ML20006E526
| ML20006E526 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 02/20/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20006E523 | List: |
| References | |
| GL-87-09, GL-87-9, NUDOCS 9002230475 | |
| Download: ML20006E526 (5) | |
Text
p.
y y1 UNITED STATES -
./
r NUCLEAR REGULATORY COMMISSION 7,
<t WASHINGTON, D. C. 20555 f.
, ~. -
l ie..+
[
SAFETY EVALUATION-BY THE OFFICE OF NUCLEAR REACTOR; REGULATION RELATED TO AMENDMENT NO. 51 TO FACILITY OPERATING LICENSE NO. NPF-43 i
~
DETROIT-EDISON COMPANY-a WOLVERINE POWER SUPPLY COOPERATIVE, INCORPORATED u;
FERMI-2 l
DOCKET NO. 50-341
?
1.'O ' INTRODUCTION (Deco or the
.ByJletter dated September 30, 1988, licensee) requested amendinent to the Technical Specificationsthe Detroit Edison Coirpa Facility Operating License No NPF-43 for Fermi-2. The proposed amendment would Ultimate Helt Sint (UHS) quirements and surveillance requirements for the revise the LCO, ACTION re to better reflect the UHS design basis as a single water source of two one-half capacity Residual Heat Reinoval (RHR) reservoirs
- 1 capabic:of being cross-connected to supply full cocling capacity to either' division's RHR Heat Exchanger and other safety-related equipment. By letter dated December 15, 1989 the licensee proposed to change Section 3/4.7.I of 4
the bases to better reflect Surveillance Requirement 4.7.1.5.b.2.
J
,1
- 2.0. EVALUATION l
The Fermi-2 Ultimate Heat Sink (UHS) consists of two one-half capacity reinforced-concrete RHR reservoirs of Category I construction, each with a capacity of 3,450,000 gallons of water. The reservoirs are connected by j
reduridant valved lines to permit access to the combined inventory of the two reservoirs to either RHR division in the event of a mechanical failure in one of the RHR divisions. Each line contains two isolation valves of Category I construction that are remotely operable from the main control room.
Specification 3.7.1.5 of the Fermi-2 Technical Specifications does not adequately address the Ultimate Heat Sink as a single source of water to both RHR divisions.
.Instead, the Limiting Condition for Operation (LCO) and ACTION Requirernents are written to imply that each reservoir can independently provide the required heat removal capability for either RHR division. However, with one RHR reservoir inoperable, the potential exists that the two RHR reservoirs as a whole do not racet the design requirements for the UHS. The proper ACTION when the UllS design basis is not met is to require a prompt plant shutdown. This ACTION is currently specified only when both RHR reservoirs are inoperable.
To correct this situation, DECO has proposed rnodification to the TS concerning the UHS LCO.
In addition to the current requirements for each reservoir individually (which are retained as 3.7.1.5.a,b,c and f), new ccmbined water volume and maximum temperature requirements are included as 3.7.1.5.d and e.
9002230475 900220 PDR ADOCK 05000341 P,
PDC 4
n.-
I':
- .g -.
- PLANT SYSTEMS n'5' l BASES-m
. REACTOR CORE ISOLATION'C00 LING SYSTEM (Continued)
L
~ With the RCIC system inoperable, adequate core cooling is assured by the OPERABILITY of the HPCI system and justifies the specified 14-day out of service period.
1 The surveillance requirements provide adequate assurance that RCIC will~
be OPERABLE when required.
Although all active components are testable and full flow can be demonstrated by recirculation during reactor operation, a complete functional test requires reactor shutdown.
The pump discharge piping-is-maintained full to prevent water hammer damage and to start cooling at the
- earliest possible' moment.
3/4.7.5 SNUBBERS All snubbers are required OPERABLE to ensure that the structural integrity of the reactor coolant system and all other safety related systems is maintained during and following a seismic or other event initiating dynamic loads.
Snubbers excluded from this -inspection program are those installed on nonsafety-related systems and then only if their failure or failure of the system on which they 1
are installed, would have no adverse effect on any safety related system.
Snubbers are classified and grouped by design and manufacturer but not by size.
For example, mechanical snubbers utilizing the same design features of the 2-kip,10-kip, and 100-kip capacity manufactured by Company "A" are of i
the same type.
