ML20137G572
| ML20137G572 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 03/24/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20137G551 | List: |
| References | |
| NUDOCS 9704010430 | |
| Download: ML20137G572 (6) | |
Text
..
hac p
4 UNITED STATES g
j NUCLEAR REGULATORY COMMISSION i
2 WASHINGTON, D.C. 20666 4001
...../
t SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT N0. 215 TO FACILITY OPERATING LICENSE NO. NPF-3 TOLED0 EDISON COMPANl CENTERIOR SERVICE COMPANY 8@
THE CLEVELAND ELECTRIC ILLUMINATING COMPANY DAVIS-BESSE NVCLEAR POWER STATION. UNIT N0. 1 DOCKET N0. 50-346
1.0 INTRODUCTION
i By letter dated February 14, 1997_, Toledo Edison Company, Centerior Service Company, and The Cleveland Electric Illuminating Company (the licensees) submitted a license amendment request to revise the Davis-Besse Nuclear Power Station Technical Specifications (TSs).
This amendment would revise TS Section 3/4.5.2, " Emergency Core Cooling Systems, ECCS Subsystems -
T 2 280*F."
Surveillance requirement (SR) 4.5.2.f would be modified to sEatethatopeningandclosingoftheinspectionportonthewatertight enclosure for the decay heat valve pit would not require this surveillance procedure to be performed.
This amendment would also revise the applicable TS bases.
2.0 BACKGROUND
By letter dated February 13, 1997, the licensees requested that the NRC i
exercise discretion not to enforce compliance with the actions required in 1S Surveillance Requirement 4.5.2.f.
This surveillance requirement requires each Emergency Core Cooling System subsystem to be demonstrated operable by l
performing a vacuum leakage rate test of the valve pit leaktight enclosure for valves DH-ll and DH-12 to assure that the motor operators on these valves will not be flooded for at least 7 days following a loss-of-coolant accident.
The February 13, 1997, letter documented information previously discussed with l
the NRC in telephone conversations on February 12, 1997. The licensees stated during those conversations that Davis-Besse was not in compliance with i
surveillance requirement 4.5.2.f, and that TS 3.0.3, which requires a plant shutdown to begin in I hour, had been entered that morning. They further stated that TS 4.0.3 had also been entered, which allows Davis-Besse to delay the actions of TS 3.0.3 for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> so the surveillance requirement can be completed. That afternoon, the licensees determined that the surveillance requirement could not be performed at power. This determination was based on 9704010430 970324 PDR ADOCK 05000346 P
O l,
the fact that the surveillance includes a test which draws a vacuum on the leaktight enclosure, and if a loss-of-coolant accident were to occur during the test, the pressure in the area of the enclosure combined with the vacuum inside the enclosure would fail the pit cover, potentially flooding the valve operators.
Therefore, they exited TS 4.0.3, and a plant shutdown was begun in accordance with TS 3.0.3.
I The licensees requested that a Notice of Enforcement Discretion (N0ED) be issued pursuant to the NRC's policy regarding exercise of discretion for an i
operating facility, set out in Section VII.c of the " General Statement of Policy and Procedures for NRC Enforcement Actions" (Enforcement Policy),
i NUREG-1600.
They requested that the N0ED be effective immediately and remain 1
l in force until the NRC approves this license amendment request, or until Davis-Besse enters Mode 4 in an outage of sufficient duration to perform the i
l required test.
1 In the February 13 letter, the licensees stated that a plant modification was I
completed in 1986 on the decay heat valve pit to install level switches and to l
add an inspection port to the pit leaktight enclosure. One use of the inspection port is for insertion of a camera during performance of American Society of Mechanical Engineers Boiler and Pressure Vessel Code-required visual inspections, which, at Davis-Besse, must be performed in Mode 3.
They l
previously had concluded that the port could be opened and closed without the need to perform surveillance requirement 4.5.2.f after closure. On February 11, 1997, Davis-Besse staff identified the concern regarding whether opening and subsequent closure of the decay heat valve pit port constituted a breach in the leaktight enclosure, hence requiring performance of surveillance requirement 4.5.2.f.
