ML20011D248
| ML20011D248 | |
| Person / Time | |
|---|---|
| Site: | FitzPatrick  |
| Issue date: | 12/15/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20011D247 | List: |
| References | |
| NUDOCS 8912260057 | |
| Download: ML20011D248 (5) | |
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NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555
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SAFETY EVALUATION BY THE OFF_ ICE OF NUCLEAR REACTOR REGULATION RELATED TO AMEFDMENT NO. _147 TO FACILITY OPERATING LICENSE NO. DPR-59 POWER AUTWORITY OF THE STATE OF NEW YORK JAMES A. FITZPATRICK NUCLEAR POWER PLANT
_ DOCKET NO. 5_0_-333 INTRODUCTION By letter dated December 11, 1989, the Power Authority of the State of New York (PASNY), the licensee for the James A. FitzPatrick Nuclear Power Plant, requested an emergency Technical Specification (TS) amendment in order to change the differential pressure setpoint specified for the High Pressure Coolant Injection System high steam flow isolation.
Specifically the change would affect Item 31 in Table 3.2-2 on page 706, by changing the value from 106 in. H 0 dp to 160 in. H,0 dp. A Temporary Waiver of Compliance 9
incorporating this change'was issued by letter from B. A. Boger to J. C. Brons,
. dated December 11, 1989.
DISCUSSION-
- t The purpose of the HPCI steam line isolation is to limit reactor coolant inventory loss and the offsite radiological consequences in the event of a break in the HPCI piping.
The analytical limit for determining if a break exists in the HPCI system pipino is stated in FSAR Section 7.4.3.2.7 as a HPCI steam line flow of 300 percent of rated steam flow. At the FitzPatrick plant, the HPCI. steam line flow rate is sensed by di##erential pressure elbow taps on the HPCI steam line.
Determination of the differential pressure setpoint that will result from a steam flow of 300 percent was most recently addressed in Amendment No. 68, which was issued by letter dated March 4, 1982. A correction to the calculational methods used by the licensee in that amendment resulted in a change of the setpoint from 230 in. H O to 106 in. H 0.
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During the recently completed 1989 mid-cycle maintenance outage, a significant amount of maintenance, including replacement of the HPCI turbine cor. troller, was performed.
Upon return to service, HPCI was tested in accordance with Technical Speci#ication 4.5.C.I.
HPCI failed this test due to an auto-isolation high steam line flow. The cause of this isolation was dttributed to improper Venting of the instrumentation. Since subsequent testing was successful, no additional investigation was performed, g 22ggg{ h)
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-2 Repeat of the same isolation signal during a surveillance test conducted on December 4,1989, led the licensee to investigate other possible causes of the event. The HPCI system was put through a series of tests with additional instrumentation installed to isolate the root cause of the inadvertent isolations.- At this time, the proximity of the normal start-up steam flow transient to the isolation setpoint was detected and confirmed. Because the installed steam line elbow tap dp instrumentation used to sense steam flow does not behave linearly with the actual start-up steam flow transient, the possibility existed that the instrumentation may be generating an isolation signal during any normal HPCI start-up. This apparent randomness to 1.he generation of isolation signals made it very difficult to isolate the root i
cause of the inadvertent isolation and pointed out the need to use more extensive temporary test instrumentation and detailed data analysis.
EVALUATION General Electric Company Nuclear Services Information Letter (SIL) No. 475, Revision 2, "RCIC and HPCI High Steam Flow Analytic Limit," was issued November 28, 1988.
Its purpose is to describe the test method and calculational method used for determining instrument setpoints which will ensure that-isolation will occur when steam flow reaches 300 percent.
This method uses measured data from the as-built HPri system to determine the rated flow elbow tap instrument reading, and then applies several factors to calculate the elbow tap instrument reading corresponding to 300 percent rated steam flow. Using this method, it was determined that isolation was actually occurring at a differential pressure corresponding to approximately 200 percent and that the proper setpoint (corresponding to 300 percent steam flow) was 160 in. H O dp.
2 Therefore, increasing the setpoint to 160 in. H O dp will result in a more 2
reliable HPCI System since it will no longer be susceptible to inadvertent isolations from high steam flow.
It will, however, trip at the flow value which would indicate a break in the steam line to the HPCI turbine. The effect of the change is to restore the instrumentation setpoints to the conditions which are assumed to exist in the desion criteria.
Based on this analysis, the staff finds the proposed TS change acceptable.
STATEMENT OF EMERGENCY CipCUSTANCES The emergency situation developed as a result of the time involved in conducting tests, analyzing test data, research, indepth assessment of previous test failures and resulting changes, and discussions with industry technical representatives which were conducted when, from the routine monthly surveillance test conducted on December 5, 1989, it became obvious to the licensee that repeated surveillance test failures were occurring.
