tank and the valves to and from the test tank will be returned to their normal positions. This will ensure that there is no misalignment of the valves after the tests are completed.
Based on the above, the staff has determined that the proposed SR changes in conjunction with other surveillance tests identified in the existing plent Technical Specifications for the BFN units, ensure the operability of the SLC system and thus satisfy the applicable requirements of General Design ~ Cri-terion 27, " Combined Reactivity' Control System Capability" of 10 CFR Part 50, Appendix A.
3.0 ENVIRONMENTAL CONSIDERATION
S The amendments involve a change to a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes to the surveillance requirements. The staff has determined that the amendments involve 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 these amendments involve no significant hazards consideration and there has been no public comment on such finding. Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environmental impact statement nor environmental assessment need be prepared in connection i
with the issuance of these amendments.
4.0 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, and (2) such activities will be conducted in compliance with the~ Commission's regulations, and the issuance of the amendments will not be inimical to the common defense and security nor to the heal'h and safety of the public.
c Principal ~ Contributor: Thyagaraja Chandrasekaran/ Rex Wescott Dated: August 21, 1987
- - _ _