Followup by plant staff discovered that the port had been opened and closed since the last performance of surveillance requirement 4.5.2.f.
At that time, TS 3.0.3 was entered, as discussed above.
On March 5, 1997, the staff issued an N0ED (No. 97-6-003) which remains in effect until the processing of the proposed amendment evaluated below.
3.0 DISrVSSION AND EVALUATION 3.1 VALVE PIT FLOODING SAFETY CONCERN The Valve Pit serves as a leaktight enclosure for motor-operated valves (DH-11 and DH-12) in the " drop" line that connects the reactor coolant system (RCS)
Loop 1 hot leg to the decay heat pump suction ccnnections.
These valves are motor-operated and normally-closed.
They must be opened in order to establish j
the shutdown cooling mode of operation. They would also be opened under loss-l of-coolant accident (LOCA) recovery procedures, for the boron dilution mode of operation, an action that would be taken to reduce the possibility 9f boron i
precipitation in the core region.
If the decay heat pit enclosure is not leaktight, the high water level in containment that results from a LOCA could flood the DH-11/12 electric motor operators and thereby preclude their opening.
The watertight integrity of the enclosure is verified by vacuum testing periodically and after any action that could affect leaktightness. The enclosure is provided with non-safety high and high-high level switches. An l
alternate method of boron dilution is available by use of auxiliary spray as described in the Final Safety Analysis Report (FSAR) Section 6.3.3.1.2.
3.2 VALVE PIT INSPECTION PORT The valve pit is provided with an inspection port that was installed as a modification to permit RCS piping inspection for leakage during RCS hydro-static testing without having to remove the large (19'x7') valve pit cover 1
plate. The valve pit cover is difficult to reinstall and reseal following
)
removal. The inspection port is normally sealed-closed with a "Kamlok" cap.
It was the discovery that a leak test had not been performed following the last closure of the Kamlok cap that led to the shutdown action.
The licensees had conservatively assumed that if valve pit enclosure is not leak-tested following replacement of the Kamlok fitting, leak-tightness is not ensured.
However, it is the licensees' position that the design of the Kamlok fitting is such that its design precludes the possibility of inspection port leakage.
3.3 LEAKTIGHT DESIGN OF KAMLOK CAP The Kamlok closure device consists of an adapter that is welded to the 4-inch pipe that rises from the pit cover, and a cap and gasket assembly that clamps over the adapter.
To seal the cap in place, it is placed on the adapter and two levers are positioned such that cams on the levers engage a groove in the i
adapter while compressing the gasket in the cap.
If the gasket is in place and the levers properly positioned, gasket compression, and thus tight sealing, is assured.
The licensees have implemented administrative procedures i
to verify that the cap is properly installed following reinsta11ation.
3.4 PROPOSED TS CHANGE The licensees have requested an amendment to the facility Technical Specifications that would add the following statement to TS 4.5.2.f:
l The inspection port on the water tight enclosure may be opened without requiring performance of the vacuum leakage rate test, to perform inspections. After use, the inspection port must be verified as closed in its correct position. Provisions of TS 3.0.3 are not applicable during these inspections.
3.5 EVALUATION The Kamlok cap is a robust design that can withstand temperatures and pressures much higher than expected post-LOCA at Davis-Besse.
In addition, the test history of the cap since installation confirms that it has consistently maintained integrity through many opening / closing cycles.
Because of the robust design and test history of the Kamlok cap, the staff has concluded that the cap provides a high degree of assurance of proper sealing.
The staff also considered the consequences of failure of the cap to seal under post-LOCA conditions. Any failure of leaktightness would not afftct the ability of the plant systems to respond during the first seven days of the event because the valve operators are not needed during this stage of a LOCA.
,,- In addition, for the longer-term boron dilution capability, an alternate method of boron dilution is available by use of auxiliary spray as described above. Therefore, the current design provides a diverse method for dilution.
