ML20246L751
| ML20246L751 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 05/10/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20246L747 | List: |
| References | |
| NUDOCS 8905180397 | |
| Download: ML20246L751 (5) | |
Text
_ _ _ _ - _ _ _ _ _ _ - -
/ y%
UNITED STATES 9.*
[
i NUCLEAR REGULATORY COMMISSION j
WASHINGTON, D, C. 20555 rr 1
i SAFETY EVAlllATI0t! EY THE OFFICE OF NUCLEAR REACTOR REGULATION FELATED TP Al'ENDMENT NO. u TO FACILITY CPERATING LICENSE NO. NPF-63
{
DETROIT EDISON COPPANY VOLVEPINE POWER SUPPLY COOPERATIVE, INCORPORATED FERMI-2 DOCKET NO. 50-341
1.0 INTRODUCTION
requtsted arendrent to the Technical Specifications (TSs)y (Deco or the licensee)
- 0) letter dattc April 20, 1989, the Detroit Edison Compan appended to Facility Operating License No. NPF-4.1 for Fermi-2. The proposed amendment would revise the TSs Secticn 3/4.C.I. 1 to charce the required Action statement concerning wher, one of the two redundant vacuum breaker position indicators is inoperable.
P.0 EVALUATION The suppression chamber-to-drywell vacuum breakers must bc closed during norral cperation te prevent steam flow from a postulated LOCA from passine through the vacuer breakers directly to the suppression chamber atmosphere.
This wculc' bypass the pressure quenching effect of the suppression pool and letc' te an unacceptable pressure in the suppression chamber.
For this reason, the TSs require position indication of the vacuum breakers, j
When one cf the two redundant divisional position indicators is inoperable, the TSs Action statement is provided to give additionel assurance that the associated vacuum breaker is closec. This assurance is needed as soon as practical ano also is provided periodically with a two week interval.
The current Action statement 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 within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> 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. Three-limit-switch irdicators are provided for the vacuum breakers. The two closed I
l position indicators are in the TSs and are the subject of the proposed amendment.
The open-limit-switch indicator is not in the TSs. The position indicator is demonstrated tc be OPERABLE by performing Surveillance Requirement 4.6.4.1.b.2, which strokes the vacuur breaker and assures that the indication follows the i
vacuen breaker movement (i.e., cicsed indication lamp extinguishes, the open-l limit-switch larp is 111 urinated, then the close indication lamp is again illuminated).
l 8905180397 890510 PDR ADOCK 05000341 P
PDC l
4
' The proposed change mcLes the provisions for the initial assurance more clear la specifying that the position indicator relied upon is to be verified OPERABLE.
The proposel also allows the same procedure to be repeated for the two week interval surveillance required until restoration of the inoperable indicator.
The test specified in the current ACTION c would be reserved for situations where the redundant position indicator cannot be verified to be OPERABLE and hence the vacuum breaker cannot be verified to be closed with the limit switches.
In this case, the specified test is given as an alternative method to verify that the vacuum breaker is closed.
The proposed change in the Action statement in Section 3/4.6.4.1.c of the TSs is justified based on the following:
(1) The two methods (position indication and pressure test) of verifying that the vacuum breaker is closed both provide assurance that the vecuum 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. Therefore, designs utilizing redundant, independent position indicators may reasonably rely on the other position indicator in the event one indicator is inoperable in lieu of a pressure test.
(2) As a secondary consideration it should be noted that the test method for verifying the closed position of the vacuum breaker 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 Pressere-High scram trip set point of 1.68 psig.
This increases the risk of reactor scram from a minor drywell pressure transient which may have been managed by the operator if it occurred with a normal drywell 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.
tlRC Standard Review Plan (SRP) (NUREG-0800), Section 6.2.1.1.c covers the requirements for pressure-suppression type BWR containments. The SRP states that in evaluating surveillance and test programs for vacuum relief the staff uses "the results of previous review and operating experience with similar systems to determine their adequacy."
3.0 FINDINGS The Fermi-2 suppress #on 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. The proposed amendment does not change the intent of the ACTION statement in the TSs because the proposed change continues 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 j
be performed at twice the normal surveillance frequency.
Based on the above evaluation the staff finds the proposed change to the TSs is acceptable.
I
.~.~
' 4.0 _EX1GE_NT CIPCWSTANCES The Commission's regulations, 10 CFR 50.91, contain provisions for issuance of aundments when the usual 30-day public notice period cannot be met. One type of special exception is an exigency.
