ML18032A231
| ML18032A231 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 05/15/1987 |
| From: | TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML18032A230 | List: |
| References | |
| TAC-00176, TAC-00177, TAC-00178, TAC-176, TAC-177, TAC-178, TAC-R00176, TAC-R00177, TAC-R00178, TAC-R176, TAC-R177, TAC-R178, NUDOCS 8705270362 | |
| Download: ML18032A231 (9) | |
Text
ENCLOSURE 1
PROPOSED TECHNICAL SPECIFICATIONS REVISIONS BROWNS FERRY NUCLEAR PLANT UNITS 1, 2, AND 3 (TVA BFN TS 229) 8705270362 870515 PDR ADOGK 05000259 P
P DR/
3.7/4.7 CONTAINMENT SYSTEMS
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LIMITING CONDITIONS FOR OPERATION 3.7.D. Primar Containment Isolation Valves SURVEILLANCE REQUIREMENTS 4.7.D.
Primar Containment Isolation Valves 4.7.D.l.b (Cont'd)
(2)
With the reactor-power less than 757, trip main steam isolation valves individually and verify closure time.
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(Deleted)
- d. At least once per operating cycle, the operability of the reactor coolant system
~ instrument line flow check valves shall be verified.
- 2. In the event any isolation valve specified in Table 3.7.A becomes INOPERABLE, reactor power operation may continue provided at least one valve in each line having an INOPERABLE valve is in the mode corresponding to the isolated condition.
- 2. Whenever an isolation valve listed in Table 3.7.A is INOPERABLE, the position of at least one other valve in each line having an INOPERABLE valve shall be recorded daily.
- 3. If Specification 3.7.D.1 and 3.7.D.2 cannot be met, an orderly shutdown shall be initiated and the reactor shall be in the Cold Shutdown condition within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
BFN Unit 1 3.7/4.7-18
I,
3.7/4.7 CONTAINMENT SYSTEMS LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS 3.7.D. Primar Containment Isolation Valves 4.7.D.
Primar Valves II Containment Isolation 4.7.D.l.b (Cont'd)
(2)
With the reactor power less than 757., trip main steam isolation valves individually and verify closure time.
c ~
(Deleted)
- d. At least once per operating cycle, the operability of the reactor coolant system instrument line flow check valves shall be verified.
- 2. In the event any isolation valve specified in Table 3.7.A becomes INOPERABLE, reactor power operation may continue provided at least one valve in each line having an INOPERABLE valve is in the mode corresponding to the isolated condition.
- 2. Whenever an isolation valve listed in Table 3.7.A is INOPERABLE, the position of at least one other valve in each line having an INOPERABLE valve shall be recorded daily.
- 3. If Specification 3.7.D.1 and 3.7.D.2 cannot be met, an orderly shutdown shall be initiated and the reactor shall be in the Cold Shutdown condition within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
BFN Unit 2 3.7/4.7-18
- 3. 7/4. 7 CONTAINMENT SYSTEMS LIMITING CONDITIONS FOR OPERATION 3.7.D. Primar Containment Isolation Valves SURVEILLANCE REQUIREMENTS 4.7.D.
Primar Containment Isolation Valves 4.7.D.l.b (Cont'd)
(2)
With the reactor power less than 757.,
trip main steam isolation valves individually and verify closure time.
c ~
(Deleted).
- d. At least once per operating cycle, the operability of the reactor coolant system instrument line flow check valves shall be verified.
- 2. In the event any isolation valve specified in Table 3.7.A becomes INOPERABLE, reactor power operation may continue provided at least one valve in each line having an INOPERABLE valve is in the mode corresponding to the isolated condition.
- 2. Whenever an isolation valve listed in Table 3.7.A is INOPERABLE, the position of at least one other valve in each line having an INOPERABLE valve shall be recorded daily.
- 3. If Specification 3.7.D.l and 3.7.D.2 cannot be met, an orderly shutdown shall be initiated and the reactor shall be in the Cold Shutdown condition within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
BFN Unit 3 3.7/4.7-18
ENCLOSURE 2
DESCRIPTION AND JUSTIFICATION BROWNS FERRY NUCLEAR PLANT (BFN)
UNITS 1, 2, AND 3 Descri tion of Chan e
The amendment would delete surveillance requirement 4.7.D.1.C, the twice pex week partial closure test of the main steam isolation valves (MSIVs) for uni'ts 1, 2, and 3.