Finally, the staff noted that the licensees have implemented administrative procedures to verify that the cap is properly installed following reinstallation. This verification process adds assurance that the potential for a human performance problem will be minimized.
j Because of the robust cap design, acceptable test history, existence of a diverse boron dilution method, and minimized potential for a human performance problem, the staff has determined that the proposed changes to the TSs are acceptable.
In addition, the licensees' proposed changes to the TS bases are consistent with the proposed changes to the TSs and are therefore acceptable.
4.0 EXIGENT CIRCUMSTANCES
The Commission's regulation,10 CFR 50.91, contains provisions for issuance of i
amendments when the usual 30-day public notice period cannot be met. One type of special exception is an exigency.
An exigency is a case where the staff and licensee need to act quickly (that is, before the usual 30 day comment period), and the staff determines that the amendment involves no significant hazards considerations (NSHCs).
Under such circumstances, the Commission notifies the public in one of two ways: by issuing a Federal Reaister notice providing an opportunity for hearing and allowing at least 2 weeks for prior public comments, or by issuing a press release discussing the proposed changes, using the local media.
In this case the Commission used the former approach.
The licensees submitted the request for amendment on February 14, 1997.
It was noticed in the Federal Reaister on February 26, 1997 (62 FR 8783), at which time the staff proposed a NSHC determination.
In the request, the licensees asked that the amendment be issued on an emergency basis pursuant to 10 CFR 50.91(a)(5), unless enforcement discretion was granted. They stated that prompt processing was being requested to avoid a plant shutdown.
Since the N0ED was issued by NRC on March 5, 1997, the staff is issuing this request on an exigent basis pursuant to 10 CFR 50.91(a)(6), and consistent with the NRC's policy regarding exercise of discretion to minimize, for example, the potential safety consequences of unnecessary plant transients, as set out in Section VII.c of the " General Statement of Policy and Procedures for NRC Enforcement Actions" (Erforcement Policy), NUREG-1600.
Further, the Commission has determined that the licensee promptly requested the amendment within days of identification of the concern regarding the surveillance requirement.
There were no public comments in response to the notice published in the Federal Reaister.
l lr
5.0 FINAL NO SIGNIFICANT HAZARDS CONSIDERATION
DETERMINATION The Commissior.'s regulations in 10 CFR 50.92 state that the Commission may make a final determination that a license amendment involves no significant i
hazards considerations if operation of the facility in accordance with the 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 any accident previously evaluated; or (3) involve a significant reduction in a margin of safety.
i This amendment has been evaluated against the standards in 10 CFR 50.92.
The Commission has made a final determination that the amendment does not involve a significant hazards consideration because:
There is no significant increase in the probability of an accident because the special coupling is passive and cannot interact with any of the systems which have been analyzed for failures which lead to accidents. There is no significant increase in the consequences of an accident because of the design of the coupling, the verification of proper installation of the coupling, and the alternative means to provide boron dilution in the event that the coupling does fail and affect valve operability.
The possibility of a new or different kind of accident from any accident previously evaluated is not created because the coupling is passive and cannot interact with any system important to safety, and hence cannot initiate an accident.
There is not a significant reduction in a margin of safety because the design of the coupling, the plant procedures that verify proper closure of the coupling, and the alternative methods for boron dilution ensure that the capability for boron dilution will be available post-accident.
Based on the above considerations, the staff concludes that the amendment meets the three criteria of 10 CFR 50.92.
Therefore, the staff has made a final determination that the proposed amendment does not involve a significant I
hazards consideration.
6.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Ohio State official was l
notified of the proposed issuance of the amendment.
The State official had no l
comments.
7.0 ENVIRONMENTAL CONSIDERATION
This amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 or changes a surveillance requirement.
The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types,' of any effluent that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a
i
.: 1 proposed finding that.the amendment involves no significant hazards L
consideration and there has been no public comment on such finding L
(61 FR 52970). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to l
10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
l
8.0 CONCLUSION
i 1
i l
The staff has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public j
will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the. commission's regulations, and-(3) the-issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
W. Long Date:
March 24, 1997 i
I l
1 i
i a
i I
l 8
s
.