NRC-89-0103, Application for Amend to License NPF-43,changing Tech Spec 3/4.6.4.1 Re Suppression Chamber Drywell Vacuum Breakers

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Application for Amend to License NPF-43,changing Tech Spec 3/4.6.4.1 Re Suppression Chamber Drywell Vacuum Breakers
ML20246D334
Person / Time
Site: Fermi DTE Energy icon.png
Issue date: 04/28/1989
From: Orser W
DETROIT EDISON CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20246D340 List:
References
CON-NRC-89-0103, CON-NRC-89-103 NUDOCS 8905100196
Download: ML20246D334 (10)
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Detroit .. -

Ecison EEE " S. C-April 28,1989 NIC-89-0103 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 l

References:

1) Fermi 2 NIC Docket No. 50-341 NIC License No. IFF-43
2) Detroit Edison letter to NIC, NIC-88-0233,

" Proposed Technical Specification Change (License Amendment) Suppression Chamber -

Drywell Vacuum Breakers (3/4.6.4.1)", dated i December 22, 1988

Subject:

Proposed Technical Specification Change (License Amendment) Suppression Chamber - Drywell Vacuum Breakers (3/4.6.4.1)

Pursuant to 10CFR50.90, Detroit Edison Company hereby proposes to amend Operating License NPF-43 for the Fermi 2 plant by incorporating the enclosed changes into the Plant Technical Specifications. The proposed change to Technical Specification 3/4.6.4.1 will modify the  ;

required ICTION when one of two redundant vacuum breaker position l indicators is inoperable. l Detroit Edison believes that this proposal arises from circumstances that do not allow sufficient time to use the normal public notice and comment procedures. Therefore, it is requested that this proposal be l processed under the provisions of 10CFR50.91(a)(6) as an exigent i Technical Specification change. This proposal presents an equivalent i alternate provision to the existing ACTION requirement which eliminates unnecessary potential challenges to the plant and its operators. Approval of this proposal is requested by May 10, 1989.

Detroit Edison has evaluated the proposed Technical Specifications against the criteria of 10CFR50.92 and determined that no significant ,

hazards consideration is involved. The Fermi 2 Onsite Review l Organization has approved and the Nuclear Safety Review Group has reviewed the proposed Technical Specifications and concurs with the i

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UStGC April 28,1989 tEC-89-0103 Page 2 enclosed determinations. In accordance with 10CFR50.91,' Detroit niison has provided a copy of this letter to the State of Michigan.

If you have any questions, please contact Mr. Glen Ohlemacher at (313) 586-4275.

Sincerely, Enclosure i

cc: A. B. Davis R. C. Knop  ;

W. G. Rogers ]

J. F. Stang j l Supervisor, Advanced Planning and Review Section, <

Michigan Public Service Commission I

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i April 28,1989 NFC-89-0103 Page 3 I, WILLIAM S. ORSER, do hereby affirm that the foregoing statements are based on facts and circumstances which are true and accurate to the best of my knowledge and belief.

l WILLIAM S. ORSER Vice President Nuclear Operations .

On this <S day of [O . 1989, before me personally appeared William S. Orse'r, being first duly sworn and says that he executed the foregoing as his free act and deed.

l tbn 0. dux2dG No'tary Public ROSAVE A. ARMETTA NotoryPubHc MonroeCounty,M WCommission E4*esJon.1t,q ac 1

i Enclo::ure to NRC-89-0103 Page 1 INTRODUCTION Vacuum breakers between the suppression chamber atmosphere and drywell provide vacuum relief to the drywell after a postulated Loss Of Coolant Accident (LOCA). The condensing steam from a LOCA could cause a drywell vacuum condition to occur beyond its design value without these vacuum breakers. With the drywell in a vacuum condition, the suppression chamber-to-drywell vacuum breakers open to vent non-condensables from the suppression chamber atmosphere to the drywell. This equalizes the pressure between the drywell and suppression chamber. If a primary containment vacuum condition still exists, the Reactor Building-to-suppression chamber vacuum breakers will open to equalize the pressure between the Reactor Building and the suppression chamber. The suppression chamber-to-drywell vacuum breakers also act as check valves during a LOCA to prevent steam flow from passing through the vacuum breakers directly to the suppression chamber atmosphere (e.g., the valves close when drywell pressure is greater than or equal to suppression chamber air space pressure). The vacuum breakers are equipped with pneumatic actuators operated by pushbuttons from the main control room.

