ML20236A676
| ML20236A676 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 03/09/1989 |
| From: | NRC |
| To: | |
| Shared Package | |
| ML20236A670 | List: |
| References | |
| NUDOCS 8903200109 | |
| Download: ML20236A676 (2) | |
Text
~ p Qw..
'[*
- UNITED STATES 4
-- g,
' NUCLEAR REGULATORY. COMMISSION i
9, 3
j WASHINGTON, D. C. 20655 1
]
]:
y SAFETY' EVALUATION BY THE OFFICE OF' NUCLEAR REACTOR' REGULATION SUPPORTING AMENDMENT N0.105L TO FACILITY OPERATING LICENSE N0; DPR-77?
4
~ AND AMENDMENT NO.194 TO FACILITY OPERATING LICENSE NO. DPR-79 TENNESSEE VALLEY AUTHORITY iSEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328
1.0 INTRODUCTION
By letter of December 6 -1988, the Tennessee Valley Authority (the ' licensee)
, proposed to modify)the Sequoyah Nuclear Plant, Units l'and 2 TechnicalSpecific (SR)-4.4.3.2.3 for the pressurizer power-operated relief valves (PORV) and associated block valves.
The pressurizer PORVs have been changed from air-operated to solenoid-operated-valves' The PORVs are now' permanently aligned to the 125-volt (V) direct current (dc). Vital battery boards, which are the emergency power supply. The block valves are motor-operated valves (MOVs) powered.from the 480-V reactor MOV boards, which are powered by the shutdown boards. The emergency power transfer is performed at the feed to the.6.9-kilovolt (kV) shutdown boards 1
by transfer from offsite power to the diesel generators.
Emergency power l
supply operability to the shutdown boards is accomplished by SR 4.8.1.1.2.
The licensee, therefore,-proposed that since the PORVs are powered by the 125-V dc vital battery boards and since surveillance of the emergency power supply transfer to the shutdown boards is accomplished by SR 4.8.1.1.2, then SR 4.4.3.2.3 may be deleted.
Its elimination removes an unnecessary burden to
.the operators and avoids potential confusion about the intent of the requirement.
2.0 EVALUATION The SRs to demonstrate the operability of the two PORVs and their associated block' valves are numbered SR 4.4.3.2.1, 4.4.3.2.2, 4.4.3.2.3 and 4.4.3.2.4.
The first SR, in addition to the requirements of Specification 4.0.5, requires that each PORV be demonstrated OPERABLE at least once every 18 months by:
(a) performance of a CHANNEL CALIBRATION, and (b) by operating the valve through one complete cycle of full travel.
The second SR requires that each block valve be demonstrated OPERABLE at least once per 92 days by operating the valve through one complete cycle of full travel.
8903200109 890309 PDR ADOCK 05000327 P
PNu
W.
)
l y
The third SR, which is proposed for deletion, is for the emergency power supply j
for the PORVs and block valves to be demonstrated OPERABLE at least once per 18 months by the following:.(a) transferring motive and control power from the l
nonnal to the emergency power supply and (b) operating the valves through' a-l complete cycle'of full' travel.
o The fourth SR is for inspection of repair welds and adjoining piping which l
is not relevant to.the proposed SR except for renumbering it if the third SR is l
deleted.
J 1
It is the staff's interpretation that' valve OPERABILITY'is demonstrated by 1
conformance with surveillance requirements one and two above.
The third I
requirement applies to the demonstration of the transfer of the motive and control power supply followed by a repeat of the' valve operability demonstration on emergency power.
As the PORVs are now permanently aligned to the vital bus', there is no power j
realignment to test.
In a somewhat similar manner, the MOV boards receive a continuous power supply' from the 480-V' shutdown boards regardless of whether power is from the normal supply or the emergency supply. -Existing diesel generator =(DG) requirements-in SR 4.8.1.1.2 ensure the capability of the DGs to automatically start and energize the shutdown boards.
Therefore, the staff agrees with the licensee that sufficient surveillance requirements are provided to assure operability of the pressurizer PORVs and l
associated block valves and to confirm availability of power to the valves without SR 4.4.3.2.3.
The requirement in SR 4.4.3.2.3 to operate the valves through a complete cycle of full travel every 18 months remains in
'SR 4.4.3.2.1 and 4.3.2.2 for the PORVs and associated block valves, i
respectively.
The staff concludes that the licensee's proposed action is acceptable and SR 4.4.3.2.3 may be deleted as proposed.
The change will not diminish safety l
or increase the probability of an accident in any area of the plant, j
3.0 ENVIRONMENTAL CONSIDERATION
These amendments involve changes to the surveillance requirements.
The staff j
' has determined that the amendments involve no significant increase in the j
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.
l 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 I
environmental impact statement nor environmental assessment need be prepared in connection with the issuance of these amendments.