Following
.this test the system was maintained in an inoperable status until effective corrective action could be accomplished. Once the problem was determined, insufficient time was available to process the resulting TS change without exceeding the 7-day Limiting Condition for Operation specified in TS Section 3.5.C.1.b.
.,. The proposed TS change is required to allow the licensee to change the HPCI steam line high flow setpoint to 160 in. H,30 dp.
If the amendment is not issued, the plant would be required to conduct a normal shutdown and place the reactor in the cold condition with pressure below 150 psig within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, since operability of the HPCI System could not be assured.
In this condition, testing of the HPCI System could not be conducted since steam at rated pressure would not be available.
Based upon the above, we conclude that the licensee has adequately addressed the standards of 10 CFR 50.91(a)(5) with regard to demonstrating the need for an emergency license amendment. We further conclude, based on the efforts required to perform the extensive analyses (including recently completed confirmatory testing) of the HPCI system, that the licensee has not abused the emergency provision by failing to make timely application for the amendment.
S_TAFF CONCLl!SION The staff has concluded that the licensee has made a timely amendment application ence the problem was discovered and analyzed, that the licensee has justified the need for emergency action, and that the proposed setpoint change is necessary and proper.
FINAL OFTERMINATION OF N0 SIGNIFICANT HAZARDS CONSIDERATION The' foregoing evaluation demonstrates that the actions and evaluations taken by the licensee will enhance the reliability and operability of the HPCI System by preventing unnecessary isolations while, at the same time, maintaining the required isolation capability when it is required. We, therefore, conclude that operation of the facility in accordance with the proposed amendment would not:
a.
Invc1ve a significant increase in the probability or consequences of an accident previcusly evaluated. The HPCI system is designed to mitigate the consequences of a small break Loss-of-Coolant accident and as backup to the Reactor Core Isolation Cooling (RCIC) system for loss-of-Feedwater transients by providing a source of high pressure coolant injection into the reactor. The proposed change will reduce the probability that the HPCI system would be unavailable upon demand due to inadvertent isolation.
Changing the HPCI high steam flow instrument setting cannot initiate any previously evaluated accidents. The prebability and consequences of a HPCI steam line break ooing undetected or unisolated is unchanged, because this break would result in steam flows significantly in excess of the proposed isolation setpoint.
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-The 300 percent rated flow isolation signal is relied upon in the licensee's high energy line break (HELB) enalysis to limit the-amount of steam released into the reactor building. Since the proposed amendment does not change the 300 percent analytical limit, it does not result in a change to HELB environmental parameters for the reactor building or affect any of the results of the HELB
- analysis, b.
Create the possibility of a new or different kind of accident from any accident previously evaluated. Changing the HPCI high steam flow instrument setting cannot initiate any type of accident. The HPCI system is designed for standby service and only functions to mitigate accidents by providing a high pressure source of water to the reactor. No new failure niodes are created by the_ proposed change in instrument setpoint.
In addition, the proposed change restores the HPCI system high steam line flow setpoint to the value assumed in the system analyses, c.
Involve a significar.t reduction _in a margin of safety. The proposed change provides greater assurance that the HPCI system would be available to mitigate an accident as designed. HPCI would also be less likely to fail surveillance tests due to inadvertent isolations.
This improved reliability reduces the number of unnecessary tests performed on the HPCI and other ECCS systems as required when HPCI is inoperable. There is no reduction of any margin of safety.
STAFF CONSULTATION The appropriate representative of the State of New York was notified of this amendment. The State of New York contact had no comments.
ENVIRONMENTAL CONSIDERATION This amendment involves a change to a requirement with respect to the installation or use of a facility con'penent located within the restricted area, as defined in 10 CFR Part 20, and changes to the surveillance requirements. The staff has determined that the amendment involves no I
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 no significant hazards consideration finding with respect to this amendment. Accordingly, this amendment meets 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 preparea in connection with the issuance of this amendment.
5-CONCLUSION We have concluded, based on the consideration discussed above, that:
(1) this emergency situation could not be avoided; (?) the licensee acted in a timely manner with respect to responding to this emergency. (3) the amendment does not involve a significant increase in the probability or consequences of an accident
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previously evaluated, does not create the possibility of a new or different type of accident from any evaluated previously, and does not involve a significant reduction in the margin of safety; (4) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner; and (51 such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical sto the common defense and security or to the health and safety of the public.
Dated:
December 15, 1989 P_RINCIPAL CONTRIBUTOR:
D. LaBarge l-I l
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