Specification 3.6.4.1 ACTION c provides the current ACTION requirement for the inoperability of one of the two redundant closed position indicators for one or more suppression chamber - drywell vacuum breakers:

c. With one of the closed position indicators of one or more suppression chamber - drywell vacuum breaker (s) inoperable, verify the associated vacuum breaker and all other breakers to be closed within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, restore the inoperable position indicator to OPERABLE status within 14 days or verify the vacuum breaker (s) with the inoperable position indicator to l be closed by conducting a test which demonstrates that the j drywell to suppression chamber 4P is maintained at greater '

than or equal to 0.5 psi for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> without makeup within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and at least once per 15 days thereafter. Otherwise, be in at least HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

The proposed ACTION c is as follows:

c. With one of the position indicators of any suppression chamber - drywell vacuum breakers inoperable, verify that all other vacuum breakers are closed within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and:
1. Verify the vacuum breaker (s) with the inoperable position indicator to be closed by demonstrating the other l i

Enclosure to NRC-89-0103 Page 2 position indicator to be OPERABLE within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and at least once per 14 days thereafter, or

2. Verify the vacuum breaker (s) with the inoperable position indicator to be closed by conducting a test which demonstrates that the drywell-to-suppression chamber 4 P is maintained at greater than or equal to 0.5 psi for one hour without makeup within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and at least once per .

14 days thereafter.

Otherwise, be in at least HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

The proposal modified the ACTION to allow use of the OPERABLE position indicator to determine the vacuum breaker position every 14 days instead of requiring the specified test every 15 days in all cases.

The test requirement would be reserved for cases where verifying the redundant position indicator is impractical (i.e., the vacuum breaker can not be opened).

EVALUATION As described above, the suppression chamber-to-drywell vacuum breakers must be closed to prevent steam flow from a postulated LOCA from passing through the vacuum breakers directly to the suppression chamber atmosphere. This would bypass the pressure quenching effect of the suppression pool and lead to an unacceptable pressure in the ]

suppression chamber.  ;

When one of the two redundant divisional position indicators are 2noperable the ACTION is provided to give additional assurance that the associated vacuum breaker is closed. This assurance is needed as soon as practical and is also periodically provided with a two week interval.

The current ACTION provides the initial assurance that the affected vacuum breaker is closed by verifying the vacuum breaker to be closed within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. The method of verification is not specified.

However, the only practical method for verification in the specified time is to verify the other position indicator is OPERABLE and utilize its indication. The position indicator is demonstrated to be OPERABLE by performing Surveillance Requirement 4.6.4.1.b.2, which strokes the vacuum breaker and assures that the indication follows the vacuum breaker movement.

The proposed change makes the provisions for the initial assurance more clear by specifying that the position indicator relied upon is to i

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. Enclosure to' NRC-89-0103

.Page 3 be verified OPERABLE. The proposal also' allows'the same procedure to be used for the two week verification'that the-vacuum breaker is closed. The test specified in.the current ACTION.c would be reserved

.for. situations where the redundant position indicator cannot be I verified to be OPERABLE because the associated vacuum breaker can not l be cycled. In ' this case,- the .specified test is given. as an .. j alternative method to verify that the vacuum breaker'is~ closed.

Since the situation can arise where the vacuum breaker lcan not be stroked when the initial verification ic required, the proposal allows the test method of verification that the vacuum breaker-is closed.

Since the test specified is more complex and has the potential to challenge the plant safety systems the proposal allows 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to complete the verification. This allows sufficient time for. planning and preparation and thus enhances plant safety by reducing the probability of operational error during the test.

