ML20138L821
| ML20138L821 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 02/20/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20138L819 | List: |
| References | |
| NUDOCS 9702250101 | |
| Download: ML20138L821 (4) | |
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO ANEIENENT N05.127 AND 119 TO FACILITY OPERATING LICENSE NOS. DPR-42 AND DPR-60
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NORTHERN STATES POWER COMPANY i
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PRAIRIE ISLAND NUCLEAR GENERATING PLANT. UNIT NOS. I AND 2 DOCKr N05. 50-282 AND 50-306
1.0 INTRODUCTION
i By letter dated February 6,1997, as supplemented by a letter dated l
February 12, 1997, the Northern States Power Company (NSP or the licensee) requested amendments to the Technical Specifications (TS) appended to Facility Operating License Nos. DPR-42 and DPR-60 for the Prairie Island Nuclear Generating Plant, Unit Nos. I and 2.
The proposed amendments would revise TS i
3.3.A and the associated Bases to allow safety injection pump testing and evolutions during low-temperature shutdown conditions provided control for reactor coolant system (RCS) conditions are in place to provide low temperature overpressurization protection. The current TS do not allow the testing and evolutions to be performed.
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The low temperature overpressure protection (LTOP) system is provided to assure that under low temperature operating conditions the integrity of the reactor vessel is not compromised by violating 10 CFR Part 50, Appendix G requirements. The design of the LTOP system is based on an analysis considering a credible mass addition or heat addition transient during low temperature operating conditions. In the limiting mass addition transients at i
different operating temperature, some safety injection pump (s) (SIPS) are assumed incapable of injection water to the RCS upon an inadvertent safety injection signal.
TS 3.3 provide restrictions for the SIPS' ca> abilities during low temperature operations to assure that the plant will l>e operated j
within the configurations consistent with the analysis assumptions.
l 2.0 EVALUATION i
The current TS 3.3.A.2.g requires that the licensee place at least one SIP control switch in the control room in the pullout position whenever RCS temperature is less than 310 *F and both SIP control switches in the pullout position whenever RCS temperature is less than 200 *F.
However, the TS allows NSP to run both SIPS while conducting the integrated SI test when j
either there is a steam or gas bubble in the pressurizer and the SI discharge j
valves are shut or the reactor vessel head is removed.
i 9702250101 970220 PDR ADOCK 05000282 3
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j 4 By letters dated February 6,1997, and February 12, 1997, the licensee proposed a modified TS 3.3.A.2.g that would allow the licensee to run both SIPS for up to I hour while conducting the integrated SI test when there is a 4
i steam or gas bubble in the pressurizer and an isolation valve between the SIP i
and the RCS is shut or the reactor vessel head is removed.
The proposed TS j
includes a note which indicates that other SI system tests and operations may also be conducted durity the time period of conducting the integrated SI test.
Also, another note in th proposed TS points out that whenever the reactor l
vessel head is removed, this TS does not apply.
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The licensee's intent of this TS modification is to clearly specify the scope of the allowable integrated SI test to include SIP tests, SI system flow j
tests, pump breaker tests, water addition to the emergency core cooling system accumulators, and other necessary evolutions during low temperature operations, since some of these tuts and evolutions may be interpreted as outside the current TS. The licensee also modified the bases for TS 3.3 to j
indicate that during the integrated SI tests, a positive means of isolation is j
provided between the SIPS and the RCS. This isolation is accomplished by f
using either a closed manual valve or a closed motor-operated valve with the power removed.
I The licensee's proposed changes in TS 3.3 reflect the changes discussed above.
The staff has reviewed the licensee's submittal and finds that the proposed TS will continue to assure that the reactor vessel will be protected from low l
temperature overpressure events. Therefore, the changes are acceptable.
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3.0 EXIGENT CIRCUMSTANCES
The Commission's regulations,10 CFR 50.91, contain provisions for issuance of amendments where the Commission finds that exigent circumstances exist, in that a licensee and the Commission must act quickly and that time does not permit the Commission to publish a Federal Reaister notice allowing 30 days i
for prior public comment. The exigency exists in this case in that the l
proposed amendments are needed prior to the restart of Prairie Island Unit 2
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and time does not permit the Commission to publish a notice allowing 30 days for prior public comment. The licensee discovered on February 3, 1997, that 1
the existing TS would preclude testing of the safety injection system that is required prior to restarting the unit. The licensee submitted the amendment I
request on February 6,1997, and supplemented it on February 12, 1997. The staff has determined that the licensee used its best efforts to make a timely l
application.
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Accordingly, the Commission has determined that exigent circumstances exist i
pursuant to 10 CFR 50.91(a)(6), the submittal of information was timely and i
could not hav,e.been avoided, and that the licensee did not create the
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exigency.
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( l 4.0 FINAL N0 SIGNIFICANT HAZARDS CONSIDERATIONS DETERMINATION l
i The Commission's regulations in 10 CFR 50.g2(c) state that the Commission may make a final determ< nation that a license amendment involves no significant hazards consideration if operation of the facility in accordance with the proposed amendment would not (1) involve a significant increase in the i
pro > ability 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) result in a significant reduction in the margin 4
of safety. The NRC staff has made a final determination that no significant i
hazards consideration is involved for the proposed amendments and that the 1
amendments should be issued as allowed by the criteria contained in 10 CFR 50.91. The NRC staff's final determination is presented below.
l (1)
The pr sed changes would not involve a significant increase in the i
probab ty or consequences of an accident previously evaluated.
The proposed changes would allow the licensee to operate the SIPS as i
i necessary for required testing and evolutions at low RCS temperatures.
l The proposed changes also include controls to ensure that the RCS continues to be protected from low temperature overpressure events.
l Therefore, the changes do not involve a significant increase in the consequences or probability of a previously evaluated accident.
(2)
The proposed changes would not create the possibility of a new or different kind of accident from any accident previously evaluated.
The proposed changes would allow the licensee to operate the SIPS for required tests and evolutions. The affected TS establish limiting l
conditions for operation to protect the RCS from low temperature overpressure events. The proposed changes also include controls to i
provide this protection. Therefore, a new or different kind of accident is not created.
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(3)
The proposed changes would not result in a significant reduction in the j
margin of safety.
.The proposed changes would allow the licensee to perform required tests and evolutions involving the SIPS. However, the proposed changes also include controls to ensure that the RCS continues to be protected from j
low temperature overpressure events. Therefore, these changes do not i
involve a significant reduction in a margin of safety.
5.0 STATE CONSULTATION
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i In accordance with the Commission's regulations, the Minnesota State official 4
was notified of the proposed issuance of the amendments. The State official j
had no comments.
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- 6.0 m i
The amendments chage a requirement with respect to installation or use of a j
facility component located within the restricted area as defined in 10 CFR Part 20. 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 i
significant increase in individual or cumulative occupational radiation i
exposure. The Commission has made a final finding that.the amendments involve i
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 environmental assessment need be prepa) red in connection with the issuance i
1 of these amendments.
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5.0 CONCLUSION
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The Commission has concluded, based on the considerations discussed above, l
that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such l
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 i
defense and security or to the health and safety of the public.
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j Principal Contributor: Chu-Yu Liang f
Date:
February 20, 1997 i
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