Deletion of this test requirement would allow the valve partial closure to be tested quarterly, consistent with the requirement in table 4.1.A for the Reactor Pxotection System (RPS) scram on MSIV closure.
Reason for Chan e
This change would remove excessive testing requirements for the MSIVs.
The result would be less burden on and distraction of the contxol room operators and a decrease in the probability of accidental transients caused during performance of the surveillance test.
Justification for Chan e
Two MSIVs, one on each side of the primary containment barrier, in each of four main steam lines, close automatically to prevent damage to the fuel barrier during a loss of coolant accident outside the primary containment and/or limit release of radioactive materials to the environment after a postulated accident.
Deletion of the requirement to conduct an MSIV partial closure test as described in FSAR section 4.6.5 twice per week will result in a decrease in the probability of inadvertent scrams and transients
- and, therefore, an increase in safety.
(The pushbutton used for this test has been involved in five unit scrams at BFN since 1977.)
This increase in safety may be partially offset, by the decrease in surveillance frequency for the MSIVs; however, this decrease is limited by the surveillance requirement in table 4.1.A which requires the MSIVs to be partially closed at least once per quaxter to functionally test the RPS scram fox MSIV closuxe.
Also, the MSIVs will still be tested in accordance with SR 4.7.D.l.B., which is consistent with the valve testing requirement of ASME Section XI.
The twice-weekly test only demonstrates that the mechanical portion of the MSIV is not stuck in the open position because it does not utilize the controls which normally trip the MSIVs.
Failure of the mechanical portion of the valve has not been a dominant failure mode.
The valve vendor, Atwood and Morill, has provided concurrence with the once per quarter testing frequency.
Finally, this amendment would be consistent with the guidance provided by NRC in NUREG-0737, Item II.K.3.16, reducing challenges to the x'elief valves by reducing MSIV testing.
Therefore, TVA concludes that no significant reduction in the margin of safety will occur as a result of this amendment.
ENCLOSURE 3 DETERMINATION OF NO SIGNIFICANT HAZARDS CONSIDERATION BROMNS FERRY NUCLEAR PLANT (BFN)
UNITS 1, 2, AND 3 Descri tion of Amendment Re uest The amendment would delete the twice per week closure test of the main steam isolation valves (MSIVs).
Deletion of this test requirement would allow the partial closure to be tested quarterly, consistent with the requirements of table 4.1.A for functionally testing the reactor scram on MSIV closure.
'asis for Pro osed No Si nificant Hazards Consideration Determination The Commission has provided standards for determining whether a significant hazards consideration exists as stated in 10 CFR 50.92(c).
A proposed amendment to an operating license for a facility involves no significant hazards consideration if operating of the facility in accordance with a proposed amendment would not (1) involve a significant increase in the probability or consequences of an accident previously evaluated, or (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.
A discussion of these standards as they relate to this amendment follow.
1.
The proposed amendment would not involve a significant increase in the probability or consequences of an accident previously evaluated because the technical specification change will not eliminate or modify any protection functions nor permit any new operational conditions.
- However, it does decrease the frequency of surveillance testing on the MSIVs and, therefore, may result in some decrease in reliability of the MSIVs.
- However, any decrease associated with this change is shown to be insignificant for the following reasons.
The nuclear industry, and BFN in particular, have both demonstrated a high degree of reliability in MSIV closure.
The MSIVs will still be tested in accordance with ASME Section XI testing requirements, which have been accepted as sufficient.
Finally, the MSIVs will be tested beyond that of ASME Section XI by the requirement to perform a partial closure of the MSIVs once per quarter to test a Reactor Protection System (RPS) scram.
2.
Likewise, the change would not create the possibility of a new or different kind of accident since deletion of a surveillance requirement does not modify plant equipment or provide any new operational conditions.
Basis for Pro osed No Si nificant Hazards Consideration Determination (Continued) 3.
Finally, the proposed amendment does not involve a significant reduction in a margin of safety since the remaining, technical specifications would still require the MSIVs to be operated quarterly.
The requirement, to test the MSIVs per specification 4.7.D.1.b will also remain in the technical specifications.
Furthermore, deletion of this testing requirement will result in a decrease in the probability of accidental transients which have been caused during the performance of this test.
The amendment is also consistent with the guidance provided by NRC in NUREG-0737, Item II.K.3.16.
Therefore, TVA proposes to determine that the proposed amendment does not involve a significant hazards consideration.
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