ML17278A258
| ML17278A258 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 06/25/1985 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17278A255 | List: |
| References | |
| NUDOCS 8507030044 | |
| Download: ML17278A258 (7) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION AMENDMENT NO.
11 TO NPF-21 WPPSS NUCLEAR PROJECT NO.
2 DOCKET NO. 50-397 INTRODUCTION By [[letter::05000397/LER-1985-028, :on 850426,unsealed Penetration in Reactor Bldg Fire Barrier Floor Discovered.Caused by Failure to Install Fire Seal During Const.Hourly Fire Watch Patrol Placed on Penetration Until Seal Installation Completed|letter dated May 16, 1985]], the licensee requested an amendment to the Technical Specifications Sections 3.3.3 and 4.3.3.1 of the WNP-2 license NPF-21.
EVALUATION As currently installed, the automatic depressurization system (ADS), through selected safety/relief valves, functions as a backup to the operation of the high pressure coolant systems.
The ADS depressurizes the vessel so that -low pressure systems may inject water into the reactor vessel.
The ADS is typically activated automatically upon coincident signals of low water level in the reactor vessel, high drywell pressure, and any low pressure ECCS pump running.
A time delay of approximately two minutes after receipt of the coincident signals allows time for the automatic blowdown to be bypassed manually if the operator believes the signals are erroneous or if the water level can be restored.
For transient and accident events which do not directly produce a high drywell pressure signal (e.g.,
stuck open relief valve or steam line break outside containment) and are degraded by a loss of high pressure coolant
- systems, manual actuation of the ADS is required to provide adequate core cooling.
An important consideration is that proposed modifications to the ADS logic should be'uch that operator actions which may be required during an ATWS should not be complicated by the ADS.
As a result of the accident at Three Mile Island; NUREG-0737 addressed this difficulty as Item II.K.3.18 which resulted in a discussion in Supplement.4 to the WNP-2 Safety Evaluation Report (NUREG-0892).
Section 6.3 of the WNP-2 SSER 4 is quoted in its entirety as follows:
sso7osoo4s ssosss PDR ADOCK 05000397 P
PDR "6.3 Emer enc Core Coolin S stem 6.3.6 TMI Action Items II.K.3.18 Modification to ADS Lo ic In a letter dated July 26, 1983, the applicant committed to modifying the automatic depressurization system (ADS).
The design modification will bypass the high drywell pressure trip'ortion of the existing ADS logic and add a
manually operated inhibit switch.
This modification is Option 2 of the BltR Owners Group Report (Dente, 1982) and has been approved by the staff (Houston, 1983).
The applicant's conceptual design is acceptable with the following conditions:
(1)
Use of 'the manual inhibit switch must be addressed in the plant emergency procedures.
(2)
Surveillance requiremenxs for the inhibit switch must be included in the plant Technical specifications.
(3)
The modifications must be complete before startup following the first refueling outage."
As indicated, the Supply System has endorsed the BWR Owners Group recommendations and elected to implement Option 2 as their. specific resolution of the THI Action Item II.K.3.18.
The three conditions imposed by the staff have also been met:
(1) 1JNP-2 plant emergency procedures have been modified to incorporate use of ihe manual inhibit switch.
The Hay 16, 1985 request specifically expresses their intent to incorporate the use of the inhibit switch into the emergency procedures and the sta f has been informed by telephone that the emergency procedure modifications have been made.
(2)
Surveillance requirements for the inhibit switch have been included in Table 4.3.3.1-1 as amended.
(3)
The modifications will be complete before startup following the current maintenance outage which is approximately one year before the first scheduled refueling outage.
Based on the foregoing consideration, the staff finds the proposed modifications to the l(l/P-2 Automatic Depressurization System to he acceptable.
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FINAL NO SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION A proposed amendment to an operating license for a facility 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 probability or consequences of an accident previously evaluated; (2) create the possibility of a new or different kind of accident from an accident previously evaluated; or (3) involve a significant reduction in a margin of safety.
The licensee has determined and the NRC staff agrees that the requested amendment per 10 CFR 50.92 does not:
1)
Involve a significant increase in the probability or consequences of an accident previously'evaluated because the proposed changes provide additional assurance of adequate core cooling by extending the operation of the ADS to encompass additional accident and transient conditions which do not directly produce a high drywell pressure signal.
Thus the acciaent probability is actually decreased while the accident consequences are unchanged.
