ML20039C401
| ML20039C401 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 11/18/1981 |
| From: | Guldemond W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Konklin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| Shared Package | |
| ML20039C399 | List: |
| References | |
| IEB-80-12, TAC-42114, TAC-42115, NUDOCS 8112290314 | |
| Download: ML20039C401 (2) | |
Text
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UNITED STATES i
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799 ROCSEVELT ROAD N
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GLE N E Lt.YN. ILLINOIS 60137 November 18, 1981 MEMORANDUM FOR:
J. E.
Konklin, Chief, Projects Section 2A FROM:
h.
G.
Culdemand, Senior Resident Inspector, Point Beach Nuclear Plant SUBJ ECT:
LICENSEE TEClINICAL SPECIFICATION CHANGE REQUEST 72 The sugject change request responds to an August 14, 1981 letter from Mr. R. A. Clark (NRC) to Mr.
S.
Burstein (hE) on the subject of redundancy of decay heat removal systems at Point Beach.
I have revi ewed t he current technical speci fication requirements and the letter and IE Bulletin 80-12 and have the following comments:
1.
The current Peint Beach Technical Specifications do not include the mode approach to plant status.
Instead, the Technical Spec' fications define hot shutdewn as having the reactor suberitical by a specified amount with T greater than or equal to 540F, coldshutdownashavingtSEEreactor suberitical by at least 1% with reactor coolant temperature less than or equal to 200F, and refueling shutdown as having the reactor suberitical by at least 10% with T, E0cen 540F less than or equal to 140F.
The operational condition bN and 200F is not defined. The change request does nothing to rectify this situation.
2.
Technical Specification 15.3.1. A.2(a) presently requires that, "One steam generator shall be operable whenever the average reactor coolant temperature is aboVe 350F."
This requirement is cited in the August 14, 1981 letter as satis fying, in part, the necessary requirements for decay heat removal. The subject change request climinates this requirement and replaces it with requirements only for the temperature range of 350F to 140F.
Thus, no requirements would exist for the range of 540F to 350F.
Technical tecifica 'on 15.3.4.A establishes requirements for h'at removal capah-lity above 350F but only as a prerequisit-to criticality.
3.
One of the purposes for establishing requirements for decay heat removal redundancy is to prevent uncontrolled mode changes.
If one accepts the definition for cold shutdown as a mode, then the proposed technical specifications do not satisfy this purpose. This is based on the fact that steam generators are not an effective means of decay heat removal except at temperatures in excess of 200F.
4.
The footnote t o proposed Technical Speci fication 15.3.1. A.2.a( 1) defeats the redundance requirement by allowing only a single power supply to redundant means of decay heat removal.
The problem is further highlighted by the fact that the power supply to the train A auxilary feedwater pump is the same as the power supply to the train A RHR loop.
Thus, a single power supply failure could negate the effectiveness of both 8112290314 811221 DEC 3 1980 PDR ADOCK 05000266 p
diverse redundant means of decay heat removal.
5.
Proposed Technical Specification 15.3. A.2.b(3) should be changed to replace the words, "in the reactor decay heat load," which is uncontrollable, to'in reactor coolant system temperaturc7 which is controllable, f.
The proposed basis for propose d Technical Specification 15.3.1. A.2 states, "A single reactor coolant loop with tts associated steam generator or a single residual heat re.noval loop provides sufficient heat removal capacity for removing the reactor core decay heat."
The license power limit for Point Beach is 1518.5Mwt. Table 6.2-7 of the Point Beach Final Facility Description and Safety Analysis Report lists the design _ heat duty of a single IUIR heat exchanger as 24.15 x 10 BTU /hr. This corresponds to approximately.47%
cf the rated core thermal output.
In the basis for exi st ing Technical Specification 15.3.3 the decay heat load 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after reactor shutdown from 100 days at full power is listed as.62 Thus, the proposed basis as quoted is valid only af ter the reactor has been shut down for some period in excess of 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. The implication is that in order to achieve redundarcy in fact as opposed to redundancy in numbers the licensee has to establish and maintain at 1 cast two trains of RHR and one steam generator operable until such time as one train of RHR is capable of independently handling the decay heat load. At that point in time the requirements could be relaxed to something similar to what has been proposed.
7.
The licensee, in proposed Technical Specification 15.3.1, has adopted the concept of an RHR loop.
The same should be done for Technical Specification 15.3.3 allowing specifications 15.3.3.A.1(d) and (c) to be combined into a single requirement.
8.
Proposed Technical Specification 15.3.3. A.2(b) and (c) should be zodified to include wording requiring testing upon discovery of an inoperable component as well as prior to initiating repairs.
In conclusion, the licensee's 'lechnical Specification change request suffers from several noteworthy shortcomings.
The first of these is the assumption that one RHR loop is capable of removing all core decay heat below 350F.
Based on published numbers this is not the case.
Second, the licensee is relying on the steam generators as a redundant means of decay heat removal below 200F.
This is unrealistic. Third, the licensee has eliminated any requirements for decay heat removal capability above 350F.
This is inappropriate.
It is requested that these comments be forwerded to the Office of Nuclear Reactor Regulation for consideration during the review of Technical Specification Change Request Number 72.,
$$,cgr.. -
t W.
G.
Guldemond Senior Resident Inspector Point Beach Nuclear Plant