An exigency is a case where the staff ard licensee need to act promptly, but failure to act promptly does not involve a plant shutdchn, deratin5, er delay in startup. The exigency case uscelly represents an amendment involving a safety enhancement to the plant.
The Commission has determined that the licensee used its best efforts to make tirely application for the proposed change and that exigent circumstances do exist and were not the result of any fault of the licensee. The exigent circumstances resulted from the fact that one position indicator for suppression chamber-to-drywell vacuum breaker, T23-400F was discovered on April 2f,1989, to be inoperable. With one position irdicator on a vacuum breaker inoperable, the Technical Specifications for Fermi-2 require that the associated vacuum breater and all other vacuum breakers be verified closed within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.
In addition, the licensee has 14 deys to restore the position indicator to operable or verify the vacuum breater with the inoperable position indicator te be closed by conducting a test which demonstrates that the drywell to suppression chamber differential pressure 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 15 days, thereafter.
Upon discovery of the inoperable indication, the licensee began troubleshooting activities er the inoperable indicater and complied with the provisions to verify the closure cf 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 completion of the subsequent required test for vacuum closure was begun in the event that the troubleshooting effort was unsuccessful.
1he unc' desirability cf the use of the pressure test method for verification of vacuum breaker closure then became evident. The licensee 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 crose fron en unexpected plant event and, therefore, could not have been reasonably foreseen.
Subsequently, it has been determined that the plant must be placed in COLD SHUTDOWN to repair the inoperable position indicator.
Eased on the above, the NRC staff finds that exigent circumstances do exist and the licensee has acted in a timely manner.
$.0 FINAL DETERMINATION OF NO SIGNIFICANT HAZARDS CONSIDERATION The Commission has provided standards for determining whether a significant hazardsconsiderationexists[10CFR50.92(c))foraproposedamendmenttoa facility operating license. A proposed amendment to an operating license for a facility involves oc significant hazards consideration if operation of the facility in accordance with the proposed amendment would not: (1) Involve a previously evaluated; or (2) probability or consequences of an accidentCreate the po significant increase in the of accident from any accident previously evaluated; or (3) Involve e significant reduction in a margin of safety.
____ _. _j
4 4
4 4
\\1; The preposed cFenge does not involve a significant increase in the prctability or consequences of an accident previously evaluated. The intent of the TS ACTION staten.ent is not changed because the position of the vacuum breaker will still be determined on an accelerated basis.
In eddition, the vulnerability of placing the plant in a transient condition has been reduced. The proposed change also 1E days when corplying with the existing TS) prevents the routine (every release of gaseous effluents in order to return to ncrmal primary containment pressure.
(i) The proposed change does not create the possibility of a new or different kinc cf accident frcn. any accident previously evaluated. The proposed an.endrent decs rot introduce new modes cf plant operation nor involve a physicel modification to the plant. The method of verifying that the vacuum breaker is closed is censistent with existing TS surveillance requireccnt 4.6.4.1.b.2.
The two position indicator circuits on each stive are divisional such that an inoperable circuit will net aff ect an GFERAELE circuit.
(?' The proposed change does not involve a significant reduction in the margin of saitty. The proposed amendment reduces the probability of placing the plant into a transient condition, reduces the number of gaseous effluent releasts, and maintains the intent of the TS. The proposed change will rcduce the probability of placing the plant into a transient condition by not requirirg a pressure test that verifies a vacuum breaker is closed, when an OPERACLE position indicator is indicating the vacuum breaker is closed. The proposed amendment will reduce the number of gaseous affluent releases that are required subsequent to performing the subject iressure test by reducing the situation when this off-normal test is perfor ed.
On the basis o the above consideration, the staff finds that the change to the TSs does not involve a significant hazards consideration.
In accordance. tith thc Commissien's regulations, efforts were made to contact the Michigan State representative. A representative was contacted and had no comments.
6.0 ENVIRONMENTAL CONSIDERATION
This amendment involves a change in the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and a change to the surveillance requirements. The staff has determined that this amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents which 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 j
that this amendment involves no significant hazards consideration and there has j
been no public comment on such finding. Accordingly, this amendment meets the l
eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
i Pursuant to 10 CFR 51.22(b), oc environmental impact statement or environmental assessment need be prepared in connection with the issuance of this amendment.
) l I
7,0 COICLUSION itt staff hcr concluded, based on the considerations discussed above, that (1) there is reasonable assurance that the health and safety of the public will nct be endangered by operation ir the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of this amendrent will not be inimical to the common defense and security cr to the health and safety of the public, Principcl Centributcr:
John Stang Date: May 10, 1989 l