ML19347F018
| ML19347F018 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 04/16/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19347F016 | List: |
| References | |
| NUDOCS 8105150094 | |
| Download: ML19347F018 (4) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR _ REGULATION SUPPORTING AMENDMENT TO PROVISIONAL OPERA 11NG LICENSE NUMBER DPR-21 NORTHEAST NUCLEAR ENERGY COMPANY MILLSTOME NUCLEAR POWER STATION Ui4IT 1 DOCKET N0. 50-245
1.0 INTRODUCTION
AND DISCUSSION By letter dated September 9,1980 (Reload 7 application) Ncrtheast Nuclear Energy Company (NNECo) (the licensee) proposed changes to the Technical...
Specifications for Millstone Nuclear Power Station, Unit 1, relating to fourteen (14) separate concerns.
NRC Amendment No. 73 to Provisional Operating License No. DPR-21, dated March 11,1981, approved six of NNECo itemized requests and tnis Safety Evaluation documents the staff review and evaluation of the following four additional items:
a Multiplier for APRM Rod Block Monitor Setting e Surveillance Testing of EC,CS and SLC Equipment o Rod Worth Minimizer Diagnostic Test c Housekeeping Changes Evaluation of the remaining NNECo Technical Specification change requests continues.
2.0 EVALUATION 2.1 Averace Power Rance Monitor (APRM) Multiolier The licensee proposed to replace the multiplier in the flow-biased APRM rod block and APRM scram algorithm with a new factor which allows for the diversity of fuel assembly designs which may be present in the core.
Instead of a multiplier which depends on the core maximum peaking fa.ctor, the licensee has proposed one which depends on the maximum fraction cf limitingpowerdensity(MFLPD).
For er.h assembly segment in the core, the maximum linear heat generation rate in that segment is c:mpared to the limiting heat generation rate for that particular type of assembly (for example 8 x SR assemblies have a heat generation limit of 13.4 kilowatts per foot).
The ratio of the maximum linear heat generation rate to the miting value is the fraction of limiting power density (FLPD) for t segment.
The maximum value of the FLPD in the core ("FLPD).is cbtained and the rati:
of this quantity to the core power, expressed as the fracticn of rated ;; ce-(FRP), is used as the multiplier en the f109. biased rod block and scra.
- i rcui ts.
Inus these settines :ec:.e:
m s1so *
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P00R OR1 L
'o 2-Rod Block Setting '. (0.65 U + 42) i F PD Scram Setting 1 (0.65 W + 55)
F PD Where W is the recirculation flow rate in percent of full rated flow.
If this ratio is greater than unity a value of 1.0 is used.
Thus the only potential effect on the trip set. tings of this change is to lower them.
At power less than 90 percent of rated power the proposed Technical Specification change would also permit scram setting adjustments of less than 10 percent to be made by adjusting the gains of the APRM channels by a factor which is the inverse of the trip setting adjust-ment (i.e., by MFLPD/FRP).
On the basis that the proposed changes are merely revised algorithms for accomplishing the same purpose for a mixed core as had previously been done for a homogeneous core, we find this proposed Technical Specification change to be acceptable.
2.2 Surveillance Testina of ECCS and SLC Eouipment The licensee has proposed Techaical Specification changes related to the Emergency Core Cooling Systems (ECCS), i. e. Low Pressure Coolant Injection (LPCI), Core Spray, Containment Spray, and Emergency Serv' ice Water, and Standby Liquld Control System (SLCS).
The current Millstone Unit tio.1 Technical Specifications, in the event a subsystem or component is our of service, require the. remaining subsystem or train of that system, and the other core and containment cooling system, and emergency power sources to be tested immediately and daily. thereafter.
The proposed Technical Specification changes would eliminate the pre-sent requirements to test the remaining train (s) of the ECCS and SLC systems when one train has a component out of service so that there is always at least one train in the proper lineup to perfcrm its design function. The licensee notes that the proposed changes would make the Millstone Unit ?!o.1 Technical Specifications consistant with the BWR Standardized Technical Specifications for ECCS and SLC surveillance testing.
In response to "f1RC Guidelines for Excluding Exercising (Cycling) ' tests of Certain Valves During Plant Operation," which was forwarded to the licensee by letter dated flavember 1976 and discussed in Section V-6 of the Safety Evaluation Report that accompanied License Amendnent tio. 54, dated September IS,1979, the licensee reports that valve and pump operation in the test modes may defeat the system's ability to perform as is, in effect, a redunction of plant safety margin, compared to the proposed changes.
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_r The referenced NRC guidelines notes that when one train of a redundant system such as in the Emergency Core Cooling System (ECCS) is inoperable, nonredundant valves in the remaining train should not be cycled since tneir failure would cause a loss of total system function.
The Technical Specification changes proposed by the licensee would ful-fill the agreement documented in Amendment 64 whereby NNECo was to review the Millstone 1 Technical Specifications and propose changes where appropriate.
Under the criteria for acceptance, equipment, system or
~
components are assumed to be OPERABLE if the associated surveillance activities have been satisfactorily performed within the specified time interval.
The proposed changes are in accord with the BWR Standard Technical Specifications that have been approved by the NRC.
We have concluded that the proposed change to the Technical Specification are in accordance with the referenced NRC Guidelines and therefore acceptable.
2.3 Rod Worth Minimizer Diacnottic Test The licensee proposed to delete the Technical Specifications requirement for the rod worth minimizer computer line diagostic test. However after further discussion of the request, NNECo and NRC representatives agreed that the words "com uter line" only should be omitted. We concluded that e
the requirement for the rod worth minimizer diagnostic tests, should remain.
The original intent of the Technical Specification remains unchanged.
Accordingly, the superfluous words " computer line" were removed from the amendid Technical Specification.
2.4 Housekeepinc Chances All of the changes proposed by the licensee, with the foliosing axceptions, are acceptable for the reasons stated in the NNECo September 9,1980, sub-mittal.
Folloviing the initial Se:tember 9,1931 request, Amendment No. 73 dated March 11, 1981, changed some of the pages. With NNECo's concurrence these affected pages have been substituted.
Page 3/4 7-15 Includes Amendment 73 changes 3/4 11-1 Includes Amendment 73 changes B3/4 6-4 Includes Amendment 73 changes B3/4 4-1 Rejected Amendment 73 adequate B3/4 7-2 Rejected Amendment 73 adequate B3/4 7-9 Rejected - No justification us conclude,that the proposed Technical Specification changes, as modified above, are acceptacle for the reasons stated in the licensee's submittal.
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3.0 ENVIRONNENTAL CONSIDERATION We have determined that the amendment does not authorize a change in effluent types or total amounts nor an increase ir. power level and will not result in any significant environmental impact. Having made this determP.ation, we have further concluded that the amendment involves an action which is insignificant from the standpoint of environmental impact and pursuant to 10 CFR 551.5(d)(4),
that an environmental impact statement or negative declaration and environmental impact appraisal nced not be prepared in connection with the issuance of this amendment.
4.0 CONCLUSION
We havc. concluded, based upon the considerations discussed above, that: (1) because the amendment does not involve a significant increase in the probability or consequences of accidents previously considered and does not involve a significant 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 regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Date:
April 16,1981 6
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