2)
Create the possibility of a new or different kind of accident than previously evaluated because no new accident scenario is created by changing only the control logic for a safety system.
3)
Involve a significant reduction in the margin of safety beca'use the criteria for the performance of the ADS have not been changed and the control logic modifications extend the capability for the system to respond to additional accident scenarios not previously considered.
Accordingly, the Commission has determined that this amendment involves no significant hazards consideration.
BASIS FOR EI1ERGENCY SiTUATION This amendment is being issued on an emergency basis.
Restart of the
'IJNP-2 power plant is now scheduled for June 25, 1985.
The staff has reviewed and evaluated the Supply System's request for an emergency circumstance (letter G02-85-302 from Sorensen, Supply System, to Butler, NRC, dated June ll, 1985) and agrees that the Supply System has set out an adequate explanation why this emergency situation occurred and why it could not avoid this situation.
ENVIRONHENTAL CONSIDERATION This amendment involves a change to the requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
The staff has determined that the amendment involves no significant change in the types or significant increase in the amounts 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 determined that this amendment involves no signif-icant hazards consideration.
Accordingly, this amendment meets the
4 eligibility criteria for categorical exclusion set forth in 10 CFR Section 51.22(c)(9).
Pursuant to 10 CFR 51.22(b),
no environmental impact statement or environmental assessment need be prepared in connection with the issuance of this amendment.
CONCLUSION Ve have concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public.will not be endangered by operation in the proposed manner; and (2) such activi-ties will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the coo+on defense and security or to the health and safety of the public.
t ated:
JUN 3 >
~ y Docket No. 50-397 JUN ss Igy Nr. G. C. Sorensen, llanager Regulatory Programs llashington Public Power Supply System P. 0.
Box 968 3000 George Hashington Hay Richland, bfashington 99352
Dear Nr. Sorensen:
SUBJECT:
ISSUANCE OF AMENDl1ENT NO.
11 TO FACILITY OPERATING LICENSE NPF-21, HPPSS NUCLEAR PROJECT NO.
2 The U. S. Nuclear Regulatory Commission has issued the enclosed Amendment No.
11 to Facility Operating License NPF-21 to the llashington Public Power Supply System for 'tlPPSS Nuclear Project Ho. 2, located in Benton County near Richland, Washington.
This amendment is in response to your letter dated tray 16, 1985.
This action amends the NHP-2 Technical Specifications Emergency Core Cooling System Activation Instrumentation, Tables 3.3.3-1, 3.3.3-2 and 4.3.3.1-1 to remove the Automatic Depressurization System's (ADS) high drywell pressure instrumentation and add manual inhibit switches to the ADS logic.
A copy of the related safety evaluation supporting Amendment No.
11 to Facility Operating License No. NPF-21 is enclosed.
Sincerely, Qrg Q sf8ned bv:
Halter R. Butler, Chief Licensing Branch No.
2 Division of Licensing
Enclosures:
l.
Amendment Po.
11 to Facility Operating License NPF-21 2.
Safety Evaluation cc w/enclosures:
See next page
"'Previously concurred:
DL:LB82 DL'2
- JBradfute:1am E
ton 06/19/85 06/$i /85 OELD
- llPaton 06/2085 DL:LBP2 HButler 06/p )/85 TMN k
06/g%/85
3.
This amendment is effective as of the date of issuance.
FOR THE NUCLEAR REGULATORY COMMISSION IS<~ b Walter R. Butler, Chief Liconsing Branch No.
2 Division of Licensing
Enclosure:
Changes to Technical Specifications Date of Issuance:
aON 3 ~
DL: tB2 L:LB82 E
on: 1 am JBradfute 06/P /85 06/(y/85 S
- RS OELD DL:LBIV2 BSher on WPaton Butler 06/g f/85 06/pg /85 06/ g/85 AD/L/DL TNovak 06/p+/85
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y Issuance of Amendment No.
11 to Facilit' eratin License No.
NPF-21 JPPSS Nuc ear Pro'ect No.
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Docket 10H NRC PDR Local PDR PRC System NSIC LOP2 Reading EHylton JBradfute TNovak JSaltzman, SAB
- Paton, ELD OHiles NUenton JRutberg AToalston
'l(tlil~er, LFtlB JPartlow EJordan BGrimes LHarman TOarnhart (4)
EButcher