ML19248D445
| ML19248D445 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 07/23/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19248D442 | List: |
| References | |
| NUDOCS 7908160179 | |
| Download: ML19248D445 (5) | |
Text
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,c, UNITED STATES y
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NUCLEAR REGULATORY COMMISSION p.f E
WASHINGTON, D. C 20555 J//
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 39 TO LICENSE NO. DPR-16 JERSEY CENTRAL POWER & LIGHT COMPANY OYSTER CREEK NUCLEAR GENERATING STATION DOCKET NO. 50-219 Ir.trcdac tion 6y letter dated May 23, 1979 (Addendum 1 to Change Request No. 72 dated May 19.1979), Jersey Central Power & Light Company (the licensee) requested an amenament to the Technical Specifications of License No. DPR-16 for the Cmer Creek Nuclear Generating Station. The proposed changes would revise the Appendix A Technical Specifications to add a limiting safety systen setting for the automatic initiation of the Isolation Condenser on a reactor low-low water level to Section 2.3.
Table 3.1.1 would also be revised to reflect tnis change.
Discussion On May 2,1979, a less of feedwater transient occurred at the Oyster Creek Nuclear Generating Station which resulted in a low-low low (triple low) water
'evel alam. The NRC evaluated the event and corrective actions proposed to prevent recurrence (Reference 1). Three changes to the Technical Specifications were proposed as a result of the event:
- 1) the triple low water level was defined as a Safety Limit for all modes of reactor operation, 2) a new Safety Limit was defined which requires two recirculation loops to have the pump suction and discharge valves open at all times, and 3) a limiting safety system setting for automatic initiation of the Isolation Condenser on a reactor low-low water level signal was proposed.
License Amendment No. 36, dated May 30, 1979 (Reference 2), approved changes li and 2) above. This proposed amendment would incorporate the remaining proposed change, change 3) above, into the Technical Specifications.
Prior to the May 2,1979 loss of feedwater transient, the NRC was reviewing the
'.icensee's operation of Oyster Creek, osing previously approved restrictions of Maximum Average Planar Linear Heat Generation Rate (MAPLHGR) limits (originally cathcrized by Amendment No. 30, dated March 14,1978). Since Oyster Creek was ore-ating with only 4 of the five recirculation loops and with MAPLHGR limits 7908166}Y7
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bfMMiG approved by Amendment No. 33, dated November 11, 1978, which did not consider 4-loop operation, we concluded that a Technical Specification change M Section 3.10 was necessary.
The licensee agreed.
As a result license Amendment No.
35 was issued.
However, Amendment No. 35 referenced incorrect MAPLHGR associated
- urves even though the proper limits were incorporated into the Technical Specifi-ca ti ans. This license amendment would correct this administrative error, but
..e conclusions and results of Amendment No. 35 and its related Safety Evaluation PcpM Mcf erence 3) are not affected.
E'cluation Linitina Safety Svsten Settinos To assure that the triple-low water level safety limit will not be violated'during 7
'# m ient, the licensee has analyzed the transient which results in the laroest loss of coolant system inventory. The licensee states (Reference 4) tnat a loss of feedwater (LOFn') starting from full power, results in the most severe reduction in reactor vessel water level.
- "= *eviewed the licensee's analysis including:
- 1) codes an( methods, 2)
- lmt inventory loss assumptions, 3) coolant inventory distribution assumptions,
~
and i) the results.
In our Safety Eval'ution Report dated May 30,1979 (Reference 1), we concluded that-
- 1) the liccsee's assumptions provide an adequately conservative basis uren which to calculate the minimum core water level attained during the limiting loss of coolant inventory transient, 2) with only one recirculation loop as.ured urisolated, recirculation ficw is sufficient to prevent boiloff from reducing core water level below 6'7" above the top of the active fuel, and 3) the triple-low water level fuel cladding integrity safety limit would not be violated, therefore, the results of the limiting loss of coolant inventory transient are acceptable.
However, because of the importance of automatic actuation of the Isolation Condenser at low-low level, both the low-low level and the maximum time delay before Isolation Condenser valve opening should be included as limiting safety system settings.
To assure the proper initiation and operation of the Isolation Condenser on low-iow water level in the annulus in accordance with the bounding analysis assumptions, the licensee has proposed to add a limiting safety system reouire-ment to Section 2.3 of the Oyster Creek plant Technical Specifications.
The Specification states that the limiting safety system setting is the low-low water level setpoint which was assumed in the bounding analysis, i.e., 7'2" above the top of the active fuel. The limiting safety system setting incorporates a maximum three second tir.e delay (Reference 4) to assure that the system will not fail to initiate because the core low-low water level momentarily clears as a result of the water level swell in the annulus caused by a simultaneous
- circulation pump trip.
