ML20249B047
| ML20249B047 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 06/17/1998 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20249B046 | List: |
| References | |
| NUDOCS 9806220013 | |
| Download: ML20249B047 (5) | |
Text
i
- '*:o l
p UNITED STATEG g
j NUCLEAR REGULATORY COTAMISSION g
WASHINGTON, D.C. 30086-0001 i
\\
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION
{
RELATED TO AMENDMENT NO. 166 TO FACILITY OPERATING LICENSE NPF-35 I
AND AMENDMENT NO.
158 TO FACILITY OPERATING LICENSE NPF-52 DUKE ENERGY CORPORATION. ET AL.
CATAWBA NUCLEAR STATION. UNITS 1 AND 2 j
DOCKET NOS. 50-413 AND 50-414
1.0 INTRODUCTION
{
l On May 14,1998, Duke Energy Corporation (the licensee) determined that Surveillance Requirement (SR) 4.4.3.3 of the Technical Specifications (TS) was not being met because the present design of transferring pressurizer heater power supply from the normal to the emergency power supply at Catawba is automatic rather than manual. SR 4.4.3.3, as currently I
written, does not reflect the plant design.
By letter dated May 22,1998, the licensee requested that the NRC exercise discretion not to enforce compliance with the actions required by SR 4.4.3.3 related to the performance, every 18 months, of a test to demonstrate that the pressurizer heaters can be manually transferred from the normal to the emergency power supply. The May 22 letter documented information j
previously discussed with the staff in a telephone conversation on May 22,1998. As a result of
{
its review, the staff verbally granted enforcement discretion on May 22,1998, and documented
{
the verbal authorization by a Notice of Enforcement Discretion (NOED) letter dated May 26, 1998. The NOED will expire upon issuance of these amendments to revise SR 4.4.3.3.
By a separate letter also dated May 22,1998, the licensee submitted a request for amendments, on an exigent basis, to revise SR 4.4.3.3 of the Catawba Nuclear Station, Units 1 l
and 2, TS for pressurizer heaters to change the existing design requirement to be consistent I
with the plant design. The staff's evaluation of that request follows.
l l
2.0 DISCUSSION AND EVALUATION Currently SR 4.4.3.3 states:
"The emergency power supply for the pressurizer heaters shall be demonstrated OPERABLE at least once per 18 months by manually transferring power from the normal to the emergency power supply and energizing the heaters."
The proposed SR 4.4.3.3 would read as follows:
l "At least once per 18 months, verify required pressurizer heaters are capable of being powered from an emergency power supply."
9006220013 980617 PDR ADOCK 05000413 P
peg
.. For each Catawba unit, two groups of pressurizer heaters (designated 1 A,1B,2A, and 2B for Units 1 and 2, Trains A and B, respectively) are supplied from the 600 V Blackout Auxiliary
)
Power System, one heater group per power train. Power is available to each heater group from
]
the offsite power system or from the onsite emergency power system. For each unit, heater
)
. group A and B is fed from 600 V blackout load centers LXI and LXH, respectively. LXI and LXH j
are fed from 4160 V blackout switchgear FTA and FTB, respectively. During normal operations (i.e., with offsite power available), the 4160 V switchgear is fed from the offsite power source.
During a loss of offsite power, the 4160 V switchgear bus is automatically transferred via load j
sequencer logic to the emergency diesel generators.
]
1 SR 4.4.3.3 requires that the emergency power supply for the pressurizer heaters shall be l
demonstrated OPERABLE at least once per 18 months by manually transferring power from the q
normal to the emergency power supply and energizing the heaters. The present design of transferring pressurizer heater power supply from the normal to the emergency power supply
- at Catawba is automatic rather than manual because, during a loss of offsite power, the 4160 V switchgear bus is automatically transferred via load sequencer logic to the emergency diesel generators. The method used by the licensee to satisfy this SR involves overlapping procedures PT/1(2) /A/4200/09, " Engineered Safety Features Actuation Periodic Test," and PT/1(2)/A/4600/M, " Surveillance Requirements for Unit Startup." PT/1(2)/4200/09 is performed every refueling outage. This test simulates a loss of offsite power and causes the 4160 V blackout switchgear bus to be automatically loaded onto the 4160 V essential switchgear bus via load sequencer logic. Once this occurs, the 600 V blackout load center busses are verified to be energized. During this test, the pressurizer heaters' breaker control logic is verified to be energized without actually energizing the pressurizer heaters. The heaters are not actually energized bacause this test is performed during a plant mode when there is insufficient water in the reactor coolant system and in the pressurizer to allow the heaters to be energized without damage. However, the heaters are verified to be energized during unit startup per PT/1(2)/4600/16 prior to entry into Mode 3 following a refueling outage. The heaters are also verified to be energized in accordance with SR 4.4.3.2 that requires that the capacity of each of the required groups of pressurizer heaters shall be verified by energizing the heaters and measuring circuit current at least once per 92 days. The licensee has, thus proposed to modify SR 4.4.3.3 for the pressurizer heaters to change the existing requirement to be consistent with the plant design.