The principal change' contained in the proposal is to allow the'use of the test. method of verification of vacuum breaker closure to be reserved for situations where verification of closure using the redundant position indicator is not practical. This is justified as follows:

1) The two methods of verifying that the vacuum breaker is closed both provide positive assurance that the vacuum breaker is closed. The two redundant position indicators are divisional, so that the failure in the inoperable indicator can not affect the functioning of the OPERABLE indicator.
2) The test method requires the increase of Drywell pressure to at ,

least 0.5 psi above the suppression chamber pressure. This (

places the pressure closer to the Drywell Pressure-High scram trip setpoint of 1.68 psig. This increases the risk of reactor {

scram from a minor drywell pressure transient which may have been 1 managed by the operator if it occurred with a normal drywell. j pressure as the initial condition and increases challenges to the -]

operators. The reduction in the risk of a reactor scram is a safety enhancement of the proposed change.

3) Subsequent to the use of the test method the drywell pressure is ,

returned to normal. . This is accomplished by a small gaseous.

release of the drywell atmosphere under the provisions of the Radiological Effluent Technical Specifications. The provisions

! which allow the minimization of the use of the test method

! therefore provide an environmental benefit as compared to the existing requirements. '

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. Enclorure to NRC-89-0103 Page 4 l

NRC Standard Review Plan (SRP) (NUREG-0800) Section 6.2.1.1.c covers the requirements for pressure-suppression type BWR containments. This section does not directly address the ACTIONS to be taken for an inoperable position indicator. However, the SRP states that in evaluating surveillance and test programs for vacuum relief the staff j' uses "the results of previous reviews and operating experience with similar systems to determine their adequacy."

The Fermi 2 suppression chamber-to-drywell vacuum breaker design is similar to the design at Hope Creek Generating Station . The proposed ACTION c is modeled after the Hope Creek ACTION statement for the same situation.

Based upon the above, Detroit Edison believes that the proposed change represents a safety enhancement and therefore requests prompt approval of this proposal. This proposal is independent of the change proposed to Specification 3/4.6.4.1 in reference 2.

SIGNIFICANT HAZARDS CONSIDERATION l

In accordance with 10CFR50.92, Detroit Edison has made a determination that the proposed amendment involves no significant hazards considerations. To make this determination, Detroit Edison must establish that operation in accordance with the 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.

1) The proposed changes do not involve a significant increase in the probability or consequences of an accident previously evaluated because the intent of the Technical Specification is not changed and the vulnerability of placing the plant in a transient condition has been reduced. The proposed change also prevents the routine (every 15 days when complying with existing ACTION statement 3.6.4.1.c pressure test) release of gaseous effluents in order to return to normal primary containment pressure.

It is not necessary to perform the ACTION statement 3 6.4.1.c pressure test to verify that a Suppression Chamber Drywell vacuum breaker is closed when an OPERABLE position indicator is indicating the vacuum breaker is closed and the OPERABLE indicator's Technical Specification surveillance test is performed at twice its normal frequency. Performing the subject pressure test will increase the Drywell pressure decreasing the margin to the Drywell Pressure-High scram trip setpoint of 1.68 l

I Enclosure to NRC-89-0103 Page 5 psig. . This increases the risk of a reactor scram from a minor drywell pressure transient which may have been managed by the operator if it occurred at the normal drywell pressure and increases challenges to the operators. Additionally, subsequent to the existing ACTION statement 3 6.4.1.c pressure test drywell pressure.is returned to normal. This is accomplished by a small gaseous release of the drywell atmosphere under the provisions of the Radiological Effluent Technical Specifications. The. j provisions which allow the reduction of the use'of the pressure test method therefore provide an environmental benefit as-compared to the existing requirements. i