The same design mechanical snubbers manufactured by Company "B" for the purposes of this Technical Specification would be a different type, as would hydraulic snubbers from either manufacturer.
A list of individual snubbers with detailed information of snubber location and size and of system affected shall be available at the plant in accordance with Section 50.71(c) of 10 CFR Part 50.
The accessibility of each snubber shall be determined and approved by the Onsite Review Organization.
The determination shall be based upon the existing radiation levels and the expected time to perform a visual inspection in each snubber location as well as other factors associated with accessibility during plant operations (e.g., temperature,
}
t,tmosphere, location, etc.), and the recommendations of Regulatory Guides 8.8 and 8.10.
The addition or deletion of any hydraulic.or mechanical snubber shall q
be made in accordance with Section 50.59 of 10 CFR Part 50.
The visual inspection frequency is based upon maintaining a constant level of. snubber protection to each safety-related system.
Therefore, the required inspection interval varies inversely with the observed snubber failures on a i
given system and is determined by the number of inoperable snubbers found during an inspection of each system.
In order to establish the inspection frequency for each type of snubber on a safety-related system, it was assumed that the frequency of snubber failures and initiating events is constant with j
time and that the failure of any snubber on that system could cause the system FERMI - UNIT 2 B 3/4 7-2 w-
=
J 4
<. #z.
.g.
j
+
L The combined requirements. correspond to the current worst-case allowed heat capacity of the two individual reservoirs, i.e., both reservoirs at the allowed
. minimum water level:and maximum water temperature, L'
The status of the two RHR reservoirs as composing one-half of the capacity of the UHS and need to have the capability to cross-connect to the reservoirs is proposed to be included in the LCO.
In addition DECO proposed to require the OPERABILITY of the cross-connect lines and the associated motor-operated valves in new LCO 3.7.1.5.g.
The staff has reviewed the proposed LCO and finds it acceptable on-the basis that it. retains all current individual reservoirs requirements while adding j
conservative new requirements consistent with the UHS design (which was reviewed and accepted by the staff in Section 9.2.2 of the Fermi-2 Safety Evaluation Report, NUREG-0798, Supplement 6 dated. July 1985).
DECO has proposed new ACTION requirements to reflect the revised LCO.
ACTIONS a, d,-c4 and f in conjunction provide the current ACTION requirements for individual reservoirs inoperability.
Proposed ACTION b in conjunction with ACTION e assures that a' prompt plant shutdown occurs if the combined water volume and temperature requirements are not met and thus the UHS as a whole-does not meet its design requirements.
A provision to except proposed ACTION f (current ACTION d) from the provisions of Specification 3.0.4 is also proposed; evaluation of this aspect is provided separately below.
DECO has proposed in ACTION c. compensatory measure to be taken in the event of one or more inoperable cross-connect valves.
The measures provide positive assurance,. with periodic verification, that the reservoirs are cross-connected and thus the UHS is capable of performing its designed function as a single water source.'
If the design function of the UHS cannot be assured, the ACTION requires'a prompt plant shutdown.
DECO also proposes that this ACTION be exempt c
from Specification 3.0.4; this aspect is evaluated separately below.
The staff has reviewed the proposed ACTION requirements described above and finds them acceptable on the basis that all current ACTION requirements are retained and appropriate ACTION or compensatory measures are specified for new LC0 provi-sions which ensure'that either the ability of the VHS to meet its design basis is maintained or a prompt plant shutdown is required.
Since proposed ACTIONS c.
and f. allow plant operation for an unlimited period of time, provisions are pro-posed to exclude these ACTIONS from the provisions of Specification 3.0.4., which would prevent changing OPERATIONAL CONDITION while operating under the provisions of these ACTIONS.
This is consistent with guidance of Generic Letter 87-09.
When one or more of the cross-tie valves are inoperable the Ultimate Heat Sink remains OPERABLE as long as the two reservoirs are cross-connected as required by ACTION c.
Further, the cross-connect valves are located near the bottom of the RHR reservoir and potentially present an unusual difficulty for repair.