- Based on the preceding discussion, the staff concludes that the proposed change to SR 4.4.3.3 is acceptable because the underlying purpose of the requirement is to verify that the pressurizer heaters have the capability of being powered from the emergency bus irrespective of the method (manual or automatic) of powering the pressurizer heaters from the emergency bus. In
_ addition, the proposed change is consistent with the improved Standard Technical Specifications (NUREG-1431). Therefore, the staff finds the proposed change to SR 4.4.3.3 acceptable..
- 3.0 STATEMENT OF EXIGENT CIRCUMSTANCES L
The Commission's regulation, as stated in 10 CFR 50.91, provides special exceptions for the issuance of amendments when the usual 30-day public notice cannot be met. One type of
'special exception is an exigency An exigency exists when the staff and the licensee need to 4
L....-....
.. act quickly and time does not permit the staff to publish a Eederal Register notice allowing 30 days for prior public comment, and the staff also determines that the amendments involve no significant hazards consideration.
In accordance with 10 CFR 50.91(a)(6)(i)(A), the staff issued a Federal Register notice on June 1,1998 (63 FR 29759), providing notice of an opportunity for hearing and proposing that the requested amendments involve no significant hazards consideration. The public was allowed 14 days after the date of publication of that notice to provide comments. No comments were received.
On May 14,1998, as the result of a surveillance procedure working group's efforts, the licensee concluded that compliance with SR 4.4.3.3 was not being met because the present design of the Catawba power system will not allow the pressurizer heaters to be manually transferred from the normal to the emergency source without physically manipulating individual supply breakers to allow a dead-bus transfer. Between May 14 and May 22, the licensee studied the situation and finally concluded, on May 22, that SR 4.4.3.3 cannot be literally met. Thus, the licensee provided a timely request for issuance of amendments after the problem was recognized and analyzed.
On the basis of the above discussion, the staff has determined that exigent circumstances
' exist, that the licensee used its best efforts to make a timely application, and did not cause the exigent situation.
4.0 FINAL NO SIGNIFICANT HAZARDS CONSIDERATION
DETERMINATION The Commission's regulations in 10 CFR 50.92 state that the Commission may make a final determination that a license amendment involves no significant hazards considerations, if operation of the facility, in accordance with the amendment would not (1) involve a significant increase in the probability or consequences of an accident previously evaluated; (2) create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) involve a significant reduction in a margin of safety.
In its analysis of the issue of no significant hazards consideration, as required by 10 CFR 50.91(a), the licensee has provided the following:
First Standard implementation of this amendment would not involve a significant increase in the probability or consequences of an accident previously evaluated. Changing the requirements of SR [ surveillance requirement] 4.4.3.3 as previously described '
will not have any impact on accident probabilities. It merely makes the TS
[ Technical Specification) requirement consistent with the design of the pressurizer heaters and the normal and emergency power supply arrangement.
In addition, no impact on accident consequences will occur, since the design function of the pressurizer heaters will be maintained and the heaters will be L
tested according to the manner in which they were designed.
.+
a -. ~.
4 Second Standard implementation of this amendment would not create the possibility of a now or j
different kind of accident from any accident previously evaluated. Changing the l
requirements of SR 4.4.3.3 will make the SR consistent with the actua! design of
- the equipment it governs.. No design changes are being made to the plant and no changes are being made to the manner in which the plant is operated or tested.
Therefore, no new accident causal mechanisms are created.
Third Standard Implementation of this amendment would not involve a significant reduction in a i
margin of safety. Margin of safety is related to the confidence in the ability of the l
fission product barriers to perform their design functions during and following an I
accident situation. These barriers include the fuel cladding, the reactor coolant system, and the ccatainment system. The performance of the fission product -
I barriers will not be impacted by implementation of this proposed amendment.
The design function of the affected pressurizer heaters and power supplies will not be affected. Therefore, no safety margin will be adversely impacted.
The NRC staff has evaluated the amendments against the three standards of 10 CFR 50.92(c),
and on the basis of the licensee's analysis, the NRC staff concludes that the amendments meet the three criteria of 10 CFR 50.92(c). Therefore, the staff has made a final determination that the proposed amendments do not involve a significant hazards consideration.
5.0 STATE CONSULTATION
in accordance with the Commission's regulations, the South Carolina State official, Mr. Virgil Autrey, was notified of the proposed issuance of the amendments. The State official had no comments.
l
6.0 ENVIRONMENTAL CONSIDERATION
l-
.The amendments change surveillance requirements. The NRC 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 made a final finding that the amendments involve no significant hazards consideration. 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 or I
. environmental assessment need be prepared in connection with the issuance of the amendments,
~
7.0 CONCLUSION
r 1The Commission has concluded, based on the considerations discussed above, that: (1) there
' is reasonable assurance _that the health and safety of the public will nnt be endangered by
- =... u -.- =w:. --- - --- - - -- -,- =: ===:;:--------------------------->
1 I operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: Om Chopra Date:
June 17,1998 i
)
J I
l i
i l
)
4 D..
p:
- _ _.... _ _ ______._____.____ _.__________ ____ _ _ _