2) The proposed changes do not create the possibility of a new or different kind of accident from any accident previously evaluated because the proposed changes introduce no new mode of plant operation nor involves a physical modification to the plant. The method of verifying that the vacuum breaker is closed is consistent with the existing surveillance requirement 4.6.4.1.b.2. The two position indicator circuits on.each valve are divisional such that an inoperable circuit will not affect the OPERABLE circuit.
3) The proposed changes do not involve a significant reduction in the margin of safety because the changes reduce the probability of placing the plant into a transient condition, reduce the number of gaseous effluent releases, and maintain the intent of the existing Technical Specifications. The proposed change will reduce the probability of placing the plant into a transient condition by not requiring a pressure test that verifies a vacuum breaker is closed, when an OPERABLE position indicator is indicating t,he vacuum breaker is closed. The proposed changes will reduce the number of gaseous effluent releases that are required subsequent to performing the subject pressure test by reducing the situations when this off-normal test is performed.

l Furthermore, the intent of the existing Technical Specification 1 has not been changed because the proposed changes continue to require that the vacuum breaker be verified closed at the same frequency. The proposed verification method is consistent with the existing surveillance requirements and will be performed at I twice the normal surveillance frequency.

Based on the above, Detroit Edison has determined that the proposed amendment does not involve a significant hazards consideration.

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- Enclosure to NRC-89-0103 Page 6 BASIS FOR EXIGENT CIRCUMSTANCES One position indication for suppression chamber-to-drywell vacuum breaker, T23-F400F, indicated closed during the performance of Surveillance Requirement 4.6.4.1.b.2 (verification of position indication OPERABILITY during full cycle test of vacuum breaker) at 0130 hours0.0015 days <br />0.0361 hours <br />2.149471e-4 weeks <br />4.9465e-5 months <br /> on April 26, 1989 Fermi 2 was operating at 100% power at the time.- The redundant indication operated properly through.the full cycle of vacuum breaker travel. Thus, Fermi 2 is required by ACTION c to perform the verification of closure of T23-F400F using the test method by May 11,.1989 at 0130 hours0.0015 days <br />0.0361 hours <br />2.149471e-4 weeks <br />4.9465e-5 months <br /> or be in at least HOT SHUTDOWN by 1330 hours0.0154 days <br />0.369 hours <br />0.0022 weeks <br />5.06065e-4 months <br /> the same day.

Upon discovery of the inoperable indication, plant personnel began-trouble shooting activities on the inoperable indicator and complied with the provisions to verify the closure of all vacuum breakers within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. Also planning for the completion of the subsequent required test for vacuum closure was begun in the event that the troubleshooting effort was unsuccessful.

The undesirability of the use of the test method for verification of vacuum breaker closure then became evident. As described above, Detroit Edison believes that performance of the test when it is not necessary leads to unnecessary challenges to plant safety systems and unnecessary environmental impact. These circumstances arose from an unexpected plant event and therefore could not be reasonably foreseen. Subsequently, it has been determined that the plant must be placed in COLD SHUTDOWN to repair the inoperable position indicator.

Detroit Edison therefore believes that this proposed change should be approved prior to May 11, 1989 to eliminate the unnecessary performance of this test. Detroit Edison believes that the provisions of 10CFR50.91(a)(6) for exigent circumstances apply to this situation as quick action is needed to prevent the unnecessary test performance and thus prevent the unnecessary potential challenges to the plant.

Therefore, Detroit Edison requests that the procedures of 10CFR50.91(a)(6) be utilized to grant this proposal by May 10, 1989 Detroit Edison recognizes that the use of local media per 10CFR50.91(a)(6)(1)(B) may be required.

ENVIRONMENTAL IMPACT Detroit Edison has reviewed the proposed Technical specification change against the criteria of 10CFR51.22 for environmental considerations. The proposed change does not involve a significant hazards consideration, nor significantly change the. types or significantly increase the amounts of effluents that may be released m___.______.____

. Enclosure to NRC-89-0103 Page 7 offsite, nor significantly increase individual or cumulative occupational radiation exposures. The proposal decreases the amount of gaseous effluent which may be released offsite. Based on.the foregoing, Detroit Edison' includes that the' proposed Technical Specification meets the criteria given in 10CFR51.22(c)(9) for.a categorical. exclusion from the requirements for an. Environmental-Impact Statement.

CONCLUSION Based on the evaluation above: 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 proposed amendments will not be. inimical to the common defense and security or to the health and safety of the public.

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