In view of these circumstances, DECO believes that a change in OPERATIONAL CONDITION should be allowed when operating under the provisions of ACTION c.
k e
a
,a_-
f,l l, -
I-When a reservoir temperature is less than 41*F, proposed ACTION f. allows
. continued operation provided that compensatory ACTION is taken to assure that I
the Ultimate Heat Sink OPERABILITY is not degraded due to potential ice formation. Deco believes that restricting changes in OPERATIONAL CONDITION i-when operating under the provisions of ACTION f. is not warranted since h
acceptable means of assuring that the Ultimate Heat Sink remains OPERABLE exist in the Technical Specifications.
In light of these compensatory ACTIONS taken to ensure OPERABILITY and the guidance of Generic Letter 87-09, DECO is proposing that Specification 3.0.4'nct apply to proposed ACTION f.
The staff has reviewed these proposed exceptions to Specification 3.0.4 and finds them acceptable, since they meet the general requirements of Generic Letter 87-09 and, in these. cases when the plant is operating under the provisions of the subject ACTION statements, the UHS OPERABILITY is adequately assured to be fully maintained.
Further, the circumstances which required operations under these ACTIONS may not be easily reviewed during the short duration outages which may
. occur. Thus, in view of the compensatory measures to assure UHS OPERABILITY, the staff has determined the application of Specification 3.0.4 to these ACTIONS
-to be unnecessary.
Deco has modified the daily surveillance requirement to include verification of the combined reservoir water temperature and volume. This is consistent with current requirements and therefore acceptable.
DECohasalsoproposedmodificationofSurveillanceRequirement(SR)4.7.1.5.b.2, the nonthly cross-connect valve surveillance. The current SR is interpreted by Deco to assure that the two reservoirs remain not cross-connected while ensuring that the reservoirs can be remotely cross-connected from the Control Room even under the loss of either division of AC power. Deco has proposed to modify the surveillance requirement to solely assure that if not cross-connected the reservoirs can be remotely cross-connected in the event of the loss of either division of AC power.
(Since the two valves in each cross-connect line are pow-ered from different civisions, ensuring that one valve in each electrical divi-sion is open ensures that the reservoirs are cross-connected or that a second valve can be opened in at least one line.) By letter dated December 15, 1989 the licensee proposed changes to Bases Section 3/4.7.1 to clarify and indicate the purpose of surveillance requirement 4.7.1.5.b.2 to ensure that TS users fully understand the purpose of the requirement.
The staff has reviewed the bases changes and finds them acceptable.
The two RHR reservoirs are designed to be capable of being separated in order to mitigate the consequences of a below-grade breach of the Category I RHR complex structure below the grade level. Deco asserts that this event is highly unlikely and would be easily detected and mitigated since the water inventory loss would be limited to approximately 10 percent of the UHS capacity by the site ground water level.
The staff review has determined that:
The below-grade breach of the Category I RHR corrplex structures is extremely unlikely particularly in conjunction with an event which would require the full capacity of the UHS;
(5
~
~
g g
^[ df e
,q
~,
..T.
Thi additional water loss from the postulated breach when the 1 reservoirs are cross-connected is approximately 5% of the UHS-capacity; The. postulated breach.can be easily detected by the daily surveillance requirements and the UHS heat capacity can be easily supplemented by. pumping' water from Lake Erie or other close-by water sources; DECO-has committed to maintain a normal' system line-up of the two reservoirs not cross-connected; The addition of;further requirements to assure the reservoirs are'not normally; cross-connected adds undue complexity to an already complex TS; and Since the proposed surveillance assures that the two reservoirs can be remotely cross-connected in the event of the failure of either AC power division, the proposed surveillance requirements are acceptable.
Based'on the above evaluation the staff finds the proposed changes to TS acceptable.
-3.0 ENVIRONMENTAL-CONSIDERATION a
This amendment involves a change in a requirement with respect to the installation
- or use of a facility component located within the restricted area as defined in 1
10 CFR Part 20 and changes in surveillance requirements.
We have determined that this amendment involves no significant increase in the amounts, and no significant change-1n the types, of any effluents which may be released offsite, and that s
there is no significant increase in individual or cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding.
Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
L
' 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.
l*
4.0 -CONCLUSION l
l We have concluded, based on the considerations discussed above, that (1) ll 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 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 l
security or to the health and safety of the public.
l Principal Contributor:
John Stang Date:
February 20, 1990 i
n