Additionally, based on our review of actual plant enerating data of isolation condenser initiations and possible isolation, a
- e delay of three seconds or less will not cause the isolation condensers to
- clate on high flow conditions caused by recirculation pump coastdown effects.
m s time delay is also adecuate for recirculation flow coastdown effects
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applicable to four loop operation. The limiting conditicas of operation and surveillance requirements for the isolation condenser v.ll not be changed.
Based on the above, we find the proposed Technical Specification change acceptable.
"" HC.7 1.iri ts We have reviewed operation of Oyster Creek with 4 recirculation loops using the MAPLHGR limits approved with License Amendment No.16 and based on combined General Electric and Exxon analyses. Although these limits were previously approved for 4 loop operation, we have reevaluated the limits using current criteria.
Based on this reassessment we have concluded that:
- 1) the ECCS evaluation for operation with one loop out of service approved in License Anandment No.16 is fully applicable to the present core configuration, 2) with' U.c present restriction of Technical Specification 3.3.F.2, idle loop startup a mi the cold water reactivity addition accident is not a concern, 3) the manner of accounting for backflow through the inactive loop is acceptable, 4) the locked rotor event while operating with four recirculation pumps is bounded by the previously reviewed transient analysis and remains acceptable, and 5) thc r.c. sly proposed MAPLHGR limits are based on calculational methods previously e a;tel, they do not change MAPLHGR limits previously found acceptable, but, only cxtend the previous calculations to higher fuel exposures and are therefore accepta ble.
Baccd cn the above conclusions, the staff issued License Amendment No. 35 (Reference 3). However, the Technical Specification changes incorporated with License Amendment No. 35 were incorplete. Although the proper limits had been incorporated some of the text material still referred to the limits established by License Amendment No. 33, dated November 11, 1978. To correct these inconsistencies, the following changes should be made. The licensee agrees with these changes: 1) reinstating the Assembly Averaged Power Void Relationship for all fuel types on page 3.10-2 which was removed by Amendment No. 33, 2) delete the word Interim from the title of Figure 3.10-1. which was on the copy submitted by the licensee and inadvertently not removed, 3) remove Figure 3.10-2 and delete the reference to Figure 3.10-2 from page 3.10-1 since the axial multiplier was derived for the less restrictive MAPLHGR limits approved by License Amendment No. 33.
These three changes correct the inconsistencies between the use of the limits approved by License Amendment No. 35 and License Amendment No. 33.
Since the changes are administrative and establish the more restrictive limits approved by License Amendment No.16 and 35 they are acceptable.
Suma ry The changes to the Technical Specifications to include the automatic initiation
" the Isolation Condenser as a limiting safety system setting was evaluated and found acceptable in our Safety Evaluation Report dated May 30, 1079 ref erence 1), the change in the Technical Specifications to use the more
~ Itrictive MAPLHGR limits for 4-loop operation were evaluated and found WMB acceptuole in the Safety Evaluation Report issued with License Amendment No. 35 cated May 30, 1979.
This amendment would incorporate the Limiting Safety System Settings for automatic initiation of the Isolation Condenser and correct admini-strative errors in License Amendment No. 35.
For the reasons stated in this evaluation we find the proposed Technical Specification changes acceptable.
environmental Consiaerations
'ae have determined that the unendment does not authorize a change in effluent typas or total amounts nor an increase in power level and will not result in any sigr.ificant environmental impact.
Having made this determination, we have further concluded that the amendment involves an action which is insignificant from the standpoint of environmental impact and pursuant to 10 CF? !51.5(d)(4) that an environmental impact statement or negative declaration and environmental imnac+ anpraisal need not be prepared in connection with the issuance of this amendment.
Conclusion Wo hava cnncluded, based on the Considerations discussed above, that:
(l) because this amendment does not involve a significant increase in the probability cr censequences of accidents previously considered and does not involve a signi-ficant decrease in a safety margin, the amendment does not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) such activities will be conducted in compliance with the Commission's regulation and the issuance of this amendment will not be inimical to the common defense and security cr to the health and safety of the public.
Date: July 23,1979 e
REFERENCES 1.
Safety Evaluation Report dated May 30, 1979, Review of the May 2, 1979 Transient at the Oyster Creek Nuclear Generating Station.
!icanse Amendment No. 36 dated May 30, 1979, Modification of Section 2.1.D
^
to extend the applicability of the minimum water level Safety Limit to a'il Modes of Operation and Addition of a new Safety Limit in Section 2.1.F to Require that Two Recirculation Loops Remain Open During All Modes of Opcration.
3.
L kense Amendment No. 35 dated May 30, 1979, for the Oyster Creek Nuclear Generating Station.
':tt:r dated May 19, 1979 from. I. R. Finfrock (JCP&L) to NRC enclosing an analysis titled " Bounding Loss of Ccolant Inventory Transient for the Oyster Creek Plant."
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